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Date: Mon,  8 Jan 90 01:22:14 -0500 (EST)
Subject: SPACE Digest V10 #384

SPACE Digest                                     Volume 10 : Issue 384

Today's Topics:
                 Antigravity
              Pegasus situation?
       Re: Scientific value of Apollo (was Re: Motives)
            Re: New years eve 1999
            Re: Big Bang:  Did it happen?
----------------------------------------------------------------------

Date: 30 Dec 89 08:31:04 GMT
From: samsung!uakari.primate.wisc.edu!caesar.cs.montana.edu!milton![e-mail]  (Mikel Stromberg)
Subject: Antigravity



There was a lot of interest in this area of study back in the fifties,
but it was determined that the effect arrises from the interaction of the
gyroscope and the methods used to measure it's mass.  There is no actuall
mass loss.  I forget what the name of this principle is, but there was once
an engine based on the effect called the 'Dean Drive'.

Ryan, The Tall Guy

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

Date:     Tue, 19 Dec 89 8:27:16 CST
From: Will Martin <[e-mail]>
Subject:  Pegasus situation?

I just checked all the recent SPACE Digests and see no mention of "Pegasus"
in the ones since #347. The following was from #344, and inspires a query
(below). I've seen absolutely nothing in local media on the results of the
test and would have been surprised to have seen anything, actually. Info
on things like this *should* be posted to SPACE; people can't expect to
get info on such things out of the general media these days. So was it
a successful test?

>Date: 13 Dec 89 19:45:10 GMT
>From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
>Subject: NASA Headline News for 12/13/89 (Forwarded)
>
>Preparations are underway for the second captive flight of the
>Pegasus air launched space booster Thursday morning.  During the
>flight a NASA B-52 will carry the 50-foot long winged booster to
>an altitude of 41,000 feet over the Pacific Ocean 50 miles off
>the California coast.  If all goes well...the first flight test
>of the Pegasus will be as early as mid-January.  The booster will
>carry a DoD and a NASA experimental payload.

Now, my query: assuming this test goes [went] OK, why is the plan to
wait until another month passes before doing it for-real? I get the
impression for the above and other net postings that this is a final
test -- everything is set up like the real launch, except they just
don't hit the "start" button. The live payload is on-board, the fuel
and consumables are all loaded, etc. The only difference is that they
then fly back to base with the vehicle still attached to the B-52.
Am I wrong on this? [If I am, then cancel this query.]

Certainly, if there are problems, they need to take whatever time is
necessary to fix whatever might have been discovered in this test. But,
if everything works OK, why wait a month? Why not then go up in a day or
two and do it for real? What's the purpose of forcing a month's delay in
any case?

Regards, Will

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

Date: 19 Dec 89 18:57:59 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: Scientific value of Apollo (was Re: Motives)

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>The point is, people keep saying [that the Moon could have been explored
>more cheaply unmanned than manned] without proving it.

Not much of a point; lots of unproven-in-detail assertions fly around
here on both sides of the issue, including from Henry.  On to something
more interesting.

>                                                         Apollo
>accomplished much more than some of its detractors admit,

There's some fancy Latin name for this argumentative fallacy but I
forget what it is.  There are people who think Apollo was a fake;
Apollo sure accomplished more than THOSE detractors admit, dinnit?

>                                                           and it would
>have taken a very large and costly unmanned program to get similar
>results.

This assumes that the exact laundry list of whatever finally happened to
get done on Apollo missions is actually what we needed to do.  But the
science Apollo did consisted of what could be shoehorned into the
incredible constraints of a manned mission profile.  It's to NASA's
great credit that they did as much as they did under the circumstances.
But science NEVER CAME FIRST as it can with an unmanned mission.

>           It *may* be true that it would have been cheaper to do things
>that way, but it is *not* a self-evident fact.

Who decided that "self evident fact" was the operative standard here,
I wonder.  Pretty strong!  We must remember this phrase later Henry :-)

>                                                 Claims to that effect
>would be much more credible if they included numbers, e.g. volume of
>samples, number of missions involved, estimated cost based on existing
>missions, etc.

Worth working up.  One model to shoot for would be, "Surveyor with a
sample bucket and a return engine."  My claim is that if Earth scientists
had had the luxury of a few unmanned landings with good stereo photographic
site documentation and a bucket of *ANY* rocks and soil taken therefrom,
they'd have learned a hefty fraction of what we now know about the Moon's
origins and composition.  They'd certainly be in a good position to
suggest followup trips; and they might still/even be doing them now.

Question to ponder: Would you rather the Apollo 17 results were being
obtained RIGHT NOW?  It would mean it took many extra years to get them;
but it would also mean we were still at work today.

>It's interesting that some of the people who said that Apollo was a
>ridiculously expensive way to get minimal results are now the ones who
>are saying that Apollo completely explored the Moon, so we should forget
>the Moon and press on to Mars.

Bah.  Claims to this effect would be much more credible if they included
names and statements...
--
Annex Canada now!  We need the room,    \)      Tom Neff
    and who's going to stop us.         (\      [e-mail]

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

Date: 19 Dec 89 19:16:33 GMT
From: wshb![e-mail]  ( WSHB employee)
Subject: Re: New years eve 1999

In article <[e-mail]>, [e-mail] (Usenet file owner) writes:
> The decade from 1 AD to 9 AD was defective, as it was only 9 years long.
>

For the past year I have been trying to teach my five year old daughter
to start counting at zero, not one. My wife and her teachers think I'm nuts.


--
Michael Batchelor -- Systems/Operations Engineer
WSHB - An International Broadcast Station of
          The Christian Science Monitor Syndicate, Inc.
uunet!wshb!michaelb                 803/625-4880

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

Date: 20 Dec 89 15:42:07 GMT
From: zaphod.mps.ohio-state.edu!usc!cs.utexas.edu!ut-emx![e-mail]  (Ethan Tecumseh Vishniac)
Subject: Re: Big Bang:  Did it happen?


As someone who has spent some years playing with cosmology, I'd thought
I'd kick in a few comments on the Big Bang.

There are at least two senses in which people are using that
phrase.  In one sense it refers to the idea that are universe is
currently expanding, has been doing so for some time, and at some
finite time in the past (somewhere between 10 and 20 billion years ago)
was extraordinarily hot and dense.  In another sense it refers to
the idea that the universe began with an initial singularity, and
"before" this point neither time nor space existed.  The first version
of this idea can be analyzed using  our current understanding of
physics (like GR, particle physics etc.) and by choosing to approximate
our universe as homogeneous and isotropic.  This usually goes by
the name of the "standard model".

There is an impressive amount of evidence in favor of the first
idea and no compelling evidence against it.  Besides being consistent
with physics as we know it, it  can be tested by comparing the
current blackbody background temperature (probably 2.75pm.05)
with the estimates of the primordial abundance of certain light
elements (H, He3, He4, D, Li7).  Consistency between these
figures can be used to constrain the average baryonic density
of the universe (This does not represent a trivial prediction.
It is difficult to get consistency and easy to imagine answers
for the elemental abundances which would be inconsistent with this
picture.)  In addition, it has been used to predict the number
of light, or massless weakly interacting particles (i.e. neutrinos).
This prediction has just been verified.  It is probably worth
noting that the predicted abundance of baryonic matter is not
inconsistent with dynamical estimates of the mass density of the
universe.  It has already been mentioned here that this model
has the only consistent explanation for the blackbody background.

The weakest aspect of this model is that it does not incorporate
galaxy formation.  There are a number of  galaxy formation models
that are consistent with the standard model, some of which cannot
be ruled out at the present time.  None of them is particularly
compelling, although models using cold dark matter are probably
ahead of the rest.  These models may fail if current observations
of large scale structure and motion hold up.  One of the tightest
constraints on all such models is the incredible isotropy of
the blackbody background.  The growth of gravitational structure
in an expanding universe is slow enough that the perturbations
that would have to grow into galaxies should have left some
remnant disturbance in the blackbody background.

Inflation is a way of explaining the features of the standard model
by using particle physics, and appealing to the high temperatures
present at *very* early times.  It is a nice idea, but has problems
and may not end up as part of the standard model.  As someone
else has noted it does seem to predict that the universe is
very close to critical density.  It does *not* predict that
the universe is closed or open (although specific models of inflation
do make such predictions).  The bulk of the observational evidence
seems to indicate that the universe has a much lower mean density.
Inflation (at least in some versions) also predicts a power spectrum
for temperature anisotropies in the blackbody background.

The idea of the Big Bang as a  real singularity in the fabric of
space-time is another issue.  This view results from an unreasonable
extrapolation of classical GR into temperature regimes where quantum
effects must be important, and there is no consensus view on how to
make  such corrections.   There have been many speculative papers on
how to do away with the initial singularity without changing the
standard model appreciably.  None of them command general assent, nor
are they likely to in the near future.

The bottom line is that the initial singularity and inflation could
be disproved (in some sense) tomorrow and our view of the universe
would not have changed a great deal.  I certainly wouldn't regard
it as the death of the "Big Bang Theory".
--
 I'm not afraid of dying     Ethan Vishniac, Dept of Astronomy, Univ. of Texas
 I just don't want to be     {charm,ut-sally,emx,noao}!utastro!ethan
 there when it happens.      (arpanet) [e-mail]
    - Woody Allen            (bitnet) [e-mail]

These must be my opinions.  Who else would bother?

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

End of SPACE Digest V10 #384
*******************