Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_4/V15NO402.TXT

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Date: Tue, 10 Nov 92 05:00:07
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #402
To: Space Digest Readers
Precedence: bulk


Space Digest                Tue, 10 Nov 92       Volume 15 : Issue 402

Today's Topics:
              "Earth Gains a Retinue of Mini-Asteroids"
                      astronauts voting (2 msgs)
                             Clarke's Law
                    Collisions and P/Swift-Tuttle
                           Hubble's mirror
                     Lunar "colony" reality check
            Making up nonsense (was Re: Man in space ... )
                      Man in space ... (2 msgs)
                             Metric again
                     More lunar gravity questions
                        NASA Coverup (3 msgs)
          NEWS: Galileo Cleared of Heresy Charges by Vatican
                       Putting air on the moon
                Swift-Tuttle Comet a threat to earth?

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

Date: Mon, 09 Nov 92 18:05:25 GMT
From: Doug Mohney <[e-mail]>
Subject: "Earth Gains a Retinue of Mini-Asteroids"
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] writes:

>With objects sized on the order of Barringer I can well imagine the
>mushroom cloud occuring: the energy is released very rapidly and in a
>very small area. Although at a certain size the explosion simply
>blows a hole in the atmosphere, ie it is a circular curtain rather
>than a mushroom cloud.

I wonder how much trouble it would be to try to recreate one of those events
under controlled and monitoried conditions.

All we need is an asteroid, a vacant plot of land, and a lot of confidence
in our aiming.

                :-)

                 Play in the intelluctual sandbox of Usenet

  -- >                  [e-mail]                        < --

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

Date: Mon, 9 Nov 1992 14:16:47 GMT
From: Gary Coffman <ke4zv!gary>
Subject: astronauts voting
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Leigh Palmer) writes:
>In article <[e-mail]>
>
>Steve Maclean (probably misspelled) was actually in orbit when Canada held its
>recent "referendum" on constitutional matters. If the Canadian Space Agency was
>on its toes then he must have cast an absentee ballot. Not to have done so
>would have been politically incorrect. Canada had approximately three quarters
>of its registered voters turn out to vote in that election. How'd the US do in
>theirs?

I don't have national percentages of registered voters, but my home
county did 82%. The total vote count was a national record.

Gary

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

Date: Mon, 9 Nov 1992 18:07:12 GMT
From: James Davis Nicoll <[e-mail]>
Subject: astronauts voting
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Leigh Palmer) writes:
>
>Steve Maclean (probably misspelled) was actually in orbit when Canada held its
>recent "referendum" on constitutional matters. If the Canadian Space Agency was
>on its toes then he must have cast an absentee ballot. Not to have done so
>would have been politically incorrect.

    With the exception of voters in  Quebec (Quebec ran its own
'referendum' with slightly different rules), I do not think Canadians
were allowed absentee ballots  in  the recent 'referendum'.

                        James Nicoll

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

Date: Mon, 9 Nov 1992 10:57:02 MST
From: "Richard Schroeppel" <[e-mail]>
Subject: Clarke's Law

I always liked

  Any technology distinguishable from magic is insufficiently advanced.

Rich Schroeppel   [e-mail]

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

Date: Mon, 9 Nov 1992 12:18:39 GMT
From: [e-mail]
Subject: Collisions and P/Swift-Tuttle
Newsgroups: sci.astro,sci.space

=======================================================================

Some comments on the following : Duncan Steel, 1992 November 9th

>Well, I've just had a good laugh after reading a half page article on the
>possible Swift-Tuttle impact in our Sunday paper.
>
>Although the article contains the usual misinformation, speculation and
>sensationalism that the papers (and this one in particular) are renowned
>for, I note some rather disturbing comments made by Dr Ken Russell at the
>Anglo-Australian observatory.
>
>In it he is quoted as saying "A chance of one in 400 is not small when you
>are talking about the extinction of the human race."
>
>1 in 400?  Where did this figure come from?  I thought it was 1 in 10000, and
>that at a back-of-the-envelope calculation.  Has the knowledge about Swift-
>Tuttle's non-gravitational forces suddenly taken a gigantic leap forward?
>Hardly.
>
>He is also quoted as saying "All life would be grilled to death."  I presume
>he was quoted out of context here.
>
>At least they got the bit about the recovery of the comet correct.
>
>The article goes on to say that the "International Astronomical Union then
>warned its member nations that Swift-Tuttle would cross earth's path in
>August 2126."
>
>News to me!  Anyone care to comment?


1 in 400: that is the figure first quoted in NEW SCIENTIST of October 24th
which N.S. took out of context from comments from Brian Marsden.  400 is
simply the number of times 3.5 minutes goes into a day; 3.5 minutes is approx.
time to cross Earth's path at 60 km/sec.  When Marsden was unwillingly pushed
for an estimate of the probability he said 1 in 10,000 since the time of
periohelion passage in uncertain by about 25 days (10,000 = 25 x 400).
Even 1 in 10,000 is large (in terms of a hazard) since if there are 10
billion people alive in 2126 then the expectancy of deaths is about a million.

"Grilled to death": maybe not ALL LIFE, but a good proportion.  You should see
recent work on KT extinction  etc. which shows this to be a likely actual
mechanism (e.g. Chyba et al., and Melosh, at COSPAR, The Hague, 1990; should
have appeared in Adv. Space Res. by now).  The mechanism is the rock thrown
out in the impact on ballistic trajectories through the whole punched in the
atmosphere by the incoming projectile then re-enters, as a mass of meteors
which COVER the sky i.e. a griller.  No wonder 90%+ of the biomass was
incinerated at the KT.

"Recovery of comet correct": In fact it appears that P/ST was recovered but
not announced/recognized by an amateur Italian group in January 1992.  The
single position obtained could well be of great use (prior to non-grav
forces on pre-perihelion leg).

IAU "warning" as such: see IAU Circular 5636.  Certainly the Earth does
pass through the comet's orbit each August: that's why the Perseids are so
prominent (unlike, say, the Halleyid showers which are more diffuse/longer
shower duration since P/Halley does NOT intersect the terrestrial orbit
now; meteoroids from P/Halley observed apparently were released many
centuries/millenia ago).  The point is: instead of just being hit by bits
of P/ST (the Perseid meteoroids) will we be struck by the largest particle
in the stream next time around.  The uncertainty is in where the comet will
be in its orbit, not whether that orbit crosses the Earth's path.

Please let me re-iterate what I previously stated in a message: The chance
of being hit by some asteroid or comet as yet undiscovered, and yet large
enough to have global effects (i.e. end of civilization as we know it),
before 2126 is of order 10 times as high as the chance that P/ST will
strike Earth in that year.  Instead of worrying about specifics, and the
way in which the media distorts and abuses any statement one would care to
make to them, try looking at the generalities: if there's one thing that we
need it is a public perception that there IS a real hazard.  As I've written
before, there is no reason to panic, but after 3.3 billion years of evolution
life on Earth has now reached a stage where we CAN ensure the future of our
species.

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

Date: 9 Nov 92 14:52:54 GMT
From: "William H. Jefferys" <[e-mail]>
Subject: Hubble's mirror
Newsgroups: sci.astro,sci.space

In article <[e-mail]> [e-mail] (Stick,CommoSigop) writes:
#In <[e-mail]> [e-mail] (Gerard M. Foley) writes:
#
#>[e-mail] (Donald H. Locker) writes:
#
#>> Now that I know a little about mirror-making, I'd like to hear again
#>> how the Hubble mirror contractor messed up the figure of the main
#>> mirror.  I understand it has spherical aberration, but wonder how
#>> [Rockwell?] managed to do that.
#>>
#>It wasn't Rockwell (I forget axactly who it was, but it was an
#>otherwise reputable New England outfit) and put briefly, they
#>fouled up the test, performing it incorrectly, and never
#>checked by any independent method.
#
#   According to Dr. Steve Maran, who works on the HST project at the
#Goddard Flight Center, and who was recently a guest lecturer at my college,
#none of the above is true.  The company that ground the mirror did it
#exactly to the specs they were given.
#
#   The specs were wrong.

If my friend Steve Maran really said this, then he's
incorrect. The specs were fine. What happened was that
Perkin-Elmer mis-manufactured a critical piece of
equipment, a reflective null corrector, that was used
to figure the mirror. A field lens was located 1.3 mm
out of its proper position. The reasons for this having
happened are rather complex and involved. They are
described in gory detail in the Hartford Courant
report series that I posted information about earlier.
I personally attended many days' worth of reviews where
these events were found out, so I have reason to believe
that what I say is accurate.

The poster to whom you responded had it essentially right.

I don't think that Steve would be as far off base as
this, and I suspect that you have misunderstood him.

Bill Jefferys

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

Date: 9 Nov 92 16:09:17 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Lunar "colony" reality check
Newsgroups: sci.space,alt.sci.planetary

In article <[e-mail]> [e-mail] (Nick Szabo) writes:
>Lunar "colony" reality check:
>
>* The moon has no significant sources of hydrogen, nitrogen,
>  or carbon.  Wishful thinking about polar volatiles or
>  scrounging solar wind particles are hardly significant.

We don't *know* that, no through mineralogical survey has ever been
done. We know such materials aren't as common on the exposed surface of
the Moon as on Earth, but they don't have to be sufficient to support
a planetary biosphere, only sufficient to support a modest colony.

>* A livable atmosphere is mostly nitrogen, not oxygen.

*A* livable atmosphere is mostly nitrogen, but not *every* livable
atmosphere is mostly nitrogen. All that's required is a partial
pressure of about 4 PSI oxygen, and if you want a higher atmospheric
pressure, some relatively biologically inert dilutant gas. Helium
works, as do a few other gases.

>* Plants and animals need copious amounts of hydrogen, nitrogen,
>  and carbon.

*Adult* organisms need approximately their body weight in these
elements. A stable population recycles the materials on the timescale
of an organism lifetime.

>* There is no affordable way to crack oxygen out of lunar
>  rock or to recycle it.  This would cost, at bare minimum,
>  tens of millions of dollars per astronaut per year.

100% recycling is presently uneconomic, but a large fraction can
be recycled economically. And, there are experimental processes
running *today* on lunar simulant materials that extract oxygen
economically at the make up percentage required.

>* Because of transportation costs for recycling equipment,
>  recycling on the moon is far more expensive than recycling on
>  earth.  Even on earth the best attempt at building a livable,
>  working biosphere masses hundreds of thousands of tons and leaks
>  over tens of tons of air per year.

The average nuke missile sub masses about 6,000 tons and supplies the
needs of a crew of 170 for three months. Most of that mass isn't needed
on the Moon since dives to 1000 feet aren't required and torpedos
and ICBMs aren't in great demand on the Moon. Biosphere II tried to do
recycling solely with biological materials. That is inefficient, overly
complex, and has proved a failure. Mechanical/chemical scrubbers, vacuum
distillation systems, and the like are much more compact and efficient.
One thing the Moon, and any body in space, has available in nearly
unlimited quanities is energy in the form of solar heat. With nearly
unlimited energy, lots of problems become much easier.

>* Hydrogen is extremely innefficient to transport from
>  earth.  The stoichiometric volume of LH to make water is
>  _larger_ than the volume of oxygen; huge amounts will
>  be wasted on tankage.  Much of the LH will leak before
>  it can be used; it's extremely difficult and expensive
>  to store even for the few days trip.

Which is probably why no one is proposing to ship liquid hydrogen
to the Moon in large quanity.

>* The annual per capita consumption of water in the
>  U.S. is over 500 tons.  In this as in many other
>  areas, the "colony" will be living in abject
>  poverty despite the $billions spent on its
>  construction.

Since the average American uses more water to water his *lawn* than
most of the rest of the world uses in total, this only says that
large lawns won't be popular on the Moon.

>* It takes more than a rocket payload full of hydrogen
>  to make the water needed by industry.  If we're to have any
>  significant manufacturing industry in space, we're going to need
>  tons of volatiles.  For example, here is the water used to make
>  a few kinds of products on earth:
>
>            gallons/unit
>            ------------
>finished steel, ton    40,000

Have you ever visited a steel mill? The water is used in a single
pass cooling system for the rollers in the sheet and tube mill,
and for quenching billets. That's not the only way to do it.
*Modern* mills, like Nucor's mills, use very little water, and
that in closed loop cooling systems.

>automobiles, unit    12,000

Most of the water used in auto manufacture was in the paint prep
system. That's been replaced with closed cycle vapor phase solvent
prepping in modern plants. The rest is used for cooling, again, thanks
to the clean water act, that's now closed loop as well.

>trucks, buses, unit    20,000

Ditto.

>* There is no signficant economic resource on the moon.
>  Revenues as a percentage of costs will be 0%.

With the speculative exception of He3, there is no mineable
resource on the Moon, that we know of, that can be economically
exported to *Earth*. However, manufactured products of aluminum
and titanium suitable for use in *space* can be produced as well
as bulk aggregate for concrete-like structures and for shielding.
A mass driver on the Moon can loft bulk materials to orbit cheaper
than those materials can be lofted from Earth. Building the mass
driver would be expensive, but operating costs would be low.

The most important resource exportable from the Moon, however, is
massless. That's knowledge. The Moon is a near ideal platform for
very long baseline interferometry at radio, optical, and ultraviolet
wavelengths, something that's very difficult in a free floating
micro-gravity environment unshielded from Earth radio sources and
not solidly anchored against torques. It's also a safe place to do
high energy physics, and biological experiments too hazardous to do
on Earth.

>* SSF bare-bones habitat operations costs will be $2 billion
>  per year.  Scaling for transport costs gives over $10 billion
>  per year for a bare-bones lunar "base".   Redesign will cost
>  even more than SSF cost,  since industry has no reason to
>  participate beyond the usual NASA-contractor mode.

Almost all of that cost figure for SSF is transport cost based on
Shuttle. To return to the Moon to stay, we're going to need a transport
system beyond Shuttle. Since Shuttle will be going to LEO anyway for
crew rotation and supply of SSF, with less than a full payload on most
trips, it should be possible to piggyback crews and some supplies for
the Lunar base on the trips for little incremental cost. Follow ons to
the Shuttle should be cheaper to operate, lowering incremental costs
even more.

Now we need a lunar transfer system to shuttle between SSF and the
Lunar base to complete the system. That's a much easier problem since
the remaining energy cost is low to get from LEO to Lunar orbit. An
efficient, high ISP system such as electric ion rockets can handle that,
or a nuclear system could be used without fear of contaminating
Earth. Solid rockets based on Lunar powdered aluminum could also be
used, as could mass driver launched return vehicles.

>* Calling a few astronauts huddled in a Winnebago a "base" is
>  a major exaggeration.  Calling it a "colony" is an abominable
>  misuse of the word.
>
>There are dozens of other pathways to space colonization.
>Fixation on obsolete concepts like the "lunar base" and oxymoronic
>concepts like the "lunar colony" is one of the main reasons why
>the space colonization movement lies mired in failure.

With nabobs of negativism like you around, why should we be surprised? :-)
The problems you paint for a lunar base are mostly similar to the
problems of placing a colony *anywhere* in the solar system. They
are primarily issues of sustainable recycling and transport. Exporting
materials to *Earth* is not a path to economic viability for any space
system currently envisioned. The market for materials to be used in space
is small and growing very slowly. Knowledge will remain the only viable
export to Earth for many years, probably centuries, to come.

Gary

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

Date: Mon, 09 Nov 92 18:15:13 GMT
From: Doug Mohney <[e-mail]>
Subject: Making up nonsense (was Re: Man in space ... )
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Bill Higgins-- Beam Jockey) writes:
>
>Evidently Andy has seen *Total Recall* but not *2001*, or, if he's
>seen both, he believes the former has more accurate science than the
>latter.

C'mon, you must know that Arrrrrnold would never make an inaccurate movie,
especially the parts where people shoot at him with zillions of weapons and he
somehow manages, despite his large cross-section, not to get it.

                Yah, I am Hans, and you are Franz...


                 Play in the intelluctual sandbox of Usenet

  -- >                  [e-mail]                        < --

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

Date: 9 Nov 92 18:20:37 GMT
From: Steve Jenkins <jenkins@fritz>
Subject: Man in space ...
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>As Clarke has pointed
>out, if you *expect* the decompression, you can boost your internal oxygen
>supply considerably by hyperventilating first.

But not by much.  At normal arterial O2 partial pressure (about 100 mmHg),
the blood is almost completely saturated with oxygen.  You can raise
the partial pressure by hyperventilating, but not the oxygen content.
Hemoglobin is remarkable stuff.

The best you could do in anticipation is to prepare to hold your
breath (carefully!) so as to maintain some O2 pressure in the lungs, and
hence in the arterial blood.  If the lung pressure goes to zero, so
immediately does the arterial PO2.  The transport delay from lungs to
brain is on the order of 20 seconds, so you can't expect to maintain
consciousness much longer than that.  The oxygen demand of the brain
is high, and there are no signifcant stores of oxygen anywhere in
the body outside of the lungs and arterial blood.

Note that it's the partial pressure, not the concentration that
matters.  Even breathing pure O2 from a tank doesn't help much at low
ambient pressure.  That's why climbers on Everest are at the limits
even with supplemental oxygen.

--
Steve Jenkins                  [e-mail]
Caltech/Jet Propulsion Laboratory    [phone]

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

Date: Mon, 9 Nov 1992 19:50:03 GMT
From: Nick Haines <[e-mail]>
Subject: Man in space ...
Newsgroups: sci.space

Isn't the point of hyperventilating to boost stores of ATP? Clearly
you're not going to do much to increase the oxygen in the blood, but
the brain doesn't need oxygen, it needs energy.

This is what I've always thought hyperventilating does, and it seems
to work for me :-)

Nick Haines [e-mail]

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

Date: Mon, 9 Nov 1992 17:59:33 GMT
From: Jim Sturges <[e-mail]>
Subject: Metric again
Newsgroups: sci.space

In article <[e-mail]>, [e-mail]
(Steve Linton) wrote:
>
> In article <[e-mail]>, [e-mail] (Bruce Dunn) writes:
> |> > John Roberts writes:
> |> >
> |> > By the way, I think you'll be much happier in the long run if you do your
> |> > calculations in SI (metric) units. I often do simple calculations in
> |> > standard
> |> > units, but the tough problems are much more easily handled using SI.
> |>
> |>
> |>         I am delighted to find that NASA seem finally to be moving toward
> |> metric, not just in theory but in reality.  Ron Baalke's postings about


From the society for the preservation of purity in language.....

ALL measuring systems are "metric." What we're talking about is the
difference between SI and English?

Thanks for letting me put my $.0256 in....




 ************************************************************************

Jim Sturges                                       MS 8612
602 925-7204                                Loral Defense Systems --
Arizona
602 925-6988 Fax                         P.O. Box 85
[e-mail]    1300 S. Litchfield Rd.
CIS: 72470,3117                             Goodyear-Avondale, AZ  85338

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

Date: 9 Nov 92 15:23:29 GMT
From: "Michael K. Heney" <[e-mail]>
Subject: More lunar gravity questions
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John Roberts) writes:
> [...]
>
>-References I've seen indicate that Earth's tides are responsible for
>-locking the moon's rotation to the orbit.
>
>I believe the main effects of the tides on Earth are to slow the Earth's
>rotation and to cause the moon to gradually move further from the Earth.
>If one assumes that the moon once rotated faster than it revolved, then the
>tidal forces must have been much greater than those we see on Earth, because
>of the greater mass of the Earth. If the moon were liquid at the time (which
>would fit the Earth impact model), then those tides would have stirred the
>entire body of the moon, generating tremendous friction.
>
>One aspect I'm more uncertain of: if the moon continues to move outward
>from the Earth, then the period of its revolution about the Earth must
>be increasing. If its rotation continues to remain tidally locked, then
>there must be some currently active mechanism that maintains this state.
>It would be a subtle effect, and I can think of several possible mechanisms
>to explain it, but I'm not sure of the relative magnitudes. Perhaps drag
>from the "rocking" (what's the word?) of the moon relative to the Earth is
>sufficient to account for it.
>
The word you're looking for is LIBRATION.  It's caused by the fact that
the moon's orbit is elliptical, so that while the rotation about it's axis
is constant, it's angular velocity over it's orbit changes, so it appears
to "rock" back and forth over the course of an orbit.  About 59% of the
moon's surface is visible at some point during the month.

There would be tides on a rotating moon, too, although they'd be pretty small
(a matter of inches).  Over time, it's enough for tidal braking.  Given that
the moon is not symmetrical gravitationally, it will maintain a "gravity
gradient" attitude toward the earth.
--
Mike Heney                |   Senior Systems Analyst and     |  Reach for the
[e-mail]   |  Space Activist / Entrepreneur   |  Stars, eh?
Kensington, MD (near DC)  |     * Will Work for Money *      |

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

Date: Mon, 9 Nov 92 08:38:35 EST
From: John Roberts <[e-mail]>
Subject: NASA Coverup

-From: [e-mail]
-Subject: NASA Coverup
-Keywords: snarfy concedes
-Date: 8 Nov 92 20:04:00 GMT

-    I  rented  a  videotape  called "Man to the Moon" ,produced by CBS news.
-   Timing Buzz Aldrin's leap from the 3 foot bottom rung of the Lunar Module
-   ladder , I come up with about 1 second ,which would be consistent with  a
-   lunar  gravity  of  1/6. Although he still to be holding on to the ladder
-   throughout the leap , it seems that it is just to steady himself , not to
-   slow the fall.

-    On this basis then, I concede that the lunar gravity is 1/6 .

If that's the documentary produced in 1989 (the one *not* hosted by Walter
Cronkite), then watch out for one inconsistency - they use extensive footage
from missions *after* Apollo 11, while giving the impression that it's from
the Apollo 11 mission. For instance, they show the takeoff from the moon as
seen by the camera on the lunar rover, while in fact there was no lunar
rover on the Apollo 11 mission. That was an editorial decision by CBS, not
a deception by NASA. I suppose one could argue that it could *just barely*
be excused as artistic license, though it reduces the documentary value of
the program.

-    I  apologize  ,publicly  ,  over the net, to the general class of people
-   known as "NASA Scientists" who I accused of concealing  the  truth  about
-   the lunar gravity.

-    I  am  , at least,gratified to learn that Velikovsky's idea of planetary
-   collisions , long scorned and ridiculed by the scientific community ,  is
-   now the prevailing theory explaining the origin of the moon.

The Voyager images made it clear that numerous massive collisions were
a system-wide phenomemon of the early solar system (several bilion years
ago), not just local to the Earth-moon region. This awakened greater interest
in the concept of catastrophic collisions as a significant factor in the
formation of the solar system. Velikovsky thought that spectacular (and
mathematically insupportable) events took place only a few thousand years
ago.

(The strongest piece of scientific evidence to support Velokovsky's theories
is the existence of "Velokovsky's Right!" T-shirts. :-)

John Roberts
[e-mail]

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

Date: Mon, 9 Nov 1992 13:33:31 GMT
From: Paul Dietz <[e-mail]>
Subject: NASA Coverup
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]>, [e-mail] (Gary Coffman) writes...

 >>A capture theory requires the influence of a third body, or as you state,
 >>artificially generated thrust. Both are extremely unlikely. Currently,
 >>the most popular theory is that the Moon is a result of a collision with
 >>the primordial Earth by a third body similar in mass to the present day
 >>Mars. The result of the collision is the much smaller present day Earth
 >>and the Moon.

Gary is a bit off here: the proto-Earth would have been *smaller* that
our current Earth.

 > Wouldn't a collision with something that size totally destroyed the Earth,
 > blasting it (and the Mars-sized thing) out of existance leaving not
 > much more than an asteroid belt?  If not, wouldn't the system be in a
 > rather elliptical orbit?

Answered in order: (1) no, there is insufficient energy available
(recall that the gravitational binding energy of a sphere at constant
density goes as the 5/3 power of the mass), and (2) the earth *is* in
an elliptical orbit.  Just how elliptical would depend on when the
earth was hit.  A collision near apohelion of the proto-earth's orbit
could decrease, rather than increase, eccentricity.

 >Could the Earth have captured the Moon if the Moon was originally a separate
 >planet in "somewhat the same orbit" as the Vice President would say, and
 >eventually the Earth-moon perturbed each other into a common orbit?
 >
 >Also the process that forms binary stars must be common, why not have the
 >same process form a sort-of binary planet?

Capture without some sort of dissipation (like collision) is very
difficult; this has effectively ruled out this theory.  Also, if the
moon formed in "roughly the same orbit", where are the volatiles?  By
volatiles I mean elements up to *lead*, not just things like hydrogen
and carbon.

Binary stars coaccrete; they don't form then become bound (well,
except in very dense cores of globular star clusters where 3-body
collisions can occur).

    Paul F. Dietz
    [e-mail]

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

Date: 9 Nov 92 16:18:46 GMT
From: Gary Coffman <ke4zv!gary>
Subject: NASA Coverup
Newsgroups: sci.space,alt.conspiracy

In article <[e-mail]> [e-mail] writes:
>
>    I  will  continue , however to point out alternative theories to account
>   for various facts  of  nature.  Theories  are  not  science,  but  merely
>   suggestions  of  possible  explanations  for  observed  phenomena  .   An
>   alternate theory need only be logically and mathematically consistent  to
>   be as viable as relativity , or any other theory.

No, to be viable, a theory must make useful, testable, predictions that are
*better* than existing theory, or contain fewer unconstrained variables
while at least equalling the predictive power of existing theory.

>    I  am  , at least,gratified to learn that Velikovsky's idea of planetary
>   collisions , long scorned and ridiculed by the scientific community ,  is
>   now the prevailing theory explaining the origin of the moon.

Velikovsky's ideas are still scorned and ridiculed because they violate
known facts. No one disputes the likelyhood that planetary bodies collided
in the formative stages of the solar system, but equally true is that no
competent scientist supports the idea that such collisions have occurred in
historic times. The geologic record clearly denies such collisons, and
celestial mechanics says that a ping pong Venus is not dynamically possible
as Velikovsky describes it.

Gary

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

Date: 9 Nov 92 13:39:28 GMT
From: Thomas Clarke <[e-mail]>
Subject: NEWS: Galileo Cleared of Heresy Charges by Vatican
Newsgroups: sci.space

Maybe the high gain antenna will deploy now.

--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
[phone], FAX: [phone], [e-mail]

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

Date: Mon, 9 Nov 1992 16:21:57 GMT
From: Nick Haines <[e-mail]>
Subject: Putting air on the moon
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John Roberts) writes:

   [about big telescopes]

   The formula I found for the diffraction resolution limit of a telescope
   (which ought to be put in the FAQ list) is
     alpha = 2.1E5 x lambda / d

   where alpha is the resolution in arc seconds, lambda is the
   wavelength being observed, and d is the diameter of the telescope
   (same units as lambda).

The easy formula is

    alpha = lambda / r

where alpha is in radians, and r is the radius of the telescope.

Since you've got a value in radians, you can then multiply by a
distance to get a linear resolution:

    f = lambda . D / r

(D is the distance to the object, f is the resolvable feature size).
Plugging in units for light-years and light wavelengths, this gives:
f = 5.3e3 * D/r, where D is in light years and f and r are in km.

Nick Haines [e-mail]

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

Date: 9 Nov 92 13:08:01 GMT
From: S S Sturrock <[e-mail]>
Subject: Swift-Tuttle Comet a threat to earth?
Newsgroups: sci.astro,sci.space

In article <[e-mail]> [e-mail] (keith farmer;S10000) writes:
>In article <pad.720924805@probitas> [e-mail] (Paul A Daniels) writes:
>>    Geologists belive that the earth originally had a super continent
>>don't ask me to spell it's name. I'm just curious, could it have broken
>>up due to a meteor stike?

Not likely, the break up of continents is the result of plate tectonics and
is going on all the time, shunting the continents around, creating new bits
and destroying other parts.  Most of the super continent exists today, it's
just spread around a little more :-)

If I remember correctly the super continent was not the start as such, it
was formed from smaller parts and then broke up again.


--
Shane Sturrock, Biocomputing Research Unit, Darwin Building, Mayfield Road,
University of Edinburgh, Scotland, Commonwealth of Independant Kingdoms.  :-)

Civilisation is a Haggis Supper with salt and sauce and a bottle of Irn Bru.

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End of Space Digest Volume 15 : Issue 402
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