Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v16_6/v16no630.txt

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Date: Wed, 26 May 93 05:22:23
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #630
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Space Digest                Wed, 26 May 93       Volume 16 : Issue 630

Today's Topics:
          August Meteor Shower May Threaten Earth Satellites
Comet Shoemaker-Levy, Possible Collision With Jupiter in 1994 (3 msgs)
              Detecting planets in other system (6 msgs)
                    Kepler's dream of space travel
                        Launch Vehicle Permits
                          non-solar planets
       Tom Wolfe's THE RIGHT STUFF - Truth or Fiction? (4 msgs)
                Why is everyone picking on Carl Sagan?

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----------------------------------------------------------------------

Date: 26 May 1993 03:24 UT
From: Ron Baalke <[e-mail]>
Subject: August Meteor Shower May Threaten Earth Satellites
Newsgroups: sci.space,sci.astro

PRESS NOTICE FROM ROYAL ASTRONOMICAL SOCIETY
NEWS AND INFORMATION SERVICE

PHONE  AND FAX[phone] (GREAT BRITAIN)
EMAIL TO    JMITTON <[e-mail]>

Date: 17 May 1993

Ref. PN 93/4
 Issued by:
 Dr Jacqueline Mitton
 RAS Public Relations Officer
FAX & Tel. Cambridge [phone]


Astronomers warn of danger to artificial satellites in August meteor shower

Two astronomers from the University of Western Ontario, Canada, are
warning of the potential danger to orbiting artificial satellites if the Earth
runs into a dense clump of meteoroid particles streaming through space
during the Perseid meteor shower this coming August. Writing in the 1
June issue of the Monthly Notices of the Royal Astronomical Society, Drs
Martin Beech and Peter Brown point out a combination of circumstances
that increases the probability of a damaging impact on a large satellite,
such as the Hubble Space Telescope, to a level that is not negligable. At
the same time, observers may be treated to an exceptional meteor display
in the early hours of 12 August.

The Perseid meteor shower is one of the most prominent of the regular
annual showers, peaking on about 12 August each year. Like all meteor
showers, it takes place when the Earth in its orbit round the Sun crosses
through a stream of meteoroid particles. Bright meteors, or 'shooting
stars', result when the meteoroids burn up in the Earth's upper
atmosphere. It has been known for a long time that the Perseid
meteoroids come from the periodic Comet SwiftTuttle and are scattered
all around the comet's orbit. Comet SwiftTuttle takes about 135 years to
go round the Sun and made one of its rare returns to the vicinity of the
Earth and the inner solar system at the end of last year.

Over the last few years, meteor watchers have noticed an enhanced
activity peak in the Perseids lasting for about one hour. Material ejected
recently from the comet appears to be responsible. This year, the Earth
will cross the Perseid meteoroid stream behind the comet when it has not
long passed our way. Peter Brown noticed that the circumstances of this
encounter will be very similar to the ones that produced the spectacular
Leonid meteor storms of 1966 and 1833. Beech and Brown reckon that the
likelihood of an enhanced display from the Perseids this August is
therefore high, though there is the usual note of caution since the exact
distribution of dust particles in the wake of the comet is not known. Their
best guess is that an outburst will begin at about 1 a.m. GMT (2 a.m. BST)
on 12 August.

Martin Beech said, " We do not know how strong the Perseid meteor
storm may be or how long it will last, if it occurs, so we haver based out
arguments on previous Leonid and Draconid meteor storms."

"The idea that satellite damage may occur became clear once we are able
to derive a value for the number of 'large'  meteoroids (that is, weighing
several micrograms or more) that may encounter the Earth during a
Perseid storm. There has not been a spectacular meteor storm since 1966
when the space age had hardly begun, so we thought it was worth trying
to speculate on possible damage."

The impact probability for a typical communications satellite is small but,
given the large number of such objects in Earth orbit, the possibility of
one being damaged is reasonably high. Larger satellites, like the Hubble
Space Telescope (HST), have higher impact probabilities. Beech and
Brown note, for example, that the probability of the HST being struck by
a Perseid meteoroid during a storm that lasts for about 15 minutes is the
same is its being struck by a one-metre-sized object in a 17-year period:
0.1 per cent.

"The satellite impact probabilities we find are certainly small, but are not
negligable", says Martin Beech. "Given the uncertainty in our knowledge
of the Perseid stream structure near the nucleus of Comet SwiftTuttle,
our results could be out by a factor of ten either way. We shall have to
wait and see what happens."

Martin Beech and Peter Brown will be travelling to Europe in the hope of
observing the Perseids. They will be joining a group of observers from the
International Meteor Organization at Puimichel in the Alpes de Haute
Provence.

********************************************************

Contacts for further information:
Dr Martin Beech Dept. of Astronomy, University of Western Ontario,
London, Ontario N6A 3K7, Canada. Tel [phone], FAX [phone],
E-mail [e-mail].
Dr Peter Brown Dept. of Physics, University of Western Ontario, London,
Ontario N6A 3K7, Canada. Tel [phone], ext. 6358, E-mail
[e-mail].

********************************************************

Notes

1. A typical Perseid meteoroid that produces a visible meteor of
magnitude 2.5 has a mass of around 2.5 micrograms and a velocity of
order 60 kilometres per second. Such a meteoroid would inflict severe
damage  a crater of 5 cm diameter has been estimated  if it struck an
artificial satellite.

2. The observed activity of a meteor shower is measured in terms of
'Zenithal Hourly Rate' (ZHR). The normal peak ZHR of the Perseids is
around 100. The Leonid storm in November 1966 had a ZHR of 100,000
for a period of 2040 minutes.
********************************************************

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Never laugh at anyone's
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/  |_|/       |_____|/                     |

------------------------------

Date: Wed, 26 May 1993 02:12:10 GMT
From: "Phil G. Fraering" <[e-mail]>
Subject: Comet Shoemaker-Levy, Possible Collision With Jupiter in 1994
Newsgroups: sci.space

[e-mail] (Steinn Sigurdsson) writes:

>Please don't write off for a form unless you think
>you might seriously enter a serious proposal to NASA.

Hey, according to the IAU Circular, there's a 50 % chance
of impact.

While Hubble is a poor choice compared to a probe, we won't
be able to get a probe there in time.

How often do we get to see this sort of thing?

> If there's anything to be seen from HST for P/S-L then
>chances are it has been claimed - I think you can also
>review accepted proposals and time-lines electronically,
>see README file at ftp site above. If not, Directors
>Disgressionary time is only chance at this stage,
>amateurs qualify for that.

Isn't there time set aside for "emergency" observations like
supernovae and the like?

Wouldn't a major "impact" count?

>|  Steinn Sigurdsson    |I saw two shooting stars last night        |
>|  Lick Observatory    |I wished on them but they were only satellites    |
>| [e-mail] |Is it wrong to wish on space hardware?        |
>| "standard disclaimer"    |I wish, I wish, I wish you'd care - B.B. 1983    |

Up above the world you fly,
Like a tea-tray in the sky...
--

+-----------------------+---------------------------------------+
|Phil Fraering          | "...drag them, kicking and screaming, |
|[e-mail] | into the Century of the Fruitbat."    |
+-----------------------+-Terry Pratchett, _Reaper Man_---------+

------------------------------

Date: Wed, 26 May 1993 02:33:28 GMT
From: "Phil G. Fraering" <[e-mail]>
Subject: Comet Shoemaker-Levy, Possible Collision With Jupiter in 1994
Newsgroups: sci.space

[e-mail] (Steinn Sigurdsson) writes:

>In article <[e-mail]> [e-mail] (Phil G. Fraering) writes:


>   Finally: where *do* I get those forms for Hubble Telescope
>   Time?

>   Is there a place I can write off for them?

> "ftp stsci.edu" "get how_to_submit"

In the directory 'proposer'.

I found it. It's mostly about what other stuff you need to get.

Thanks!

I'll also need to get the specs on how fast the photometer works, and
which of the other instruments might be useful...

The photometer would be the most useful instrument in this case, I
think...  the spectrum of the cometary materials would probably be a
blackbody as the comet is heated up... and the blackbody curve of the
comet debris and the planet (especially the planet) is going to drown
out the spectrum of any plasma in the explosion.

Anyone have any other ideas?

--

+-----------------------+---------------------------------------+
|Phil Fraering          | "...drag them, kicking and screaming, |
|[e-mail] | into the Century of the Fruitbat."    |
+-----------------------+-Terry Pratchett, _Reaper Man_---------+

------------------------------

Date: Wed, 26 May 1993 05:11:52 GMT
From: Henry Spencer <[e-mail]>
Subject: Comet Shoemaker-Levy, Possible Collision With Jupiter in 1994
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Phil G. Fraering) writes:
>I'll also need to get the specs on how fast the [HST] photometer works, and
>which of the other instruments might be useful...

The photometer is the instrument that will be sacrificed to accommodate
the COSTAR fix-the-mirror-aberration optical bench this December.  It
won't be available for HST observations next year.
--
SVR4 resembles a high-speed collision   | Henry Spencer @ U of Toronto Zoology
between SVR3 and SunOS.    - Dick Dunn  |  [e-mail]  utzoo!henry

------------------------------

Date: Wed, 26 May 93 02:20:28 BST
From: Ata Etemadi <[e-mail]>
Subject: Detecting planets in other system
Newsgroups: sci.space

Sender: [e-mail]
Source-Info:  Sender is really [e-mail]

G'Day Dave

In article <[e-mail]>, [e-mail] writes:
-| In article <[e-mail]>, [e-mail] (Ata Etemadi) writes:
-|
-| (Hi Ata!)
-|
-| > Anyone considered using Kilometric radiation ? I know we're being bathed in
-| > it but it shouldn't be too difficult to filter out the near-Earth stuff using
-| > two sensors (since its coming from close by). Planets with magnetic fields would
-| > likely be emitting coherent radiation at these wavelengths making the job a
-| > little easier. What you need is an underwater detector to filter out some of the
-| > noise, since Kilometric radiation penetrates water a long way down. This would be
-| > a darn good use for all those nuclear submarines out there. BTW I think the
-| > military use this wavelength of radiation for communicating with their subs.
-| >
-| >     best regards
-|
-| I can see a few problems with this suggestion...
-| (1) Isn't there a plasma frequency effect in the interplanetary medium that
-| blocks off kilometric radioation from outside the solar system? I remember A.C.
-| Clarke talking all about this in Imperial Earth, but I don't remember any
-| scientific analysis of this...

I hadn't heard of this effect. I'll catch some of the experts around here
tomorrow and ask them. I would guess he was referring to ionospheric effects
as opposed to magnetospheric/solar system.

-| (2) If planets with magnetic fields emit strong polarised radioation at theese
-| wavelengths, won't magnetic stars do it even more? Since you'd have hardly any
-| angular resolution at these wavelengths, how would you twell whether it was a
-| planet or a star?

Its coherent meaning a kilometric laser (kaser ?) as opposed to polarisation.
Sorry I didn't make it clearer. Its a matter of the scale-length on which the
effect occurs. Not all planets would exhibit this lasing effect. On stars the
scale-lengths are too large I guess. This is a guess since no one to my
knowledge has done science at this wavelength. If they did, they sure kept it
quiet. Hopefully some planets would stand out really well over the background.
What's needed is to connect up a detector to a long barbed-wire fence and see
what you can detect. I'm not joking, since this is a detector of sufficient
length and spread. Also its free (I don't think farmers could take you to
court for using their fence as a detector :-). I was originally thinking of
a kilometric observatory on the dark side of the moon (to avoid emissions from
the Earth). Usually I don't make such suggestions since it appears outlandish
or sci-fi and some old fossils find it humourous. The folks in this group seem
open-minded though (I think).

    best regards
        Ata <(|)>.
| Mail          Dr Ata Etemadi, Blackett Laboratory,                          |
|               Space and Atmospheric Physics Group,                          |
|               Imperial College of Science, Technology, and Medicine,        |
|               Prince Consort Road, London SW7 2BZ, ENGLAND                  |
| Internet/Arpanet/Earn/Bitnet [e-mail] or [e-mail]  |
| Span                              SPVA::atae       or     MSSLC:atae        |
| UUCP/Usenet                       [e-mail]        |

------------------------------

Date: 25 May 1993 22:35:33 -0400
From: Pat <[e-mail]>
Subject: Detecting planets in other system
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>There is currently a project at Ames working on this using a spaced based
>photometer.  The idea is that they will look for millimagnitude variations


They can't use the photometer on the HST already?

pat

------------------------------

Date: Wed, 26 May 1993 02:30:55 GMT
From: Leigh Palmer <[e-mail]>
Subject: Detecting planets in other system
Newsgroups: sci.space

In article <[e-mail]> Frank Crary,
[e-mail] writes:
>The star will always be brighter, but the real question is how much
>brighter? For (say) a 2.3-m gaussian apadized mirror at 23 microns,
>two objects would have to be ~1E-6 radians (0.2 arcsec) apart
>per three magnitudes of brightness difference (actually, per e-folding,
>but...) For the 14 magnitude difference between Jupiter and the
>Sun, that would mean a 1 arc-sec seperation... That would work
>for a star within 5 parsec.

I think you're off an order of magnitude on the angle; it's 1.E-5 radians,
or 2 arcseconds. And actually isn't an e-folding closer to one magnitude?
I'm unfamiliar with the resolution criterion you're using, but I see your
idea. The angle I get for Jupiter-sun is more like 28 arcseconds if I use
one magnitude per 2 arcsec, limiting our survey to a sphere of radius
0.04 parsecs or less, which contains only one known star. I just did that
survey with another technique last night, and yes, that star has a
Jupiter.

Actually the aperture function must extend out as many e-foldings as the
wings you plan to work in to still yield effective apodization. A mirror
large enough to give that performance would have to be, um, 30 meters in
diameter and have a smoothly varying filter from perfectly transparent
at its center to optical density 5.5 at the edge. When you look at it
this way, perhaps the 500,000 km infrared interferometer is easy!

How does one apodize a large mirror in that way? Can of spray paint? Hire
a grafiti artist? :-))

Leigh

------------------------------

Date: Wed, 26 May 1993 02:39:55 GMT
From: Leigh Palmer <[e-mail]>
Subject: Detecting planets in other system
Newsgroups: sci.space

In article <[e-mail]> , [e-mail] writes:
>There is currently a project at Ames working on this using a spaced based
>photometer.  The idea is that they will look for millimagnitude
variations
>over time for 10's of thousands of stars.  They are concentrating
>on late-type cool stars and they have already modeled the anticipated
>results and it is doable.  They hope to detect jupiter size dark objects
>around G-K stars.  If the funding goes well the hope to be up by
>the end of the decade.

What are they looking for? Eclipses will surely be rare, and the intrinsic
millimag variability characteristic of late type stars is unknown until
the
space-based photometry is done.

Leigh

------------------------------

Date: Wed, 26 May 1993 06:32:55 GMT
From: Robert Casey <[e-mail]>
Subject: Detecting planets in other system
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>G'Day Dave
>
>Its coherent meaning a kilometric laser (kaser ?) as opposed to polarisation.
>Sorry I didn't make it clearer. Its a matter of the scale-length on which the
>effect occurs. Not all planets would exhibit this lasing effect. On stars the
>scale-lengths are too large I guess. This is a guess since no one to my
>knowledge has done science at this wavelength. If they did, they sure kept it
>quiet. Hopefully some planets would stand out really well over the background.

I vaguely remember seeing a discription of a satellite with extremely long
antennas (hundreds or maybe even thousands of meters long) ten or fifteen
years ago.  Don't remember if it actually flew, or was just a proposal.
It was to do observations of very low frequency radio radiation from
natural sources in the sky.
Henry?

------------------------------

Date: Tue, 25 May 1993 22:35:54 GMT
From: Stupendous Man <[e-mail]>
Subject: Detecting planets in other system
Newsgroups: sci.space

   Robert Dempsey says (on the subject of detecting planets orbiting
   other stars)

> There is currently a project at Ames working on this using a spaced based
> photometer.  The idea is that they will look for millimagnitude variations
> over time for 10's of thousands of stars.  They are concentrating
> on late-type cool stars and they have already modeled the anticipated
> results and it is doable.  They hope to detect jupiter size dark objects
> around G-K stars.  If the funding goes well the hope to be up by
> the end of the decade.

    I happened to hear several presentations on this subject by
Bill (it _is_ Bill, isn't it?) Borucki, NASA/Ames, several years
ago.  Looking at an article in the conference proceedings "Advances
in Robotic Telescopes" (ed. M. Seeds), I can state a few pertinent
facts:

    Why space-based?  The main problem on the ground is scintillation
noise due to the atmosphere.  Borucki estimates that one needs a
9-m scope and 8 hour exposure on the ground to reduce scintillation
noise to 1 part in 100,000, but only a 1 to 2-m scope and 30-minute
exposure in space.

    Assuming a solar-type star, Borucki finds the expected signal
to be a 1% decrease in light for Jupiter, 0.1% for Uranus and 0.01%
for Earth.  These are really tough limits; solar-type stars themselves
tend to vary by ~ 0.1% or so (= 0.001 mag = 1 millimag) on short time
scales, which makes looking for Earth-sized planets very hard indeed.

    Why so many systems (tens of thousands quoted above)?  Because
you expect to see very few events per year in an individual system;
the numbers Borucki quotes are between 10^(-2) per year (for planets
with orbital radii 0.3 AU) to 10^(-6) per year (10 AU).  So you have
to look at lots and lots of systems to see more than a very few
events.

    It's an interesting idea, but very tough in practice.

--
-----                                                    Michael Richmond
"This is the heart that broke my finger."    [e-mail]

------------------------------

Date: Wed, 26 May 93 04:11:00 GMT
From: "John C. Baez" <[e-mail]>
Subject: Kepler's dream of space travel
Newsgroups: sci.physics,sci.space

I have just begun reading "Kepler's Dream" by John Lear, and while I
haven't gotten too far yet, I highly recommend it to everyone who likes
the little mind-blowing nooks and crannies of history.  Kepler's
"Dream," or "Somnium," was a book he died before publishing, and which
seems to have remained fairly obscure.  It is written in the form of a
fantasy about space travel, but its subject is apparently mostly lunar
geography.  (Selenography, perhaps?)

I will describe it more when I have read it all, but for now I just
CAN'T resist giving you all this little puzzle.  To WHOM did Kepler
write a letter in 1610 saying:

Who would have believed that a huge ocean could be crossed more
peacefully and safely than the narrow expanse of the Adriatic, the Baltic
Sea or the English Channel?  Provide ship or sails adapted to the
heavenly breezes, and there will be some who will not fear even that
void.... So, for those who come shortly to establish this journey, let
us establish the astronomy....

I had been a fan of Kepler ever since reading the details of how he
found that planetary orbits were elliptical, etc. (an incredible train
of thought and lots of hard work!), but this really bowls me over.

------------------------------

Date: 25 May 1993 22:46:06 -0400
From: Pat <[e-mail]>
Subject: Launch Vehicle Permits
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
|
|>Questions like "What happens
|>when it reenters, if we launch into a real low orbit" need to be answered.
|
|I think you basically have to make OCST happy about this -- shouldn't be
>hard since nobody else does much about the matter -- and that's it.  The
>US government, not you personally, is responsible for any damage.

Somehow I think they will manage some way to collect any payments
from the launch organization.  Put an IRS lien on everyone involved :-)

------------------------------

Date: Wed, 26 May 1993 02:52:22 GMT
From: Leigh Palmer <[e-mail]>
Subject: non-solar planets
Newsgroups: sci.space

In article <[e-mail]> Victor Laking,
[e-mail] writes:
>Years ago, I was at a lecture by the head of the local planetaruim and
he
>mentioned that some bodies (believed to be gas giants at the time) were
>discovered around Vega.  Apparently they discovered them by accident.
>From what I remember, they wanted to calibrate a new sattelite
>(pre-Hubble) and chose a known star to work with - Vega.  They noticed
>discrepancies and eventually realized that it was due to planets.

There is a dust ring around Vega, I believe, but I've heard nothing of
planets.

>Is anything more known about this or any other bodies orbiting other
>stars?  Does anyone know how many and/or what type of planets have been
>found around which stars?

Alexander Wolzczan (I know it's spelled wrong, sorry) has discovered two
and possibly three "planets" orbiting a pulsar by measuring the Doppler
shift in its pulse period. The trouble with these planets is that no one
can figure out how planets could possibly have survived the supernova
explosion which is the only current mechanism proposed to create pulsars.
Several other reports of extrasolar planets have appeared in print in the
past decades, but none has been declared iron-clad certain.

Leigh

------------------------------

Date: 25 May 1993 22:39:55 -0400
From: Pat <[e-mail]>
Subject: Tom Wolfe's THE RIGHT STUFF - Truth or Fiction?
Newsgroups: sci.space,sci.space.shuttle,rec.arts.books

Henry makes a comment abou;t grissoms command for apollo.

I assume Grissom, chaffee and white were one single crew.

THey were going to fly Apollo 6, then?

I can imagine his first words on making orbit :-)

------------------------------

Date: 25 May 1993 22:43:16 -0400
From: Pat <[e-mail]>
Subject: Tom Wolfe's THE RIGHT STUFF - Truth or Fiction?
Newsgroups: sci.space,sci.space.shuttle,rec.arts.books

Wolfe's book seems to be a serious of personal vignettes on events.
I only read part of the book,  but it seemed like the book "Freedom
at Midnight".  The general complaint on this sort of book, is that
individual perceptions of events differ from hte "Official"
history.  I am not sure how to view such books,  because the
feelings of people who were there make up at least the milieu
even if other people have different feelings.  Look at the
debate on the kennedy assasination.  Everyone has adifferent
take on the events.

pat

------------------------------

Date: Wed, 26 May 1993 03:34:14 GMT
From: Dave Michelson <[e-mail]>
Subject: Tom Wolfe's THE RIGHT STUFF - Truth or Fiction?
Newsgroups: sci.space,sci.space.shuttle,rec.arts.books

In article <1tul9r$[e-mail]> [e-mail] (Pat) writes:
>
>Henry makes a comment abou;t grissoms command for apollo.
>
>I assume Grissom, chaffee and white were one single crew.
>
>THey were going to fly Apollo 6, then?
>
>I can imagine his first words on making orbit :-)

Grissom, White, and Chaffee were assigned to AS-204 which was later named
Apollo 1.  They were designated command pilot, senior pilot, and pilot,
respectively.

Regarding your comment about imagining "his first words on making orbit":
If that's a joke, it's too obscure for me.

--
Dave Michelson  --  [e-mail]  --  University of British Columbia

------------------------------

Date: Wed, 26 May 1993 05:09:39 GMT
From: Henry Spencer <[e-mail]>
Subject: Tom Wolfe's THE RIGHT STUFF - Truth or Fiction?
Newsgroups: sci.space,sci.space.shuttle,rec.arts.books

In article <1tul9r$[e-mail]> [e-mail] (Pat) writes:
>Henry makes a comment abou;t grissoms command for apollo.
>I assume Grissom, chaffee and white were one single crew.

Correct.

>THey were going to fly Apollo 6, then?

Well, whatever number it was. :-)  The crew was calling it Apollo 1, the
booster people were calling it Apollo 4, and the only official name it
had was Apollo 204.  After the fire, NASA HQ honored a request from the
crew's widows that it be designated Apollo 1 the way the crew wanted it.

The mission they were to fly was approximately that flown by Apollo 7.
--
SVR4 resembles a high-speed collision   | Henry Spencer @ U of Toronto Zoology
between SVR3 and SunOS.    - Dick Dunn  |  [e-mail]  utzoo!henry

------------------------------

Date: Tue, 25 May 1993 17:26:33 GMT
From: Stupendous Man <[e-mail]>
Subject: Why is everyone picking on Carl Sagan?
Newsgroups: sci.space

  Some people don't believe that Carl Sagan (a professor of
astronomy at Cornell, not Columbia ;-) is "well-respected".
For example, Frank Crary says

>> Have you ever read any of his professional papers? The one I look up
>> last month, for example, was truely pathetic (Wallace and Sagen's
>> 1979 paper on the stability of water on Mars, under an insulating
>> layer of ice.) While it was an interesting idea, their model was
>> completely and obviously bogus (unless you think it's safe to assume
>> five meters of ice is totally transparent, among other things...)

  And Tom McWilliams adds

> Well, well-respected in some circles.  BTW, he isn't an astronomer.  He's
> an astro-biologist.  At least, that's what his degree is in.  It's quite
> an accomplishment to get a degree in something whose subject matter
> doesn't actually exist.  Well, carbon compounds...

     Tom, you are wrong.  I just looked up his dissertation in
two places (an on-line system and the Men and Women of Science).
Both sources state that he received his Ph.D. in 1960 from the
University of Chicago in "Astronomy and Astrophysics".  The title
of his dissertation was "Physical Studies of Planets".  I see from
a list of abstracts of AAS meetings in 1960 that he gave talks
on "The Surface Temperature of Venus" and "Molecular Synthesis
in Reducing Atmospheres" (the latter work with Stanley Miller).

> The story I heard is that after his defense, the astronomers were shaking
> their heads, muttering "Well, at least he knows biology" and the
> biologists were shaking their heads, saying "Well, at least he knows
> astronomy".  :-)

     Can you provide the source of this story?  I see no reference
to "biology" in his dissertation or degree.  Or is this merely
hearsay, or a story someone made up completely?  I suspect the latter.

> Any respect Sagan has in professional circles, from what I gather, is due
> to his influence on students and the public at large, in creating
> interest and support for astronomy and science in general.

     Let me point out several features of Sagan's career: between 1969
and 1983, Sagan was author or co-author on at least 194 papers in the
refereed literature and at conferences.  Between 1969 and 1979, he
was the Editor of "Icarus", the professional astronomy journal devoted
to objects in the solar system.  Since 1980, he has remained as an
Associate Editor for "Icarus."

     I think this qualifies him to be "well-respected" among astronomers.
Sure, many people (I suspect Frank and Tom are two) are jealous of
his status and prominence in the public eye.  As I said in an earlier
post, "so what?"  One cannot deny that he has been a major player in
our understanding of the solar system, especially in the late sixties
and seventies.

     Now, I don't know Sagan, I've never met him, and I don't work
on objects in the solar system.  But I'm an astronomer, I respect
the work he's done, and it annoys me to see people spouting nonsense
about him.  I don't deny that one of his papers may have made
unrealistic assumptions, but I think that most of his work has stood
up very well with time.

     If I may drag Dave Tholen into this - forgive me, Dave - you,
too, are an Associate Editor for "Icarus."  How do YOU feel about
Sagan's credentials as another Associate Editor?

                                 Michael

--
-----                                                    Michael Richmond
"This is the heart that broke my finger."    [e-mail]

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End of Space Digest Volume 16 : Issue 630
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