Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_3/V15NO373.TXT

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Date: Tue,  3 Nov 92 05:03:46
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #373
To: Space Digest Readers
Precedence: bulk


Space Digest                Tue,  3 Nov 92       Volume 15 : Issue 373

Today's Topics:
          ANSWER: Recognizing a Dyson sphere if you saw one
                 Automated space station construction
                        HRMS for ETI (2 msgs)
                             NASA Coverup
                          Pumpkins to Orbit
      Surveyor landings (was Re: QUESTIONS: Apollo, Earth, Moon)
                Swift-Tuttle Comet a threat to earth?
                          Why Vote? (3 msgs)

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

Date: 3 Nov 92 02:21:26 GMT
From: Erik Max Francis <[e-mail]>
Subject: ANSWER: Recognizing a Dyson sphere if you saw one
Newsgroups: sci.astro,sci.space

[e-mail] (Frederick A. Ringwald) writes:

> My thanks to all who e-mailed me on this thread, here are the results.
> A Dyson sphere would probably look like a slowly rotating, old-disk F-K
> dwarf (i.e., Sun-like) star with a small IR excess, with the spectrum
> of a 300 K blackbody of size on the order of 1 AU.

An F-K _dwarf_?  How's that?

Seems to me that a globe with a radius of 1 au and a temperature of 300 K
would look like an infrared supergiant or, perhaps, a protostar.


----------
Erik Max Francis   Omnia quia sunt, lumina sunt.  Coming soon:  UNIVERSE _ | _
USmail:  1070 Oakmont Dr. #1 San Jose CA 95117  ICBM:  37 20 N  121 53 W _>|<_
UUCP:  ..!apple!uuwest!max   Usenet:  [e-mail]   464E4F5244   |

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

Date: Tue, 3 Nov 1992 01:31:32 GMT
From: "I am a terminator." <[e-mail]>
Subject: Automated space station construction
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (mike) writes:
|> In article <[e-mail]> [e-mail] (Andrew Haveland-Robinson) writes:
|> >
|> >In article <[e-mail]> [e-mail] (I am a terminator.) writes:
|> >
|> >>Can robots be launched to build the space station? They can work overtime.

|> The original poster asked if robots could be used to build the space station.
|> The answer is yes, they could, but they won't.  The technology is too young
|> to be trusted yet.

What kind of snags can be foreseen? Can a robot launched now meet and
work with a robot launched a bit earlier? Can we demonstrate that some
pie in the sky can be built? Arms and eyes on rockets slinging
snap-together parts? I thought this would be commonplace stuff by now.

|> Virtual Reality is not viable because of long transmission
|> lags (up to 7 seconds, I hear) from down to up and back.  If we designed Space
|> Station for robotic compatibility, AND we had a closet full of replacement
|> robots, the technology is there, and it would be a lot cheaper (albeit slower).
|> I hear it takes $55000/hour of support to have an astronaut in a spacesuit.

Gimme a few hours worth of money (n x 55000) and some rockets and I bet
I can whip up robots that'll put together a space station. I wouldn't
care if the robots didn't last or anything. I wouldn't have spent a whole
lot of cash and I'd have some knowledge to show for it. All I need is a bit of
time, and a bit of knowledge about getting a piece of machinery to work
in space, and I can build something that can Move. I can cut costs by
not worrying about paperwork and all that. I can follow standard procedure
to avoid colliding with satellites and such stuff. Don't those people at NASA
have skunkworks?

Henry Choy
[e-mail]

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

Date: Tue, 3 Nov 1992 01:14:18 GMT
From: Marc Roussel <[e-mail]>
Subject: HRMS for ETI
Newsgroups: sci.space,sci.bio

In article <[e-mail]> [e-mail] (Stanley Friesen)
writes:
>In article <[e-mail]> [e-mail]
>(Paul Dietz) writes:
>|Prebiotic Miller-Urey type
>|experiments have not, to my knowledge, ever produced nucleotides, nor
>|have they produced anything but racemic mixtures of mostly
>|biologically irrelevant molecules.
>
>I am fairly sure I heard about the production of nucleotides, and even short
>poly-nucleotides, in Meller-Urey type experiments.  True, they were still
>racemic.

     I'm not sure I understand the significance of this.  What's wrong
with racemic mixtures?  It would seem to me that a preferred chirality
would have arisen at a relatively late stage of biotic (not prebiotic)
development.  The only reason that we have any preferences that way is
that we rely on enzymes to speed things up.  It's only after enzymes get
sufficiently complicated that chirality would start to matter.  At that
point, there would be selective pressures to make most of the
biochemistry "fall into line" with whatever the first few enzymes
required.
     On more fundamental grounds, the free energy difference between two
chiralities of the same molecule is very small.  The kinetic properties
of the two (in the absence of enzymes) are also nearly identical.
Prebiotic synthesis can therefore not have generated significantly
different amounts of (for instance) R- and L-amino acids.  Whatever
differences in the distribution of the two we see now must have arisen
as a consequence of biological evolution and not as a prelude to it.  To
put it yet another way, it's not much of a criticism of Miller-Urey
experiments to say that they produce only racemic mixtures.  (Paul's
other points are harder to dismiss.  Our understanding of prebiotic
evolution is, if you'll pardon the pun, primitive.)

                Marc R. Roussel
                                [e-mail]

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

Date: Tue, 3 Nov 1992 01:27:59 GMT
From: Paul Dietz <[e-mail]>
Subject: HRMS for ETI
Newsgroups: sci.space,sci.bio

In article <[e-mail]> [e-mail] (Stanley Friesen) writes:
>In article <[e-mail]> [e-mail] (Paul Dietz) writes:

>|Sure, we've made RNAs in the laboratory -- using purified, chiral
>|tri(?)phosphorylated nucleotides, which (correct me if I'm wrong)
>|are extracted from biological sources.
>
>The *key* point is that we have made one that is *self-reproducing*,
>not merely that it was RNA.


But would they be self reproducing in any realistic mixture?  The
polyphosphorylated nucleotides are very unstable, as they have
considerable chemical energy.  Moreover, in any real system,
they would be mixed with many times their own concentration
of other random molecules, which would jam replication: deviant
bases, nucleosides with incorrect base-sugar connections, etc.

Also, is this system really self-reproducing?  I thought
to get actual exponential growth one needs to add an enzyme.


>|Prebiotic Miller-Urey type
>|experiments have not, to my knowledge, ever produced nucleotides, nor
>|have they produced anything but racemic mixtures of mostly
>|biologically irrelevant molecules.
>
>I am fairly sure I heard about the production of nucleotides, and even short
>poly-nucleotides, in Miller-Urey type experiments.  True, they were still
>racemic.

I'd like to see a reference, please.

    Paul F. Dietz
    [e-mail]

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

Date: 2 Nov 92 21:05:25 GMT
From: [e-mail]
Subject: NASA Coverup
Newsgroups: sci.space,alt.conspiracy

  In   message-ID:  <[e-mail]>  (Dillon  Pyron)
  writes:

  >incoherent babblings deleted

  >You know, it is dangerous to scarf that many peyote buttons in one sitting!

   I don't do drugs. I appreciate the attempt at humor ,  however.   If  you
   really  find  my  reasoning defective or incoherent ,I would like to know
   just what it is you are having difficulty with.   In  the  alternative  ,
   please provide me with the name of your learning disability.

   snarfy

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

Date: Tue, 3 Nov 1992 01:44:10 GMT
From: Bruce Dunn <[e-mail]>
Subject: Pumpkins to Orbit
Newsgroups: sci.space

Now is your chance!  For years you have been working in your basement on a
mass driver system for space applications, and haven't been able to get the
public interested.  Your problem is that you haven't had the proper forum to
demonstrate your device and get international publicity.  The following
excerpt from the weekend magazine of the Washington Post details the ideal
way to show that your space-related mass driver actually has earthborne
relevance:

(begin quote)

Autumn.  The leaves have turned brown, the air cold.  Political Washington
has worked itself into a fever pitch.  Perfect time to head for the beach.
And don't forget to pack your pumpkin.

On the first Saturday after Halloween [Nov 7], the first town (Lewes) in the
first state (Delaware) engages in a proud tradition:  They call it Punkin'
Chunkin'.

Last year, about 7,000 people gathered for the annual competition, the object
of which is to hurl your pumpkin farther than anyone else's, using a
contraption of whatever design - catapult, slingshot, centrifuge, crossbow -
you think will do the job.

In 1986, the event's first year, the winning team lobbed its gourd 60 feet.
The current record, 775 feet, was set in 1990.  The rules are simple:

1) Pumpkins shall weigh between 8 and 10 pounds.
2) Pumpkins shall leave intact.
3) No part of the machine shall cross the starting line.
4) No explosives are allowed.

What's the use of trying to propel a pumpkin without explosives, you ask?
Well, for starters, it demands a certain amount of ingenuity.  Past
competitions have seen devices that relied on, amoung other things, 40 steel
railroad car springs, a 1949 Model A John Deere tractor, a tree trunk and an
airplane.

This year, several engineering schools have expressed interest, so it's
anyone's guess how far the pumpkins will fly.

Which raises the question:  Are we safe here in metropolitan Washington?

"Oh, I don't think they'll fly that far," says a Lewes Chamber of Commerce
spokesman, pausing a beat and adding, "Give us anouther couple of years."

(end quote)

     Here is your chance.  Just think of the papers which could be written.

"The optomiziation of a linear propulsion device for vegetable matter"
"The subsonic and suspersonic aerodynamics of pumpkins"
"Investigation of maximal G forces sustainable by living tissue, using a
novel inexpensive surrogate for the human head"

        Seriously, if anyone goes and watches the contest, a posting
describing the event would be interesting.



--
Bruce Dunn    Vancouver, Canada   [e-mail]

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

Date: 3 Nov 1992 05:36:59 GMT
From: Scott Fisher <[e-mail]>
Subject: Surveyor landings (was Re: QUESTIONS: Apollo, Earth, Moon)
Newsgroups: sci.astro,sci.space

chris@kbsw1 (Chris Kostanick 806 1044) writes:

>In article <[e-mail]> [e-mail] writes:
>>further  reduce the descent velocity.  At 4.3 km above the surface, the
>>three thrusters were shut off, and the spacecraft simply dropped the
>>remainder of the way down, landing at a velocity of 11 km/hour.
>>


>If I understand you correctly, this means that I could drop over
>a mile on the moon and walk away from the landing. (I can walk into
>a wall at better than 6 miles an hour and not get hurt.) This

If you are lucky.   I have hurt myself standing still :-)

Scott.
_______________________________________________________________________________
Scott Fisher [[e-mail]]  PH: Aus [61] Perth (09) Local (380 3272).
                                                             _--_|\       N
Department of Psychology                                    /      \    W + E
University of Western Australia.      Perth [32S, 116E]-->  *_.--._/      S
Nedlands, 6009.  PERTH, W.A.                                      v

    *** ERROR 144 - REBOOT? is a registered trademark of ENSONIQ Corp ***
-------------------------------------------------------------------------------

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

Date: 2 Nov 92 17:18:53 EST
From: [e-mail]
Subject: Swift-Tuttle Comet a threat to earth?
Newsgroups: sci.astro,sci.space

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

In article <[e-mail]>, [e-mail] (Scott D. Young) writes:
> In <[e-mail]> [e-mail] (Thorsten Altenkirch) writes:

>    According to the data I have seen (I will try and find the reference),
>    a comet 1 mile in diameter moving at an averge orbital velocity (what
>    ever tht means) would cause a crater 40 miles diameter, and destroy
>    everything for 100 miles. 400 million cubic *miles* of dirt would be
                               ^^^^^^^^^^^^^^^^^^^^^^^^^
A 20 mile radius sphere only contains 33,500 cubic miles.  400 Mega cubic
miles of dirt would be a sphere of roughly 450 mile *radius* or 900 mile
diameter.

--

   Jim Batka  | Always remember ...                        | Buckaroo
   Modemman   |    No matter where you go, there you are!  |   Bonzai
--------------+--------------------------------------------+--------------
It is very    | Work Email:  [e-mail] | Elvis is
often easier  | Home Email:  [e-mail]      |   DEAD!
to get for-   |--------------------------------------------+--------------
giveness then | 64 years is 33,661,440 minutes ...         | Beatles:
permission    |    and a minute is a LONG time!            |   Yellow Submarine

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

Date: Tue, 3 Nov 1992 02:15:46 GMT
From: Erik Russell <[e-mail]>
Subject: Why Vote?
Newsgroups: sci.space

t follow?  Who gets the electoral votes in a
state is determined by the popular vote in the state.

This is not really true.  A few states have laws that mandate the electoral
college to vote for their canidate due to popular vote.  This is not true
is many and therefore, the electoral college members can vote for the other
canidate.

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

Date: Tue, 3 Nov 1992 05:18:20 GMT
From: Ray Fischer <[e-mail]>
Subject: Why Vote?
Newsgroups: talk.abortion,soc.motss,sci.space

<[e-mail]> writes ...
>
>                                      Democracy is the recurrent suspicion that
>                                      more than half of the people are right
>                                      more than half of the time.
>                                                      --E.B. White

On one occasion I remarked ... that democracy had at least one merit,
namely, that a Member of Parliament cannot be stupider than his
constituents, for the more stupid he is, the more stupid they were to
elect him.
    -- Bertrand Russell

--
Ray Fischer                   "Convictions are more dangerous enemies of truth
[e-mail]                 than lies."  -- Friedrich Nietszsche

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

Date: Tue, 3 Nov 1992 05:14:12 GMT
From: Ray Fischer <[e-mail]>
Subject: Why Vote?
Newsgroups: talk.abortion,soc.motss,sci.space

[e-mail] (David Knapp) writes ...
>Clearly, an individual's vote doesn't matter at all as evidenced by the
>way the election turns out whether they vote or not. Voting is a symbolic,
>not a functional, act.

If you're a Republican: Yes, you are correct.  Don't bother.
If you're a Democrat:   Bullshit.  Get your lazy ass in there and VOTE.

:-)

--
Ray Fischer                   "Convictions are more dangerous enemies of truth
[e-mail]                 than lies."  -- Friedrich Nietszsche

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

End of Space Digest Volume 15 : Issue 373
------------------------------