[RAW TRANSCRIPT -- NOT YET REVIEWED FOR CORRECTIONS BY CASSINI
PERSONNEL]{.underline}

**[FTS-NASA-VOICE]{.underline}**

**[Moderator: ]{.underline}[Trina Ray]{.underline}**

**[June]{.underline}[ 26]{.underline}[,
200]{.underline}[7]{.underline}**

**[1]{.underline}[:]{.underline}[0]{.underline}[0
]{.underline}[p]{.underline}[m CT]{.underline}**

[Trina Ray: ...has joined me back in. Can you all hear?]{.underline}

[Rosalie Lopez: Yeah.]{.underline}

[Trina Ray: I hope. All I could hear was music.]{.underline}

[ Okay. And she made the announcement for starting the
recording.]{.underline}

[Rosalie Lopez: Yes.]{.underline}

[Trina Ray: Okay. Thanks Rosalie.]{.underline}

[Trina Ray: Well, welcome everyone to the CHARM telecon for June. We
have a very exciting presentation for you today.]{.underline}

[ As is our tradition, the CHARM telecon in June is our anniversary
edition. As most of you know, we arrived at Saturn on July 1, 2004 and
once every year, we ask five science experts \-- one from each science
discipline \-- to summarize the major highlights from their discipline
over the last year.]{.underline}

[ And today, we are joined by an outstanding panel.]{.underline}

[ Dr. Rosalie Lopez is the investigation scientist for the Cassini Radar
Team and she will be sharing with us all the highlights of Year 3, which
many on the mission call our "Titanium Year" and you'll find out why in
a little bit. Especially, she'll be giving us some of the highlights
from the radar team and the radar instrument.]{.underline}

[ Dr. Paul Helfenstein, who's on the Cassini Imaging Team is an
associate with them, he'll be bringing us up-to-date on what's been
happening with the I2 satellite over the last year.]{.underline}

[ Dr. Kevin Baines will be joining us a little bit later. He's the lead
Saturn scientist for the Visual and Infrared Mapping Spectrometer. And
he will actually be calling in to us from Europe today, he's at a
science meeting there, and he'll be discussing with us everything about
the giant gas planet that we've been orbiting now for three years and
he'll be telling us what we've learned about it in this last
year.]{.underline}

[ Our fourth panelist is Dr. Tamas Gambosi. He's the interdisciplinary
scientist for the magnetosphere, and he's also actually taking time out
of an important conference today to share with us the highlights from
the last year.]{.underline}

[ And finally, Dr. Jeff Cuzzi, who's our interdisciplinary scientist for
ring, he'll be closing out the telecon with all of the third year
highlights from ring scientists.]{.underline}

[ So with that short introduction of the panelists, let's go ahead and
get started.]{.underline}

[ Many of you are already familiar with the Cassini Huygens Mission, but
for those of you who've joined us recently, I wanted to do sort of a
five-minute introduction to the mission.]{.underline}

[ So if you all go to Slide 3 of the presentation, you'll see a nice
graphic here.]{.underline}

[ The Cassini Huygens Mission to Saturn is very international. We have
over 200 scientists and even more engineers spread out over 17 countries
supporting this mission.]{.underline}

[ On Slide 4, you see a very nice diagram of the spacecraft. The
spacecraft is very large. It's one of the largest interplanetary
spacecraft ever flown. It stands at an amazing 22 feet tall and weighs
in at over 6 tons when it's in Earth's gravity and fully
fueled.]{.underline}

[ It's extremely well-instrumented. We have 12 instruments on the
orbiter and six on the probe. We're not really going to be talking very
much about the Huygens Probe today. We did have an excellent review last
year in February by Dr. Ralph Lorenz summarizing the results of the
Huygens Probe Mission; it was a very, very nice CHARM telecon and I
would recommend that everybody download that presentation and audio file
if you haven't already heard it.]{.underline}

[ So we really don't have time today to talk too much about the probe.
But all that great information is there in Ralph's
presentation.]{.underline}

[ So again, summarizing the instruments on board the orbiter, we have 12
instruments on board the Cassini spacecraft and they break down into
three basic categories that you see there.]{.underline}

[ We have optical remote sensing instruments, there are four of them.
These are basically cameras at various wavelengths. They're all
co-aligned, that means they always look together at some remote target
to take images, either Saturn, Titan, the rings, something like that. So
they're always looking at things that are far away \-- remote
things.]{.underline}

[ We have five magnetospheric and plasma instruments, which we sort of
collectively call "map instruments." These are instruments that are more
interested in measuring the local condition: how many dust particles are
there in the area, you know, right now that the spacecraft is flying
through, what is the strength of the magnetic field right here, that
sort of thing, sort of, you know, the fingers of the spacecraft so to
speak.]{.underline}

[ And then finally, we have two microwave remote sensing instruments.
These two instruments use the High Gain Antenna to either send microwave
signals from the spacecraft to Earth when something interesting is in
the way, like the rings and that way we learn about the rings of Saturn;
or the radar instrument uses the High Gain Antenna to bounce a signal
off a target like Titan and receive it back at the spacecraft. It's very
effective instrument for high resolution surface mapping of
Titan.]{.underline}

[ And then, just to remind everybody of a few dates. We launched in
October of (2007) so our ten-year anniversary is coming up later this
year, very exciting. Everybody's starting to plan T-shirts and things
like that already.]{.underline}

[ We arrived at Saturn seven years after that on July 1, 2004. And we
are currently completing our third of our four-year primary mission.
Sort of some of the highlights that - of the mission.]{.underline}

[ Of course, we had 75 orbits or in the prime mission, in the four
years, we had 75 orbits of Saturn, we had 45 targeted Titan flybys and
nine targeted icy satellite flybys \-- the basic stats.]{.underline}

[ Okay. If you go on to Slide 6 - I'm sorry, Slide 5. Slide 5 is a nice
figure of Saturn with its majestic ring system. This figure is to scale
to give you some sense of the size of the Saturn system and the rings.
And there are the Earth and Moon, both to scale with their distance, and
of course, the magnetic bubble that surrounds Saturn is quite a bit
larger than this entire slide and there's a very nice graphic of that a
little bit later that you'll see.]{.underline}

[ If you go on to the next slide, Slide - I think I'm on Slide 6 now.
Slide 6 has two panels. In the upper panel is a figure with all of the
satellites of Saturn to scale. And this is a figure that's been updated
recently by our mission planning team, in particular Dave Seal who's
very - really, really good at putting together these graphics, and he's
actually collected images taken by the Cassini spacecraft for this
diagram here and updated it with actual images which makes a very nice
update to this famous graphic.]{.underline}

[ All of the icy satellites here are to scale. You can see Titan \--
much, much larger than most of the other icy satellites. In fact, Titan
is the second largest moon in the solar system and is larger than the
planet Mercury.]{.underline}

[ On the bottom panel, we also have another graphic to scale of the
system. You could see Saturn on the left with its main ring system and
then all of the icy satellites that are sort of embedded close to the
main ring and then you've got Mimas, Enceladus, Tethys, Dione on this
actual - and Rhea on this screen here and then Hyperion and Iapetus and
Phoebe and Titan are all far off to the right, but also, a very nice
graphic to give you a sense of scale of the Saturn system.]{.underline}

[ So let's go on to Slide 7 which is a summary of the third year of our
Titanium - what we call our "Titanium Year" here on the
mission.]{.underline}

[ The Cassini Orbiter has completed its third year and all orbiter
systems are performing normally and all consumables are running per
predict. That's a really great place to be: about three quarters of the
way to your prime mission.]{.underline}

[ We arrived at the magnetotail and then we proceeded with the
180-degree transfer.]{.underline}

[ The 180-degree transfer was a really terrific mission phase for many
of us. It achieved sort of three goals all at once. It rotates the
petals from midnight to noon. Now recall that when Cassini orbits
Saturn, it orbits in an ellipse and so the petals stick out in some
direction and then relative to direction of the sunlight coming in, we
call those petals if they're pointed towards the Sun, we call it noon
and if they're pointed away, we call it midnight and then dawn and
dusk.]{.underline}

[ So we did a nice rotation of the petals by sort of going up and
sliding over so the petals rotated almost 180 degrees which is where the
maneuver gets its name.]{.underline}

[ It has many, many low Titan flybys, which is always exciting for the
science teams here. And also, it cranks the orbits up to a high
inclination which both rings and magnetosphere scientists very much like
to have that happen.]{.underline}

[ This is a real breakthrough in the initial prime mission tour design.
Before the 180-transfer was discovered what we used to do was rotate
around the petals by staying in equator because that's how you can do it
cheaply and then used to crank up to a higher inclination and then crank
down and then rotate some more. And so, being able to crank up and flip
the petals to the other side and do a lot of Titan flybys all at one
time was really, really a coup.]{.underline}

[ You can imagine how pleased the scientists were when the tour
designers came up with that one \-- a good day for Cassini mission
planning.]{.underline}

[ Okay. So let's see, the spacecraft has returned a staggering amount of
data in the last year \-- 68 gigabytes, just a fantastic amount of data.
We've completed 22 orbits, 19 targeted flybys, again, almost all of them
Titan flybys in this last year.]{.underline}

[ And let's go on to Slide 8.]{.underline}

[ On Slide 8, you see a nice graphic also produced by our mission
planning team. This plots a series of interesting parameters over the
four-year prime mission. And you can see there the 180-degree transfer
fairly easily and the inclination profile and also you - I've
highlighted there the Titan flybys that made that possible.]{.underline}

[ On Slide 9, I've included for your reference just a list of all the
targeted flybys in Year 3 with their targets, their spacecraft event
times and dates for your reference.]{.underline}

[ And then on Slide 10, sort of highlighted an activity that's been
happening this year which is we've been - the science teams in the
project have been working very hard on planning the extended mission,
and the extended mission goes from July 2008 to July 2010. This has not
yet been approved by NASA headquarters so this is a preliminary product
at this point; we still have to go through a series of reviews from NASA
headquarters.]{.underline}

[ I wasn't going to talk about it too much because we're already running
a little bit late on time so I just included there for your reference
because we want to get right into the Year 3 stuff.]{.underline}

[ And so, at Slide 12 is just a nice summary of the - of Titan just
there for reference. And with that, I'll hand it over to Dr.
Lopez.]{.underline}

[Rosalie Lopez: Hello all.]{.underline}

[ Thank you, Trina, for making this nice summary slide of
Titan.]{.underline}

[ In fact, we used to say that Titan was larger than Mercury and Pluto,
but now we just say Mercury. And it's a planet in its own right. It's
the only satellite in the solar system that has a substantial atmosphere
and that makes it very different from everything else that we have in
the Saturn system as well as elsewhere.]{.underline}

[ So I'll just leave you with this basic information but remind you that
the surface is very, very cold and so, materials behave very
differently. For example, ice at those temperatures behave like rocks.
And on Titan, we have the - what's called the methanological cycle which
is similar to the hydrological cycle on Earth.]{.underline}

[ The next slide, which Trina also put together, is just a collage of
some of the great data that we got, not just in the past year but
before. We see here on the right hand side, top right from Huygens data.
And I would just like to point out that the figure that says river
channels, those are actually maps so the white is not from the radar
data, they are maps. But we find clouds on Titan, we find mountains, we
find rivers \-- a lot of geological processes, and I'll be talking more
about those individually.]{.underline}

[ The next slide, Slide 14, shows an ISS map of Titan. They do not have
much coverage of the northern hemisphere yet because that is just
starting to come into sunlight now.]{.underline}

[ I'd like to mention here the name for Titan. In fact, there is a Web
site called planetarynames.wr.usgs.gov where you can find the whole
planetary nomenclature Web site. You can also just Google "planetary
nomenclature" and you get this.]{.underline}

[ And the - each planet or satellite has its own convention with a
scheme. And on Titan, it's actually very nice because all the names have
something to do with wisdom or happiness or peace. And for example, the
craters are named after gods and goddesses of wisdom and the fluctus
which are like the flows are named after gods and goddesses of beauty.
So, we want to keep Titan a happy place.]{.underline}

[ The next slide, Slide 15, shows a similar map but that's made by
(unintelligible) infrared mapping spectrometer using three of their
(bands). And it's very good to compare what we have with ISS, with VIMS
and with radar.]{.underline}

[ The ISS gives you albedo features, whether something at visible or
near-visible wavelengths is dark or bright; VIMS gives you differences
in composition on the surface; and radar gives you the highest spatial
resolution, let's say, geological details on the surface.]{.underline}

[ The next slide, Slide 16, shows a radar map. Each radar flyby, we get
like a lone noodle above 200 kilometers across and several thousand
kilometers long. And what we're using is the synthetic aperture radar
mode of the radar.]{.underline}

[ Now, radar can penetrate through clouds and haze so it's an ideal
instrument for Titan. And in fact, I'm sure many of you have seen images
of the Earth obtained with radar because, again, that can penetrate the
clouds and the atmosphere of the Earth.]{.underline}

[ The next slide, 17, shows a schematic of radar. We use side beam,
actually construct an image. And we have several modes in the diagram
here on the left hand side. We show the altimeter footprints that when
we are looking straight down and we actually get site information only
using a central beam, or we look to the side synthetic aperture radar
and we actually get the images.]{.underline}

[ Now, radar images can be harder to interpret than visual images.
Something that's radar-bright generally means rough but it also could -
the slope towards the radar that's being illuminated. So it takes quite
a bit of training to get, you know, get yourself comfortable with radar
images. But you can do that just, you know, if you stare at them long
enough or enough of them, you will eventually get quite comfortable with
them.]{.underline}

[ So, next slide, 18, the geology of Titan from radar. We have found
that the surface is very young, very dynamic. There are only three
definite impact structures that we have identified and that makes the
surface very young because, as most of you probably already know, the
longer a surface is exposed to meteorite impact, the more scars from
this meteorite impact it's going to have.]{.underline}

[ So Titan surprised us because the surface is very young.]{.underline}

[ We have seen a number of other features that we call suspiciously
circular features and they could be roads of impact craters. But we are
in the (unintelligible) at the moment. So, at the bottom of the slide,
the bottom left, you see one of our impact craters called
Sinlap.]{.underline}

[ And then going on the other geological processes, they are very
similar to the Earth and in fact, the great thing about Titan from a
geology point of view is that you find all the major processes that
contribute to modifying the surface of planets, of solid planets, we
find they're taking place on Titan. We find volcanism, we find tectonism
and those are what we call the endogenic processes that come from the
interior. And we also find the exogenic processes which are erosion and
impact cratering.]{.underline}

[ Now, erosion on Titan happens by wind, Titan has an atmosphere, and
also by the methanological cycle; we have rivers, we have
lakes.]{.underline}

[ So Titan is really the most Earth-like body, I think, that we have in
the solar system. You know, in my opinion, Mars is a close second. Some
people say that Titan is the Mars of the outer solar
system.]{.underline}

[ So let's look at the processes in a bit more detail. And Trina, please
keep an eye on time because I know I have a lot to get
through.]{.underline}

[ Endogenic processes, we have cryovolcanism and we see here - some of
you may be familiar with these features because they were, you know,
mostly from the early part of the mission, Ganesa Macula about 180
kilometers diameter, we have some very large flows.]{.underline}

[ The depressions that the lakes are in at high latitudes, there are
some people in the team who think that they may be similar to volcanic
calderas; others think that they may be most similar to karst or
dissolution process.]{.underline}

[ We also see Tortola Facula which was nicknamed VIMS "snail" which was
found early in the mission.]{.underline}

[ But just to show you that we do see a variety of volcanic features,
but they're not everywhere, we don't see a lot of them. And so far, we
have not demonstrated, although there are some hints from VIMS data that
there is some volcanic activity going on on Titan at the
moment.]{.underline}

[ Now, just a reminder that there's material that's erupting in the
(volcanic) with molten rock or magma like on Earth but is actually
material from the interior of Titan that is cryovolcanic is mixtures of
slushy ice with probably some ammonia, maybe some methanol.]{.underline}

[ The next slide, 20, shows the Ganesa Macula region that is a composite
of the TA image and T23 that shows that we have a very large volcanic
region with many flows and then, we have not seen the whole of this
region yet. There are, you know, probably other flows that go both south
and north, and that's the largest volcanic feature we've seen on
Titan.]{.underline}

[ The next slide shows cryovolcanic flows. Again, the top picture is a
combination of TA and T23 and that's an area that we named Winia Fluctus
\-- very, very large area.]{.underline}

[ And then at the bottom is another feature named Rohe Fluctus \--
smaller, the flow is coming out of a crater.]{.underline}

[ Now, you might ask how do we know that is a volcanic flow rather than
fluvial? Well, there are some hints such as association with a crater or
a caldera or a fissure that would be very difficult to make from, you
know, fluvial. And also, some of these are extremely large which you can
explain by volcanic processes but, you know, fluvial would get
harder.]{.underline}

[ And next slide, 22, endogenic processes, tectonism. There is a paper
actually in press by Jani Radebaugh, who is an associate of the radar
team, mapping a series of these mountains on Titan.]{.underline}

[ So there are several processes, maybe (crust or compaction) thrusting
out some blocks - ice from below; some features like Xanadu may be a
layer of material that's been stripped. But most of the - Titan's
topography is very subdued that's what we have been finding with
altimetry. And there are some mountain ranges that are 1 kilometer also;
I'm going to show you one from them later on.]{.underline}

[ So there are some isolated mountain ranges at Titan. It's not a place
with lots of very high ups and downs.]{.underline}

[ And there seems to be fewer mountain chains at higher latitudes,
that's something that, you know, I'm working on at the moment is the
global distribution of these geological processes.]{.underline}

[ Exogenic processes. There are impact craters. These are the three - or
in Slide 23 that we have identified so far \-- Menrva, Sinlap, and
Ksa.]{.underline}

[ As I mentioned before, there are some suspiciously circular features,
but we have not identified them as features.]{.underline}

[ And, so far, we have not seen any crater terrains on Titan. And since
we have seen about 20% of the surface with radar, maybe there aren't any
crater terrains, but, you know, we've - it's a little soon to
tell.]{.underline}

[ Next slide, 24, erosion.]{.underline}

[ Erosion plays a key role on Titan and in fact, we find that the
landscape has been modified by various like processes including forming
sand dunes, river channels, lakes, lakes with channels running out of
them, and so on. We find the river channels at many different
resolutions \-- Huygens saw them \-- so we know there are some, you
know, very small ones, we know there are some very large
ones.]{.underline}

[ On the right hand side, top right, that image is about 200 kilometers
high. So there are river channels that are, you know, a couple of
hundred kilometers in length or more, and then there are some small ones
that Huygens has seen.]{.underline}

[ Dunes, I'm going to go a little more into them, but they can be tens
of kilometers long as well.]{.underline}

[ Next slide, the fluvial erosion, again, showing you some - several
pictures, the same that was on the last slide, about 200 kilometers up.
And then, there are a number of channels distributed all over (as
well).]{.underline}

[ So we know that fluvial processes take, you know, take place all over
Titan, maybe some differences that Ralph Lorenz is looking at in the low
latitudes versus high latitudes in the morphology of the
channels.]{.underline}

[ Next slide, 26, Aeolian deposition. Jani Radebaugh and Ralph Lorenz
have both written papers about dunes. And then, they're mostly
distributed around the equator. They can extend up to about 60 degrees
latitude. And this is consistent with the lower latitudes being
relatively dry because you can't saltate particles to form sand dunes if
they're wet.]{.underline}

[ On the other hand, we do see channels at lower latitudes. So there was
probably a difference in time from when the channel formed and when the
dunes formed.]{.underline}

[ And then, here is a map that is in Jani Radebaugh's paper that's been
accepted now by Icarus.]{.underline}

[ And then, the picture at the bottom, you can see how the sand dunes
are diverting against topographic highs.]{.underline}

[ Next slide shows again the dunes diversion over topographic highs, the
bright areas that in fact we call "the elephant" because it looks like
an elephant's trunk. The sand dunes are going around it. And then,
towards the south of the picture, this is from T21, there are some
patches that, you know, appear to have far less material so that's
probably, you know, a different supply of sand and some places get more
and some get less.]{.underline}

[ Next slide, number 28. We think that these are longitudinal or also
called linear dunes on Earth. This is the type of dune that are formed
when you have one dominant wind direction, in this case, is a line west
to east. But there are - but the wind diverts by a small amount, you
know, around it so that it shepherds these dunes and like, you know,
sweeps them into long linear dunes. And there's plenty of work on that
that's being done on this type of dunes.]{.underline}

[ Finally, we've gone to lakes, Slide 29.]{.underline}

[ Now, a word about the lakes. ISS has seen a feature that looks like a
lake, and that's at the bottom left, on the south pole. Now, as I
mentioned before, ISS has not been able to image the north polar regions
yet because those are in darkness.]{.underline}

[ But there was for years and years a question of where is the methane
impact in plasmasphere coming from. Is it coming from cryovolcanism or
from the interior or are there large bodies of liquid on the surface
that are evaporating and supplying the methane to the
atmosphere.]{.underline}

[ Back in the 1980s it was postulated that we might have a notion on
Titan that Titan might be covered by a giant ocean. We have not found
that. And we were looking for the lakes and we did not see them until we
had the first radar flyby over the north polar regions in July of last
year, and then, there were the lakes.]{.underline}

[ So in T7, as you can see from the top right, a feature that could be a
lake embayment, and we think now it is. But we have not seen the really,
really radar-dark regions which means that whatever material is there,
it's very, very smooth and likely to be liquid.]{.underline}

[ So here, you see from T16 and T19 and we have done a series of flybys
over the north polar region at the moment and then we have great
distribution of lakes, including some that are so large that we are
actually requesting the IAUs to call them "seas." And then, I don't know
if they accepted yet. I am actually the head of the Nomenclature
Committee for the Outer Planets, so we'll see if I have some influence
or not.]{.underline}

[ This next slide, Slide 30, shows one of the large lakes that has an
island in the middle. And the island is very large; it's the size of
Kodiak Island or the Big Island of Hawaii.]{.underline}

[ And the next slide, 31, shows a comparison of Titan's lakes or seas
with Lake Superior, and the Titan lake is greater than 100,000 square
kilometers. And the question of whether it's a lake or a sea, in fact,
we probably will hint to the argument on the percentage of Titan's area
that is covered by a particular feature that we want to call a sea, you
know, as opposed to, you know, seas on Earth, what percentage of the
Earth they cover.]{.underline}

[ But we found out that there is not actually a very good definition of
seas for us and they can get into the same type of argument as the
definition of a planet, which I really don't want to go in.]{.underline}

[ Next slide, 32, there is actually a movie that I'm not showing here
but you can get from photo journal.]{.underline}

[ And this is radar data over ISS. Now, as ISS started to be able to see
close to the north polar region, they found a large dark area and this
connects very nicely to one of the radar (unintelligible) lakes, the one
with the island on it so we think it's all part of a really large
sea.]{.underline}

[ Slide 33, getting to the end now, is a schematic put together by Steve
Wall from the radar team about Titan's methanologic cycle. And so, it
just explains how the - it works similar to the hydrological cycle on
Earth but it was methane.]{.underline}

[ The methane evaporates, brings back to form channels, clean out
mountain ridges which, you know, appear bright and then form debris, et
cetera, et cetera. Methane is also replenished by - from below by
cryovolcanism. There are probably several processes at play to re-supply
the methane.]{.underline}

[ Now next slide is from VIMS. I know that I focused on some radar and
I'm not apologetic because radar is what I know about.]{.underline}

[ But VIMS had a flyby last December I think it was, (unintelligible).
That's the highest spatial resolution that they've been able to get with
VIMS. And they imaged a mountain and actually found this mountain range
which seems to be the largest we have found on Titan, is about 1.5
kilometers high.]{.underline}

[ We do not have radar data on the same mountain range, but this is
consistent with some of the highest mountains we've been able to measure
from radar data. They have also spotted some orographic
clouds.]{.underline}

[ And Slide 35 shows what the thing - ISS has begun to be able to see,
the northern regions and it's going to be, you know, really interesting
eventually, assuming we're still flying by then, if ISS can actually get
some more overlap with radar.]{.underline}

[ And on the left hand image, you see here that dark squiggle at the
part close to the terminator is the sea that connects to one of the
radar (post) lakes.]{.underline}

[ And finally, Titan's atmosphere is - I'm not going to go into the
atmospheric studies because that's not my specialty. My specialty is
surface.]{.underline}

[ But VIMS has found a huge cloud system covering the north pole of
Titan and this is very consistent with the story of the lakes and the
methanologic cycle. The methane from the lakes is evaporating and
contributing to these huge clouds which are then causing rain to fall
and the whole cycle to go on.]{.underline}

[ So, we have one more slide, in fact, that Trina put in.]{.underline}

[ INMS and, you know, and all the different things that INMS has been
able to measure, and I would not say that I actually can say the name
for all of them. But it's very interesting, the - you know, the variety
of ion composition that INMS has been able to measure at Titan compared
to, you know, what they would be able to measure at Venus, Mars, et
cetera.]{.underline}

[ So, you know, Titan is a really diverse, very complex place. And I'm
sure that with Cassini, you know, as much as we're making great
discoveries, we're going to end up with a lot of questions for our next
mission to try to answer.]{.underline}

[ Okay. So I think this is all I have. I'll take a few questions
now.]{.underline}

[Trina Ray: Yeah, let's take a few questions if we have
any.]{.underline}

[Man: (Unintelligible). Can you hear me?]{.underline}

[Trina Ray: Yes. Go ahead.]{.underline}

[Man: Yeah. Slide 37 seems broken in the PDF. Can you describe what it
was we're supposed to be looking at?]{.underline}

[Rosalie Lopez: I'm seeing it in the PDF fine. It's a table of ion
composition at the electron density peak in solar system ionosphere. So
we're - it shows what INMS - what ion composition they would be able to
detect if they flew by Venus, Earth, Mars, Jupiter, and Titan and it
shows you that Titan has the most chemically complex ionosphere in the
solar system.]{.underline}

[ And so, while for example, on Earth there are only, you know, five ion
compositions that INMS would be able to detect, so on Titan, well, you
know, there are, you know, seemed like 20 or so.]{.underline}

[Trina Ray: It's about 50.]{.underline}

[Rosalie Lopez: About 50?]{.underline}

[Trina Ray: Yeah.]{.underline}

[Rosalie Lopez: Okay. Trina actually put together the slides. So, would
you like to say anything else, Trina?]{.underline}

[Trina Ray: No, that's - I actually got the slide from Hunter Waite,
he's the INMS - but that's exactly the concept is Titan's chemistry in
the atmosphere is tremendously complex and tremendously interesting to
the chemists and this is the most chemically complex atmosphere that
we've ever detected.]{.underline}

[Man: Thank you.]{.underline}

[Trina Ray: Do we have any more questions for Rosalie?]{.underline}

[Man: Yes, I have a quick question.]{.underline}

[Trina Ray: Okay.]{.underline}

[Man: Doubt that these are lakes or seas at the north pole?]{.underline}

[Rosalie Lopez: No. We - although we don't have - you mean that they are
liquid?]{.underline}

[Man: Yes.]{.underline}

[Rosalie Lopez: Okay. Although we don't have any measurement that can
say at the moment okay, absolutely, we made this measurement, we, you
know, proved it's liquid. The body of evidence is overwhelming. We see
the whole morphology is that of liquid. We see channels draining out of
them. We see changes in the radar darkness that actually may relate to
how deep the lake is.]{.underline}

[ And we are actually looking for definite proof. And what would, I
think, be definite proof would be if we managed to detect a change and
that's what we're looking for because we have some overlap between
flybys.]{.underline}

[Man: That's what I wanted to ask you about, yes, the most recent
flybys, I haven't seen anything published yet and exactly on that
question.]{.underline}

[Rosalie Lopez: Okay. Yeah. You see, it can be very difficult to unravel
because there are differences in look angle that, you know, can give you
differences in the radar image that may not indicated a real change. So,
you know, we're actually doing a lot of work on that at the
moment.]{.underline}

[ And first of all, you know, I mean, the minute that, you know, if we
convince ourselves that something has changed then, you know, so we're
going to go press pretty quickly.]{.underline}

[ And the second thing is that we actually, you know, putting together a
polar mosaic that's showing all the swaths. And we are, you know,
talking about when and where we are going to release that now. But, you
know, and that's colorized as well so it's going to be quite
nice.]{.underline}

[ And so, we were, you know, thinking of saving it for a science paper
but now, we found we have too much to say so we had to publish somewhere
else.]{.underline}

[ Anyway, I predict it's going to come out soon.]{.underline}

[Trina Ray: Rosalie, one final question. In addition to seeing changes,
if somebody detected a specular reflection that would also be very
telling.]{.underline}

[Rosalie Lopez: Yes. But for the specular reflection, you need ISS or
VIMS and for - the specula point. And we may be able to do that later in
the mission, but then, you know, so far we haven't been able
to.]{.underline}

[ Also, apart from a couple of the seas, these lakes are quite small,
you know, relatively small if you're looking for the specula
point.]{.underline}

[Trina Ray: Okay. I don't want us to get too far off track. We've got a
lot of disciplines to cover today.]{.underline}

[ Thank you very much, Rosalie. Hopefully you can stay on line as long
as possible to answer other questions. But let's go ahead to our next
topic.]{.underline}

[ Dr. Paul Helfenstein is here to tell us about icy satellites in this
year.]{.underline}

[ Paul, are you muted? Don't tell me we lost Paul.]{.underline}

[Paul Helfenstein: No, you have me.]{.underline}

[Trina Ray: Okay, there you are.]{.underline}

[Paul Helfenstein: Okay. Sorry.]{.underline}

[Trina Ray: Shoot.]{.underline}

[Paul Helfenstein: I was rambling on into my (doctor),
but...]{.underline}

[Trina Ray: Okay. Well, you were muted for the first part so you have
start over.]{.underline}

[Paul Helfenstein: Good to know.]{.underline}

[ Well, thank you very much and good afternoon. I'm going to talk a
little bit about satellites here.]{.underline}

[ Saturn's system has 47 different satellites that are so small and far
away from planet. There are eight major icy satellites, not including
Titan. They are Mimas, Enceladus, Tethys, Dione, Rhea, Hyperion,
Iapetus, Phoebe. The major ones are located outside the major ring
system, vary in size from Phoebe which is 137-mile diameter up to Rhea
which is 915 miles.]{.underline}

[ Their surfaces are dominated by water ice and multi-shaped by forces
of tectonics, (evaporating), erosion, in the case of Enceladus, even
cryovolcanism.]{.underline}

[ The densities range from about 6 grams - 0.6 grams per cubic
centimeter for Hyperion to 1.6 grams per cubic centimeter for
Enceladus.]{.underline}

[ And if you go to the next slide...]{.underline}

[Man: Could you speak up, we can hardly hear you.]{.underline}

[Paul Helfenstein: Okay. Is that better?]{.underline}

[Man: Yes.]{.underline}

[Trina Bay: Yes it is.]{.underline}

[Paul Helfenstein: Okay. Yeah. I have a headphone on so I can use my
fingers on the keyboard here.]{.underline}

[ Okay. You've seen this cartoon. I'd like you to pay particular
attention to the bottom one. We're going to be talking mostly about the
larger satellites, Mimas through Rhea and Iapetus, and what I want you
to pay attention to is the position starting from Mimas and moving
outwards toward Rhea of the major satellites relative to the
E-ring.]{.underline}

[ The E-ring is a diffused - a thin diffused ring that actually has
rings that extend far beyond the - fairly far beyond the orbit of
Enceladus. Enceladus seems to be embedded in the middle of the E-ring,
and there's probably a good reason for that as you'll see a little
later.]{.underline}

[ Next slide.]{.underline}

[ Okay. Then, as you probably surmised from the earlier slides, it's
been a pretty quiet year for icy satellites other than Titan. That's not
to say that we haven't gotten any new data at all. There are sort of
three classes of images and data that we've gotten this
year.]{.underline}

[ The first are zero-phase images of Dione, Iapetus and Enceladus. By
zero phase, I mean, images where the phase angle was zero so that they
look - they're illuminated sort of like the same way that your full moon
is illuminated where the whole disk is visible and illuminated by
sunlight.]{.underline}

[ These are neat to people who do photometry because they provide most
accurate measurements of albedo and color for the
satellites.]{.underline}

[ Because you can see zero-phase from Earth, they provide us also - they
provide a very good tie to Earth-based telescopic observation and
observations say from the Hubble Space Telescope.]{.underline}

[ And then finally, these fall within the area and they actually define
the opposition effect for each satellite.]{.underline}

[ The opposition effect is a peculiar optical effect, an amplification
of light that tends to happen almost always at very tiny phasing and can
lead to reflectances oddly not greater than unity for things like
Enceladus and snow and frost-covered surfaces.]{.underline}

[ In addition, we've gotten some new close-up views of Tethys, Dione,
Rhea, and Mimas. They are in the order of about a kilometer or pixel for
better resolution.]{.underline}

[ So, this will help us complete our global mapping of the satellites
and provide new geological details about features and topography because
they provide us with stereo views often of features that we can use to
interpret elevations, do some rainmaps for instance.]{.underline}

[ And finally, we've gotten new Enceladus plume observations. These - as
you will recall in the - in 2005, Cassini discovered that this little
500-kilometer-sized moon Enceladus is actively - cryovolcanically active
and it's erupting huge plumes of water vapor and ice particles out -
directly out of the south pole through a series of parallel fractures
called "tiger stripes."]{.underline}

[ These new data will actually allow us to look for temporal changes in
the eruptions that might be, for instance, associated with tidal flexing
of the solid surface in Enceladus.]{.underline}

[ Go on to the next slide, if I can go on to the next slide
here.]{.underline}

[ Okay. This - the next slide will show you satellites at opposition.
These are what - the ones that we had from Cassini that are illuminated
at or near zero-phase.]{.underline}

[ Dione, Iapetus, Enceladus, and Rhea, I have not done anything to the
sizes of these satellites to adjust them to their correct relative size
nor have I tried changing their orientation. What I have done is
radiometrically corrected these satellites so that their relative
brightnesses are correct for things that are close to
zero-phase.]{.underline}

[ So you can see that in Iapetus, you have Cassini Regio, which is a
very, very dark spot that covers nearly half of Iapetus. The brightest
feature that you would see - the darkest features that you would see
there are on order of 8% at zero-phase.]{.underline}

[ In contrast Enceladus - the brightest areas of Enceladus actually have
albedos of about 1.4. In other words, it seems kind of odd that this
opposition effect business can lead to reflectances that are almost 50%
higher than unity.]{.underline}

[ So anyway, go to the next slide. This should be 42.]{.underline}

[ Okay. Forty-two is an example of some of the close-up views. I'm not
going to go through all the close-up views because otherwise I'd just be
showing you a lot of craters and fractures.]{.underline}

[ But this is a representative example of Dione images that we got in
April 25 of this year. The resolution - the best resolution here is
about 700 meters per pixel and it shows the leading side of Enceladus -
I'm sorry, of Dione.]{.underline}

[ On the right, you'll see actually one of the close-up images for
scale. That crater was a prominent central peak. I think that's about -
I think it's about 60 kilometers in diameter. There's a large basin
immediately above it, that's on the order of 250 kilometers in
diameter.]{.underline}

[ So you basically see some old impact craters with prominent central
peaks. There are some interesting fractures. But we're looking here
towards the south pole. The fractions seem to be roughly north-south
trending, I guess. This will allow - these types of images will allow us
to do a more complete global mapping, and it's really the global maps
that show us most of the interesting geology. That's a project in work
for all of the satellites.]{.underline}

[ Okay. And rather than I go on and show you a lot of pictures of
craters, I thought I'd talk about Enceladus, whereas we haven't gotten a
lot of images, a lot of progress has been made in the scientific
analysis of this body in particular.]{.underline}

[ First, just to review some basic Enceladus properties. It's got a
triangular shape and a mean - it's got a mean radius of about 250
kilometers.]{.underline}

[ Its density is 1.6 grams per cubic centimeter so it's actually
significantly denser than ice. If you're to take all the rocky, all the
(non-ice) material and basically send it to the center of Enceladus and
bring all the water ice towards the surface, you'd have a crust or an
outer layer of ice that might be on the order of 100
kilometers.]{.underline}

[ Its gravity is 11.3 centimeters per second squared, compare that to
Earth which is like 986 centimeters or 808.6 centimeters per second
squared \-- very tiny gravity.]{.underline}

[ It's - like a lot of these large satellites, it's locked in
synchronous rotation around Saturn so that the same side always faces
Saturn. It rotates - it goes - rotates on its axis and orbits Saturn
once every 1.37 Earth days.]{.underline}

[ The main surface temperature is about 72 degrees Kelvin or 330 degrees
below zero Fahrenheit, and it's got a visual albedo of about 1.4 and
that's confirmed from Earth-based observations from Hubble
telescope.]{.underline}

[ Well, if you go on to the next slide, Slide 44.]{.underline}

[ Okay. As we mentioned earlier, one of the most spectacular things that
Cassini, I think, has found is that Enceladus is erupting these huge
plumes of water vapor and ice particles out the south pole. And this
image that I've shown you from April 24 of this year, the south pole is
actually to the right.]{.underline}

[ So essentially what you see here are a series of plumes. If you look
really closely, you can see individual jets emanating from the
surface.]{.underline}

[ A lot of study with - particularly with Carolyn Porco and her group,
they've been doing stereo analysis and triangulating where - which
particular parts of the surface these plumes are coming from and they
conclude that they are coming through a series of rifts through the
surface that are affectionately known as tiger stripes.]{.underline}

[ If we go to Slide 45, it's all - here, it is also found that the tiger
stripes are unusually warm compared to other parts of the surface, on
the order of 80-85 degrees Kelvin for reasons that their spatial
resolution - enough to see deep down into the central part of the
fracture, essentially though they could be more than a few degrees
warmer than the average surface, meaning that the warmer elevated
temperature and the fact that the plumes seem to be erupting from these
tiger stripes suggest that either there's a reservoir of water
underneath like an ocean or an under-surface aquifer.]{.underline}

[ Or more recently, Kieffer and others had suggested that there are
materials - unstable materials that are water-bonded on (unintelligible)
that when they're exposed to vacuum and slightly elevated temperatures
can release their water and that's perhaps another alternate possible
reservoir for the types of materials that are coming - forming the
plumes.]{.underline}

[ At this point, it's a mystery. Nobody really knows what's causing the
plumes, whether they're from a reservoir of water or a reservoir of
clathrate.]{.underline}

[ There are some interesting - there's some interesting work though
that's been done that (unintelligible) tests of what might be
controlling the plumes themselves and when they occur.]{.underline}

[ Some recent work by Hurford et al. has been published in which they
consider the possibility that tidal flexing of Enceladus that as
Enceladus goes back and it goes around its orbit, it actually flexes
back and forth and the tides can introduce stresses at the surface that
can reactivate fractures that are already there and you can more or less
open and close them.]{.underline}

[ So, on the right part of this slide, you'll see a cartoon that shows
the outlines of four major tiger stripes. And the areas in green are
areas that Hurford et al. predict should have been opening up, for
instance, during this last observation on April 27.]{.underline}

[ I can't say too much about the work that's being done because it's
unpublished. But what has been reported so far suggests that there's a
partial agreement with this model but it's in - you know.]{.underline}

[ Go to the next slide, Slide 46.]{.underline}

[ There is an alternate theory. One theory, as I was mentioning, is that
there's a reservoir of water under the surface of the south pole and if
there is, based on the spacing of target stripes themselves, we estimate
that the thickness of the crust or thickness of the lithosphere there
may be on the order of 10 kilometers to 30 kilometers. So the waters
there may be very deep.]{.underline}

[ The alternative model that there may be a clathrate has gotten more
recent attention by (Nimo) et al. this year in which they present these
clathrates and heat will cause them to release water vapor and as a
mechanism for - they've also looked at tidal deformation mechanism. And
they point out that during different parts of the orbit of Enceladus the
tidal stresses can result in the tiger stripes shearing back and forth,
sort of like you're rubbing your hands together, and that may produce
enough energy to cause the clathrates to become unstable and release the
plume vapor that we see.]{.underline}

[ Let's go to the next slide.]{.underline}

[ Okay. So it's probably no coincidence that the eruptions that we're
seeing are happening exactly at the south pole.]{.underline}

[ In 2006 (Nimo) and (unintelligible) provided a good working - what I
would call a good working model of why the area of volcanism has ended
up at this sort of peculiar orientation exactly at the south pole. What
they postulate is that there may be warm plume material that's lower in
density than the surrounding ice that causes Enceladus' rotation to come
off balance enough or perturb the moment of inertia enough that over
time it actually ended up trying to reach a more stable rotational
scheme which places it at the south pole.]{.underline}

[ So they provided a mathematical model that seems to make sense. But so
far, you know, over the last year and probably over the next few years,
we'll be looking for proof that this might have actually occurred or if
some variation of it occurred.]{.underline}

[ Go to the next slide.]{.underline}

[ Okay. Well, I'd like to focus in a little bit more on the south polar
terrain itself.]{.underline}

[ It's a very peculiar terrain on Enceladus. There are almost no impact
craters that can be found. We know that it's very geologically young; it
hasn't been around long enough to accumulate impact
craters.]{.underline}

[ It's roughly about 200 kilometers in diameter with a circumpolar
chain. In this slide that you see where you see letters that are called
A, B and C, they're basically separated - the south polar terrain is
separated from other terrains by a very distinct circumpolar chain of
scarps that are on the order of a kilometer or so high.]{.underline}

[ The area covers about 70,000 square kilometers and it's - you'll
notice the area is - that the points labeled A in this feature show that
there are these little cuspate intersections that are very reminiscent
of similar types of features that we see due to (unintelligible) sphere
or even (plate thickness) on Earth.]{.underline}

[ Over by (unintelligible) intersections take the form of something that
looks a little bit like a wedge and may in fact be acting like a wedge.
If you look very closely in these features, it's just continuity in the
margin called (unintelligible), actual icy mountain range, a little
(pole) belt. The mountain ranges - the mountains are on the order of a
kilometer or a little less size but it's - there's very strong
indications here that what's happening at the edge of this margin is
that there's...]{.underline}

[((Crosstalk))]{.underline}

[Man: Hello.]{.underline}

[Paul Helfenstein: Going on and the...]{.underline}

[Man: Hello. How are you?]{.underline}

[((Crosstalk))]{.underline}

[Paul Helfenstein: Relative to tiger stripes...]{.underline}

[ Go to the next slide.]{.underline}

[ Okay. We have here (unintelligible) I've been able to use over the
last year or so, I've been able to use stereo information to drive some
topography of the south polar region.]{.underline}

[ You can see actually that it's a topographically depressed area.
Towards the center, it's roughly 500 meters below the average Enceladus
height mountain chain, color-coded here as well, are on the order of 100
meters above the main surface so that the total drop in topography from
the top of the mountain floor of the south polar terrain is on the order
of a kilometer.]{.underline}

[ We've done some preliminary geological mapping of
Enceladus.]{.underline}

[ On Slide 50, you'll see a view from - on the left from - looking from
the south pole of a stereographic - polar stereographic map and on the
right, looking down at the north pole. Right away you begin to see some
very interesting symmetry.]{.underline}

[ First of all, you can see in pink the south polar terrain region. The
area is labeled A. It shows us sort of the directions of force that are
applied by the morphology of these mountain chains that seem to form
around the outer periphery.]{.underline}

[ You'll also notice in blue, these areas that are - represent old
crater terrains, areas that haven't really been tidally disrupted too
badly. There's an interesting symmetry here in that the - because
Enceladus is tidally locked, the plane that goes from zero degrees to
180 degrees in longitude and around the pole is - you might call that
the tidal plane. Well, the areas of old crater terrains seem to form
almost a band all the way around Enceladus to perfectly sort of align or
nearly perfectly align with the Saturn and sub-Saturn
direction.]{.underline}

[ On the leading edge and trailing edge of Saturn - of Enceladus
however, the surface is badly sort of tidally broken up into a very
elaborate series of different terrain providence or provinces that vary
in age.]{.underline}

[ If we go to the next slide, okay, yeah, if the only thing that
happened - this represents kind of the first level of the test of the
(unintelligible) idea that polar wander has occurred. If the only thing
that has occurred over time is polar wander from one (unintelligible)
for instance or one port or basin, you might expect that Enceladus would
be completely cratered except for the south pole. In fact, we find these
in many other areas that are also tectonically
(disruptive).]{.underline}

[ So, in this particular view, we found features that appear to be
almost relic features which might have been ancient areas like the south
polar terrain that may have erupted in the past in similar patterns
(unintelligible).]{.underline}

[ In this particular slide, polar (viewgraphic) projection, like the one
shown earlier at the south pole, except now we're pointed at the equator
in an area called (Serendip Initio) and what we see is an area that the
dark - the bluish material, the crater terrain sort of wrapping around
at least part of this in about the same geometry as the perimeter of the
south polar terrain wraps around that province.]{.underline}

[ If we look a little closer at these images \-- go to Slide 52 \-- we
see our Label D features that crudely look reminiscent of tiger stripes
in both their placement and orientation. We also see features like that
Label C that appear to be features that may have formed under
compression, these are ridges that look as if material has been extruded
up through them perhaps by compressional forces.]{.underline}

[ In the area labeled A, you can actually see sort of an arcuate band, a
grooved terrain that at least in plan form resembles some of the banding
that you see in the south polar terrain.]{.underline}

[ Now the topography is very subdued. But what's interesting about this
subdued - that nearby there are craters that appear to (unintelligible).
They've been heated from below and their topography is (unintelligible)
that it might have been one time - look more like (unintelligible)
around the south polar terrain except that over time being
(unintelligible).]{.underline}

[ Okay. So, go to the next slide.]{.underline}

[ Okay. And I'd like to return now to the Enceladus plume.]{.underline}

[ As I mentioned before, Enceladus is embedded in the E-ring and this is
one of the images that we returned last year. The little dot there with
sort of - that's sort of highlighted in the inset is
Enceladus.]{.underline}

[ You can see sort of the bright or exposed areas below are plumes that
are coming out of Enceladus and there are actually little filaments of
water vapor and ice that are - you can see twisting around Enceladus.
This is sort of the smoking gun, if you will, that shows that Enceladus
is actually the culprit that's been feeding the E-ring with ice
particles.]{.underline}

[Woman: (Unintelligible).]{.underline}

[Paul Helfenstein: Okay. Now, this makes it more
interesting.]{.underline}

[ If you go to the next slide, okay, Enceladus - it's a bit of graffiti.
I've stolen the title here from a recent paper by (Ann Berbicer). And
(Ann Berbicer) has been analyzing Hubble Space Telescope data, again,
observation of the Saturnian satellite at exactly zero phase as we were
talking about before.]{.underline}

[ And so, what you'll see in this figure is a plot. There are two
panels. The top shows the albedo, the reflectances of the major icy
satellites as a function of their distance away from
Saturn.]{.underline}

[ So the scale here, RS, is in Saturn radii or multiples of Saturn
radii - the radius of Saturn. Saturn is about 120,000
kilometers.]{.underline}

[ So what you see is close to Saturn. You see Janus, Epimetheus, they're
small icy satellites, and then Mimas and Enceladus and Tethys, Dione and
Rhea. Enceladus is obviously, from this plot, the brightest and most
frost-covered of these satellites.]{.underline}

[ And as you move farther away from the south, you notice that Tethys is
the next closest, it's also next brightest. And Mimas is further -
slightly further its way - farther away, but it's also fairly
bright.]{.underline}

[ It appears that as you move farther away from Enceladus, the
satellites are getting a little darker. And if you also look below,
okay, below is a plot of the reflectance or the albedo of the E-ring and
it basically mimics the brightness of the satellite. So the conclusion
that we derive is that Enceladus is spray painting its neighbors
across.]{.underline}

[ Then we go to the next slide, and this will be my last one because I'm
probably way over time.]{.underline}

[ Essentially, you know, one thought here is that if it is spray
painting its neighbors, you would think that Tethys and Mimas, the
nearest neighbors, would just be spray painted white, you wouldn't be
able to see any albedo or color markings.]{.underline}

[ Mimas just about foots the bill. This is a view taken - I believe
taken towards the end of last year of Mimas that shows, I think, the -
it's probably the leading - I'm sorry. I've got my notes a little messed
up here.]{.underline}

[ Anyway, the only color variations that we really see that are
significant on Mimas are due to a large crater - impact craters called
Herschel. They're very muted color differences.]{.underline}

[ If you look at Tethys though, over on the right, you'll see that
there's an albedo variation in a very peculiar tongue-shaped band that
extends - it's parallel exactly to the equator and extends plus or minus
(15) degrees latitude and goes at least halfway around Mimas on the
leading side. It's not too prevalent on the trailing side.]{.underline}

[ So, if Tethys is being spray painted by Enceladus, it's being done so
in such a way that albedo variations can be preserved on one side and
not on the other that suggests for instance perhaps the magnetosphere is
dragging ice particles into one side and Tethys itself is shielding the
surface from that bombardment on the other side.]{.underline}

[ I think that's about all I have for you right now, so I will turn the
floor over to questions.]{.underline}

[Trina Bay: We have - we are running over so let's just take - let's
see, let's take one question.]{.underline}

[ And if there isn't one, that's okay because we've got plenty of
material yet to go.]{.underline}

[ Paul, are you going to be able to stick around for a while
or...]{.underline}

[Paul Helfenstein: (Unintelligible).]{.underline}

[Trina Bay: Okay.]{.underline}

[Paul Helfenstein: Thank you.]{.underline}

[Trina Bay: Last call for any questions. One question for icy
satellites.]{.underline}

[ Yeah. Go ahead.]{.underline}

[Man: What can you tell us about the composition of the
plumes?]{.underline}

[Paul Helfenstein: Plumes are almost entirely water vapor and I don't
think - I think, you know, Enceladus itself is almost - if you look at
VIMS data, the surface itself is almost pure water. There are very small
trace amounts of carbon, mostly in the form of carbon - frozen carbon
dioxide.]{.underline}

[ People have been trying to come up with - trying to see if they could
measure something like - particularly things like ammonia because for
water to exist, the temperature in Enceladus is so cold that one almost
needs some type of material to depress the freezing - or to raise the
melting point in order to get water.]{.underline}

[ So the people are looking at - we're hoping that something like
ammonia would exist. And so far, people have only been able to put VIMS
and other people have only been able to put limits on the amount of -
there and it's generally less than a couple of percent if it's
there.]{.underline}

[Man: Thank you.]{.underline}

[Trina Bay: Okay. Thanks very much, Paul. We truly appreciate you taking
the time today.]{.underline}

[ Let's go on to our next topic.]{.underline}

[ I have - Kevin joined us.]{.underline}

[Kevin Baines: Yeah. Can you hear me?]{.underline}

[Trina Bay: Yes, we can hear you just fine, Kevin. We're running a
little bit behind schedule so as long as we sort of keep it moving,
we'll be fine.]{.underline}

[Kevin Baines: I'm trying to. I just had a little computer crash and my
computer is finally coming up. I was looking at our talk and it just
went down on me, but I'm trying to get it back up here. I'm sitting here
in Trent trying to communicate, you know, from the hotel in Trent. But
it's going back up and I have to wait another second or so, but we can
talk a little bit about Saturn.]{.underline}

[ Saturn is sort of the lord of the whole system that we've been hearing
about with the ring system and the satellites and Titan and they all
circle Saturn.]{.underline}

[ And I see that you were helpful here, Trina, coming up with a summary
of Saturn here on this slide and it's, you know, it is the second
largest of all the planets, Jupiter of course being the largest
one.]{.underline}

[ I should say that Saturn has a diameter ten times larger than Earth's
diameter ‑- almost exactly ten times. So it's got 1000 times of volume
of the Earth. And so, it's a gigantic planet.]{.underline}

[ But just like all the large planets, the reason why it's large is
mainly because it's made of hydrogen. And hydrogen, as we all know, is
the most prevalent molecule in the universe and so, when you can grab on
to hydrogen and make a planet out if, it's usually large. That's the
reason why Jupiter is so large and the outer planets are large because
they can grab on to the hydrogen and keep it whereas the inner solar
system planets can't hold on to the hydrogen basically.]{.underline}

[ Sunlight basically matches in the hydrogen power so now the atmosphere
is - so that you can't really keep too much hydrogen around the inner -
but outside of Jupiter and beyond, you can keep it.]{.underline}

[ So, we've got the second largest planet in the solar system sitting
there \-- Saturn.]{.underline}

[ And the second large - the most prevalent component of course is
helium and it comprises (unintelligible) of the planet. There's also
methane and ammonia in the planet as trace constituents, down about 0.1%
or so. And then there's phosphene and a number of other constituents
there, which, all together, we believe, kind of gives some of the
coloring that you see on Saturn and also on Jupiter.]{.underline}

[ We think these are traces, you know, trace chemistry going on with
photochemistry, sunlight coming in, matching to some of these molecules
and then creating other molecules and then eventually get the kind of
colors that we see on these planets.]{.underline}

[ The clouds that you see on Saturn, the whitest clouds we'll be talking
about later, we believe are mostly ammonia. There's an outstanding
problem there that no one yet has spectroscopically identified ammonia
on Saturn. We've done it on Jupiter, but so far have been (staked) out,
haven't been able to figure out how to do it on Saturn, how to get - to
really expect spectroscopically identify as ammonia.]{.underline}

[ But we believe from (turbo dynamics), knowing how much ammonia gas
there is there and seeing the temperatures that we know that ammonia
should condense out and form clouds at that level. So we think that we
really have ammonia there.]{.underline}

[ Okay, let's go on to Slide 56. Okay, I thought 57 - get my computer to
behave right.]{.underline}

[ And the theme I'm going to try to talk about is the polar science that
we've done this past year. You know, we finally with this tour been able
to crank up over the pole and this has allowed us now to really, you
know, observe the poles for long periods of time, watch what's going on.
And we find that each pole is different.]{.underline}

[ The north pole has this strange hexagonal feature which we see
probably on this image, a six-sided feature of the pole. And then the
south pole seems to have a hurricane-like feature complete with towering
(I) clouds that rise up 50 kilometers above the base and you can
actually see the shadows of the clouds that are being cast on the clouds
below. That's sort of the thing that we found.]{.underline}

[ So each pole seems to be different. And we'll talk about that a little
bit more.]{.underline}

[ So, on Slide 58, you see a typical - what I call a typical picture of
Saturn with a beautiful ring system. It's the - the planet itself - the
left side is lit up by daylight. At night side on the right, you can see
the shadow of the night side cast on the ring system -- a beautiful
picture there.]{.underline}

[ This has been overexposed in a sense so it's not quite fair what I'm
really talking about. But if you just go on your slideshow and then
click on the next picture, we've overlaid on there then what it looks
like in an infrared, but a picture that was taken a short time after
this picture was taken and you can see (unintelligible) characters to
the planet.]{.underline}

[ So where in the first picture, you were seeing daytime only and you
had a nighttime, on this picture here you're actually seeing a red glow
all the way around the planet. And what you're seeing here is the red
glow from the depth of Saturn.]{.underline}

[ Saturn itself just like the Earth, if you go down deep enough, you
find heat and that heat then tries to get out of the planet. And if you
look at the right wavelength, in this case 5 microns in the red color,
you'll see the clouds above trying to block the heat and so, what you
see is clouds in silhouette. And so, the black areas on this image in
red are clouds that are blocking light trying to get out from
below.]{.underline}

[ And those clouds are deep down in the atmosphere. It's not the thin
hazes of above that we see typically. These are distinctive storm
clouds, meteorological features that are down at around the two to three
or even four-bar level in the atmosphere. That is about two or three or
four times as deep as the typical (unintelligible) that you
see.]{.underline}

[ And so we're looking down at almost 100 kilometers below what you
actually - typically see what it's like at sunlight.]{.underline}

[ And we're getting down to the fun part of Saturn where it's active and
we're actually seeing the dynamics.]{.underline}

[ What this reveals is that the upper hazes that we're seeing is just
the skin of Saturn and all the excitement is down below and perhaps
these hazes up above are part of the reason why they're there is because
of meteorology, things like convection going on, bringing up particles
from below and then depositing them in the upper stratosphere - the
higher region of Saturn where they sit around for a while. But really, a
lot of this - a lot the stuff that we see in the upper atmosphere could
be created from down below. Other stuff is created in the stratosphere
due to photochemistry.]{.underline}

[ But this type of imagery showing the depths of Saturn is a revelation
basically of the Cassini mission and this was done with the VIMS
instrument, the Visual Infrared Mapping Spectrometer.]{.underline}

[ Now, in this picture, again, I'm talking about Slide 59, it's a very
interesting picture because this is a night side view of the ring. The
ring we see shimmering away. It's really a translucent image of the ring
and that's why the ring looks different.]{.underline}

[ You see a big black band in the middle of the ring and that's really
because the ring is so thick that it's blocking all the light and that's
the big black belt that you see on the ring. But there's other little
ringlets around that are actually letting the Sun kind of shimmer
through and you see it.]{.underline}

[ So, we're looking basically at the north pole here where, you know, at
the northern - at the back side of the ring here. And then up at the
pole itself, there is some sunlight hitting the pole and that's why
(unintelligible).]{.underline}

[ What I've done here again on Saturn is I've got - the red image is 5
micron below, sort of an oven effect of the glow of Saturn glow trying
to get through. But then I've also combined some reflected sunlight and
you see a little green - greenish (unintelligible) hemisphere. But you
see in the southern hemisphere, halfway down the picture, you'll see
that it all of a sudden gets brighter.]{.underline}

[ And so that basically tells you that there's a hemispherical
difference in Saturn. This is something that we've really been looking
into in the last year ‑- that Saturn has a hemispherical difference in
upper cloud layers. And so, the hazes in the upper atmosphere can
reflect sunlight but they're doing much more prevalently down the south
than the north. Now, part of that is due the fact that the Sun is
shining a lot stronger on the south than the north \-- the south in
summer right now and north in winter.]{.underline}

[ So what's happening is that we're getting some sunlight reflecting off
the southern hemisphere. But you can't explain that whole difference
from that. There's definitely a distinctive difference in the northern
hemisphere and southern hemisphere almost by a factor of two in the
aerosol continent and that's something that we really started to nail in
the last few months.]{.underline}

[ And what we're going to look for now is as Saturn starts tilting back
and as the north pole becomes summer. Right now, the north pole is in
winter and coming into almost in the spring.]{.underline}

[ As we (unintelligible) we're going to watch to see it's been flipped.
If the north pole becomes covered with clouds and the south pole starts
opening up so you can see the glow better from the south.]{.underline}

[ So, a lot of information in this one type of picture. And this kind of
shows what you can do when you have multiple wavelengths. You can do a
three-dimensional study of an atmosphere.]{.underline}

[ In this case, you can tell readily that the - that over the north
pole, we've got very few hazes but you've got lots of new clouds deep
down and over the south pole, you've got a lot more hazes up high and
there's also some deep clouds down below but they're hard to see, again,
they're being muted that. Those southern clouds are moving out the glow
coming in from the south and it basically tells you there are pretty big
particles actually in the south pole.]{.underline}

[ So there's probably a particle difference in size as well as in
content or in the amount of stuff. There's actually a difference in
particle size and the particles are bigger in the south than they are in
the north right now.]{.underline}

[ So we'll watch this over the next few years to see if we can see
seasonal changes and try to figure out what's really going on with the
different types of weather systems and what happens with - when you have
this amount of sunlight hitting the upper atmosphere and causing the
particles to form.]{.underline}

[ Okay. Let's go on to the next slide, 60. And again, this explains
basically what I was talking about that we have freezing colors there.
The red color is 5 micron, again, the glow of the internal heat of
Saturn trying to get out, being blocked by clouds.]{.underline}

[ In this case, every cloud tries to block it but because the light is 5
micron, only big particles will actually block it very well and that's
why you see those very distinctive black areas so that's where deep down
in the hemisphere there are some very distinctive thunderstorms and
things like that that are blocking the light. But the upper hazes are
small particles so they're not really going to do much that
(unintelligible) hemisphere.]{.underline}

[ Then down the green wavelength is 3 microns and that's just again
reflective sunlight again. But what's interesting here, by the way, you
noticed that the rings only show blue.]{.underline}

[ And so what we picked here was red and green to be colors of that
water in the ring would actually absorb the light. And the only color
then that the ring shows up is blue, we'll put the wavelength here,
which is very unique in that the ring itself reflects - that Saturn
itself likes to absorb it.]{.underline}

[ So, in that northern hemisphere part of Saturn because the 2.3 micron
is absorbing in methane and a little bit of hydrogen, you see very
little blue in the picture. You do see some aqua color in the southern
part of the picture,]{.underline}

[ Again, when you have high hazes over the south, well then you can
actually get some of the blue light to come back and to reflect off and
come back.]{.underline}

[ Now, I just had another glitch on my computer - it keeps going on. It
keeps - I just lost the - back up again.]{.underline}

[Trina Bay: I just wanted to give you a heads up, Kevin, we're running
late. You've got just about another five to ten minutes.]{.underline}

[Kevin Baines: Well, now (unintelligible) take a question while I'm
trying to get my computer to come back up with this thing. It just went
berserk on me and I just dropped the whole (unintelligible) on my
computer. But I could, you know, take questions if you want until I get
back up again.]{.underline}

[Trina Bay: Would you - it's possible that Tamas is online. Would you
like to - for us to go to maps and then come back to you?]{.underline}

[Kevin Baines: Well, I don't know. I'm afraid this computer - I don't
know maybe this file is so big that as I go through it, it tends to lose
it. It's going to keep happening, but okay.]{.underline}

[Trina Bay: Look at your original presentation that you sent me because
it was unchanged, if that would help.]{.underline}

[Kevin Baines: Right, right. That might - that's a good suggestion. But,
you know, it takes awhile to get this going up again, and this has
happened twice, you know, in the last five minutes.]{.underline}

[ It was working fine when everybody else was talking. Just one minute
before we changed my computer just decided to go berserk on me. So, I
don't know what's going on but it's coming up again and we'll just kind
of get down there.]{.underline}

[ So anyway, I was going to take - I have to see what the next picture
is because I don't have it on my slide. Again, we can take questions if
anybody has any questions out there while I'm trying to get this thing
to come up.]{.underline}

[Trina Bay: Are there any questions about Saturn?]{.underline}

[Kevin Baines: Well, I just wish I remember where I am in the
slide.]{.underline}

[Trina Bay: The next slide is the red north polar hexagon.]{.underline}

[Kevin Baines: Right. Okay, so we'll talk about that it's like coming up
now.]{.underline}

[ So, one surprise that we got was that this - that when you looked at
north pole, you see a strange six-sided figure, very interesting. Now,
what's known from Voyager that it's - it was there at Voyager but they
had a pretty core view of it in the sense that the Voyager spacecraft
was flying over the equator and so, in order to see the north pole, they
have to look at a very long slant (tap up) so the pole and so they got a
very poor - what we call (poor shortened) view.]{.underline}

[ And they put together a nice image, but it was - they had to wait for
the planet to rotate around and kind of piece together what they were
seeing.]{.underline}

[ In our case here, we had a beautiful view looking straight down at the
north pole \-- well, not quite straight down but from a very good angle.
So you can see the whole hexagon at one fell swoop and you can see it
sitting there. And there it is in this picture here where I've got,
again, I use red light for 5 microns.]{.underline}

[ Now again, we're using 5-micron light here to image it which means
you're looking at the glow of Saturn coming through the cloud. And so,
this is a nighttime view as was mentioned earlier, Saturn, the northern
hemisphere is at night right now because it's winter up there, polar
winter and so, you don't see it in similar light watching the glow come
through.]{.underline}

[ Now in a year or two, the Sun's going to rise over the pole. In fact,
you can see it starting to happen, you know, on that far LM, the blue
glow that sunlight over there is on the LM, it's trying to get up to the
pole but it's not quite there yet.]{.underline}

[ Within about a year and a half, they should be getting sunlight at the
pole and they should start being able to see the hexagon is reflecting
sunlight and that's the camera I'm talking about \-- the ISS camera
which has a very good spatial resolution that you can see very clearly,
and we'll be able to do it too with our VIMS camera that I'm part
of.]{.underline}

[ We also have reflective sunlight wavelength that I've shown you
earlier. And so, we're both really looking at reflected sunlight and
looking at the dimensionality of this, whether how high does this polar
hexagon go. What we see here is that the polar hexagon is a deep-seated
feature. We already know from Voyager images that were in reflected
sunlight that leap back to 1981 they were seeing it very high up in the
atmosphere as well.]{.underline}

[ So, we will be getting a full set of data simultaneously looking at
high and low in this atmosphere and really seeing how deep it's going to
go.]{.underline}

[ So that's Slide 61 showing that glowing away.]{.underline}

[ Slide 62, if you click on it, it should be a movie. You can see the
hexagon is spinning and what we're looking at there is about two and
half hours' worth of observations on it, (unintelligible) ten minutes
images and, again, at 5 microns.]{.underline}

[ And the planet of course is spinning under it and the planet rotates
about ]{.underline}\
[10-1/2 hours and - or like 2-1/2 hours it spins about one quarter of
the way around, you can see those corners kind of moving around about a
quarter of the way.]{.underline}

[ So it's not the actual spin of the atmosphere that we're seeing. We're
seeing that the - the spin of the planet is what we're
seeing.]{.underline}

[ So, one of the things that we've been looking at, the next slide shows
(unintelligible) Slide 63 is well, see how fast does this hexagon, this
figure, this six-sided figure actually rotate in the Saturn system. And
what we find is that it's rotating just as fast as Voyager found it,
20 - over 25 years ago that it is fixed in what we used to call the
nominal rotation rate of the planet.]{.underline}

[ Now there's an outstanding problem with Saturn and that is, what is
the length of a day on Saturn. It turns out that Voyager measured it
using radio signals from the planet and - that are generated, we think,
by the magnetic field and interactions with the magnetic
field.]{.underline}

[ And so the question is, you know, is that rotation rate that you
measured with radio is that the correct rotation rate? And what we found
for the first time amongst any planet is that when we revisited Saturn
on this mission, we find that the rotation rate by the radio is
different than it was in the early '80s.]{.underline}

[ And in fact, on the bottom of the slide, I think (unintelligible)
really playing out it's like too much - yeah, I do have it there. So you
can see that in the early - it's different now than what it was in the
early '80s.]{.underline}

[ So we had a big problem with that, what is the rotation rate of Saturn
because it's doesn't seem to keep the same rotation rate. Therefore,
what this is saying is that the radio signals are being affected by some
other processes. There's something else going on so you really can't
rely on the radio signals to tell you rotation rates.]{.underline}

[ It's because of magnetic field we believe. But we know magnetic field
is lined up with the spin of Saturn. And so therefore, you don't have
much of a wobble to this magnetic field that you can use to measure the
length of (unintelligible) like lighthouse effect that goes on on the
other planet.]{.underline}

[ But the other planets magnetic field off set and so, as the planet
rotates, you see a little lighthouse kind of effect come by and you can
just measure it and stay very (constant). And this planet has such a
weak signal because the poles that it's lined up with the rotation that
we really don't know what it is.]{.underline}

[ But the dipole of the hexagon here is maintaining the rotation rate it
had 20 years ago and it's very close to what we saw with the radio
signal back then. So one idea might be that gee, Voyager really did get
the right rotation rate and this guy is fixed to move all the
planets.]{.underline}

[ And we're seeing changes now due to other external circumstances which
might have to do - one very recently is with Enceladus that's putting
out all that junk out there which then gets to the magnetic field and
maybe it slows down the magnetic field a bit and kind of drags on it and
maybe causing the rotation rate to look like it's (six minutes) longer
than it used to be.]{.underline}

[ So we might find that a little clock that we were using for measuring
the rotation rate of Saturn is really dependent on Enceladus' volcanism.
And if it's not putting out a fountain of water for a while then things
get cleaned up in that (unintelligible) well then maybe this clock sets
back to the right time.]{.underline}

[ So, it's very intriguing kind of thing going on with this clock
(unintelligible). It's like the tail wagging the dog here in the Saturn
system.]{.underline}

[Trina Bay: Kevin, I hate to interrupt, but we really need to move much
faster.]{.underline}

[Kevin Baines: Well okay.]{.underline}

[Trina Bay: Okay.]{.underline}

[Kevin Baines: So now next image is the nighttime equatorial view of
Saturn and that shows you a fuller view of the nighttime glowing
away.]{.underline}

[ You see those pictures halfway at the planet. Those are the string of
pearls. And the next image shows us the string of pearls over many days,
or actually many months here about 14 months' worth of data between this
picture and the next picture.]{.underline}

[ Slide 66 and we have a very strange wave light feature with a little
brightening that we don't quite understand going around the planet. So
that's another strange thing we've seen.]{.underline}

[ And we'll just skip on to 67 which shows the extent of the
pearls.]{.underline}

[ And then a very nice movie is on Slide 68 \-- hopefully you can see
that. I call that rolling Saturn because Saturn is out of sight so you
can see it's kind of rolling past you as if there's an axle with that
hexagon. And it really does display the whole northern hemisphere very
well of what's there on Saturn that you can see just by staring at it.
This is a ten-hour long movie we did about - almost a year ago
now.]{.underline}

[ So I'll just skip through that. You guys
(unintelligible).]{.underline}

[ And then the southern hemisphere is showing this very strange
bellybutton-like feature at the pole which is a hurricane-type feature.
It's not really a hurricane. It's almost an inverted hurricane and the
way it works physically. But you still get the morphology of a deep
center like the eye of a storm surrounded by a ring of clouds that are
high altitude, and the blue picture shows that.]{.underline}

[ And then of course on Slide 70, I'm showing my favorite glowing again
to show what's deep down. It's the red spots all the way around the
planet. There's a deep cloud - some of them are deep clouds, some of
them are high. But that shows you just many clouds are down there
blocking the light, and there's a lot of things going on. We think a lot
activity, a lot of convection, a lot of stuff just happening to south
pole and we're starting to study that as well.]{.underline}

[ Next slide is - it should be a movie if it works right which shows you
the shadow effect, if you play that movie on Slide Number 71, you'll see
that you have the shadows in sort of the middle there kind of rotating
around. This is the movie where the longitudes - the 300 degree
longitudes is straight up. And so what you're watching is the Sun
rotating around the planet and you'll see the shadow cast kind of
rotating as well and that's kind of proof positive that you've got high
clouds casting shadows all the way around this thing.]{.underline}

[ The first time anything like this that has been seen on, I think, on
any giant planet where you have such a huge set of shadows being cast
from clouds that are, you know, 50 kilometers above the rest of the
planet.]{.underline}

[ So we're starting to study more of the 3D dynamics of that
feature.]{.underline}

[ I'm going to skip on now to - yeah down to Slide 73. That's again the
hemispherical effect showing up there. I like this picture. It's a
beautiful picture. You see the shadow of the rings on the northern
hemisphere allowing, you know, blocking - deflecting sunlight but you
still get the red glow of Saturn coming through.]{.underline}

[ And again, you can see the northern hemisphere - the southern
hemisphere on the right, it's bluer, dimmer at the top there than it is
in the bottom. And over on the left, you see that at 5 microns the top
is lighter than the bottom. And both effects are due to one and the same
thing, that is, again, the upper hemisphere - aerosol being a factor
too, more prevalent in the southern hemisphere than in the northern
hemisphere. It all works out nicely.]{.underline}

[ The next figure I was going to add a little more detail, but we'll
skip it, Figure 74.]{.underline}

[ And then we talked about, you know, looking at seasonal effects in the
future on this (unintelligible).]{.underline}

[ Now there's something - I mentioned that earlier that the rotation,
one other thing you can see in Saturn and the other thing that can
disrupt your radio waves is lightning. And one thing that ISS has done -
sorry, yeah, the imaging people have done is to try to find storms at
the same time that they were looking at the radio wave. And we now think
we have seen lightning in the depths of Saturn but again, it's done with
radio wave and correlating with clouds.]{.underline}

[ And the next figure tries to go over that. And there seems to be a
period after these - with the storms that we're seeing with RPWS. So we
think we've actually gotten storms at certain latitudes on Saturn that
we've seen.]{.underline}

[ And the final thing I'm going to talk about very briefly is again that
we can also look at the composition of some of the species in the
atmosphere and this is a (series) spectrum here on Slide 78 showing some
of the species you could see in the upper atmosphere, in the top 100
millibars and so of Saturn. And you're getting - the methane up there is
being smashed into by UV light and by also by some ions and things. So
you can create all sorts of weird chemicals and that may be some of the
hazes that are seen.]{.underline}

[ And then the final and I think is Slide 79, and that shows that the
specie that you see vary with latitude as if with the seasonal effect.
And you expect that to happen, that is, more Sun coming in you might
create more things, and that seems to be going out on some of these
things that we're seeing in the upper atmosphere.]{.underline}

[ I guess I do have some parting shot here of backside of Saturn on
Figure 80 and 81. And this was a very popular shot so I put it in here
so people had it again.]{.underline}

[ This is Saturn in eclipse basically. The Sun's behind Saturn and
you're seeing the light shimmering around the rings. But then you go to
81, you actually can see the Earth back there kind of through the rings,
looking through the Saturn system, even through the rings in a sense,
the outside of the rings and you can actually see the Earth and the Moon
sitting there, you know, a billion - about a billion miles - kilometers
away.]{.underline}

[ So that's basically it for now. And I'll take any questions if there's
any time left.]{.underline}

[Trina Bay: Let's take one question only since we are way
behind.]{.underline}

[Kevin Baines: Even though I talked so fast?]{.underline}

[Trina Bay: I know, I was surprised, but it happened.]{.underline}

[ Okay. Well if there's no question actually that's great. We can maybe
make up a little bit of time.]{.underline}

[ Tamas, have you joined us?]{.underline}

[Tamas Gambosi: Yes.]{.underline}

[Trina Bay: Wonderful. Thank you so much for taking time out of your
(mock) meeting to join us. And we're running a little bit behind, but go
ahead and take over.]{.underline}

[Tamas Gambosi: Okay. I'd like to talk about some of the latest
discoveries and development with respect to Saturn's magnetosphere. And
Slide 83 summarizes some of the basic facts about the magnetospheres of
Earth, Jupiter, and Saturn.]{.underline}

[ And there are some very interesting facts here mainly that the
magnetic field strength at the surface of the planet is about
(unintelligible) of Earth, about 15 times larger as the surface of
Jupiter. But Saturn's surface magnetic field is comparable to Earth;
it's about twice as big.]{.underline}

[ The other very important difference is the rotation rate which is of
course 24 hours at Earth, and it's about ten hours plus or minus a
little bit both at Jupiter and Saturn.]{.underline}

[ The (fallback lens) is that the ratio of the (unintelligible)
acceleration and the gravitational acceleration at the equator is
dramatically different as Earth is 0.3% as Jupiter and Earth is around
(Ulysses) - Jupiter and Saturn is around (Ulysses).]{.underline}

[ So, at Saturn, the ratio of centrifugal and gravitational acceleration
are quite comparable.]{.underline}

[ The other very important factor is the amount of mass that is added by
the planet or the planetary system to the magnetosphere.]{.underline}

[ At Earth, the total mass is coming from the ionosphere and this is
around a couple of kilograms per second. It's due to the outflow from
the high latitude ionosphere.]{.underline}

[ Jupiter, as we know, Io is the engine of the system. And Io is
spitting out around a metric ton of material a second. And just for
comparison, this is very comparable to a very active comet.]{.underline}

[ So Io basically releases as much material in the Jovian magnetosphere
as for instance an active comet like Halley, releases a few - a couple
of astronomic (unintelligible) from Earth than it was highly
difficult.]{.underline}

[ At Saturn, there are multiple mass sources and these are the
ionosphere itself which is not very significant. The biggest mass source
at Saturn is Enceladus. And this was a huge discoveries a couple of
years ago and I think that on the telecon a year ago that Enceladus
plume and outflows of geysers, anything you want for them
(unintelligible).]{.underline}

[ There is some mass coming from Saturn and from the rings. But the
total mass production in Saturn's magnetosphere is about 10% -- 10% to
20% of that in the Jovian magnetosphere.]{.underline}

[ So if someone wants to compare these three magnetospheres; at Earth,
the solar wind basically controls the interactions. This is with a very
slow rotation. At Jupiter, Io is absolutely dominant. The solar wind
interaction is quite insignificant compared to the Io mass
ejection.]{.underline}

[ At Saturn, these things are much more comparable and delicate
interplay between the phase in our control and multiple mass sourcing,
mass loading sources and the fast rotation and the solar wind to some
extent really made the situation much more interesting, much more
complex.]{.underline}

[ So if we want to understand our solar system at least in the magnetic
sense, you really need to understand the Saturnian
magnetosphere.]{.underline}

[ Another very interesting fact is that the size of the magnetosphere,
the distance from the center of the planet to the south polar magnetic
pulse, and the magnetic pulse is the surface that separates the solar
wind cloud mass from the magnetospheric cloud mass is about
(unintelligible). The north (unintelligible) is about 6400 kilometers or
so. So we are talking about 60,000 kilometers which is actually
comparable to the radius of Saturn and Jupiter.]{.underline}

[ So at Earth, the whole magnetic (batter) is confined to a size that is
comparable to the size of Saturn.]{.underline}

[ At Saturn, the magnetic pulse system is about 25 Saturn radii. Really
this is over 200 Saturn radii. So the whole magnetic bubble around
Saturn the magnetosphere is much, much, much bigger. Actually, this is
the biggest volume around in the Saturnian system. So, understanding the
magnetosphere is really a very important thing.]{.underline}

[ The next viewgraph basically just shows a schematic of the Saturnian
magnetosphere with some of the elements, and this is - I'm talking about
the Viewgraph 84 now. And this is matter of a summary of what I said
that the magnetic bubble is - the state of the magnetic bubble is
basically determined by the fact that the solar wind is streaming from
the upstream direction. The day side magnetic pulse is about 25 Saturn
radii from the planet. And Titan is orbiting at 20.]{.underline}

[ So Titan is orbiting just inside the magnetosphere. And this is a very
important factor in basic (unintelligible) the density of ions that
originates from Titan. And I will talk about it a little bit
later.]{.underline}

[ Inside the magnetosphere, there is - there are various typical plasma
phenomena like ring current and aurora phenomena, I will talk about them
a little bit later.]{.underline}

[ The mass source - the main mass source regions is the
(unintelligible), the rings, and, of course, especially
Enceladus.]{.underline}

[ And then there is the magnetospheric tail and this extends - to a very
large extent. So a very long distance is several hundreds and even
thousands of Saturn radii. Then you can even measure the presence of
ions originating in the Saturnian system.]{.underline}

[ If you go to the next slide, here I just summarized some of the main
discoveries this year that I am going to talk about.]{.underline}

[ The (unintelligible) from Enceladus sphere - the magnetosphere,
developed a neutral. And when the neutral becomes ionized, they must
load the (inner) plasma.]{.underline}

[ Mass loading actually means that the newly created ion must
accommodate the plasma flow and therefore they are accelerated to the
general plasma velocity. And this, the energy and momentum for this
acceleration process must come from somewhere and it comes from the
ambient plasma. And this process is called mass loading.]{.underline}

[ So Enceladus is the main plasma source and we made a lot of progress
in understanding how this works.]{.underline}

[ The huge surprise this year from the point of view of plasma science
was the discovery of very heavy positive and negative ions in the upper
atmosphere of Titan, and I will talk extensively about this on the next
few new graphs.]{.underline}

[ And this is really why it's so much fun to be exploring (class mix)
and because this is a surprise and it's fun to figure out about what's
going on.]{.underline}

[ There were (field aligned) plasma flows discovered along magnetic
field lines and these plasma flows are strongly associated with aurora
phenomenon.]{.underline}

[ And finally, Kevin was talking a little bit about the rotation rate -
the radio rotation rate of Saturn. And as I will discuss, the heavy the
mass load of inner plasma (field), the plasma in the inner magnetosphere
is the process that creates the things - the variation in the rotation
rate and the discrepancy between the radio rotation rate and the
planetary rotation rate.]{.underline}

[ So, just to kept this together. The magnetospheric plasma sources and
things at Saturn are Enceladus as the primary plasma field. Titan and
especially nitrogen from Titan because the main constituent emanating
from Titan. But nitrogen is a minor constituent in the magnetosphere
mainly because Titan is orbiting so close to the magnetic pulse that the
nitrogen from Titan is very, very rapidly loss from the
system.]{.underline}

[ And of course there are other plasma sources but they are just not
helping to understand the delicate balance in the system.]{.underline}

[ And the primary loss mechanism is the so-called interchanging
stability than heavily mass loaded magnetic flux tube. These are
magnetic flux tubes containing a lot of heavy Saturnian ions, change
place with light and empty magnetic flux tube. And this is the process
through which the plasma is basically emptied from the Saturnian
magnetosphere.]{.underline}

[ The cartoon on Slide 87 basically just summarizes the role of
Enceladus as the main plasma source. And this is a very nice cartoon
basically showing that Enceladus as it rotates around Saturn is a very
major source of primarily water. And these water molecular gas rapidly
ionize and they form the major plasma source of water group ion. These
are water ions or OH radical ions oxygen ions. These are 16, 17, 18, and
sometimes, in the vicinity of Enceladus, (HCO plus) is the dominant ion,
so mass 19 is also right upon them in the Saturnian
magnetosphere.]{.underline}

[ Slide 88, so the discovery of the negative ions in Titan's hemisphere.
Now, probably most of you are not very familiar with the visualization
methods of the plasma instrument so let me just try to explain what you
see.]{.underline}

[ These are time, energy and flux diagram of negatively charged
particles. As the Cassini slide through the upper atmosphere. Titan, in
this case, is at an altitude of about 1000 kilometers.]{.underline}

[ Now, I'd like to mention that Titan has a very dense atmosphere. At
the surface, the pressure is about 4 tons higher than the pressure at
the surface of Earth. So this is a heavier atmosphere than Earth. Its
composition is very different than the Earth's atmosphere. It's full of
hydrocarbon, methane, and heavier hydrocarbons.]{.underline}

[ So, at 1000 kilometers, which is just below the (homo pulse), the
(homo pulse) is 1100 to 1200 kilometer. The (homo pulse) is the region
below which atmosphere and ionosphere is very well-mixed. The
concentration of - the relative concentration of each piece is pretty
much constant below this.]{.underline}

[ Above the (homo pulse) is the so-called heterosphere. And the
heterosphere, different species have different scale heights. Therefore,
the composition rapidly changes latitude.]{.underline}

[ So in the upper homosphere - and the upper homosphere (mirrors) that
this is still a well-mixed atmosphere so it's relatively
dense.]{.underline}

[ This instrument - the electrons sensor - the electron spectrometer on
Cassini basically measures the energy (unintelligible). This is the
vertical axis versus time. And the color then - color indicates the
number of (cons), the particles (unintelligible).]{.underline}

[ Now, the velocity of this ion is pretty low, therefore the relative
velocity between the detector or the spacecraft and the atmosphere is
pretty much the orbital velocity of the spacecraft.]{.underline}

[ So using this fact we basically can use the electron spectrometer
basically as a mass spectrometer in which we can measure the masses of
the individual particles, not only (unintelligible).]{.underline}

[ The surprising thing is that you see these vertical stripes, which I
marked as negative ions. These are particles with energy per charge in
the 10 to 100, 10 to 1000 region. This means that these are negative
charges where the energy per charge or master charge of the particles is
in the 10s, the 100s, and even in the 1000s in units of atomic
mass.]{.underline}

[ So these are particles with masses of about 1000 tons the mass of a
proton and that have charges between a single electron and about five
electrons. And these particles were repeatedly detected on various
flybys \-- T16, T17, T18, and T19.]{.underline}

[ So this is a steady (unintelligible). This came as a huge surprise.
Nobody expected it. I mean, there were no theoretical predictors
whatsoever. So, this was a big shock for the plasma science
community.]{.underline}

[ The next viewgraph, Viewgraph 89, shows some of the heavy neutral
measures by the ion nuclear mass spectrometer and some of the heavy
ions. And it shows that the - that heavy neutrals are heavy organic type
molecules and the heavy ions are the ionized versions of the - these are
the positively charged ions.]{.underline}

[ On the right hand side, there is a line flow that shows the number of
particles per unit volume at about - at an altitude of 1000 kilometers
as a function of mass. And you can see that these are the negatively
charged particles. You can see that the negatively charged particle
density actually peaks around 300 and then that easily drops. This means
that these are very, very large particles.]{.underline}

[ Actually what's happening is that, as it was pointed out in a recent
paper by Hunter Waite and co-authors, Hunter is the lead of the Ion
Neutral Mass Spectrometer team.]{.underline}

[ Heavy ion or heavy aerosol formation is taking place in the upper
(homo pulse) - the homosphere then at 1000 kilometer. And this particle
is very - readily can acquire extra electrons. So this forms heavy
negative ions, which actually are negatively charged
aerosols.]{.underline}

[ The positive ions are the natural, very heavy particles that these are
the organic molecules that are formed in the atmosphere. They are
relatively - they are mixed at all altitudes and they acquire positive
charges. And these are the heavy positive ions.]{.underline}

[ Slide 90 shows the (unintelligible) profile obtained as a combination
of several Titan flybys. The red square shows heavy negative ions and
the blue dot show basically the positive ions between 10 and 100 atomic
mass unit.]{.underline}

[ One can see that the maximum density of the heavy negative ions, the
heavy negative aerosols can exceed 1000. And the peak altitude is
between 950 and 1000 kilometers.]{.underline}

[ So this is still a huge surprise, to some extent a mystery and I can
tell you that most of the modelers and their assistants on the plasma
science team are feverishly working on models to understand the
phenomenon.]{.underline}

[ So the next viewgraph basically just summarizes some of the
(unintelligible) and these are how do we make positive ions, what keeps
them afloat at these high altitudes in the atmosphere, what are the
current carriers and the negative charges are in the heavy
(unintelligible).]{.underline}

[ So this is work in progress and stay tuned, I'm sure there will be a
lot of fun things that's coming out.]{.underline}

[ The next topic I want to talk about very briefly is particles that
create the aurora. This is on Slide 92.]{.underline}

[ And for the first time, we measured by various instruments, the
(unintelligible) currencies are electric current and other big particle
streams that move along the magnetic field line that connects the aurora
region and these heavily charged particles, primarily electrons create
the aurora. And on the left side of the slide, you can see three aurora
images made by the HST telescope.]{.underline}

[ The next slide, Slide 93, shows some of the details of these
measurements.]{.underline}

[ On Orbit 34, Cassini crossed the magnetic field line that's connected
to aurora regions, at distance from the center of the planet of about
four Saturn radii.]{.underline}

[ On the right hand side you can see the plasma (unintelligible). This
is again frequency, time, spectrogram similar to the spectrogram I
showed before. So time is on the horizontal axis. The frequency of the
wave is on the vertical axis and the color basically represents the
intensity of the wave at a given frequency at a given time.]{.underline}

[ The aurora is the (thread three) between 10 and 1000 hertz near
(close-up approach). And this (close-up approach) was exactly when the
spacecraft intersected the aurora magnetic field line and this aurora is
associated with field lines - streaming particles that will hit the
atmosphere and generate the aurora. So this is really not unexpected but
very important discovery.]{.underline}

[ The next shows the (unintelligible) - the next viewgraph, Viewgraph
94. So the actual particle of that measurement, this scientific - these
are again spectrogram and you can see that there are - on the frequency
diagram, there are - the aurora beams between about 10 and a few 1000
hertz. And there is an insert showing the particles fluxes which
coincide with these (three).]{.underline}

[ So these are actually the aurora that is coming from the particles and
the particles streaming down the field line.]{.underline}

[ The next viewgraph, Viewgraph 95, deals with a different subject and
this is a subject that Kevin was talking about a little bit that one of
the mysteries that we are still trying to figure out is that the radio
rotation rate of Saturn and the (unintelligible) seem to be
different.]{.underline}

[ This viewgraph basically summarizes a number of measurements from
Voyager to Cassini, optical measurement and radio measurement. And the
most important thing is that the minimum rotation rate, the slowest
rotation rate basically comes from the radio rotation measurement. And
this is also varying as time goes on, so even the radio measurement, the
radio rotation rate is not constant. It's slowly varying.]{.underline}

[ And Kevin indicated that the emerging consensus is that basically the
delay or the slowdown of the radio rotation rate is due to some kind of
plasma process.]{.underline}

[ And some of the models are emerging that are able to explain this
process. And one of these models is schematically shown on Viewgraph 96.
This is the so-called rotational slippage model, and I don't want to go
into much details of this pretty complicated plasma physics
process.]{.underline}

[ But the bottom line is that the plasma that is primarily originating
from Enceladus is fundamentally moving outward in the equatorial plane
mainly because of the very fast rotation of the planet. The centrifugal
force focuses most of the mass to the rotational equator.]{.underline}

[ This mass needs to be as it moves out, its angular momentum must be
increasing if it wants to keep up with the rotation of the planet
because the rotation rate remains the same as the rotation radius
increases that for the plasma needs to be accelerated. This energy must
come from somewhere.]{.underline}

[ And through the electromagnetic coupling between this plasma region
and the high latitude Saturnian ionosphere, the energy's actually coming
out of the planetary rotation or the rotation of the high latitude
ionosphere.]{.underline}

[ So, since the radio emission is mainly originating from the high
latitude, the difference between the planetary rotation and the radio
rotation is an indication of the amount of mass that is produced by
various processes in the inner magnetosphere of Saturn and that is
moving outward various - through various processes and that is energized
more and more by this rotational interaction.]{.underline}

[ So this is where we are with the understanding of the rotation rates
and these are some of the major highlights of the Year 3 discoveries.
And, you know, the fun is still going on as Fred Scarf, one of the
founding fathers of planetary plasma physics, said many years ago, "Half
of the fun is just to be on orbit." And with Cassini, we are having more
of - more than half the fun from being in orbit. So I'm ready to take
questions.]{.underline}

[Trina Bay: Okay. Do we have a question for Tamas?]{.underline}

[ No questions? Well, that's - we're running very late. But of course,
the NASA - those people would never kick us off the line, don't let us
run over as long as it can. Hopefully, Jeff is still on
line.]{.underline}

[Jeff Cuzzi: Yeah, I'm here.]{.underline}

[Trina Bay: Thank goodness, Jeff.]{.underline}

[ You're our last speaker for today, and like I said, the telecon people
are not going to turn it off, so you can - as quickly as you
like.]{.underline}

[Jeff Cuzzi: Well, I'll try to go very quickly because I understand
people often have other commitments. So, and I'm going to focus really
on the third year of Cassini.]{.underline}

[ And I also suspect it's a regular audience so I'm not going to spend a
lot of time on reviewing what the rings are. I think most people that
are on kind of know that, that the first chart in here that Trina
provided somewhat summarizes all that. So let's just go right to the
next one, Slide 98.]{.underline}

[ For the last - during the second year of Cassini we spent the whole
year in geometry somewhat like this, we're in equatorial orbit so it
wasn't a real exciting year from the standpoint of ring scientists but
it gives you have nice indication of exactly how flat and thin the rings
really are.]{.underline}

[ In fact, exactly how flat and thin the rings really are is on the
order of (ten conveners) and that's one of our important scientific
questions, which I'm going to get to a little bit later.]{.underline}

[ Let's go on to the next slide.]{.underline}

[ In Year 3, this indicates a schematic of our orbit. This was already
discussed.]{.underline}

[ Pretty much for the whole year, we started off the year kind of going
up into highly inclined orbits and the orbits just got higher and higher
until we were at latitudes above the planet of around 60 degrees. And
then towards the end of the year this summer or so we're pretty much
back down recently, more or less on the equator point.]{.underline}

[ So it's a very, very exciting time for us. We did observations that we
have never done before, and we're frantically working on all that data
and all the results are really not yet in. But I'm going to just set
some highlights.]{.underline}

[ On the next slide, Slide 100, kind of - one of the things that emerged
this year is the D-ring which is an almost invisible ring that's between
Saturn's atmosphere and the C-ring, which you can also hardly see in a
lot of pictures. The D-ring actually was really discovered by Voyager
but Cassini has really advanced our understanding.]{.underline}

[ One of the really cool things that emerged about the D-ring this year
is it looks like it's got a warp in it. And the top image there is a
little bit hard to interpret. But if you look out at the turnaround
points, you know, the furthest points to the right, you see that they -
there's sort of a jag or a jog or a zigzag in them right at the farthest
distance from Saturn.]{.underline}

[ That's exactly what you would see looking at the schematic below if
you had a very optically thin almost transparent ring, which we know the
D-ring is. And it had a little ripple in it and that's what you would
see. You'd see some regions brighter than others.]{.underline}

[ And the radii where the brightness peaks is offset between the near
side and the far side as you're kind of looking at the other side of the
hill if you like.]{.underline}

[ So we actually think this is tilted. Inside the blue square shows a
high resolution image of a tiny piece of this region showing these very
regular patterns which have now been observed both from Cassini and also
from stellar occultation by Hubble almost 20 years ago or maybe only ten
years ago. Where the spacing of those ripples is different.]{.underline}

[ So what we think is something happened, something actually hit the
ring not that long ago, maybe in 1984 or so, kicked up a tilted sheet of
material that's out of Saturn's equator point and as this stuff
(recesses) around Saturn at different rates depending on where it is, it
starts to wrap up like a spiral and that's what we're seeing and we can
actually measure the wrapping rate.]{.underline}

[ So we know this catastrophic collision, whatever it was, happened at
about 1984. So very dynamic stuff going on there.]{.underline}

[ Let's go to the next slide.]{.underline}

[ Slide 101, this is actually a movie. Anybody who - I won't go over it
because the fun of it is in the movie, it's called, ring_crossing_movie
and you download a very nice graphic that was put out by the imaging
team.]{.underline}

[ The cool thing about it is if you play it, you can see when the
spacecraft goes to the lit side through (edge on) ring. They pretty much
disappear. And then we come up on the unlit side of the ring and the
ring looks completely different.]{.underline}

[ So that's kind of fun, but the fun is in the movie.]{.underline}

[ So the next slide, 102, gets back to discussion well, how really thick
are the rings. There's a cartoon, what we call a classical ring model,
what we used to believe 20 years ago, shows the particles that are, say
centimeters to meters in size and they're very - they're spread out
vertically over a thickness of maybe 100 meters or so.]{.underline}

[ The particles are widely space and they're widely spaced because
they're moving with respect to each other. The speed may be 1 centimeter
per second even though they're going around Saturn at 15 kilometers per
second, you know, just like the cars on the freeway are just moving in
relative sense, relatively slowly compared to each other.]{.underline}

[ Okay, so this has some observational implications is that these
particles will cast shadows on each other.]{.underline}

[ And the next slide shows the observation that we were planning on
using and now have used to constrain the thickness of the ring called
the opposition effect. It was observed from the Earth almost a century
ago, realized that the rings got very, very bright when the Sun, the
Earth and the rings are all in a line, that is, just like you're flying
in an airplane and you're looking out the window and you see a shadow of
the plane on a cloud or in the trees and you notice that that little
patch of trees is much brighter than the surrounding patches of trees
because you're not seeing any shadows, all the shadows are covered up by
the lit leaves. If you look a little bit further away in angle, all of a
sudden looks dark. That's the opposition effect.]{.underline}

[ Here we're seeing the little bright spot there is actually the Sun in
direct back scatter behind our head, behind the spacecraft and you look
a little bit away from the Sun, it's a little bit darker.]{.underline}

[ So exactly how sharp that bright spot falls off an angle was going to
tell us whether or not this opposition effect was really the
explanation. And we can actually watch the Sun move through the rings
and then measure how thick the rings were everywhere, not just on an
average, everywhere. So it's a very important observation.]{.underline}

[ So the next slide shows basically a similar picture. This is one of
these blurry pictures from the VIMS instrument which doesn't have as
good a spatial resolution that cameras do. But what it does have is a
lot better sampling of different wavelengths so it can be used to look
at this opposition effect in wavelengths where the rings are dark and in
wavelengths where the rings are bright.]{.underline}

[ In fact - and then measure the shape of that opposition effect in both
places, in both wavelengths. And what we got was a big surprise which is
that the width on the right hand plot there, the width of this sharp
spike you see over on the left is actually larger over on the right in
the wavelength where the ring particles are dark and it's actually quite
narrow in places where the ring particles were quite bright and that's
exactly the opposite of what the shadowing effect would
predict.]{.underline}

[ So what this tells us is that it's another phenomenon, probably,
that's causing this opposition effect. It's called coherent back
scattering where the photons hit the surface and they actually ravel
around in the surface of a particle and then they come back out again
and they can interfere with each other. And that theory actually
predicts that the shape would be sharper in the regions where the
albedos are higher.]{.underline}

[ So this kind of tells us that while we're not really seeing shadows at
all, we can't really measure the volume density of the rings at
all.]{.underline}

[ And the next slide shows you what this probably implies about the
vertical structure of the rings that instead of being many particles
thick, they're probably pretty well-packed and flattened down into the
equatorial plane of Saturn because of all these collisions which are
slightly inelastic, they absorb energy and the particles just kind of
settle down. So this is a very interesting result that just came out
this year.]{.underline}

[ And so now, what we have is a situation where the rings being so
flattened and dense with the collisions being so slow even their weak
gravity starts to play an important role in their dynamics. That's
illustrated in the next slide.]{.underline}

[ There's a movie associated with this slide, which I also - those of
you who might have downloaded already can play it. I'm just going to
have to describe it that these - this looks - thing that looks like a
field of uniform particles here, once you turn on the gravity and let
everything orbit, these things start to coalesce into strands, aligned
strands of particles that then get stretched and torn out by Saturn's
tides.]{.underline}

[ So sort of at the bottom of this slide it gives you an indication of
what that might look like. These strands are tilted with respect that
that is a light in angle with respect to the direction to
Saturn.]{.underline}

[ So, depending on the longitude that you look, they're aligned
differently as you see them. So the upper left you see - this is a slide
from the UVIS experiment that watches stars go by behind the rings. That
yellow streak is actually a star going behind the rings.]{.underline}

[ And it doesn't always go right through the middle that way, sometimes
they follow these other dashed lines like indicated by one or two. And
depending at the angle on which it goes by behind the rings, you get
these different orientations of these wakes. So when you measure the
blockage of that starlight by the rings it varies depending on what your
geometry is.]{.underline}

[ So now, because you've got this varying geometry, these stars also
come in at different, you might say, elevation angles; some of them are
coming in rather steeply compared to the ring; some of them come in at
rather grazing incidents.]{.underline}

[ The UVIS instrument and also the VIMS instrument, which takes stellar
occultation, now are creating and building up what we call a 3D CAT scan
of the ring. So with this kind of CAT scan, watching the starlight
coming through at all these different angles, we can see structure
that's ten times finer than any of the best camera images. And what we
can learn from that is sort of indicated on the next slide.]{.underline}

[ This is - the blue line there shows the total optical depth or the
amount of material in - just in the A-ring or just the outer or A-ring
of Saturn.]{.underline}

[ The green symbols show you the amount of material that's in these gaps
between these fingerlike strands, and you can see that's pretty low.
It's - and it varies a little bit from place to place. That's kind of
cool. You know, why does it go up and why does it go down in some
places?]{.underline}

[ And the red symbols indicate because now we have this 3D CAT scan, we
can actually say something about the thickness, the vertical thickness
of these thick regions, the wakes themselves compared to their width,
their radio width. And what those symbols - the red symbols show is that
they kind of get thicker and puffier as you go out to the rings and then
maybe - it looks like they get flatter again as you go away out in the
ring.]{.underline}

[ So that's a very interesting result as well on the list here. So we're
really starting to get us a look in at the ultra fine micro scale
structure of the rings.]{.underline}

[ Next slide kind of shows now - the UVIS is continuing to map out the
rings in general and not just the A-ring. Now this is the whole ring
system here.]{.underline}

[ The A-ring is on the outside. It's mostly blue. And we have the
Cassini division which is yellow and the bright stuff and all through
the middle part of the pictures are the B-ring and the C Ring is over in
the left with sort of the undulatory structure and the sort of narrow
band.]{.underline}

[ So the colors indicate sort of where you have more wakes and where you
see a lot of blue, you see a lot of this wake activity where you've got
a lot of these strands and a lot of fragmentation going on in the rings.
And the yellow regions are places where you just don't have quite as
much.]{.underline}

[ So we're really starting to map this out.]{.underline}

[ The optically thinner regions like the C-ring and the Cassini division
don't have much. That's not hard to understand because there's not very
much self gravity there.]{.underline}

[ The B-ring, the outer part of the B-ring where it's very, very thick
also doesn't have very much, it's probably because it's just - particles
are just too jammed in for anybody really to move anywhere. But the
inner part of the B-ring actually shows as much of the wake activity as
the - almost as the A-ring does and that's a brand new result this year
as well.]{.underline}

[ The next slide actually shows a few more kind of interesting things. I
think in the interest of time, I'm going to just skip right over this
slide and go on to the next one.]{.underline}

[ Okay, so here's a - this beautiful picture that was shown before by
Kevin. Now, we're looking down at the north side of the system from
about 55 or so degrees elevation angle.]{.underline}

[ The north pole is in the shadow. The Sun is on the other side,
lighting up the south face of the ring and we're looking through. So, as
Kevin said, where there's the most amount of material in the B-ring
there that actually looks rather dark.]{.underline}

[ So just being able to observe in these new - these geometries have
never been seen before by anybody, not Voyager or anywhere, so we're -
and we're just getting started analyzing them with models of scattering,
which, as you might imagine, are going to be very complicated by all
these stranded wake-like structures where the brightness varies in
longitude. So that's an adventure that's just getting
started.]{.underline}

[ The next slide shows a close up. In both these slides, they're color
pictures and you get a sense of the sort of tawny tan color of the rings
in both these pictures.]{.underline}

[ If you're looking in a low light situation, you can kind of tell in
this picture that it's the Cassini division, it's in this - runs right
through the center of the picture. And that's a little bit more neutral
gray in color than the tawny looking A-ring on the lower left or the
tawny looking B-ring on the upper right.]{.underline}

[ We've known this for a while that the color of the particles in the
rings is kind of different from place to place. But images like this one
are really going to allow us to nail that down. It's kind of a pretty
image.]{.underline}

[ If you look at - there's a sort of a narrow ringlet in the outer dark
part of the Cassini division and you can maybe tell it's got a slightly
different color to it. Just keep that in mind and I'll get back to that
in a few slides.]{.underline}

[ Okay. One of the interesting results of the last year is we're really
seeing a lot more activity in these gap regions we're studying. There
are several empty gaps in the rings. This is a picture of the A-ring, in
the middle is the Encke gap which is about 300 kilometers wide, and then
to the lower left there's a dark gap that's called the Keeler gap that's
only about 30 or so - 40 kilometers wide, then we have a bright bend in
the edges, the A-ring there.]{.underline}

[ In the Encke gap you can see all these bright ringlets. In fact, if
you look closely at the outer edge of the gap, you can see a broken sort
of discontinuous ring with a very, very near the outer edge. This one,
from my knowledge, we've never seen before. I mean, I've seen ringlets
kind of all over of this gap, including Voyager saw one very near the
inner edge of the gap, the first time we've seen one that near the outer
edge of the gap.]{.underline}

[ So we know that there is a moonlet in that gap it's called Pan. It's
what keeps the gap clear. But there apparently are a number of moonlets
in that gap because these ringlets don't come from nowhere; they
probably come from just stuff getting busted up every now and
then.]{.underline}

[ So it's a very interesting situation. The imaging team is continuing
to look for more stuff in there.]{.underline}

[ The next slide shows a close up of that outer gap, which I just showed
you, called the Keeler gap, a much more narrower gap. Cassini discovered
a little moon in there called Daphnis. This is a picture of Daphnis.
These pictures are from this year, but Daphnis was discovered awhile
ago.]{.underline}

[ But we're really starting to get a better handle on Daphnis by
tracking it around. We don't know if its orbit really is circular or
eccentric in that whether it's circular or eccentric might help us
understand why the ripples that it causes and the edges surrounding it
are so spiky as they are.]{.underline}

[ What's happening here is the moon is just perturbing that surrounding
ring material. Remember I said the rings, because of the many particles
and their general collisions, have the property of a fluid so here we
have like a river or stream flowing over a rock in the stream. There's a
ripple downstream from the rock. The ripple sticks to the rock, the
water flows right through the ripple.]{.underline}

[ So here we have ring fluid, let's say in the right hand side, flowing
upwards past Daphnis and then the ripples develop up, you know, above
Daphnis. On the other side of the gap, the ring material is flowing
downward, passes Daphnis and the ripple. But you see the ripples are
different on either side so that's kind of curious so that's something
that we need to understand dynamically.]{.underline}

[ Okay, next slide.]{.underline}

[ Even more bizarre I think is that the structure we're seeing in the
F-ring, which I'm sure most of you know, is the stranded ringlet that
lies outside - just outside the A-ring, just outside the main rings.
It's got a main strand. It's got a few subsidiary strands.]{.underline}

[ Some of the best stuff we got this year, like these images here which
show very high resolution pictures of the F-ring, are just full of
action and just clearly lots of stuff going on. Things are colliding.
You're seeing little clumps with trails following them. This stuff
almost never repeats; it never looks quite the same way
twice.]{.underline}

[ We know that during last year, Cassini actually discovered a little
moonlet that crosses through the F-ring, sometimes you see it on the
outside; sometimes you see it on the inside.]{.underline}

[ So this whole region is just, you know, a fireworks display and stuff
going on, very interesting to track all this material.]{.underline}

[ Next slide shows a result that the UVIS team got with one of their
stellar occultations. The upper right hand insets there show UVIS
stellar occultation that went through the F-ring. And just by chance,
they - it looks like they actually caught one of these little moonlets,
that's what the really small inset shows, light going down to zero over
about 600 meters. So this is, you know, a little - getting a little
small even for the cameras to see but UVIS got one.]{.underline}

[ So now as we start building up more and more of these events, we can
start to look at the size distribution of stuff in around the rings. The
larger chart shows numbers of particles, their function, their size, the
line goes from the upper left to that empty box. Those are sort of the
main ring particles from say centimeters in size, 10 meters in
size.]{.underline}

[ And then you see the steeper lines that go down to the bottom right.
Last year, we discovered these objects that are in the A-ring called
Propellers and it looks like they're lying on sort of a steeper line
that heads towards these triangles at the bottom which are actually the
movements of Pan and Daphnis.]{.underline}

[ So we think there are actually, you know, a whole distribution of
objects, different sizes in - refer to a football field size \-- 100
meters, a couple of hundred meters sprinkled somewhat through the main
ring.]{.underline}

[ But this object that UVIS discovered, which is this gray box labeled
Left Ring with these red circles, looks like that's somewhat off the
line. So there's probably a whole different population of little
moonlets sitting out there in the F-ring just waiting to be
discovered.]{.underline}

[ Okay, next slide.]{.underline}

[ This is a schematic showing the diffused parts of the ring system. At
the top is Enceladus and the E-ring. The bottom shows the G-ring with an
arc in it; you can't really see it very well.]{.underline}

[ The next slide actually is a movie, but I'll have to leave it to you
that have the movie to be playing the movie. You can actually see this
arc move right through your field of view.]{.underline}

[ So that's a brand new discovery.]{.underline}

[ Something has recently happened in the G-ring that's now starting to
spread out and maybe that's what preserving the G-ring.]{.underline}

[ Okay. Next slide is a beautiful picture. I'll say a little bit more
about this.]{.underline}

[ It's been shown before, but this was really a unique measurement that
Cassini did this third year. We were able to take pictures from way, way
far away from Saturn during the time when the Sun was behind the planet
for hours and hours.]{.underline}

[ So we could do big maps of the system with narrow angles and wide
angles and at scattering angles that are much, much smaller than we can
ever see any other way because we can't look to folks (unintelligible)
the cameras.]{.underline}

[ So here because the Sun was behind the planet, we could look at the
very high phase angle, this is what people call the Windshield Effect
like when you're driving into the Sun is when you finally notice how
dirty your windshield is because all the little particles that are the
same size of the wavelength of light kind of focus the scattered light
in the forward direction making them much more visible.]{.underline}

[ So here we can really see the E-ring very obvious here. The G-ring is
also quite obvious as is all kinds of little fine dust that's sprinkled
all around in the main ring. It's a beautiful picture.]{.underline}

[ Next slide shows - of course VIMS can do this too but they're all at
different wavelengths. So, I see the same general thing, but new
discoveries by comparing the behavior between VIMS and ISS.]{.underline}

[ Next slide is I think especially interesting result. This is now the
Cassini division again.]{.underline}

[ I've showed you a picture before of the Cassini division where I
pointed out a ringlet that you could barely see in the outer part of the
Cassini division. It's this picture on the right only stretched
around.]{.underline}

[ So here on the right - on the left, showing the same region. This
picture on right black in the left, the black and white picture shows
this ring within the outer part of the Cassini division that you could
almost never see, only in this geometry at high phase angle, it's the
brightest thing in the field.]{.underline}

[ So that tells you this little ringlet is just full of dust and that's
actually supported by the image on the right where this little - faint
little ringlet is also very blue. Well, we know that blueness is a
characteristic of tiny particles.]{.underline}

[ So here we have clearly a very strong case for some rings that we
never saw before, Voyager never saw it. In fact, it might not have even
been there when Voyager went by. Cassini never saw it in the early part
of the mission and now all of a sudden it's just knocking our eyes out.
So another kind of evidence for time variability in the ring \--
something happened there.]{.underline}

[ Okay. This picture's been shown before so I'm not going to - let's go
on to Slide 122. And I want to point out where most of you, I think,
know what spokes are, where Voyager saw lots of them, they've been quite
rare with Cassini, but we are starting to see more of them.]{.underline}

[ The explanation for this is that when the Sun - when the rings are
wide open to the Sun, the flecks of sunlight charges up the rings,
ejects electrons on the rings so the rings get positively charged and
all these electrons form a cloud around the rings so that's all negative
clouds so there's electric field between the rings and the surroundings.
If any little dust particles gets kicked up into this electron cloud, it
gets charged and it gets sucked right back down on the ring like an
electrostatic precipitator they use in smokestacks.]{.underline}

[ But as we now are going toward Saturn's equinox where the Sun is
starting to set on the ring, we're going to see more (spot), and we are
seeing a few more as is indicated here.]{.underline}

[ I also want to point out in this picture some of you might be able to
see some kind of feathery irregular (as mutual) variations in the rings.
It's not quite regular as you go, you know, from left to right; some of
the structure seems to be sort of irregular. This is a new thing, next
slide shows that too.]{.underline}

[ As we get more and more of these really high resolution pictures that
we're getting, you can see sort of in the bottom left - bottom center
band that goes through (unintelligible). There's actually fluctuations
in the brightness as you go around an angle.]{.underline}

[ So this stuff is just flopping and waving around in various ways \--
very complicated. Nobody has much of a theory about this yet. We're
going to need a lot more data to understand that. New things from this
year though.]{.underline}

[ Okay. So final, just to sum up.]{.underline}

[ It was a big year for us. We had our highest ever elevation viewing.
Lots of our best (in tour) observations, which really haven't even been
analyzed yet because people are still working on them.]{.underline}

[ This ultra high phase angle geometry that we got - that we are not
going to get again \-- not even in the extended mission unfortunately
\-- revealed all kinds of new rings and ringlets in the main
ring.]{.underline}

[ We've been constraining the subgravity wakes. We've got the new
regular structure. All this dynamic stuff going on in the F-ring, in the
D-ring, this collision that went back to 1984, collisions are going
now - going on now today in the F-ring \-- a very, very dynamic
situation.]{.underline}

[ So that's all I have to say.]{.underline}

[Trina Bay: Great Jeff.]{.underline}

[ Okay. Do we have any questions on the ring?]{.underline}

[ Okay. Well, in an effort to move things along, I will just very
quickly do the last few slides which is just a nice wrap-up of some fun
facts. I'll just leave it there for you to read \-- we've got how many
orbits, how much data was returned from the spacecraft that sort of
thing, how many maneuvers did we do?]{.underline}

[ On Slide 128 is one of my favorite statistics which is how many miles
did we travel this last year. And we traveled 89 million
miles.]{.underline}

[ In Year 3, we used only 21 gallons of fuel so our miles per gallon is
about 3.5 million miles a gallon.]{.underline}

[Woman: Oh my god.]{.underline}

[Trina Bay: Yeah. One of my favorite statistics.]{.underline}

[ Let's see, on Slide 129 we have a nice summary of what to expect in
Year 4 and just sort of want to draw your attention to some - two sort
of very exciting things.]{.underline}

[ The first one is that we have our one and only targeted Iapetus flyby
of the mission and of the extended mission also; we're not planning one
in the extended mission. So that's in September of this year and that
should be very exciting and hopefully, we'll see some terrific stuff
come out of that flyby.]{.underline}

[ And also, we have a couple of other non-targeted icy satellite flybys.
Non‑targeted just means we don't do maneuvers to control the spacecraft;
we just let the spacecraft fly by. But both of these are less than
10,000 kilometers so that makes them very close and very interesting to
the scientist.]{.underline}

[ We have Rhea on August 30 of this year and we have Epimetheus on
December 3 of this year.]{.underline}

[ And then finally, we have the last targeted Enceladus flyby of the
prime mission on March 12 next year.]{.underline}

[ But for most of Year 4 what we're going to be doing is we're going to
be increasing the inclination.]{.underline}

[ Jeff just mentioned how exciting the observations were for rings when
they got up to 50 and 55 degrees above the ring plane. Well, at the end
of the prime mission, we're going to crank up the inclination up to over
70 degrees above the ring plane and that is, in fact, we will in the
mission at our highest inclination.]{.underline}

[ So that quickly sort of is our summary of what to expect in Year
4.]{.underline}

[ The last slide or the next Slide 130 is just a nice summary \-- that
same one that I showed early, the mission planners that shows the high
inclination towards the end and also highlights the Iapetus flyby, sort
of our two big highlights.]{.underline}

[ Slide 131 is the list for your reference of the targeted flyby
summaries for Year 4.]{.underline}

[ And then the final slide of this fantastic presentation, Slide 132, is
just our Web site to remind everybody to go and take a look at our Web
site. We try to update it every day with something new and exciting that
the Cassini mission is doing or learning.]{.underline}

[ And with that, we'll go ahead and see if there any final
questions.]{.underline}

[Man: Yes, I have a question.]{.underline}

[Trina Bay: Sure.]{.underline}

[Man: Where is the CHARM audio file that was mentioned very early in
this presentation? I couldn't find it.]{.underline}

[Trina Bay: The CHARM audio files are online. They are very near the PDF
that you downloaded. They usually become available about 24 to 48 hours
after the telecon has occurred. And so, if you go to the place where you
downloaded the PDF, you'll see in the column right next to that the
audio file.]{.underline}

[ And if you have any trouble...]{.underline}

[((Crosstalk))]{.underline}

[Man: ...archive of older ones?]{.underline}

[Trina Bay: Yes, we have an archive of it.]{.underline}

[((Crosstalk))]{.underline}

[Man: I couldn't find them.]{.underline}

[Trina Bay: Yes. So if you take a look at the invitation that you got
originally, at the bottom is some information for how to log in to the
password-protected site.]{.underline}

[Man: I got that.]{.underline}

[Trina Bay: That has all the old audio files and all the old PowerPoints
going all the way back to 2004. We only don't have audio files for the
first two or three CHARM telecons because we didn't realize how
important that was going to be so we didn't make a recording of
those.]{.underline}

[ And I would - of course, you just heard the three-year anniversary,
both the two-year and the one-year anniversary CHARM telecons were also
fantastic.]{.underline}

[Man: Another question.]{.underline}

[Trina Bay: Sure.]{.underline}

[Man: Which is the gas mileage thing, but have you done a confirmation
for the whole ten years roughly of the mission starting from
(unintelligible) all the way out?]{.underline}

[Trina Bay: I have not, but I can add that to my list of things to do
because I know just how to find that information.]{.underline}

[Man: And then lastly, how did they do the 180-degree (flip)
(unintelligible)?]{.underline}

[Trina Bay: The 180 degree transfer is - so imagine that you are
orbiting Saturn in an ellipse that's off-center, so Saturn is sort off
to one side. And so, if you sort of - so imagine sort of your hand is
not in a circle but in an oval and Saturn is off to one side, what they
do is they crank the oval up high to about 50 degrees but while they're
doing that, they're making it more and more and more
circular.]{.underline}

[ And just at the moment, every time the spacecraft goes by Titan, it
always goes by Titan inbound to Saturn, so it goes by sort of maybe -
imagine it on the left hand side where the two are close. And if you
circularize the orbit, you can get to a point where the orbit of Titan
intersects both sides and at that point you sort of fix that side of it
and as you crank down, you let your other hand slide out, if that makes
sense. I was sort of doing it with my hands here in my
office.]{.underline}

[ But - so, if your left hand is fixed so the right in front of you and
your right hand just sort of off to the side, maybe 1-1/2 foot off to
the side...]{.underline}

[Man: (Unintelligible) rocket burn or...]{.underline}

[Trina Bay: What we do is we do a series of over almost 20 Titan flybys.
It's not - so it's not a single rocket burn, it's a whole bunch of
little ones that happen at each Titan flyby.]{.underline}

[ And we crank the orbits up to about 50 degrees. We circularize them
and then we crank them down but we go up with the petals on one hand and
we go down with the petals on the other. So that's what - where it gets
its name \-- 180-degree transfer.]{.underline}

[ Are there any other questions?]{.underline}

[ Well, I want to thank everybody for sticking with us. We went quite a
bit over today, but I know that the anniversary telecon is one of our
absolute most favorite from the listeners.]{.underline}

[ And I want to thank the scientists. They did a fantastic job and
taking their time out today to join us.]{.underline}

[ Our next CHARM telecon will be the last Tuesday in July. That's
Tuesday, July 31. We don't know what the topic is yet, but that
information will go out in an email as it always does.]{.underline}

[ And I want to thank everyone, in particular, the scientists for
joining us today.]{.underline}

[Man: You're welcome.]{.underline}

[END]{.underline}