HDTenEightyP/NetNews huggingface dataset:
From: turner@bigbang.astro.indiana.edu (George Wm Turner)
Newsgroups: sci.astro
Subject: Re: the moon
Date: 16 Aug 92 20:12:11 GMT
Reply-To: turner@bigbang.astro.indiana.edu (George Wm Turner)
Organization: Indiana University


>In article <1992Aug16.094059.830@sfu.ca>, 
>        jfaubert@fraser.sfu.ca (Jean-Paul Faubert) writes:
>I was listening to Quirks and Quarks today on the CBC while driving
>down to Seattle today and they had a spot on dinosaurs.  They were
>discussing the differences between the Mesozoic world and the present
>world, and they (whoever the scientist was) stated that the moon was
>much closer to the earth at that time and so would have appeared much
>larger in the sky.  My question, for someone out there who could
>take the time to answer it, is, how is this possible?  
> [deleted]
>Jean-Paul

in the end it deals with the conservation of angular momentum.  the earth's
spin slows down due to friction caused by the tidal effects of the
moon.  the source of this friction include the ocean tides as they slosh
in & out of tidal areas and friction caused by the tidal distrotation
of the solid earth;  the solid earth too deforms as the earths' oceans
thought the magnitude of the distortion about one third that of water.
mesaurements put the tidal distortion of the solid earth at about 20cm.
this friction is expressed as heat and the dissipation of energy is
callculated to be about 2 billon horsepower (2,000,000,000)

anyways, this friction robs the earth of rotational energy and slows
the earth's spin; (the length of an earth day lengthens by about 
0.002 second per century.) but the total angular momentum of the 
earth-moon system must be conserved causing the moon to move farther
out.  to put it another way, since there is less angular momentum in a
slower spinning earth at the center, a way to get more angular
momentum is to move the mass of the moon farther away thus keeping
the total amount of angular momentum constant.  (this theory of tidal
evolution was worked by george darwin,  charles darwin son!)

a further consequence of the moon moving farther away is that it
slows down in its orbit in accord with kepler's third law.  this leads
to a longer month since it takes longer for the moon to complete an orbit.
(slower speed & longer path).  since the days are getting longer
and the months are getting longer at some point in the future the length of 
the day will be the same as the length of the month.  at this point the
moon will be stationary over a single point on the earth.  the earth & moon 
will be locked face to face (remember, the moon is currently locked
with the same side always pointing to the earth)   the sun will still
rise & set (sunrise/sunset is due to the spin of the earth) but the
length of the day will be about 1130 hours instead of the current 24;
about 47 of our current 24 hour days.

as an exercise,  how many full moons would an earthling observe a day?

    george wm turner      turner@bigbang.astro.indiana.edu
From: lilleyc@cs.man.ac.uk (Chris Lilley)
Newsgroups: sci.astro
Subject: Re: Location of the Sun
Date: 13 Aug 92 00:48:00 GMT
Reply-To: lilleyc@cs.man.ac.uk (Chris Lilley)
Organization: Department of Computer Science, University of Manchester UK

In article <387@wavefront.wti.com> jra@wti.com (Jim Atkinson) writes:

>I am looking for an algorithm for the location of the Sun.  (I know,
>it's right up there :-)).  I am doing some computer graphics simulation
>type work and want to be able to simulate sunlight given a location on
>the surface of the earth and a time/date.  If someone has such an
>algorithm on-line that they can send me or a pointer to a book that
>contains one I would really appreaciate the help.  Thanks.

Get the package RADIANCE which is a ray tracing / radiosity hybrid.
This has various utilities to write scene descriptions, one of which
is gensky.

This takes the lattitude, data and time and generates a sky function
that includes the position of the sun. The code should give you most
of the information you need. 

More algorithmic details can be found in Duffet Smith "Practical
Astronomy with your Calculator' which is great on cookbook algorithms
for that sort of thing. Be aware that the later book "Practical
Astronomy with your home computer' is (IMHO) useless; much shorter on
explanation, and reams of BASIC to type in. Not an algorithm in sight,
all global variables and side effects - stick to the calculator
routines, which tell you what to do step by step.

You may also want to account for atmospheric haze, which relates to
sky turbidity, the hour angle of the sun and altitude. (Probably some
other factors too, I forget).

This should get you started, anyway. Do I get a free copy of wavefront
visualiser ? <grin>

--
Chris Lilley
---------------------------------------------------------------------------
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Computer Graphics Unit, Manchester Computing Centre, Manchester, UK
Internet:   lilley@cgu.mcc.ac.uk        Janet:   lilley@uk.ac.mcc.cgu
Voice:      +44 (0)61 275 6095          Fax:     +44 (0)61 275 6040
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From: njzy@vax5.cit.cornell.edu (T. Joseph Lazio, Cornell University)
Newsgroups: sci.astro
Subject: Re: Recombination Temperature Question
Date: 12 Aug 92 08:53:48 EDT
Distribution: sci
Organization: Cornell University

In article <1992Aug12.064528.22220@cco.caltech.edu>,
brandt@cco.caltech.edu (William N. Brandt) writes: 
> I would like to see or get a reference as to how the T=3000 K at 
> recombination is worked out. I assume this is a fairly complicated
> plasma physics computation, right - since you will have to take into
> account the chemical potential of hydrogen atoms, phase space filling
> factors (which might depend on the geometry of spacetime - although I
> guess by z=1500 everything was pretty flat - right?). Also, does the
> presence of helium have a significant effect - how about nonbayonic
> dark matter?

 From what I remember, one arrives at the 3000K estimate in the 
 following manner.  If one considers a hydrogen gas, the ionization 
 fraction is quite small until temperatures near 3000K or so.  Then, 
 over a fairly small range in temperature, the ionization fraction
 jumps from nearly 0 to nearly 1.  You might try playing with the 
 Saha equation; I believe that this would show such behavior.

> What is the electronic transition which happens at decoupling, anyway?
> I doubt it is free space into the n=1 quantum state (lowest level).
> How would you go about figuring this out anyway, since the bound
> state energy goes as -13.6 eV/n^2 for really big n you're basically
> in free space so coupling from free space into these states should
> be pretty easy (provided not spin forbidden etc.).

 At the recombination era, the Universe has cooled to a temperature 
 less than 13.6 eV.  Hence, there is nothing to stop the electrons from 
 dropping into the n=1 level.  

-- 

 T. Joseph Lazio                | Why relativity? and Why  
 514 Space Sciences             | turbulence?  I really believe   
 Ithaca, NY  14853              | [God] will have an answer for the
 (607) 255-6420                 | first [question].
 lazio@astrosun.tn.cornell.edu  |   -- W. Heisenberg, on his death bed
ICBM:                           |
 42 deg. 20' 08" N              |              STOP RAPE
 76 deg. 28' 48" W              |
Newsgroups: sci.astro
From: andromed@cs.dal.ca (Mike Boschat)
Subject: RZ Cassiopeia variable observation
Organization: Math, Stats & CS, Dalhousie University, Halifax, NS, Canada
Date: Wed, 12 Aug 1992 11:04:50 GMT

 I put this on te net for an observer, any others out there doing variable star
observations ? you can contact the observer of this observation..
 Thank you..
================================================================================
Date:	Wed, 12 Aug 1992 02:41:45 -0300
From:	Dominique Beauchamp <beaucham@phy.ulaval.ca>


Hi Mike,

Here are some results I got toning when I was observing the eclipsing
binary
RX Cas.  Its period is about 1d 4h.  I'm lucky because toning there was
an
eclipse and I observed a minimum.  Could you put this message on the
net
please?


night 11-12 August 1992 - near Full Moon, few cirrus and cumulus, in
the
suburb of Quebec City, half a million peoples.

2h11 UT (Aug. 12) 6.5 +/-0.1    binoc 8x56
2h27              6.4    0.1
2h57              6.4    0.2
3h14              7.0    0.2
3h30              7.8    0.1    newton 35x114
3h43              7.8    0.1
4h00              7.8    0.1
4h15              7.8    0.1
4h34              7.7    0.1
4h52              7.6    0.2

Unfortunatly, my observations end here because it was cloudy...
In first approx, the minimum was between 0400 and 0430 UT.  So,
tomorrow,
there will be a minimum at 0830 UT.  For me it is pretty difficult to
observe
at this time because in my timezone it is 4h30 AM (EDT).  But if you
live
in Atlantic provinces, Newfoundland or even in Europe, it could be a
favorable
eclipse.

Dominique Beauchamp
Societe Royale d'Astronomie du Canada, centre de Quebec
(Royal Astronomical Society of Canada, Quebec City center)
beaucham@phy.ulaval.ca
From: Bruce.Scott@bbs.oit.unc.edu (Bruce Scott)
Newsgroups: sci.astro
Subject: Re: a simple big Bang question
Date: 12 Aug 92 16:23:08 GMT
Organization: Extended Bulletin Board Service

Hayim Hendeles writes:

>I have 2 elementary questions about the Big Bang...
>
>1) ...how is it possible to have younger and older stars?...

A previous poster got this one. Basically, since star lifetimes are
highly variable (with mass), and the massive ones are so ephemeral
(few-tens Myr), much generational mixing is possible. I wanted to add
that a local neighborhood need not be anything like isochronous, since
dynamical scattering in the rotating galaxy has a time scale much
faster than most stars' lifetimes (10^8 yrs opposed to 10^9 to 10^11).

>2) ...[how does] an orderly Universe [result] due to the Big Bang vs
>total chaos?

Total chaos in this sense would just mean a homogeneous gas. But the
effects of gravity counter this. When thermal energy of localised
regions drops below gravitational interaction energy (self, or with
neighboring ones) clumps can form. The open question now is whether
clumps formed first on the largest or smallest scales (did
proto-galaxy clouds precede stars or did stars first form and then
have to collect). It seems from most models that, in addition to the
other reasons for it, some form of dark matter had to start the
clumping very early (before the recombination time, after which matter
and photons were thermally decoupled). There was a long thread, with
very low signal to noise :-), some months ago which convinced me that
"total entropy of the universe" in the sense in which thermodynamic
entropy is a subset may not be a well-defined concept.

A good book to read on this stuff would be "In Search of the Big Bang",
by John Gribbin. It should be widely available.

Gruss,
Dr Bruce Scott                             The deadliest bullshit is
Max-Planck-Institut fuer Plasmaphysik       odorless and transparent
bds at spl6n1.aug.ipp-garching.mpg.de                 -- W Gibson

--
   The opinions expressed are not necessarily those of the University of
     North Carolina at Chapel Hill, the Campus Office for Information
        Technology, or the Experimental Bulletin Board Service.
           internet:  bbs.oit.unc.edu or 152.2.22.80
From: andromed@cs.dal.ca (Mike Boschat)
Newsgroups: sci.astro
Subject: Re: Naked Eye Sunspot
Keywords: "naked eye sunspot" sunspot sun
Date: 19 Aug 92 14:26:22 GMT
Organization: Math, Stats & CS, Dalhousie University, Halifax, NS, Canada

In article <roelle.714229885@uars_mag>, roelle@uars_mag.jhuapl.edu (Curtis Roelle) writes:
|> Last night (Tue 18 Aug) I was tooling around the yard on the lawn mower
|> and recalled reading a post about a naked eye sunspot group (although I
|> do not recall the author's name).  The sun was low in the West, visible
|> through an increasingly thickening haze.  The sunspot in question was
|> quite obvious on the right hand half (Northern hemisphere), about 1/2
|> way between the center and right limb.  
|> 
|> I took only a few short glimpses because #14 welder's glass is not
|> standard equipment on most mowers.  I am not advocating true bald eye
|> observing of the sun, but given its altitude and the magnitude of
|> obscuration from haze, the welder's glass would black out what little
|> visible light was getting through (although it is other forms of
|> radiation such as infrared that eyes require protection from).  Let
|> me just say that as a general rule, one should not operate machinery
|> while staring at the sun. 
|> 


  an unimportant observation...nothing new about it..as others would say to
me..so I say...

						Mike
Newsgroups: sci.astro
From: tomrice@netcom.com (Tom R. Rice)
Subject: Re: Heavy Boots
Date: Tue, 18 Aug 92 05:46:38 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 

dant@techbook.com (Dan Tilque) writes:

>I trust you tell them that it's held down with suction cups...

	Actually, we've been talking sticky tape, but I like
	your suggestion better;  we'll see how it plays...

	trr


-- 
"Start off every day with a smile and get it over with."  --W.C.Fields
Tom R. Rice   WB6BYH                   Holler Observatory - 
tomrice@netcom.com                     Longitude:  121 d  30 m  20 s W 
CIS: 71160,1122                        Latitude:    37 d  25 m  10 s N 
Newsgroups: sci.astro
From: clarke@acme.ucf.edu (Thomas Clarke)
Subject: Re: Standard model of QSOsex
Organization: University of Central Florida
Date: Tue, 18 Aug 1992 13:31:26 GMT

In article <Bt5syD.Ipt@well.sf.ca.us> metares@well.sf.ca.us (Tom Van Flandern)  
writes:
> 
> Earlier, I wrote:
> 
> >> Quasars are not, of course, *predicted* by the standard model.  They are
> >> just part of what it attempts to explain, ad hoc.
> 
> and yaron@astro.as.utexas.edu (Yaron Sheffer) replied:
> 
> > How about this prediction:  "Shortly" after the BB, galaxies form.  Their
> > early collapse builds up a dense core of billion solar masses.  Also,
> > galaxies interact frequently thanks to higher density of the Universe.  A
> > natural consequence is the flare up of active galacic nuclei.  Prediction:
> > from Earth, 1992, these should be very bright, unresolvable, variable,
> > points of light with high cosmological redshift.  In short: QUASARS!
> 
>      Assume your theory is true.  At half the universe's present age, its
> volume would be one-eighth what it is at present.  So the frequency of such
> galaxy interactions today should be about one-eighth of what it was then.
> Then the number of new quasars today should be about one-eighth of the number
> of 5-7 billion-year-old quasars.  I don't think that can be reconciled with
> observations.  Nice try, though.  -|Tom|-
> 
I think it can be reconciled.  The nearest quasar is about z=.1.
This is pretty close.  Say N(Z) = Integral of O to Z of Z^3*Z^2 
(Z^2 for area of shell at distance Z), so N(Z) ~ Z^6. (I neglect
here csomological-model dependent corrections to the integral). 
With Zmax=3 as per observation, and N(.1)=1, as per observation,
the N(Zmax)~ 10^5.  Which is order of magnitude agreement with
observation - not bad for cosmology.

Yaron also forgot to mention that he had to introduce a population 
of small primitive galaxies to get the galactic mean free path low 
enough to better account for observed quasar density at higher redshifts.
These have now been observed in the form of the blue dwarf galaxies.

He also forgot to mention the prdiction of the presence of black-holes -
burned out quasars - in many galactic nuclei.  These are also
on the verge of being observed by HST and NGTs.

--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
(407)658-5030, FAX: (407)658-5059, clarke@acme.ucf.edu
Newsgroups: sci.astro
From: ggraef@convex.csd.uwm.edu (Gerald Luther Graef)
Subject: Re: telescope&accessories for sale
Organization: University Wisconsin - Milwaukee Physics Dept.
Date: Fri, 21 Aug 1992 17:43:13 GMT

In article <1550026@hplvec.LVLD.HP.COM> noble@hplvec.LVLD.HP.COM (Bob Noble) writes:
>
>Gee, looks like mailorder prices.  And what guarantees do YOU give?
>
>

Actually, the listed prices are below mail-order.  And there was
also the clause that offers would be considered...I not aware
of mail-order places which would encourage or even accept such offers...

In any case, a telescope in original box can't have had its warrantee
sent in (as I said, I was a dealer and this all new equipment.)

gerry graef

Newsgroups: sci.astro,rec.radio.amateur.misc,rec.radio.shortwave
Organization: Washington University, St. Louis
Date:         Wed, 12 Aug 92 08:56:05 CST
From:         Gary Kronk <C09630GK@WUVMD>
To:           NETNEWS@WUVMD
Subject:      Re: Perseids
Newsgroups:   sci.astro

I observed the Perseids from my home about 35 miles from St. Louis.
Between 4:00 and 4:45 a.m. on August 11, I counted 18 Perseids and
3 sporadics. The limiting magnitude was 6.1 at the zenith, but the
horizon was hazy enough to almost completely hide the Big Dipper.
The average magnitude of the Perseids I saw was about 2.6. Ten of the
Perseids left persistent trains.

Unfortunately, we had storms move through last night and this
morning (August 11/12). No observations were possible.

Gary W. Kronk
From: Grant_A_Prescott@cup.portal.com
Newsgroups: sci.astro
Subject: Trade Ham Gear for Telescope
Date: Fri, 21 Aug 92 14:19:20 PDT
Organization: The Portal System (TM)
Distribution: ba


I live in the South San Francisco Bay Area.  I am looking for a local trade of
my complete Ham Radio Station including an ICOM 726 XCVR(160 - 6 meters), 
ISOLOOP Ant (30 - 10 meters), MFJ-949D Tuner, Electronic keyer and many 
other accessories, for your COMPUSTAR 8" SCT WITH WEDGE AND TRIPOD. 

You may test the ham gear at my home in Santa Clara. I would also consider
an 11" SCT with wedge/tripod or a commercially made 16" or larger reflector.
Your telescope must break down into pieces that can fit into a small station
wagon.

Please call me instead of using email.  Thanks.

Grant (408) 249-3310  

P.S.  I will also have an older Dynamax 8" SCT available for trade AFTER I make
this trade, if you are interested.
Newsgroups: sci.astro,rec.radio.amateur.misc,rec.radio.shortwave
From: oler@rho.uleth.ca (Cary Oler)
Subject: Daily Solar Geophysical Data Broadcast for 19 August
Organization: University of Lethbridge
Date: 20 Aug 92 02:54:36 GMT

!!BEGIN!! (1.0) S.T.D. Solar Geophysical Data Broadcast for DAY 232, 08/19/92
10.7 FLUX=134.8  90-AVG=126        SSN=106      BKI=0021 1223  BAI=005
BGND-XRAY=B6.2     FLU1=5.8E+05  FLU10=1.1E+04  PKI=1121 2223  PAI=006
  BOU-DEV=004,004,012,009,009,015,010,021   DEV-AVG=010 NT     SWF=00:000
 XRAY-MAX= C3.4   @ 2012UT    XRAY-MIN= B4.2   @ 0104UT   XRAY-AVG= B8.8
NEUTN-MAX= +002%  @ 2345UT   NEUTN-MIN= -002%  @ 1545UT  NEUTN-AVG= +0.1%
  PCA-MAX= +0.1DB @ 1815UT     PCA-MIN= -0.6DB @ 1840UT    PCA-AVG= -0.0DB
BOUTF-MAX=55268NT @ 2257UT   BOUTF-MIN=55212NT @ 1843UT  BOUTF-AVG=55249NT
GOES7-MAX=P:+129NT@ 1658UT   GOES7-MIN=N:-001NT@ 0653UT  G7-AVG=+089,+036,+012
GOES6-MAX=P:+144NT@ 2253UT   GOES6-MIN=E:-010NT@ 1348UT  G6-AVG=+100,+000,+031
 FLUXFCST=STD:135,130,130;SESC:135,130,130 BAI/PAI-FCST=010,010,010/010,015,010
    KFCST=2224 4112 2224 4112  27DAY-AP=019,011   27DAY-KP=4433 2333 3223 3333
 WARNINGS=*SWF
   ALERTS=**245STRM:0000-1720UTC
!!END-DATA!!
From: Frederick.A.Ringwald@dartmouth.edu (Frederick A. Ringwald)
Newsgroups: sci.astro
Subject: Re: Location of the Sun
Date: 13 Aug 92 10:17:46 GMT
Organization: Dartmouth College, Hanover, NH

In article <387@wavefront.wti.com>
jra@wti.com (Jim Atkinson) writes:

> I am looking for an algorithm for the location of the Sun.

THE definitive reference is Astronomical Algorithms, by Jean Meeus
(1992, Willmann-Bell, Inc). It's a state-of-the art revision of his
renowned earlier book, Astronomical Formulae for Calculators. 

If no great accuracy is required (i.e., you're not trying to figure out
Galileo's logbooks), Meeus shows how to simplify most algorithms, so
they'll be shorter and faster. Also, the publisher has machine-readable
copies of the algorithms in C, Pascal, and BASIC, which they sell on
floppies and can save you some typing. 

Fred Ringwald
Department of Physics & Astronomy
Dartmouth College
Hanover, NH 03755-3528 U.S.A.
From: bic@piglet.mmwb.ucsf.edu (Bruce Cohen)
Newsgroups: sci.astro
Subject: Query: Is it worth buying a Barlow?
Date: 19 Aug 92 18:52:17 GMT
Organization: UCSF Computer Graphics Lab

This discussion started on eyepieces, but I would like to focus (no pun)
on Barlows.

>>the 32mm Plossl, since it is limited by the 1.25" eyepiece barrel. The 32mm
>>Plossl has greater magnification for the same field, and plenty of eye relief.
>A good combination would be the 32mm, the 17mm and the 10.5mm. I really don't
>^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>I don't understand why the 17 would be any better than the
>32mm and a barlow. whould the barlow decress the field of view a great
>deal compared to this combination?
>
>>find much use for a Barlow, I have the TeleVue 1.8x, and its pretty good as
>>Barlows go, but I never use it. Once you use the TeleVue Plossls, you probably
>^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>I am not an astronamer, don't even have a scope and hope to change that
>this week... but the book I'm reading says that the barlow will effectively
>double the focal length of the scope, thus increasing the eye relief
>for any given eyepiece. If one buys the barlow, the eye relief is better
>on the 17mm combination, you can use the 10.5 as a 6.5, and have better
>relief than with true 6mm. so I wonder why you never use your barlow?
>
>You would effectively get 4 eyepiece combinations of power for the
>price of 2 eyepieces.



Any opinions?

-- 
        Bruce Cohen                    |  UUCP:     ..ucbvax!ucsfcgl!bic
        Pharm Chem, Box 0446, Rm S-926 |  INTERNET: bic@cgl.ucsf.edu
        University of California       |  BITNET:   bic@ucsfcgl
        San Francisco, CA  94143-0446  |  VOICE:    (415) 476-8291
Newsgroups: sci.astro
From: metares@well.sf.ca.us (Tom Van Flandern)
Newsgroups: sci.astro
Subject: Re: Quasars: near versus far
Date: 14 Aug 92 04:45:15 GMT
Distribution: sci
Organization: Whole Earth 'Lectronic Link


njzy@vax5.cit.cornell.edu (T. Joseph Lazio, Cornell University) writes:

> Since all SNRs we have observed thus far have non-thermal spectra, isn't it
> a bit ad hoc to suggest that a local SNR is responsible for the microwave
> background?

     I more or less agree with the other points you raised.  But as for
supernova remnants, the point of mentioning them was that, once they reach
thermal equilibrium, their temperature is 3 degrees Kelvin.  Of course, by
that time (a few million years), their radiation will be accurately blackbody
as well.  The SNRs we observe are much too young to have reached thermal
equilibrium; and most of them still shine by the light of the star which
exploded.  -|Tom|-

-- 
Tom Van Flandern / Washington, DC / metares@well.sf.ca.us
Meta Research was founded to foster research into ideas not otherwise
supported because they conflict with mainstream theories in Astronomy.
From: j.jahn@abbs.hanse.de (Jost Jahn)
Newsgroups: sci.astro
Subject: Sunspots at 20.08.1992.
Date: 21 Aug 92 19:26:15 GMT
Reply-To: j.jahn@abbs.hanse.de
Distribution: sci
Organization: ABBS AstroMail, D-W 2121 Dahlenburg / Germany
X-Version: ZerUU V6.45c

Sunspots at 20.08.1992., 0 h UT.

No.    Pos.  Cl.  Ar.  Mag. SF  F  M  X
---------------------------------------
7260 17N 24W Eki 1300   gd  19
7262 16N 81W Cso   60   b
7264 15N 19E Bxo   10   b
7265 19S 66E Hsx   60   a


No optical or x-ray flares yesterday observed.


 
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Newsgroups: sci.astro