Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V08/V8_241.TXT

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From ota Thu Jun  2 03:05:03 1988
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Subject: SPACE Digest V8 #241

SPACE Digest                                      Volume 8 : Issue 241

Today's Topics:
         Re: anthropic cosmological principle
         Re: anthropic cosmological principle
             P.C.W. Davies Books
         Re: anthropic cosmological principle
         Re: anthropic cosmological principle
            Re: Shooting the Moon
     Re: Cometesimals (was: Millions of comets hit Earth)
            Re: Shooting the Moon
            Re: Shooting the Moon
       Re: Question about Richard Hoagland/Mars Project
            Re: Shooting the Moon
       Re: Question about Richard Hoagland/Mars Project
       Re: Shooting the Moon (really Martian ballooning) (LONG)
----------------------------------------------------------------------

Date: 6 May 88 19:24:18 GMT
From: [e-mail]  (David Wall)
Subject: Re: anthropic cosmological principle

Marc Hairston recommends _The_Accidental_Universe_, and I do so also.
It should be noted, however, that it is by A. J. P. Davies, not Paul
Davies.  I used to think they were the same (and they might be) but
their books are quite different.  My impression from reading them is
that the former is a real scientist and the latter is a mystic.

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

Date: 6 May 88 21:28:16 GMT
From: [e-mail]  (Jon Livesey)
Subject: Re: anthropic cosmological principle

In article <[e-mail]>, [e-mail] (David Wall) writes:
> Marc Hairston recommends _The_Accidental_Universe_, and I do so also.
> It should be noted, however, that it is by A. J. P. Davies, not Paul
> Davies.  I used to think they were the same (and they might be) but
> their books are quite different.  My impression from reading them is
> that the former is a real scientist and the latter is a mystic.

    I have the book in front of me:

        P. C. W. Davies.
        The Accidental Universe
        Cambridge University Press.
        1982.

    The jacket blurb begins "In 'The Accidental Universe" renowned
expositor Paul Davies grapples with the most fundamental questions of
all."

    Paul Davies is Professor of Theoretical Physics at the
University of Newcastle upon Tyne (which used to be called King's
College, Durham, when I was a tyke).

    Could you be thinking of A. J. P. Taylor, the historian?

jon.

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

Date: 8 May 88 23:39:34 GMT
From: amdahl!apple![e-mail]  (Dan Allen)
Subject: P.C.W. Davies Books

It seems that Paul Davies also goes by P.C.W. Davies.  His latest book
from Simon and Schuster is called _The_Cosmic_Blueprint_ and is on the
Scientific American reading level, along with:

    The Runaway Universe
    Other Worlds
    The Edge of Infinity
    God and the New Physics
    Superforce

Then there are his "student texts":

    Space and time in the modern universe
    The forces of nature
    The search for gravity waves
    The accidental universe
    Quantum mechanics
    The ghost in the atom

And finally there are his "technical" works:

    The physics of time asymmetry
    Quantom fields in curved space

All of the above information came from the "Also by Paul Davies" page of
his latest book, _The_Cosmic_Blueprint_.

Editorial: I have about five of his books and find them pretty good on
the whole.  I particulary like his _The_Accidental_Universe_ which is a
condensed version of the big Barrow & Tipler
_The_Anthropic_Cosmological_Principle_ book which is also very good.

His latest book (Cosmic Blueprint) is so-so.  _God_And_The_New_Physics_
is the best of his easy reading level for me, because it has a neat
philosophical side to it that the average science retelling does not
have.

I have not yet dived into his "technical" works, only because I have not
seen them for sale.  Does anyone have anything to say about them?

One final comment: on my shelf of favorite books (the ones that I would
take if on a desert island) I have the Barrow & Tipler, as well as two
of Davies student level texts.  For the curious, I also have Misner
Thorne and Wheeler's _Gravitation_, Allen's _Astrophysical_Quantities_,
Harwit's _Astrophysical Concepts_, Rindler's _Essential_Relativity_,
Feynman's _QED_, Einstein's _The_Meaning_Of_Relativity_, Tolman's
_Relativity_Thermodynamics_and_Cosmology, Eddington's _Space_Time_and_
Gravitation, and two other authors.

F.S.C. Northrop's _Science_And_First_Principles_, a classic wonderful
book by a man that I have heard so little about, and almost everything
that KARL POPPER ever wrote.

Keep in mind that this is my favorite shelf of physics books.  The rest
number in the 100s, and then there is computers, philosophy, religion...
It is so hard to make a SHORT list of favorites.  Try it sometime!

Dan Allen
Software Explorer
Apple Computer

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

Date: 7 May 88 23:33:09 GMT
From: mnetor!utzoo!yunexus!ists![e-mail]  (Mike Clarkson)
Subject: Re: anthropic cosmological principle

In article <[e-mail]>, [e-mail] writes:
> Martin Gardner has written that the FAP should be renamed the
> completely ridiculous anthropic principle (CRAP).

I like that.

> All the anthropic principles are interesting, but since none of them
> can be tested or used to make predictions, then they fall outside of
> science and into the realm of philosophy (which is nothing new to this
> group).

Not true: most of the anthropomoric principles centre around the
assumption that carbon is a a requirement for life forms as we know
them.  It turns out that the relative abundance of carbon in the
universe places some pretty severe restrictions on what must have
transpired during the first second of the universe's existence after the
big bang, so in fact the anthropomorphic principle does allow one to
make predictions.  One of the important early papers in this field was
Dirac's paper in Nature (1961 I think, sorry I don't have the reference
here).  It began "It is well known that carbon is required to make
physicists..."

When you are working in quantum mechanics, the line between physics and
philosophy is very thin; perhaps nowhere more so than in areas like the
quantum theory of gravity.  But it is most definitely science, and
predictions can be made.  Dirac was no philospher; he was an execellent
and very practical scientist.

Mike Clarkson                    [e-mail]
Institute for Space and Terrestrial Science    [e-mail]
York University, North York, Ontario,        uunet!mnetor!yunexus!ists!mike
CANADA M3J 1P3                    [phone]

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

Date: 11 May 88 23:18:17 GMT
From: oliveb!3comvax![e-mail]  (Michael McNeil)
Subject: Re: anthropic cosmological principle

In article <202@ists> mike@ists (Mike Clarkson) writes:
>When you are working in quantum mechanics, the line between physics and
>philosophy is very thin; perhaps nowhere more so than in areas like the
>quantum theory of gravity.  But it is most definitely science, and
>predictions can be made.  Dirac was no philospher; he was an execellent
>and very practical scientist.

    I am now convinced that theoretical physics is
    actual philosophy.
        Max Born

Michael McNeil

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

Date: 5 May 88 00:10:43 GMT
From: tektronix!reed![e-mail]  (P Douglas Reeder)
Subject: Re: Shooting the Moon

Does anyone know if the soviet mars probes that will travel around mars
by balloon will deploy their balloons before or after first touching
down?

For those who haven't heard: The balloons are heated by the morning sun,
adding to lift, drift with the winds during the day, and touch down
every night at a different site.

Doug Reeder

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

Date: 4 May 88 17:07:11 GMT
From: mnetor!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Cometesimals (was: Millions of comets hit Earth)

> >... Every few million years Mars warms up (since the water that is in
> >vapor form creates a greenhouse effect just like CO2); the ice thaws;
> >rivers flow on Mars...
>
> Water on Mars??  Could you please point me to references that
> substantiate this?

Well, nobody disputes the effects of water on the topography; the Viking
Orbiter images settled once and for all that Mars once had flowing water
on a large scale.  The idea that Mars's climate changes cyclically, and
that it is currently in a dry phase, is respectable speculation but not,
I believe, unanimously accepted.

 Henry Spencer @ U of Toronto Zoology
{ihnp4,decvax,uunet!mnetor}!utzoo!henry

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

Date: 4 May 88 17:36:11 GMT
From: mnetor!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Shooting the Moon

> If a telescope is too heavy/bulky/low in resolution, send down a
> Ranger type probe first.

This isn't a bad idea.  The major problem is that you may need more than
one of them to find a suitable location.

> Load it with an impact-survivable transmitter, and you have a landing
> beacon as well.  This would allow a rather stupid but accurate
> mechanism for terminal guidance.

This isn't actually necessary if you can survey the landing area well
enough.  (Doing that from orbit should suffice, the only tricky part is
picking the exact landing point.)  Cruise-missile guidance systems
should suffice to find a selected point in well-mapped terrain.

 Henry Spencer @ U of Toronto Zoology
{ihnp4,decvax,uunet!mnetor}!utzoo!henry

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

Date: 4 May 88 17:41:04 GMT
From: mnetor!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Shooting the Moon

>1. EXPLOSION ON THE PAD: Folks, the Challenger disaster was bad, really
>bad.  But imagine if it had a nuclear warhead on board.  Bye, bye South
>Florida!  A spaceship is one of the least stable places to keep a
>warhead!

Not an issue, actually.  Nuclear warheads are routinely designed to
crash at supersonic speeds or cook in a burning aircraft without doing
much more than spraying a bit of radioactive gup around the immediate
vicinity.  Getting a nuclear explosion is not that easy; nuclear bombs
are precision machinery.  Smashing one with a sledgehammer won't
detonate it.

 Henry Spencer @ U of Toronto Zoology
{ihnp4,decvax,uunet!mnetor}!utzoo!henry

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

Date: 5 May 88 06:22:13 GMT
From: well![e-mail]  (Jef Poskanzer)
Subject: Re: Question about Richard Hoagland/Mars Project

In the referenced message, [e-mail] (Henry Spencer) wrote:
}Hoagland is generally regarded as a nut.

Not by anyone who has even skimmed his book, and noted the extensive
disclaimers that it's all wild speculation.  This is very different from
the Ancient Astronauts syndrome.  I met Hoagland in 1980, and I did not
find him nutty at all -- just intelligent, creative, open-minded, and
slightly modest if you can believe that.

Now, I don't actually believe this stuff about faces, and I don't think
we should send *anything* to Mars until we have the infrastructure to
stay there, but it is interesting.

}I have not read this particular book

Well then.

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

Date: 5 May 88 05:51:36 GMT
From: [e-mail]  (Paul A. Flaherty)
Subject: Re: Shooting the Moon

In article <[e-mail]> [e-mail] (Kevin William Ryan) writes:
> Since what is wanted is a clear landing site, scout it out ahead of time.

We will have an orbiter in LMO, but as I said earlier, the resolution
isn't good enough.  And that's with a big CCD camera, and optimistically
precise optics.

Moreover, terrain assessments done in the past have tended to be just
plain wrong.  Apollo 11 had to contend with unexpectedly rough terrain;
they almost bought the farm.  We got just plain lucky with Viking.

> Now for my idea: If a telescope is too heavy/bulky/low in resolution,
> send down a Ranger type probe first.

Yep, we have said probes, but you can't get a camera with the necessary
resolution, nor can you get enough power in the package to send back
information at the required rate (Shannon et al).

> [e-mail]

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

Date: 5 May 88 16:42:30 GMT
From: ddsw1![e-mail]  (Laura Watson)
Subject: Re: Question about Richard Hoagland/Mars Project

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>> I have just finished reading a book by one Richard Hoagland called
>> _The Monuments of Mars_.  It is essentially speculative nonfiction
>> concerning some possible artificial objects on the surface of Mars.

I read in Charles Berlitz's _Atlantis_ that there are pictures of
pyramids on Mars.  This was in the part about pyramids found under the
Atlantic ocean, supposedly where Atlantis was.  If the book you're
talking about is about that, I sure going to read it.

Laura Watson             ...[ihnp4, moss, codas]!ddsw1!dino

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

Date: 6 May 88 01:19:55 GMT
From: [e-mail]  (J. Eric Grove)
Subject: Re: Shooting the Moon (really Martian ballooning) (LONG)

In article <[e-mail]> [e-mail] (P Douglas Reeder) writes:
>Does anyone know if the soviet mars probes that will travel around mars
>by balloon will deploy their balloons before or after first touching
>down?
>
>For those who haven't heard: The balloons are heated by the morning
>sun, adding to lift, drift with the winds during the day, and touch
>down every night at a different site.

As I understand it, the concept actually employs two balloons, a He (or
H) balloon which, in answer to your question, is inflated on descent,
and an open hot "air" balloon (maybe better called a "Montgolfier") made
of some black material yet to be developed.

Since the balloon fabrics are so fragile (presumably only a couple
tenths of mils thick), they must not touch the Martian surface.  Because
the Martian atmosphere is so tenuous, Montgolfier ballooning is
difficult, and every extra bit of weight must be eliminated.

I recently heard a fellow from JPL talk here (sorry, his name has long
since been filed) about the project.  It is a French concept, and the
JPLers were contributing to the design of the balloons and payload.  Our
government has, in its infinite wisdom, canceled their funding, so the
French and Soviets will have to go it alone.

The JPLers did make some significant advances in removing some of of the
inherent problems in the concept, namely ...

When the payload is on the ground at night, the Montgolfier is deflated
and being held aloft by the He balloon.  If there is any wind, the
Montgolfier will act like a beautiful spinnaker, dragging the payload
and pulling itself into the ground (bye-bye balloon).  And if the
payload drags, it may catch and be stuck forever.  What we need is a
balloon with a lifting shape (too complex to put in ascii) and a
"smooth" payload.  The JPLers came up with a lifting shape after much
head-scratching, only to discover you can buy toy kite-balloons at
K-Mart for a couple of bucks with just the right shape :-) (but much too
heavy and small).  They designed a snake-like payload of nested "dixie
cups" to give rigidity on small scales, but flexibility on large scales.
So with the wind blowing to the right, we might see this on Mars:

                    He kite-balloon
                        /
                           /
                          /
                    deflated Montgolfier
                        /
                       /
                      /
                     /
                    0
                       0
                      0
                000000        <- the payload

Tests of the kite-balloon and the payload on the only Martian surface we
Americans can reach (the CA desert) were quite successful.  Now,
designing instruments to fit in a series of squashed dixie cups might
not be so simple.

The French were impressed, but it's not yet clear whether or how much of
the design will actually be used.

disclaimer: I have no connection whatsoever with K-Mart.  I don't even
know where one is.

        J. Eric Grove
        [e-mail]
        ...rutgers!cit-vax!tybalt.caltech.edu!jeric

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

End of SPACE Digest V8 #241
*******************