HDTenEightyP/NetNews huggingface dataset:
From: caf@omen.UUCP (Chuck Forsberg WA7KGX)
Subject: Re: Heavy Boots
Organization: Omen Technology INC, Portland Rain Forest
Date: Fri, 31 Jul 1992 07:13:37 GMT

In article <1992Jul30.161658.26111@news.iastate.edu> partee@iastate.edu (Jonathan F Partee) writes:
>We read an article claiming that the average American does not know the 
>correct answer to the following question:
>
>If a pen is dropped on a moon, will it:
>A) Float away
>B) Float where it is
>C) Fall to the surface of the moon
>
>So a bunch of us TA's got together and gave our physics classes quizzes asking 
>this question.  Out of 168 people taking the quiz, 48 missed the question.

Oh dear.  I hope the crowd I took freshman physics with in '63 would
have done better than that, even without benefit of Apollo videos.

We all know gravity does not exist.  The Earth sucks.  Since
there is no atmosphere to speak of on the moon, the moon can't
suck.  Therefore those Apollo films of Aldrin stepping onto the
moon and astronauts hopping about in 1/6 - g were only special
effects exercises.  I saw a more accurate representation in an
airline advert showing luggage floating away from a lunar
astronaut (you have to be a real space cadet to get frequent
flyer awards on some airlines).

The question as written here does not specify Earth's moon.
My heavy dictionary has about 60 definitions for "drop".

Were any of your students sharp enough to choose a moon light
enough that one could drop the pen hard enough that its rebound
would exceed escape velocity?  It would have been a matter of
honor in my 3rd semester physics recitation section at RPI.

-- 
Chuck Forsberg WA7KGX          ...!tektronix!reed!omen!caf 
Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ
  Omen Technology Inc    "The High Reliability Software"
17505-V NW Sauvie IS RD   Portland OR 97231   503-621-3406
Newsgroups: sci.astro
From: STONE@Zeus.unomaha.edu (Travis R. Stone)
Subject: Addendum to Sidereal Time Algorithm
Organization: University of Nebraska at Omaha
Date: Fri, 24 Jul 1992 17:32:29 GMT
X-News-Reader: VMS NEWS 1.11

To convert GST (Greenwich Sidereal Time) to Local Sidereal
Time (LST):

  (i) Convert the GST (NOT the GST(0) I talked about in the
      previous post) to decimal hours;

  (ii) Convert your longitude (in decimal degrees) to decimal
       hours by dividing by 15;

  (iii) If your converted longitude is West, SUBTRACT it from
        the decimal-hours GST; if East, ADD it to the decimal-
        hours GST.

  (iv) Adjust the result so it lies in the 0-24 hour range
       by (a) subtracting 24 if the result is >= 24, or
       (b) adding 24 if the result is < 0.

Again...I hope this helps.

T.R. Stone
University of Nebraska-Omaha
From: bssbru01@uctvax.uct.ac.za
Newsgroups: sci.astro
Subject: Re: Galaxy Formation
Date: 28 Jul 92 14:38:07 +0200
Keywords: galaxy
Organization: University of Cape Town

In article <1992Jul27.145212.2616@newstand.syr.edu>, gjstephe@rodan.acs.syr.edu (Greg J Stephens) writes:
> I would like to know what are the conjectured differences that
> cause a galaxy to become a spiral, elliptical or irregular.

One proposed model for the formation of the different galaxy types depends
crucially on the relative magnitudes of the cooling-  and collapse 
time-scales for  protogalaxies. The cooling time-scale is defined to be 
the time needed for dissipative and cooling effects to become significant.
Similarly the collapse time defines the time scale of collapse! 

Spirals, which form about three-quarters of the known  galaxy population,
are postulated to have formed from (orginally) distinct, interacting clouds
where collisionary processes are very important and dissipation is thus
rapid. The gas, particularly in the outer regions, heats up due to the
collisions and is thus too rarified to condense efficiently into stars. The
gas near the centre of the protogalaxy is thought to be more densely 
compacted and is therefore more susceptible to gravitational forces. 

The ratio of collapse-to-cooling time-scale  thus varies from less than one in
 the centre to a value greater than one in the outer clouds. This explains(?) 
the formation of bar-like spherical structures in the centres of many spirals 
where collapse with little dissipation has taken place, but what about the 
pancake-like shape of the  galaxy as a whole? This is due to energy loss
through dissipation which takes place predominantly along  the axis of the 
angular momentum vector. This causes the collapse to be in the plane
 perpendicular  to this vector and leads to the characteristic disc shape.
The rarified gas means that star populations in well developed spirals are
fairly young  with  plenty of nebulous gas amoung them. The spiral shape 
of the arms is more a result of the nature of stellar formation - as 
borne out by stochastic simulations - than of  galaxy forming processes. 

Ellipticals account for about 20% of the galaxy numbers and are suspected
to have formed from cooler, non-interacting gas clouds. The stars in them are
mostly older (pop. 2) stars and there is very little interstellar gas, so 
that star formation is very limited or non-existant. This supports the idea
that collapse times are smaller than cooling times in ellipticals and hence
the spherical nature of gravitational collapse is not deformed by
dissipational effects. 
	Irregulars are the youngest of the three types, and in this theory
could develop into either spirals or ellipticals depending on the ratio 
of cooling-to-collapse time-scales.

 



Newsgroups: sci.astro
From: gliba@scivax.stsci.edu
Subject: Re: An Observation Question
Organization: Space Telescope Science Institute
Distribution: na
Date: Wed, 29 Jul 1992 21:32:47 GMT



How Far Can You See?


   Under moderately light polluted skies, the Andromeda Galaxy (M31) is
the most distant object visable to the naked-eye at a distance of about
2.4 million light years. If your skies are better, you may be able to see 
the galaxy M33 in Triangulum naked-eye, which is a little further. If your
skies are superb, then maybe NGC 253, a galaxy in Sculptor (Mv 7.0) can
be glimpsed, but not from midnorthern latitudes. It is considerably further
away than M31 or M33.




G.W. Gliba - 'I would rather see atarlight than streetlights'
From: cpyy@vax5.cit.cornell.edu
Newsgroups: sci.astro
Subject: Re: On the formation of black holes
Date: 23 Jul 92 10:15:05 EDT
Distribution: sci
Organization: Cornell University

Please note in my previous article that I clearly state that I am talking
about a full black hole with a singular center--a clothed singularity.

> You did not understand what I was saying,
> so instead of asking for clarification, you started patronizing me and
> other garbage.  Now you seem to be interested in the clarifications, but
> don't forget they are with respect to your original confusion.
 
Wrong.  I understood clearly what you said--absolutely nothing.
I am not interested in clarification.
 
> Huh?  he can be affected by things before the horizon, not at or after.
> Meanwhile, he "sees"--whatever that means wrt black holes--a black hole
> form in finite time.

I'm kind of glad that I couldn't parse that sentence.
 
I add that if I were to cry, it would be for your mother.

Jon C. Russo
internet : cpyy@vax5.cit.cornell.edu
phone    : 607.277.3295
Newsgroups: sci.astro
From: andromed@cs.dal.ca (Mike Boschat)
Subject: Re: Phobos and Deimos
Organization: Math, Stats & CS, Dalhousie University, Halifax, NS, Canada
Date: Fri, 24 Jul 1992 22:29:44 GMT

In article <24JUL199216135699@nssdca.gsfc.nasa.gov>, bell@nssdca.gsfc.nasa.gov (E. V. Bell, II - NSSDC/HSTX/GSFC/NASA - (301)513-1663) writes:
|> In article <1992Jul24.191933.17859@jpl-devvax.jpl.nasa.gov>, frisbee@jpl-devvax.jpl.nasa.gov (Tyler Brown) writes...
|> >I know that the moon Phobos means "fear" and was a consort of the God
|> >of war (Mars/Ares), but I forget what "Deimos" means. Could someone
|> >remind me?
|> > 
|> >			frisbee@devvax.jpl.nasa.gov
|> > 
|> > 
|> 
|> 	My recollection is that Deimos means "terror". Corrections?



  No corrections..I read that is what Deimos means."terror"




                                                 Clear skies

                                                  Mike Boschat 
 ------------------------------------------------------------
| "Our problems are man-made,      |    JOHN F. KENNEDY      |
|   therefore they can be solved   |                         |
|    by man."                      |  ASTRONOMY OBSERVATORY  |
|                                  |                         |
|     JOHN F. KENNEDY              |                         |
 ------------------------------------------------------------                                     
Newsgroups: sci.astro
From: mock@space.mit.edu (Patrick C. Mock)
Subject: Re: grav lensing
Originator: mock@benz
Reply-To: mock@space.mit.edu (Patrick C. Mock)
Organization: MIT Center for Space Research
Distribution: na,sci
Date: Mon, 27 Jul 1992 23:09:24 GMT


In article <Bs0KxG.Lo2@well.sf.ca.us>, metares@well.sf.ca.us (Tom Van Flandern) writes:
>  ...
>      My argument is simple and easy for anyone to grasp.  The counter-
> arguments you have quoted require considerable work to grasp even the
> essentials, and then they seem so skirt the basic point I have made here: the
> *shape* of the image of a point source being gravitationally lensed will be a
> ring-arc in general, or a full ring if axial alignment is quite close.
> Moreover, that is what is observed in the only cases which everyone here
> agrees are true gravitational lenses, namely galactic clusters lensing
> background blue objects.

An addendum to my previous post.  The blue background objects have been
show to be extended sources.  Using standard physics, a gravitational lens
will almost always generate an arc from an extended source.

Pat
From: wats@scicom.AlphaCDC.COM (Bruce Watson)
Newsgroups: sci.astro
Subject: Re: An Observation Question.
Date: 29 Jul 92 22:58:53 GMT
Organization: Alpha Science Computer Network, Denver, Co.

In article <92211.145626LXS117@psuvm.psu.edu| LXS117@psuvm.psu.edu writes:
|
|    I have a question about what we really see when we
|look at the stars.  I know, for example that if you are
|looking at the bright star Vega in the constellation
|Lyra, you are seeing light which has traveled 26 light
|years to earth.  However, how far are we actually seeing?
|What is our real range of vision?
|                          Thanks for enlightening me!
|
|                          Lizabeth at PSU

It depends how bright the light is. There are small earth satellites
only a few hundreds of kilometers away that cannot be seen with the
unaided eye, yet the great Andromeda galaxy can be without optical aid
and it is 2 million light-years distant.

-- 
 __________________________________________________________________________   
|wats@scicom.AlphaCDC.com|    "Another Case of too many scientists and     |
|Bruce Watson            |     not enough hunchbacks." -- Gary Larson      |
Newsgroups: sci.astro
From: schumach@convex.com (Richard A. Schumacher)
Subject: Re: Big Bang, Little Bangs and Accelerated Black Holes ...
Organization: CONVEX Computer Corporation, Richardson, Tx., USA
Date: Thu, 23 Jul 1992 20:01:40 GMT
X-Disclaimer: This message was written by a user at CONVEX Computer
              Corp. The opinions expressed are those of the user and
              not necessarily those of CONVEX.

You seem to be confusing blue galaxies with blue-SHIFTED galaxies.
The two notions have nothing fundamental in common. There are
very few blue-shifted galaxies, and all of them are quite close.
Newsgroups: sci.astro
From: vls@cube.handheld.com (Vern Stant)
Subject: Source For Image Intensifier or IR wanted
Organization: Hand Held Products, Inc.
Date: Mon, 27 Jul 1992 16:13:32 GMT

Does anyone know a source for an image
intensifier or ambient IR device?
Thanks,
Vern

--
Vern Stant              | The opinions expressed herein are
Hand Held Products, Inc.| not necessarily those of Hand 
804.784.3090 voice      | Held Products, Inc., and may not 
804.784.3147 FAX        | even be mine. Use at your own risk
Newsgroups: sci.astro
From: schumach@convex.com (Richard A. Schumacher)
Subject: Re: grav lensing
Organization: CONVEX Computer Corporation, Richardson, Tx., USA
Distribution: na,sci
Date: Wed, 29 Jul 1992 23:52:05 GMT
X-Disclaimer: This message was written by a user at CONVEX Computer
              Corp. The opinions expressed are those of the user and
              not necessarily those of CONVEX.

In <Bs647z.Hs5@well.sf.ca.us> metares@well.sf.ca.us (Tom Van Flandern) writes:

>     As this pertains to the original point, it means that lensed quasars do
>not have to be ring arcs as long as the quasars are not resolved.  But the
>same argument also precludes multiple quasar images.  So my paragraph of
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>objections to gravitationally-lensed quasars still stands.


But then goes on to write:

>     One can clearly get two images: one where the path is a minimum, and one
>on the opposite side of the lens where it is a maximum.


So which is it? Do you think that a gravitational lens can create more
than one image of a point source, or not? (Or have I misread you entirely?)



Newsgroups: sci.astro
From: youngs@ccu.umanitoba.ca (Scott D. Young)
Subject: Re: ST-4 & PHOTOMETRY
Organization: University of Manitoba, Winnipeg, Canada
Date: Tue, 28 Jul 1992 03:13:42 GMT

In <1992Jul26.231056.7584@usenet.ins.cwru.edu> bx372@cleveland.Freenet.Edu (Mr. Arthur J. Musgrove) writes:


>In a previous article, malcolm@hpwin052.uksr.hp.com (Malcolm Porter) says:

>> I would be interested in hearing about anyone's experienc

>In summary, it could be done with just a bit of enginuity...
>								Peter..

   I am just finishing my paper on using the ST-4 for CCD photometry.  We
   use IRAF to reduce the data and DAOPhot II to do the photometry.  The
   results are quite accurate, easily better than 0.1 mag for a 10th mag
   star.  For bright objects, the precision is a few hundredths or better.
   This is for unfiltered, differential photometry of uncrowded fields, 
   and was done as preliminary work for our ST-6 (which just arrived).

      The reduction of data is not for the faint of heart.  It took me all
   year to learn IRAF, Unix, and DAOPhot simultaneously.  There are a lot
   of parameters that must be understood in order to get the "best" photometry
   out of your images.  Also, flat fielding was not as straight forward as I
   had thought.  Basically, if you can run IRAF (available from DAO and Kitt
   Peak, I think, and probably lots of other places) and DAOPhot II, you can
   do useful photometry with the ST-4.  My paper will be well over 200 pages,
   (it's for a third year topics course), so please don't ask me to post it.
   With luck, an abridged version will appear somewhere like JRASC or PASP.
   I will be happy to share my experiences with anyone who wants to use the ST-4
   for photometry.


   Scott Young
   Undergrad Astronomy Student,
   University of Manitoba
   e-mail: youngs@ccu.umanitoba.ca
From: fy@lucid.com (Frank Yellin)
Subject: moon shepherding
Organization: Lucid, Inc., Menlo Park, CA
Distribution: sci
Date: 21 Jul 92 10:58:25


Can someone out there explain in moderately simple terms how a planet's
moon clears out a gap in a ring ("shepherding")?

Gravity is an attractive process, so the moon should be pulling stuff into
the gap, not pushing it out.  Intuitively obvious, put clearly wrong.

Several professional planetary astronomers that I've asked [I had five of
them sitting around a table once] seem to give the answer, "Do the math and
it just works."  Can anyone give me a more enlightening answer?

Thanks in advance.

-- Frank Yellin
   fy@lucid.com





Newsgroups: sci.astro
From: Frederick.A.Ringwald@dartmouth.edu (Frederick A. Ringwald)
Newsgroups: sci.astro
Subject: Re: Help on first scope
Date: 31 Jul 92 09:18:02 GMT
 <1992Jul30.104958.17430@dartvax.dartmouth.edu>  
 <1992Jul31.044731.3853@dartvax.dartmouth.edu>
Organization: Dartmouth College, Hanover, NH

Here's one that should go into the FAQ:
For advice on choosing a first telescope, see the articles in the 1983
October Sky & Telescope and the 1991 December Astronomy magazines. 
Newsgroups: sci.astro
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Mirror Coatings ???
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Wed, 22 Jul 1992 07:20:18 GMT

LABBEY@GTRI01.GATECH.EDU writes:

: John, the main difference between the various coatings is price.

As far as initial brightness of the image, this is certainly true.
However, there is one major advantage of the clear overcoating. People
who do not know how to properly clean their optics are less likely to
damage the metallic coat. The beryl makes is more scratch resistant. 

: For a first mirror, regular aluminum is OK.  It is cheap, and if you later
: decide to go for a better coating, you can easily have the old one removed,
: in face that is part of the process.
: 
: I have been using the same coating on my 10" since 1966.  A good one lasts
: forever!

Depends on how corrosive your atmosphere is. True, the oxide coating that
forms on the surface is pretty good at stopping corrosion, but it does
still occur. 

Bill
From: dh4j+@andrew.cmu.edu (David O Hunt)
Newsgroups: sci.astro
Subject: Re: Phobos and Deimos
Date: 27 Jul 92 15:16:54 GMT
Organization: Masters student, Mechanical Engineering, Carnegie Mellon, Pittsburgh, PA

"Fear" and "terror"

David
Newsgroups: sci.astro,rec.radio.amateur.misc,rec.radio.shortwave
From: oler@rho.uleth.ca (Cary Oler)
Subject: Daily Solar Geophysical Data Broadcast for 21 July
Organization: University of Lethbridge
Date: 22 Jul 92 04:43:35 GMT

!!BEGIN!! (1.0) S.T.D. Solar Geophysical Data Broadcast for DAY 203, 07/21/92
10.7 FLUX=108    90-AVG=129        SSN=084      BKI=0123 3432  BAI=011
BGND-XRAY=B3.4     FLU1=2.1E+05  FLU10=1.2E+04  PKI=1222 3432  PAI=011
  BOU-DEV=004,009,018,020,034,043,038,012   DEV-AVG=022 NT     SWF=00:000
 XRAY-MAX= C1.6   @ 2345UT    XRAY-MIN= B2.2   @ 2019UT   XRAY-AVG= B4.9
NEUTN-MAX= +001%  @ 0750UT   NEUTN-MIN= -003%  @ 1540UT  NEUTN-AVG= -0.8%
  PCA-MAX= +0.1DB @ 1555UT     PCA-MIN= -0.4DB @ 2150UT    PCA-AVG= -0.0DB
BOUTF-MAX=55247NT @ 1220UT   BOUTF-MIN=55201NT @ 1634UT  BOUTF-AVG=55233NT
GOES7-MAX=P:+116NT@ 1706UT   GOES7-MIN=N:-008NT@ 1451UT  G7-AVG=+081,+049,+012
GOES6-MAX=P:+124NT@ 0015UT   GOES6-MIN=E:-017NT@ 1625UT  G6-AVG=+091,+010,+040
 FLUXFCST=STD:105,103,103;SESC:105,105,105 BAI/PAI-FCST=020,015,015/020,015,015
    KFCST=3344 4333 3334 3333  27DAY-AP=022,016   27DAY-KP=4553 4333 3442 3333
 WARNINGS=
   ALERTS=
!!END-DATA!!
Newsgroups: sci.astro
From: naizer@rei2.uucp (jonathan naizer)
Subject: LED Bulb Wanted
Summary: where can I find an led bulb
Date: Thu, 23 Jul 1992 20:26:07 GMT
Organization: REI
Keywords: LED,astro

A while back, there was a company called Noctilume that carried LED flashlights
They also made LED bulbs that would fit a standard flashlight. I've think they
have gone out of business as my order to them was returned with an unforwaredable address. Does anyone know whey one could order an LED bulb that would
fit an ordinary flashlight?
:w

:q

w

Newsgroups: sci.astro
From: jfrankli@nyx.cs.du.edu (Jim Franklin])
Subject: barlow lens question
Organization: Nyx, Public Access Unix @ U. of Denver Math/CS dept.
Date: Fri, 24 Jul 92 19:32:43 GMT

any problems using 1.25" eyepieces in a 2" barlow ?

thanks in advance
jim
From: weemba@sagi.wistar.upenn.edu (Matthew P Wiener)
Newsgroups: sci.astro
Subject: Re: On the formation of black holes
Date: 28 Jul 92 22:02:09 GMT
Reply-To: weemba@sagi.wistar.upenn.edu (Matthew P Wiener)
Organization: The Wistar Institute of Anatomy and Biology
In-reply-to: anderson@fermi.phys.ualberta.ca (Warren G. Anderson)

In article <1992Jul28.180103.4359@kakwa.ucs.ualberta.ca>, anderson@fermi (Warren G. Anderson) writes:
>> Earlier we agreed to ignore the horizon expanding as the object falls in,
>> as a simplification.  If we don't, doesn't this cut off the emissions?

>I'm not sure. I have been doing quite a bit of work with the Vaidya metric
>lately, which is essentially Schwarzschild with infalling null dust. However,
>I have a very hard time visualizing the causal structure of these spacetimes.

As someone who doesn't get my hands dirty very often, I prefer to first
visualize causal structures.  And my understanding of horizons was that
they shifted continuously, even when two black holes collide.

>The easiest case I guess is an infalling thin spherical shell.

But it's also pretty far from the initial question--see the Subject!  The
newly forming black hole at the center of a supernova has a horizon deep
within the star, and material is continuously falling in, and the horizon
keeps expanding.

>							        In this case,
>I think the observer (who must have experienced an infinte force to stay 
>stationary, incidentally)

Actually, what *is* a stationary observer when the metric changes?  Is he
one of those imaginary Newtonian approximations like the rigid rod?
-- 
-Matthew P Wiener (weemba@sagi.wistar.upenn.edu)
From: higgins@fnalo.fnal.gov (Bill Higgins-- Beam Jockey)
Newsgroups: sci.astro
Subject: Rebound faster than escape velocity? (was Re: Heavy Boots)
Date: 31 Jul 92 13:11:04 GMT
Organization: Fermi National Accelerator Laboratory

In article <1992Jul31.071337.14623@omen.UUCP>, caf@omen.UUCP (Chuck Forsberg WA7KGX) writes:
> In article <1992Jul30.161658.26111@news.iastate.edu> partee@iastate.edu (Jonathan F Partee) writes:
>>We read an article claiming that the average American does not know the 
>>correct answer to the following question:
>>
>>If a pen is dropped on a moon, will it:
>>A) Float away
>>B) Float where it is
>>C) Fall to the surface of the moon
>>
> Were any of your students sharp enough to choose a moon light
> enough that one could drop the pen hard enough that its rebound
> would exceed escape velocity?  It would have been a matter of
> honor in my 3rd semester physics recitation section at RPI.

You woulda flunked if *I'd* been the T.A., Chuck-- unless you
specified that the pen has an elasticity greater than 1.  

(See the film *The Absent-Minded Professor* for a smooth line of
patter on this subject.)

In plain language, there isn't any moon *that* light.

Bill Higgins, Beam Jockey              | "Treat your password like
Fermi National Accelerator Laboratory  | your toothbrush.  Don't let
Bitnet:           HIGGINS@FNAL.BITNET  | anybody else use it--
Internet:       HIGGINS@FNAL.FNAL.GOV  | and get a new one every
SPAN/Hepnet:           43011::HIGGINS  | six months."  --Cliff Stoll
Xref: sparky sci.astro:8262 sci.space:10693 sci.misc:1381