Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v09_4/v9_457.txt

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Date: Thu, 25 May 89 03:16:39 -0400 (EDT)
Subject: SPACE Digest V9 #457

SPACE Digest                                      Volume 9 : Issue 457

Today's Topics:
        Re: Kelso's NASA prediction Bulletins
        Re: Geosynchronous debris cleanup law?
         Re: Sun's invisible partner NEMESIS
             Re: Ancient asteroid impact
   Re: Asteroids and Dinosaurs (was Re: asteroid almost hits earth)
      momentum wheel desaturations (was Re: Magellan...)
            Re: Talking about something...
            Re: New Orbiter Name Announced
             Re: Andromeda Strain
              Minimalist design
         Extinctions: Asteroids and Dinosaurs
----------------------------------------------------------------------

Date: Tue, 23 May 89 09:12:15 -0400 (EDT)
From: Ted Anderson <[e-mail]>
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Subject: Re: Kelso's NASA prediction Bulletins
CC: [e-mail] (TS Kelso)

I'd like to thank everyone for their responses to my survey about interest in TS
Kelso's orbital elements.  I was more or less flooded with replies, virtually
all of which indicated an interest in continuing access to this information.  I
will try and do something to make it a bit easier for people who don't want to
see them, but I can't promise anything soon.
        Ted Anderson

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

Date: 22 May 89 18:15:26 GMT
From: hp-pcd!hpcvlx![e-mail]  (Bill Turner)
Subject: Re: Geosynchronous debris cleanup law?

> What does this mean?  Did somebody pass a law?  Obviously inactive
> satellites can't remove themselves.  Is somebody going to fund an
> international orbit guard?

Sure, brilliant pebbles to shoot them puppies down!  (Causing even more
junk in geosynchronous orbit....)

--Bill Turner ([e-mail])

Oh, by the way, :-)

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

Date: 18 May 89 20:55:00 GMT
From: apollo!ulowell!cg-atla![e-mail]  (John Welch)
Subject: Re: Sun's invisible partner NEMESIS

In article <[e-mail]>, [e-mail] (Daniel Evans) writes:
>
>     My wife recently asked me about the Sun's partner, and I realized
> I had forgotten almost everything I had read about it.
>
>     A couple of years back, I had read some accounts about a tiny (non-
> identical) "twin" of our sun, which swings by every few million years or so.
> Someone referred to it as "Nemesis".
>
>     How much evidence is there supporting this theory?  What are the de-
> tails?  What kind of star is it?  How did they decide what its path is?  Is
> it visible through a telescope?  Was this just a trendy theory that got tossed
> out after a while?
>
>     My wife's sixth-grade students want to know...
>
>                     Thanks in advance,
>
>                     Dan
>                     [e-mail]

 Well, I hope this provides some help for you... As far as I understand
the theory, Nemesis is supposed to part of a binary star sysytem with
our sun, Sol, as it's partner. It was predicted to have a period of
about 20 million years, I think. This number, if I have the right
number, corresponds to periods of mass extinction on the Earth. The
theary is that, as Nemesis entered our star system, it would pass
through the asteroid belt. Nemesis' gravity would  disrupt the orbit of
some asteroids, and send them crashing to Earth. The resulting disaster
would in turn cause the mass extinctions.

 As far as I know, there is no astronomical support for this theory,
since Nemesis would not now be visible to any astronomers. As for the
thoery being trendy... A lot of theories have been proposed to account
for mass extinctions, some just got more attention in the popular
press.

 I hope I was some help.

        John Welch
        AFGA Compugraphic
        Wilmington Ma, 01887
        {decvax|ima|ulowell|cgeuro}!cg-atla!welch

 P.S. Sorry to waste the bandwidth, the mailer wasn't quite sure where
you lived :)

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

Date: 21 May 89 20:41:19 GMT
From: portal!cup.portal.com![e-mail]  (H Keith Henson)
Subject: Re: Ancient asteroid impact

John Roberts ([e-mail]) asked several questions on alternate
ways to explain the evidence of the Cretaceous-Tertiary boundry clay.  While
I don't think that much of the philosoply mixed into the work, _The Great
Dying_ by Kenneth J. Hsu gives an extremely good history of the work over
the last decade or so which has built up a very good picture of what happened
to life on earth and in the ocean when the big one hit.  The picture is
*much* more complex than it would seem, and I strongly recommend the book.
Keith Henson

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

Date: 22 May 89 17:23:10 GMT
From: ncrlnk!ncrcce![e-mail]  (Wayne D. T. Johnson)
Subject: Re: Asteroids and Dinosaurs (was Re: asteroid almost hits earth)

I have also heard a story about a mammoth that was found frozen in Siberia,
death was purported to have been caused by freezing, with tropical plants
still in its mouth.

I know Van Donigan (sp?, author of charriots of the gods and other such drivle) used this as proof that an advanced intellegent life existed back then.

Last I heard, he was doing 5-10 for fraud...

--
Wayne Johnson                 (Voice) 612-638-7665
NCR Comten, Inc.             (E-MAIL) [e-mail] or
Roseville MN 55113                    [e-mail]
These opinions (or spelling) do not necessarily reflect those of NCR Comten.

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

Date: Mon 22 May 89 16:21:38-PDT
From: Brian Keller <[e-mail]>
Subject: momentum wheel desaturations (was Re: Magellan...)

[e-mail]  (Charles Daffinger) writes:

>In article <[e-mail]> [e-mail] (Peter E. Yee)
>writes:
>>
>>                       MAGELLAN STATUS
>>                       May 19, 1989
>>
>>
>>       Daily momentum wheel desaturations continue as scheduled, twice
>>daily, 00:45 a.m. and 12:45 p.m. PDT, project said today.  The daily
>
>What are these momentum wheel desaturations?

Momentum wheels are one of several methods of controlling the orientation
(attitude) of a spacecraft.  When perturbations occur (due to the slight
pull of planet gravitation or solar wind or solar radiation pressure),
the spacecraft spins up its momentum wheels so that the spacecraft remains
at the desired orientation.  Effectively, the spacecreaft "pushes" against
the momentum wheel (through a motor) to stay as desired.  The momentum
wheels can also be used to make small attitude adjustments, for example,
if they are doing test adjustments or something, they might use these.

After using these for a while, they can build up too much momentum (spin),
they need to despin the wheels.  They do this by kicking on the thrusters
in the appropriate direction and torquing on the momentum wheels in the
other.  Thus they are "desaturated".  They are probably doing the de-
saturations twice a day so that they only have to do brief engine bursts,
probably to be conservative and not jiggle the communications link.

One of the benefits of momentum wheels is that if you have a periodic
perturbation, such as when you are in an orbit, the momentum wheel will
be spun up one way to counteract it and then the other way as the pert-
urbation shifts.  Thus, the momentum wheels are spun up then spun down.
If you use thrusters, you need to fire first the one way, then the other,
rapidly using up the precious fuel.

I'm not sure exactly how Magellan attitude control is set up, but I assume
the above applies.  Hope this helps!

                                               Brian S. Keller
-------

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

Date: 21 May 89 06:13:33 GMT
From: oliveb!tymix!3comvax![e-mail]  (Michael McNeil)
Subject: Re: Talking about something...

In article <[e-mail]> [e-mail] (Jim Meritt) writes:
>2. a prediction: Find a planet in orbit around its primary in which the
>temperature does not drop below the freezing point of water over a
>majority of the surface at any time and which the temperature is never
>above the boiling point of water anywhere on the surface at any time
>and on which hydrogen, oxygen, and carbon are plentiful and readily
>accessable and that this situation has existed for a period of an
>apparent 3.5 million years and you will find evidence of catabolism and
>metabolism.

I assume you mean 3.5 *billion* years.  Such a long period of time
should be more than sufficient, since there's strong evidence that
life existed within the first 1 billion years of Earth's formation.

Also, a nit:  your definition would exclude the Earth.  There are a
number of places on the surface of the Earth (Yellowstone, Kilauea,
etc.) where the temperature does regularly exceed the boiling point.
Nearly any other "Earthlike" planet would also have such hot spots.

In fact, there's good reason to believe that planets that do *not*
undergo plate tectonics like Earth would not, in the long run, be
able to support life.  Organic compounds have a tendency to migrate
downwards and eventually end up covered by sediments on the bottom
of the sea.  Without plate tectonics to subduct seabottom material
down into the mantle and later release it back to the surface via
volcanoes, there would eventually be no carbon left at the surface
for life to use.  (This may be what happened in the case of Mars.)

Harvard University's Michael McElroy estimates that the average
carbon atom has made this trip between the surface of the Earth and
mantle and back some *thirty times* over the Earth's entire history.

--
Michael McNeil            [e-mail]
3Com Corporation        hplabs!oliveb!3comvax!michaelm
Mountain View, California    work telephone: [phone] x 208

    Life, even cellular life, may exist out yonder in the dark.
    But high or low in nature, it will not wear the shape of man.
    That shape is the evolutionary product of a strange, long
    wandering through the attics of the forest roof, and so
    great are the chances of failure, that nothing precisely
    and identically human is likely ever to come that way again.
        Loren Eiseley, *The Immense Journey*, 1957

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

Date: 22 May 89 11:32:47 GMT
From: genrad![e-mail]  (Diana L. Syriac)
Subject: Re: New Orbiter Name Announced

In article <[e-mail]> [e-mail] (Scott Gibson) writes:
>Peter Scott writes:
>>whether one name will be painted on one side and one on the other, or why on
>>earth they felt it necessary to use non-American spelling at all...
>
>The Endeavour is named for a British sailing vessel of some exploratory


I thought it was interesting to note that the latest issue of AWST
dated 15-May-89 spelled the name "Endeavor", NOT "Endeavour".....

->        Diana L. Syriac                            <-
->USmail:   GenRad Inc., Mail Stop 6, 300 Baker Ave, Concord, Mass.  01742  <-
->usenet:   {decvax,linus,mit-eddie,masscomp}!genrad!dls  or [e-mail] <-
->tel:        [phone] x2459    I'D RATHER BE FLYING!!!            <-

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

Date: 22 May 89 03:18:16 GMT
From: att!pacbell!cpro![e-mail]  (J.R. Stoner)
Subject: Re: Andromeda Strain

[Note Followup-To]

From article <[e-mail]>, by [e-mail]:
>     In the *movie* version it was not an asteroid, it was a space
>     probe.

Both the movie and book used Project Scoop as a method of gathering space
material, presumable for biowar material.

>     It has been a long time since I saw it, but there was I
>     think the implication of a possibility that the probe was lanched
>     by the military in order to collect extraterrestrial material.
>     Also, It didn't decompose plastics at all.  It caused blood to
>     coagulate comletely, which kind of slowed the heart down.  In the
>     end it was found that it didn't do well in an oxygen environment.

Partially correct.  The first virulent form of the organism coagulated blood
but mutated into a form inimicable to plastic.  That is how the F-4 crashed
and how the lab seals of the lab were compromised.  If the organism had not
mutated then Hall would have died when he cut the isolation suit in the
emergency.

>     However, all of the high-tech machines broke down, for stupid reasons
>     that the movie maker thought representative of engineering narrow
>     mindedness, and so it took them much too long to figure this out.

The people in the lab were *not* informed of the crash and problems around
Piedmont because of a sliver of paper jamming a teletype bell - silly but
representative of limitations of 1965 technology.  It is fortunate they
*did* find out about the crash so they could warn of the energy efficency of
the organism and the consequences of carrying out directive 7-12.

>     By the way, I do think it is possible that an extraterrestrial bug
>     could cause problems on earth, although very unlikely. I am thinking
>     that something could evolve to live in an incredibly harsh and spartan
>     extraterrestrial environment by being able to extract energy from
>     almost any kind of molecule.  Consider for example, molds and
>     such.  They will grow on any kind of decomposing organic matter.
>     They are not in any sense host-specific.  Now imagine one that grew
>     much more rapidly in a suitable environment, say inside the lungs.

Actually I would not be surprised there is a biological isolation lab in
this country.  I would guess it is located at either Brookhaven or Oak
Creek.  There are also the CDC labs for that kind of thing.  They seem to
have no shortage of P4 rated labs.

>     You can post this to the net, but don't expect me to defend any
>     of it.
--
                | J.R. (May the Source be With You) Stoner
"Dying is easy -        | {amdahl,hplabs,decwrl}!pacbell!cpro!asgard
    Comedy is hard."    | [e-mail]    [e-mail]
                | [e-mail]    [e-mail]

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

Date: Mon, 22 May 89 17:49:27 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Minimalist design


>From: portal!cup.portal.com![e-mail]  (Mark Robert Thorson)
>Imagine the effect of hitting a clump of copper wires!  Perhaps the proper
>successor to smart rocks and brilliant peebles will be "genius dust".
>These could be naked IC's powered by the sun and propelled by tiny ion
>engines.

Don't laugh too hard. Some people I know at a government lab developed a
device to be used in tracking honeybees, in preparation for the invasion
of the "killer" bees from the south. The device is essentially a bare chip,
glued to the back of the bee. A portion of the chip is doped to act as a solar
cell, providing power. The chip gives off a signal (infrared or radio
frequency - I forgot which) that can be detected as the bees fly past
the receiving equipment.

It is hoped that eventually various kinds of miniature "machinery" can be
built onto the surface of a silicon wafer.
                                  John Roberts
                                  [e-mail]

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

Date: 22 May 89 18:16:26 GMT
From: tektronix!tekgen!tekigm2![e-mail]  (Timothy D Margeson)
Subject: Extinctions: Asteroids and Dinosaurs

Hi,

The current issue of Scientific American has an excellant article on the
extintion matter.

There have been extinctions of small and large scale every 26 million years
since fossil records began in the precambrian epoch.

Sometimes the extinctions appear instantaneous, other times they occur over
millions of years.

There is a new hypothesis about the dinosaur extintion that the impact of a
large body into Earth would spatter superheated matter over a vast area of
the planet. This with the fireball would superheat the atomospheric gases
and ignite fires over 90% of the planets surface. Soot has been found in the
iridium layer in several sites around the world.

The article also points out that the 26 million year periodicity meets
roughly with the rate at which the solar system moves through the arm of our
galaxy and some correlation is plausible.

The current rate of extintions is remarkable. The exact numbers escape me
but are on the order of 1 per hour in the Amazon region. We ARE in one of
the largest extinctions in the planets history.

The largest extinction was one in which 90% of the oceanic life died. That
particular extinction was hypothesized as caused by environmental change.

What the article points out (and the Shuttle photos of the Amazon I just
received) is that the current burning of forests and coal are making species
drop like flys. The effects are not reversible.

PS: those photos of the Amazon fires have to be seen to be believed. The
smoke covers the ENTIRE BASIN, from the Andes in Columbia and Peru to the
ocean and isle of Marajo. Look at a map for these places to see how large
an area we are talking about. In one of the photos is a detailed close up
of one fire plume estimated to be the size of all the Yellowstone fires
combined - but this Amazon burn is for clearing purposes! The smoke is so
dense over the basin that the sky probably can't be seen from the ground.
Perhaps in the outer regions one could see the ball of the sun, but I'd bet
you wouldn't have to squint.




--
Tim Margeson [phone]
PO Box 3500  d/s C1-022                          @@   'Who said that?'
Vancouver, WA. 98668
e-mail replies to: [e-mail]

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

End of SPACE Digest V9 #457
*******************