Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v09_4/v9_460.txt

Internet Message Format | 1991-07-08 | 16KB

Return-path: <[e-mail]>
X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
Received: from holmes.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr1/ota/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/AYTYhee00UkZ0G3U5y>;
          Sat, 27 May 89 03:16:59 -0400 (EDT)
Message-ID: <[e-mail]>
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Sat, 27 May 89 03:16:50 -0400 (EDT)
Subject: SPACE Digest V9 #460

SPACE Digest                                      Volume 9 : Issue 460

Today's Topics:
               RE: Space Digest V9 #443
     Re: Memes: can memetic theory explain this episode?
          Re: For the People of Planet Earth
            Re: asteroid almost hits earth
         Re: Magellan Status for 05/19/89 (Forwarded)
        Re: Geosynchronous debris cleanup law?
               Mass extinctions
             Re: Andromeda Strain
             Re: Teach your children well
              Re: spaceplane propulsion
            Re: asteroid almost hits earth
----------------------------------------------------------------------

Date: Tue, 23 May 89 15:16:38 CDT
From: [e-mail] (Who remembers 8USER.PAR?)
Subject: RE: Space Digest V9 #443

In a Larry Niven novella (The Fourth Profession), the Monks have a device
("wheapon") about the size of a locomotive which can somehow cause the sun
to go out of sequence and pop.  Mr. Niven is very careful not to specify
any details, but could some sort of energy weapon do this?

Dillon Pyron                         | The opinions are mine, the facts
TI/DSEG Lewisville Computer Services | probably belong to the company.
[e-mail]              |
[phone]                        | We try, we learn, sometimes we die.
                                     | We sit on our butts, learn nothing,
                                     | and we still die.

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

Date: 24 May 89 03:09:59 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: Memes: can memetic theory explain this episode?

Wow I haven't seen the story of THE MOVIE! posted in quite a while.
Is it always MacLeod who posts it or does the, er, meme get around?
It's a favorite of mine too.  I do think it needs backing up, I mean
is it fiction or can someone cite a reference?
--
Tom Neff                UUCP:     ...!uunet!bfmny0!tneff
    "Truisms aren't everything."    Internet: [e-mail]

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

Date: 21 May 89 20:41:39 GMT
From: jarthur![e-mail]  (Brian Evans)
Subject: Re: For the People of Planet Earth

In article <[e-mail]> [e-mail] (Friends of Earth) writes:
>A summary of
>positive replies will be made on talk.religion.newage, where future
>postings of this nature will be made.

Which is where the original posting should have been made in the first
place.  I mean really, "Friends of Earth," didn't you get the picture
the LAST time you posted this that IT DOESN'T BELONG ANYWHERE EXCEPT
TALK.RELIGION.NEWAGE!

--
Brian Evans                "It has been scientifically proven
[e-mail]             that scientists cause cancer in
[e-mail]         laboratory rats."
or !uunet!jarthur!bevans

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

Date: 23 May 89 18:10:43 GMT
From: [e-mail]  (Jonathan Patrick Leech)
Subject: Re: asteroid almost hits earth

In article <[e-mail]> [e-mail] (Keith Dancey) writes:
>My understanding is that the demise of the dinosaurs extended over a period
>of order of magnitude of a thousand years.  Certainly long enough to place
>doubt upon the viability of a single catastrophy such as the one mentioned.
>If the palaeontological evidence is not contradicted (and I have understood
>it correctly) then a *series* of such catastrophic strikes would be required.
>
>That is not say a single catastrophy is ruled out, but it looks as though
>its effects must be longer-lived than a few years.

    There is some belief that a gravitational perturbation of the
cometary cloud could produce "showers" of comets in the inner solar system.
Don't take "showers" too literally - it means a handful of hits over
long periods of time - but this has some bearing on your comments.

    Yow! Get off the net for two weeks, come back to 600 articles in
sci.space. :-)

    Jon Leech ([e-mail])
    Apple Integrated Systems, San Jose
    __@/

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

Date: 23 May 89 16:31:57 GMT
From: att!mtuxo![e-mail]  (54317-T.EBERSOLE)
Subject: Re: Magellan Status for 05/19/89 (Forwarded)

In article <[e-mail]>, [e-mail] (Colin Hunter) writes:
>
> trident.arc.nasa.gov![e-mail]  (Peter E. Yee) writes:
>
> >             MAGELLAN STATUS
> >             May 19, 1989
> >
> >    SPACECRAFT Distance  From Earth (mi)
> >    2,220,474
> >
> >    Velocity  Geocentric                         5,905 mph
> >              Heliocentric                      59,970 mph
> >
> >    Round Trip Light Time                           12.2 sec
>
> If  you  are only going to give us a date, these figures show considerable
> redundancy as far as  accuracy  is  concerned.   It is very interesting to
> have the distance from Earth given to 7 significant figures, etc, but this
> is meaningless without an equally accurate time also being stated.  Can we
> assume noon (GMT, EDT, PDT)?

Actually, you've missed the point of this data, that the very foundations
of modern physics are so much quicksand:

     2 x (SPACECRAFT Distance from Earth)/("Round Trip" Light Time =

          2 x 2,220,474 miles/12.2 sec = 364,012.13 miles/sec

The previous record for photon travel was 186,282.etc. miles/sec. However,
there are rumors steriods (or some recreational drug) were used to produce
the new record, so it may not be ratified.

Of course, there may just be reporting error, so that 12.2 seconds is the
one-half Round Trip Light Time. The foundations of physics may solidify,
but other problems arise:

 Index of Refraction = 186,282/(2,220,474/12.2) = 186,282/182006 = 1.0234934

From a problem set on page 115 of Electromagnetism by Slater and Frank, 1947,
this is higher than the 1.00015 refractive index of H2 and comparable to
the refractive index of air at about 72 atmospheres. I understand that
sunspot activity can expand the earth's atmosphere, but something seems
to be out of kilter. This may have something to do with the Mystery of
the Missing Mass, subtitled Close That Universe After You're Done With It.
However, it appears unlikely to be of much help in resolving the Problem
of Not Enough Solar Neutrinos.

I suppose there could still be a problem with the reporting of the results,
but so what.

=============================
--
Tim Ebersole ...!att!mtuxo!tee
                 or {allegra,ulysses,mtune,...}!mtuxo!tee

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

Date: 23 May 89 17:16:44 GMT
From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Geosynchronous debris cleanup law?

In article <[e-mail]> [e-mail] (Bill Turner) writes:
>> What does this mean?  Did somebody pass a law?  Obviously inactive
>> satellites can't remove themselves.  Is somebody going to fund an
>> international orbit guard?

There is a general convention, widely supported and complied with although
not carrying the force of law anywhere (that I'm aware of), that a comsat
which is about to run out of stationkeeping fuel should use the last bit
of fuel to leave Clarke orbit.  Given the relatively small amount of fuel
available for the maneuver, this usually means moving into a slightly
higher or lower orbit rather than anything really drastic, but that's
enough to take it out of the high-traffic area.
--
Van Allen, adj: pertaining to  |     Henry Spencer at U of Toronto Zoology
deadly hazards to spaceflight. | uunet!attcan!utzoo!henry [e-mail]

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

Date:       Tue, 23 May 89 18:42:45 EST
From: [e-mail]
Subject:    Mass extinctions

I  recently heard that species (both flora and fauna)  are becoming extinct
at a rate of 25 to 30 per  day.  This  works  out to 10000 per year,  which
agrees  with  a previous posting to SPACE.  As we  discuss  the  intriguing
possibility of  a  renegade  chunk  of  rock  slamming  into the planet and
causing  mass  extinction,  we  are  doing a fine  job  ourselves  in  that
direction.  When you get up to go to  work tomorrow morning,  there will be
ten less species alive on our planet that when you went to sleep.

     "Many were increasingly of the opinion that they'd all made a big
      mistake in coming down from the trees in the first place.  And
      some said that even the trees had been a bad move, and that no
      one should ever have left the oceans."
                                                --Douglas Adams

John Coughlin, BULL Kingston         [phone]         <[e-mail]>

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

Date: 23 May 89 23:26:07 GMT
From: att!cbnewsh![e-mail]  (ihor.j.kinal)
Subject: Re: Andromeda Strain

In article <[e-mail]>, [e-mail] (Henry Spencer) followups
an article in sci.space.

I've added sci.med, since that seems more appropropriate'

[original poster said]:
> >Could we imagine some nasty alien bug which
> >likes warm, moist, carbon-rich environments as energy sources, is not very
> >picky about what it eats, and which our immune system doesn't even see or
> >can't even scratch?
>

> It's possible.  Last I heard, there just doesn't seem to be any natural
> immunity to AIDS, for example -- we're very lucky that it doesn't spread
> easily.
>

In today's NY TIME, Science section, there's an article about a blood
carried parasite, found in many people of Latin America - it's not
quite as fatal as AIDS, but can be QUITE nasty, and not much
can be done to stop its spread. [can cause heart failure - and they
won't bother with a heart transplant, since it will get that also].

Apparently, the body's immune system does not react much against it,
so tests for its presence are currently NOT reliable.
[makes you want to be sure not to get sick to need a transplant :-) ].

Also, there are other diseases that our immune system seem to
be not very effective against:

    malaria, tapeworms, and most recently of note: LYME disease

    [see last week's Newsweek for some interesting reading on LYME disease:
     if the disease is not caught in its early stage
    {and some 25% of the people don't show any symptoms, so early detection
    is difficult } you are doomed to very EXPENSIVE drug treatments
    at $1000 a treatment, and they that don't necessarily work.
    While seldom fatal, it can be serious.


SUMMARY:  I'm not sure we need alien invaders, thank you.


Ihor Kinal
cbnewsh!ijk

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

Date: 24 May 89 03:13:19 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: Teach your children well

In article <[e-mail]> [e-mail] (Who remembers 8USER.PAR?) writes:
>I am never so frustrated and morose about our prospects for the future as
>when I find someone misunderstanding science.  Phrases like "it's been
>light-years since I saw home" (_Hard Time on Planet Earth_) ...

What is the difference between "light-years since I saw home" and
"miles to go before I sleep"?  Both describe a journey in terms of
the distances involved.
--
Tom Neff                UUCP:     ...!uunet!bfmny0!tneff
    "Truisms aren't everything."    Internet: [e-mail]

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

Date: 23 May 89 14:56:54 GMT
From: att!cbnewsh![e-mail]  (david.l.jacobowitz)
Subject: Re: spaceplane propulsion

In article <[e-mail]>, [e-mail] (Marcus Hall) writes:
> In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>
> There are still new boosters being designed using the RL-10.  OK, so we've
> thrown away the F-1 production, but we've also thrown away J-4 production.  It
> seems that the J-4 would have been very attractive for use in smaller boosters

Jeez, is there anything we *didn't* throw away?
--------------------------------------------
usual disclaimer implied
"F-1 Engines?  We don't need no stinkin' F-1 Engines."

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

Date: 23 May 89 09:15:43 GMT
From: mcvax!ukc!warwick!nfs4![e-mail]  (Keith Dancey)
Subject: Re: asteroid almost hits earth

In article <[e-mail]> [e-mail] (Hugh Hazelrigg) writes:
>In article <[e-mail]> [e-mail] (Keith Dancey) writes:
>>My understanding is that the demise of the dinosaurs extended over a period
>>of order of magnitude of a thousand years.  Certainly long enough to place
>>doubt upon the viability of a single catastrophy such as the one mentioned.
>
>What prevents the effects of a "single catastrophy [sic]" from propagating over
>a period of a thousand years?  On a geological scale of time, the events of a
>thousand years constitute less than a footnote in a billion-page volume.
>
True.  But you are forgetting that geology was not the issue in the
article on the relatively sudden extinction of dinasaurs.
The issue was whether a single impact could effect *meteriological*
conditions such that a species would become extinct.  For instance,
whether polluted skies would effect food chains and temperature.  But
if that scenario was to be true, then SURELY a species would die within
its lifetime.  If one dinosaur could survive its entire life under these
conditions, then so could another, and so on.  If dinosaurs took a
thousand years to become extinct, what finished off the last one that
*didn't* manage to kill its immediate forbears.  If anything, one would
assume that survivors of the first five hundred years would have been
selected to manage better under the austere conditions, rather than
the opposite.  It is also reasonable to assume that these hostile
conditions would *gradually* improve with time, thus *increasing*
the chances of species survival, rather than the opposite.
>
>Look:  a thousand years (or even five or ten) really is just a one-nighter
>(what a party!).  The earth may have lost a host of magnificent species, but
>did life disappear?
>
When you are talking about *dramatic* changes in climate and food chains
critically effecting species survival, then the time scales involved must
be of the order of seasons, rather than thousands of years.  One year of
darkness is all that it would take to destroy vegetarian dinosaurs.  But
they lasted for generations.  How?  And if even a single generation could
survive lower temperatures, why couldn't others?

>I believe the metorite/asteroid collision theory to be the best put forward to
>date to explain the demise of the dinosaurs and their ecosystem. Your objection,
>Keith, is ill-considered.
>
Far from it.  There are enormous problems with a *single* catastrophy such
as an asteriod strike *if* the palaeontological evidence is to be believed
(unless dinosaurs lived a thousand years, that is :-).
--
Keith Dancey,                               UUCP:   ..!mcvax!ukc!rlinf!kgd
Rutherford Appleton Laboratory,
Chilton, Didcot, Oxon, England  OX11 0QX
Tel: [phone]   ext 6756                JANET:       [e-mail]

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

End of SPACE Digest V9 #460
*******************