Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V12_4/V12_491.TXT

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Subject: SPACE Digest V12 #491

SPACE Digest                                     Volume 12 : Issue 491

Today's Topics:
                  Re: Pluto
             Re: Theories needed on life
             Re: Theories needed on life
                  Re: Names
            Re: Galileo Update - 10/19/90
                  Re: Hubble
             Re: Theories needed on life
             Pioneer 11 Update - 10/24/90
             Re: Homebuilt Manned Rockets
              Re: Venus/Magellan, poles
                  Re: Names

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

Date: 22 Oct 90 13:55:34 GMT
From: usc!elroy.jpl.nasa.gov!jato!mars![e-mail]  (Ron Baalke)
Subject: Re: Pluto

In article <[e-mail]> [e-mail] (David Tholen) writes:
>In article <[e-mail]>, [e-mail] (Ron Baalke) writes:
>
>> In 1978, it was known that Pluto had a light variation every 6.3867 days,
>> and this was assumed to be the planet's orbital period.  When Jim Christy
>
>The 6.3867 day period is the rotational period, not the orbital period.  The
>orbital period is a tad over 248 years.  Incidentally, the rotational period
>has been further refined to 6.387248 days, with an uncertainty of about
>0.000011 days.
>

My mistake here.  However, it does turn out that the 6.4 day figure is also
Charon's orbital period around Pluto.

>> discovered Charon in 1978, he did so because he noticed bulges in Pluto.
>
>The bulges were on the photographic images of Pluto, caused by our
>atmosphere blurring together the images of Pluto and Charon.
>
>> But the bulges were occuring in the north and south poles of Pluto.
>
>The bulge was seen in only the northerly and southerly directions on our sky.
>Because Pluto is tipped on its side, Pluto's poles lie in the east-west
>direction on our sky, therefore the bulges did not appear near Pluto's
>poles.
>

Of course, Christy initially didn't know Pluto was tipped on its side, and
the bulges were seen in Pluto's "apparent" north and south poles.
>>
>> Then a rare event occurred that only happens once every 124 years.  Starting
>> in 1985, Charon started eclipsing Pluto as seen from Earth.  This eclipse
>
>The eclipses started on 1984 December 18.  They were first detected from the
>Earth in early 1985.
>
>> season ended this year, and peaked in 1988 with the eclipsing being seen
>
>They ended 1990 October 15, but the last observable event was on 1990
>September 23; the later events occurred with Pluto too close to solar
>conjunction for observation.
>

This is good information.

>> edge on.  The eclipsing between Pluto and Charon not only determined very
>> accurately that Pluto was rotating at 94.0 degree angle, but the mass of
>
>The inclination of Charon's orbit, and by inference, the tilt of Pluto's
>rotational axis, is 99.0 degrees, with respect to the equator and equinox
>of 1950.  The uncertainty is still about 0.9 degrees. The tilt with
>respect to the ecliptic plane or the plane of Pluto's orbit is different,
>so the angle means nothing unless the reference frame is mentioned along
>with it.
>

I did a little further research on this.  In the 1990 Astronomical Almanac,
page F2, it lists Pluto  of having a 94 degree orbital inclination to the
planetary equator of 1950.  In the book called "Planets Beyond, Discovering
the Outer Solar System",  1990 edition, page 296, Pluto is also listed as
having a 94.0 degree inclination of equator to orbit.  However, in the
"The New Solar System", 3rd edition, page 291, Charon is listed as having
an orbital inclination of 98.8 degrees.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 22 Oct 90 02:43:40 GMT
From: csusac!csuchico.edu!petunia!usc!samsung!dali.cs.montana.edu!rpi!crdgw1!sixhub![e-mail]  (Wm E. Davidsen Jr)
Subject: Re: Theories needed on life

In article <[e-mail]> [e-mail] (Mike Gobbi) writes:
|
| A planet 3 or 4 times the size of earth?  Do you mean 3xmass or 3xradius?

    [ ... ]

| In the latter case, we are talking about a 27-G planet!  i think that the
| only conceivable life forms on this planet would certainly be aquatic.  That
| way they are relatively immune to the effects of their mass.

  I don't believe that's true even if you assume identical density, and
certainly isn't if you make your planet of something less dense.

  The best lengthly discussion of high gravity life forms I've read is
_Mission of Gravity_, by Hal Clement. He also postulated a rotation fast
enough to produce seriously reduced effective gravitation at the eqator.

  Without reviewing the book (I consider it great), note that a high
gravity life form must have much faster reflexes to keep up with things
falling on it, or to prevent the lifeform from falling.
--
bill davidsen - [e-mail] (uunet!crdgw1!sixhub!davidsen)
    sysop *IX BBS and Public Access UNIX
    moderator of comp.binaries.ibm.pc and 80386 mailing list
"Stupidity, like virtue, is its own reward" -me

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

Date: 24 Oct 90 01:03:57 GMT
From: ucla-seas![e-mail]  (John Price)
Subject: Re: Theories needed on life

In article <[e-mail]>, [e-mail] (Mike Gobbi) writes:
>A planet 3 or 4 times the size of earth?  Do you mean 3xmass or 3xradius?
    In this case, it doesn't make any difference.  I assume from the
way you state this that the "3xmass" planet has the same radius as the
earth, but 3x the density, while the "3xradius" planet has the same density
as the earth, but 3x the radius, hence 3^3 or 27 times the mass.

    Gravitational force, at least classically, which for this question
is all we're concerned with (I won't claim to know how it works at a
quantum or even general relativistic level), varies linearly with mass and
inversely with the *square* of the distance from the *center* of the
planet.  So, in the case I stated above, both planets have the same
gravity, which is three times that of the earth.

>     __
>    /..\      In quest of knowledge....
> --mm--mm--         Mike Gobbi

    Just trying to keep you honest...

---------------------------------------------------------------------------
  John Price                   | Internet: [e-mail]
  5-145 Knudsen Hall           | BITNET:   price@uclaph
  UCLA Dept. of Physics        | SPAN:     uclapp::price
  Los Angeles, CA  90024-1547  | YellNet:  213-825-2259
---------------------------------------------------------------------------
             Where there is no solution, there is no problem.

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

Date: 22 Oct 90 14:58:16 GMT
From: swrinde!zaphod.mps.ohio-state.edu!wuarchive!rex!rouge![e-mail]  (Fraering Philip)
Subject: Re: Names

Actually, our alphabet _is_ phonetic. You just need to use it to
write German or French. _English_ isn't phonetic.

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

Date: 22 Oct 90 17:11:35 GMT
From: csusac!csuchico.edu!petunia!usc!samsung!uakari.primate.wisc.edu!abcfd20.larc.nasa.gov!elroy.jpl.nasa.gov!jato!mars![e-mail]  (Ron Baalke)
Subject: Re: Galileo Update - 10/19/90

In article <[e-mail]> [e-mail] (Chris Duhon) writes:
>In article <[e-mail]> [e-mail] (Ron Baalke) writes:
>>
>>                          GALILEO STATUS REPORT
>>                            October 19, 1990
>>
>>     A NO-OP command was sent on October 15 to reset the Command Loss Timer
>>to 264 hours, the planned value for this mission phase.
>   *   *   *
>>All actions were successfully completed and a NO-OP command was sent to reset
>>the Command Loss Timer to 216 hours, the planned value for this mission phase.
>
>What is the "Command Loss Timer," and what is the significance of the
>various "hours" it is set to during different mission phases?
>

The Command Loss Timer is a safety feature built into the spaceraft.  If the
timer should ever countdown to zero, Galileo assumes that contact has been
lost with Earth and it automatically goes into safemode, where it then tries
to restablish contact with Earth.  The timer will only countdown to zero if
it receives no commands from Earth.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 23 Oct 90 01:02:15 GMT
From: uvaarpa!murdoch!astsun.astro.Virginia.EDU![e-mail]  (Greg Hennessy)
Subject: Re: Hubble

John Roberts writes:
#I think NASA generated a lot of
#trouble for itself by releasing certain premature conclusions. That might
#have been a good time to hedge claims, and say "we'll have a more definitive
#answer in a few days".

Strange, but when the bad news came out, I heard plenty of pissed off
people saying, "NASA has known that the mirrors were busted for TWO
WEEKS without telling us! Why they are trying to cover this up!"

NASA was also saying that better information would be available later,
but the media does not like to hear that very much, especially when
they are on deadline.


--
-Greg Hennessy, University of Virginia
 USPS Mail:     Astronomy Department, Charlottesville, VA 22903-2475 USA
 Internet:      [e-mail]
 UUCP:        ...!uunet!virginia!gsh7w

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

Date: 23 Oct 90 15:18:27 GMT
From: bu.edu!rpi!zaphod.mps.ohio-state.edu!mips!bridge2!3comvax![e-mail]  (Michael McNeil)
Subject: Re: Theories needed on life

>In article <[e-mail]> [e-mail]
>(Michael McNeil) writes:
>>It's highly likely that humanoid life wouldn't exist even on a planet
>>just like the Earth -- if life were to independently evolve again.
>>There are just too many other possible pathways for it to follow.

>In article <[e-mail]> [e-mail] (Kevin D. Quitt) writes:
>    Either that, or the humanoid form is like a chaotic attractor, and
>almost all evolutionary forms end up with it - which seems a whole lot
>more likely to me.  (Not that I feel it's all that wonderful, I just
>don't see anything wrong with it, and I doubt we're really all that
>special).

>In article <[e-mail]> [e-mail]
>(Jenni Sheehey) writes:
>>It really *is* unlikely that anything even resembling *any* species
>>presently on earth would be found on another planet by chance...

In article <[e-mail]> [e-mail] (Kevin D. Quitt) writes:
>    Unless you actually have proof of this, please label it as opinion.
>Based on our profound lack of knowledge, it is equally likely that
>*most* earth-like planets would develop humanoid life.

I see.  That's why we see all the *invertebrate* humanoids: arachnid,
crustacean, and insect humanoids -- and, in the vertebrate domain: all
the amphibian, reptilian, and avian humanoids -- and, in the mammalian
world: all the marsupial, carnivore, and rodent humanoids.  If our body
plan is such a "chaotic attractor," one would think that *some* group
in this world, somewhere -- outside of our close relatives (who have a
vaguely humanoid structure for obvious reasons, i.e., precisely because
they're our close relatives: but even they are not bipedal) -- would
have adopted our general body structure.  In the absence of *any* other
examples occurring in this world of life, my judgment is that the above
viewpoint regarding *other* worlds is anthropomorphic wishful thinking.

Even if an "insectoid" humanoid, say -- i.e., two arms, two legs, head
on top, etc. -- should evolve somewhere, people are dreaming if they
think such a creature *in detail* would look even *remotely* human.

--
Michael McNeil            [e-mail] (3comvax.UUCP)
3Com Corporation        ucbvax!hplabs!oliveb!3comvax!michaelm
Santa Clara, California        work telephone: [phone] x 5-208

    ...  Were we to meet with a Creature of a much different Shape
    from Man, with Reason and Speech, we should be much surprised
    and shocked at the Sight.  For if we try to imagine or paint a
    Creature like a Man in every Thing else, but that has a Neck
    four times as long, and great round Eyes five or six times as
    big, and farther distant, we cannot look upon't without the
    utmost Aversion, altho' at the same time we can give no account
    of our Dislike...  For 'tis a very ridiculous Opinion, that the
    common People have got, that 'tis impossible a rational Soul
    should dwell in any other Shape than ours...  This can proceed
    from nothing but the Weakness, Ignorance, and Prejudice of Men.
        Christianus Huygens, *New Conjectures Concerning the
        Planetary Worlds, Their Inhabitants and Productions*,
        c. 1670

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

Date: 24 Oct 90 15:08:03 GMT
From: csusac!csuchico.edu!petunia!usc!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Pioneer 11 Update - 10/24/90


                             Pioneer 11 Update
                              October 24, 1990

     The Pioneer 11 spacecraft emergency continues with high power uplink
support from the 70 meter stations.  Good telemetry has been processed with
the downlink configured non-coherent on channel 7.  The high power transmitter
was used from the 70 meter antenna in Spain to command a receiver swap on
the spacecraft yesterday.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 22 Oct 90 17:56:21 GMT
From: hpcc05!hpsmdca![e-mail]  (Philip Walden)
Subject: Re: Homebuilt Manned Rockets

>Is there anything inherently more complex about building a manned
>(suborbital) rocket than building a manned supersonic jet?  Would it
>be possible for a wealthy individual with the appropriate skills (or a
>wealthy individual + people with the appropriate skills -- say, EAA
>members, aerospace engineers, etc.) to do so?  I'm not talking about
>the space shuttle, but something more like Mercury or Gemini.
>
>If so, then does anyone have a guess as to how much this would cost?
>
>If not, then what specific technical problems would be show-stoppers?
>
There is excellent reading on just this subject in the current issue
of Smithsonian Air&Space. The article concerns the trial and tribulations
of a Mr. Truax who has been working putting a private citizen in space
ever since he help Evil Knevil jump the Snake Canyon. This is a case of
a person with the skills looking for a wealthy individual. The article
also talks about the money involved. Apparently, a private individual
in space is worth only 10-20 million in publicity and resulting notoriety.
Too little for the costs involved.

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

Date: 22 Oct 90 20:43:47 GMT
From: eagle![e-mail]  (Greg Macrae)
Subject: Re: Venus/Magellan, poles

>    The prime meridian of Mercury doesn't seem to pass exactly through
>anything, so I couldn't even guess at its definition.

>    All the mapped moons of the solar system have longitude defined, but
>just looking at the maps it usually isn't obvious why the prime meridian is
>where it is.  Probably the U.S. Geological Survey has a pamphlet explaining
>this sort of thing.

Mercury is tide locked with the sun.  That is one side always faces the sun.
I suspect that the prime meridian is defined the same as luna's, ie. it
splits the hemisphere that faces the body to which it is tide locked.  Most
small moons are tide locked to the planets they orbit, and the same system
would provide a definitive measure even before the surface is mapped.  It is
just conjecture on my part that this may account for many of the definitions
you found.

--------------------------------------------------------------------
     MacRae                  |      In what windy land
                             |   Wanders now my dear little
   [e-mail]  |       Dragonfly hunter?
                             |                      -Chiyo-ni
--------------------------------------------------------------------

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

Date: 22 Oct 90 23:02:13 GMT
From: mnetor!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Names

In article <[e-mail]> [e-mail] (Fraering Philip) writes:
>Actually, our alphabet _is_ phonetic. You just need to use it to
>write German or French. _English_ isn't phonetic.

Mais non, monsieur!  I don't know German, but I read/write/speak French
(not well, but enough), and French ain't phonetic no how no way.

Esperanto and Loglan are truly phonetic languages written in our alphabet
(if you're willing to allow a few diacritical marks for Esperanto).  So,
I believe, are some of the languages in places like Polynesia.  These are
all cases where the written language is a fairly recent invention, though.
--
The type syntax for C is essentially   | Henry Spencer at U of Toronto Zoology
unparsable.             --Rob Pike     |  [e-mail]   utzoo!henry

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

End of SPACE Digest V12 #491
*******************