Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V08/V8_317.TXT

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Subject: SPACE Digest V8 #317

SPACE Digest                                      Volume 8 : Issue 317

Today's Topics:
     Re: Doppler lidar, ESA publications(was: NASA news - Seasat)
                Re: Space Race
        Re: International Geosphere-Biosphere Program
          The philosophy of orbital modeling
  Re: Automated vs. personned spacecraft -- a reasonable compromise
          Re: query about 'escape velocity'
                   E stamp
             Re: Libertarian space policy
           Re: Time Travel (was Re: (none))
               Re: Time travel
         Re: Time skew -- does it hurt SETI?
----------------------------------------------------------------------

Date: 29 Jul 88 15:32:15 GMT
From: aplcen!aplcomm!stdc.jhuapl.edu![e-mail]  (Jim Meritt)
Subject: Re: Doppler lidar, ESA publications(was: NASA news - Seasat)

In article <[e-mail]> [e-mail] (Bill Higgins-- Beam Jockey) writes:
}The object is to shine a laser down, observe scattered light off dust particles
}and aerosols, and measure the Doppler shift.  Do this from two angles (two
}spots in the satellite's orbit) for the same location on the surface, and you
}have enough velocity information to get the two-dimensional wind pattern. Time
}delay of the laser pulse gives you depth. This could be a great boon to the
}weather guys, especially in the Southern Hemisphere where surface measurements
}are sparse.


You can get surface wind measurements from the altimeter of the geosat
satellite during ocean transits.  Thus, surface measurements in the
Southern Hemisphere (mostly water) are not quite as sparse as one might
be lead to believe....

(I know you can because I do.  JHU APL is the site of the geosat
ground station)



Disclaimer: Individuals have opinions, organizations have policy.
            Therefore, these opinions are mine and not any organizations!
Q.E.D.
[e-mail] 128.244.65.5  (James W. Meritt)

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

Date: 29 Jul 88 17:46:58 GMT
From: ns![e-mail]  (John Logajan x3118)
Subject: Re: Space Race

Donna Reynolds (DR9021 at UCSFVM) writes:
> some folks believe the
> Soviets initiated the race to the moon solely to draw
> attention and funds from the X-15/X-20 program,

I have no information on this, but it seems to me that this is in the same
vein as a lot of other suggestions that we are but pawns in the schemes of
our enemies.  If our space program was/is founded upon stupidity, then we
should lay the blame at the feet of those responsible for the program.
Saying, "the devil made us do it!" isn't an honest assessment of reality,
I suggest.

- John M. Logajan @ Network Systems; 7600 Boone Ave; Brooklyn Park, MN 55428 -
- {...rutgers!dayton, ...amdahl!ems, ...uunet!rosevax!mmm} !viper!ns!logajan -

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

Date: 30 Jul 88 02:37:35 GMT
From: sunybcs![e-mail]  (David Mark)
Subject: Re: International Geosphere-Biosphere Program

In article <[e-mail]> [e-mail] (Gregory Behm) writes:
>I am searching for information about the International Geosphere-Biosphere
>Program, and hope that some of you on the net might be of assistance.  Any
>information about the program, including (but not limited to) planned or
>proposed research and participating organizations, will be greatly appreciated.
>

The International Geographical Union recently sponsored a "Global Database
Planning Project" meeting.  That meeting was by no means restricted to IGBP,
but did pay considerable attention to IGBP's data-handling needs.  Two IGU
representatives will attend an IGBP meeting in Moscow in August to present
findings.  Here are electronic mail addresses for organizers of the
IGU-GDPP meeting, which I should add was held at Tylney Hall, England,
May 9-13, 1988:

Meeting Chair:          Dr. Roger Tomlinson, Ottawa, Canada;
                        [e-mail]

Scientific coordinator: Dr. Michael F. Goodchild, UC Santa Barbara;
                        [e-mail]  or [e-mail]

Meeting coordinator:    Dr. David Rhind, Birkbeck College, University of London
                        [e-mail]

Hope this is of some interest.  I have a program of the meeting.  Proceedings
will be published.
_______________________________________________________________________________

David M. Mark, Professor of Geography, SUNY at Buffalo
[e-mail]
[e-mail]

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

Date: 29 Jul 88 20:57:41 GMT
From: ns![e-mail]  (John Logajan x3118)
Subject: The philosophy of orbital modeling


I was just pondering the philosophy of orbital modeling.  Any real
orbiting object knows nothing of orbits, or ellipses or the rules
of orbits, but rather responds only to its own instantaneous velocity,
mass, and gravitation force.

But humans, upon observing orbits, noticed first the elliptical nature
of orbits.  And so was born a system by which indirect effects of
gravitation and momentum could be used to predict orbital behavior.

This "elliptical" model, of course, gets very complicated for more than
one main body.  But its value lies in that calculations for the most
part avoid the problem of cumulative error.  And that is why, in the
main, it is used for earthly satellites.

Powered flight, on the other hand, does not fit so easily into the
elliptical model.  With its constant vector changes, the only model that
can closely approximate this vehicle behavior is the dv/dt model.

- John M. Logajan @ Network Systems; 7600 Boone Ave; Brooklyn Park, MN 55428 -
- {...rutgers!dayton, ...amdahl!ems, ...uunet!rosevax!mmm} !viper!ns!logajan -

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

Date: 30 Jul 88 03:38:43 GMT
From: silver![e-mail]  (Lucius Chiaraviglio)
Subject: Re: Automated vs. personned spacecraft -- a reasonable compromise

In article <[e-mail]> [e-mail] (Will
Martin -- AMXAL-RI) writes:
>There is an obvious middle ground. This is not my original idea -- it has
>been standard in SF for decades. You send a human brain, interfaced to the
>mechanisms, and do not waste space and mass on all the gorp required to
>support a full human body.

    If you don't waste space and mass on all the gorp required to support
a human body, you have to waste space and mass on all the gorp required to
simulate a human body so that the brain will stay alive, and this is something
that we can't do at all today and which is likely at least decades away.

>                           Up until recently, that was just "pie in the
>sky" wishful thinking, but, as researchers progress more and more on
>viable interfaces for prosthetic devices and sensors, it becomes a
>reasonable way to get human thinking ability integrated on a real-time
>basis with automated deep-space probes.

    No way -- at least not today.  We can't even build an artificial heart
(which would be needed to support the brain, not to mention all the other
artificial things needed) that keeps a person alive for any great length of
time. . .

>                                        Carrying only the oxygen,
>fluids, and nutrients to support the few pounds of brain tissue, and,
>ideally, equipped with nanotechnology repair units to fix up radiation
>damage and wearing-out biological elements, a human brain with a
>spaceship body could not only explore the solar system and Oort cloud,
>but reach the stars.

    . . .and nanotechnology of the quality needed for what you propose is
well beyond the horizon, given that microtechnology other than computer chips
is only now starting to be developed in labs.

>                     The lifetime of this synergy could be centuries,
>since all the non-neurological toxin-producing parts of the body would
>be gone, and longer-lived and replaceable mechanical parts would provide
>the support functions.

    Has it ever occurred to you that maybe our neurons age partly due to
causes of their own, and not due to faults of the human body?  Of course, as
the human body ages, it does become a markedly poorer environment for the
nervous system, but machines break down too, and we self-repairing machines
are quite a long way off.

>This is a perfect opportunity for those of us with non-astronaut
>physiques. I, myself, would love such a change, to shed this wretched
>physical body and become a spaceship! (I'd probably volunteer to do it
>for even a lesser goal, like becoming a deep-diving submersible or
>a geologic exploration mechanical mole!) So you don't have 20/20 vision?
>Doesn't matter -- your eyes will be replaced with multispectral scanners
>and imagers interfaced into your visual cortex, far keener and more
>enlightening than human eyes could ever be. [. . .]

    All fine and dandy -- let me know when you find a rig of this kind
that works at all.

>The fighter pilots and jocks can keep their fine figures -- I'll choose
>a mechanical support system which can be continuously improved with
>technological upgrades over the decades. Hmmm... if those of us who
>get into this line of work write our contracts right, we'll probably end
>up owning the planet in a couple centuries, with compound interest on
>the back pay piling up while we're off to the stars...

    The way our economic systems work, once you get into this kind of
deal, IBM or Humana or NASA or the Soviet Government or a Japanese trading
house or something will own you.  My body is lousy, but at least I own it (so
far. . .) and it does work passably, which is something that no assemblage of
prostheses has been able to do or will be able to do until at least well into
the next century (even if our civilization continues to advance, which is
quite a bit in doubt).

    -- Lucius Chiaraviglio
       [e-mail]
       [e-mail]    (in case the first one doesn't work)
    "Fluke. . .Fluuuuke. . .  Let go -- and hang on.
    And if you can't be good -- at least be careful."

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

Date: 30 Jul 88 06:38:33 GMT
From: polya![e-mail]  (Roger Crew)
Subject: Re: query about 'escape velocity'

In article <[e-mail]> [e-mail] (Jonathan McDowell) writes:
> From article <[e-mail]>, by [e-mail]:
> [... question about escape velocity..]
>
>  'Escape velocity' is just the velocity needed to leave the Earth
> WITHOUT any further thrust; that is, if you freely fall with this
> velocity (in a direction away from the Earth!)

Actually, it doesn't matter what direction you're pointed in,
so long as there's nothing directly in your path that is going
to slow you down (like an atmosphere or a swarm of rocks).

Once you've got sufficient kinetic energy, that's it...

> you are on a parabolic orbit that will not return you to the Earth.

Orbital mechanics can be a bit strange sometimes (Arthur C. Clarke
had a number of good short stories along these lines...).

--
Roger Crew                    ``Beam Wesley into the sun!''
Usenet:    {arpa gateways, decwrl, uunet, rutgers}!polya.stanford.edu!crew
Internet:  [e-mail]

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

Date: 30 Jul 88 09:24:08 GMT
From: hanauma![e-mail]  (Joe Dellinger)
Subject: E stamp


    Anybody looked closely at the new U.S. "E" stamp?

    Notice anything funny about it?
    (Hint: where's the terminator, and which direction does it run?)

    Perhaps we really DO need to spend more time studying
    before launching anything!
\    /\    /\    /\/\/\/\/\/\/\.-.-.-.-.......___________
 \  /  \  /  \  /Dept of Geophysics, Stanford University \/\/\.-.-....___
  \/    \/    \/Joe Dellinger [e-mail] decvax!hanauma!joe\/\.-._

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

Date: 29 Jul 88 13:50:05 GMT
From: mcvax!ukc!etive![e-mail]  (Bob Gray)
Subject: Re: Libertarian space policy

In article <[e-mail]> [e-mail] (John Limpert) writes:
>.......  The reason for the acceptance of
>the current treaty was the perceived uselessness of Anarctica.
>If someone discovers valuable mineral deposits, the current treaty
>may not last very long.

The treaty isn't goint to last very much longer anyway. It
comes up for renewal in 1994(?). The Falklands conflict was
at least partly caused by the reports of large mineral
deposits in the area, and further to the south, all of which
will be up for grabs when the treaty runs out. Some of the
countries nearest Antartica reckon they should have first claim
on terratory there.
    Bob.

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

Date: 30 Jul 88 17:55:46 GMT
From: vsi1!unisv![e-mail]  (Mike Van Pelt)
Subject: Re: Time Travel (was Re: (none))

In article <[e-mail]> [e-mail] (Owen McArdle) writes:
>I comfort myself with the reasoning that
>even if they wanted to, and tried really hard to, do something WHICH THEY
>KNOW IN THEIR OWN TIME NEVER HAPPENED, then they can't. Some combination
>of circumstances must have prevented them.

There's a very good story by Larry Niven (who else?) which
deals with exactly this approach to the paradox problem.  The
title is something outrageously long and 'Thesis-title' sounding,
like "On Rotating Cylinders and the Possibility of Global Causality
Violation".  Two civilizations are at war, and one of them discovers
a huge neutronium cylinder left in space by some previous,
now-extinct civilization.  They figure out it was indended to be
a time machine, and was almost completed ... I won't spoil it by
telling any more.
--
Mike Van Pelt                          Here lies a Technophobe,
Unisys, Silicon Valley                 No whimper, no blast.
[e-mail]                     His life's goal accomplished,
                                       Zero risk at last.

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

Date: 30 Jul 88 19:52:32 GMT
From: [e-mail]  (Kevin William Ryan)
Subject: Re: Time travel


   Somebody (I believe Larry Niven) once said that the only possible future
was a future without time travel.  If time travel were invented at some point,
busybodies would change the past, changing their own present.  The only stable
end to this would be a future where there was no possibility of time travel -
where perhaps the inventors would never be born or something.  Simpel, eh?

   "Now look what a mess you've gotten us into!"

                                                    kwr

   "Jest so ya know..."

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

Date: 29 Jul 88 17:39:55 GMT
From: amdahl!pacbell!hoptoad!dasys1![e-mail]  (Tom Neff)
Subject: Re: Time skew -- does it hurt SETI?

In article <[e-mail]> [e-mail] (Martin Sodos) discusses
the 'time skew' factor and how it affects SETI.  He notes the slim piece
of Sagan's "Calendar" occupied by human civilization, and also the rapid
evolution of technology within this little slice of time, and concludes
it's unlikely we'll be able to contact other intelligent life even if it
exists.  I disagree with almost all of this.

First let's define the goal.  ET contact of interest to us would include,
in increasing order of desirability (but all fantastic!), any of (1)
simple DETECTION of an ET civilization, regardless of whether or not they
were technologically advanced; (2) RECEPTION of an ET signal, regardless
of whether or not answering was practicable; or (3) two-way CONVERSATION.
(If we received a signal we would probably try and answer it, but we would
have no way of knowing whether it would be received unless the distances
involved were very short.  To prove conversation, we would have to receive
a signal which recognizably referred to something we had previously sent.)

Let's also assume that by "signal" we mean some kind of radiation, be it
EM, neutrino, graviton or what have you.  If something radically different
pops up, SETI will presumably add it in but not abandon the old spectra.

Now, in the lifetime of each planet there will be an epoch of some
length (perhaps zero) wherein technological intelligence is present and
capable of leaving an EM trace of some kind.  (Assuming the inhabitants
sustain a continuous interest in SETI soon after developing the
capability, there will be a sub-epoch wherein part of the planet's EM
trace is purposefully augmented and/or organized to encourage
detection.)  Since stars grow and die within the universe's lifetime,
each such epoch is finite.  Thus each intelligence bearing planet emits
a spherical signal "shell" of finite thickness, expanding at lightspeed
through the universe.  The outer edge of each "shell" contains early
radio experiments, then brightness increases (and the spectrum widens)
farther into the shell, with ??? near the inner (terminal) edge.

What we don't know is how many EM bubbles are out there "now" (this is
the "magic number" of SETI), nor how thick they are (Sagan is no help
on this at all -- how can he know?  We just started our bubble), nor
how many intersecting bubbles our system might presently lie in.  This
latter number is equal to how many civilations we COULD detect given
the right equipment and techniques.

I cannot accept, however, that all such bubbles must be vanishingly
thin, or that only one (ours) exists.  I hope and suppose that there
are quite a few, and that many of them are thick.  They may be rather
tenuous though.

--
Tom Neff            UUCP: ...!cmcl2!phri!dasys1!tneff
    "None of your toys    CIS: 76556,2536           MCI: TNEFF
     will function..."    GEnie: TOMNEFF           BIX: t.neff (no kidding)

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

End of SPACE Digest V8 #317
*******************