Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v09_4/v9_454.txt

Internet Message Format | 1991-07-08 | 17KB

Return-path: <[e-mail]>
X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
Received: from holmes.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr1/ota/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/MYSG6Ja00UkZ0C404c>;
          Tue, 23 May 89 05:17:10 -0400 (EDT)
Message-ID: <[e-mail]>
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Tue, 23 May 89 05:17:01 -0400 (EDT)
Subject: SPACE Digest V9 #454

SPACE Digest                                      Volume 9 : Issue 454

Today's Topics:
            Re: New Orbiter Name Announced
            Re: New Orbiter Name Announced
               PHONE TREE ALERT
         Re: Sun's invisible partner NEMESIS
             Re: Andromeda Strain
           Re: citizens in space -- risk silliness
          Ballistic parachutes (was: Giotto)
             Re: Andromeda Strain
               Re: SPACE Digest V9 #432
               Re: SPACE Digest V9 #443
----------------------------------------------------------------------

Date: 20 May 89 13:01:48 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: New Orbiter Name Announced

Two notes on the Endeavour/Endeavor mix up (NASA *would* snatch confusion
out of the jaws of clearness now wouldn't they?? <grin>)

 1. The schools that submitted names split (unevenly) between the
British and American spellings also.  Evidently some of them had trouble
reading their predigested NASA "curriculum materials."  The original
vote tallies article has expired here, perhaps Peter could repost it
for posterity.

 2. AvWeek said 'Endeavor' in its announcement of the name selection.
--
Tom Neff                UUCP:     ...!uunet!bfmny0!tneff
    "Truisms aren't everything."    Internet: [e-mail]

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

Date: 19 May 89 18:12:47 GMT
From: hpfcdc!hpfcdj![e-mail]  (Bob Myers)
Subject: Re: New Orbiter Name Announced

>The ultimate reusable booster!!!

>It never leaves the ground.  Needs no refurbishing before reuse.
>No need for downrange recovery ships, aircraft, or crews.

>Probably exceeds local noise limits, though.

But was the Columbiad an "assault rifle"?

:-)


Bob "Of course, our fine, upstanding American hunters NEED 900-foot-long
     rifles for SPORTING PURPOSES!" M.

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

Reply-To: mordor!rutgers!pnet01.cts.com![e-mail]
Date: Sat, 20 May 89 09:43:20 PDT
From: mordor!rutgers!pnet01.cts.com![e-mail] (Jim Bowery)
To: hplabs!hpcea!hp-sdd!crash![e-mail]
Subject: PHONE TREE ALERT

Phone Tree Alert

Date:          5/20/89

Subject:       Terminate spending for NASA's space station program

Target:        Rep. Jamie L. Whitten, Chairman
               House Committee on Approrpriations

Address:       Hon. Jamie L. Whitten
               U.S. House of Representitives
               Washington, DC 20515-2401
               202-225-4306

Message:       Call or write Chairman Whitten expressing your
               support for his opposition to further wasteful
               spending on NASA's space station project.

               The Senate goes out on Memeorial Day recess on 19
               May and the Hous goes out on 25 May.  Therefore,
               activists have until the 25th to target the
               chairman of this important committee.

               Activists should also try to make appointments
               with their congressional representatives durring
               this recess.  The next several weeks will be
               crucial to showing the political leadership that
               Americans want a space program which they can be
               proud of!

Add'l Brief:   In your letter or call, try to relate the waste
               on the space station program to fact that while
               his favorite programs are being cut to the bone,
               NASA and aerospace contractors are posing as a
               grassroots space activist network to ensure continued
               budget inflation for themselves.

               For tips on how NASA and aerospace contractors
               are successfully posing as grassroots activists,
               read the Space Activists Handbook, available from
               SPACEPAC.  Write or call David Brandt at NSS HQ.
               Or inquire on this net to Jordan Katz.
---------------------------------------------------------------------------
Jim Bowery    Phone: [phone]
PO Box 1981                  Join the Mark Hopkins Society!
La Jolla, CA 92038   (A member of the Mark Hopkins family of organizations.)

UUCP: {cbosgd, hplabs!hp-sdd, sdcsvax, nosc}!crash!pnet01!jim
ARPA: crash!pnet01![e-mail]
INET: [e-mail]

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

Date: 19 May 89 20:49:45 GMT
From: [e-mail]  (Jordan Kare)
Subject: Re: Sun's invisible partner NEMESIS

In article <[e-mail]> [e-mail] (Ed Nather) writes:
>In article <[e-mail]>, [e-mail] (Daniel Evans) writes:
>>     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?
>
>None.
>>  What are the details?
>There aren't any.
>> How did they decide what its path is?
>
>They were trying to explain "periodic" mass extinctions in the fossil record
>by invoking comets to smash the earth and create a "gravitational winter" by
>ruining the earth's ecology, on a regular basis.  The "periodicity" was, at
>best, suspect, but why not try?  They invoked the mythical "Oort cloud" of
>comets that supposedly (and invisibly) surrounds the solar system, and placed
>the mythical "Nemesis" in an orbit that would perturb them periodically, thus
>raining destruction on our unsuspecting planet and its inhabitants.
>

Oh, come now!  I take it, Ed, that you will not consider Nemesis to
exist unless/until it is directly observed.  Does this mean you won't
accept the existence of electrons until someone takes a photograph of one?

The Nemesis hypothesis postulates that the Sun is part of a binary
star system. At perihelion (closest approach to the Sun), the
companion passes through
the quite non-mythical Oort cloud (a large and only roughly-defined
region surrounding the Solar System where, based on numerous
observations of first-pass and long-period comets, most comets
appear to originate).  The companion is big enough and slow-moving
enough to "scramble" the orbits of many comets, some of which
fall into the inner solar system (most are ejected into deep space).
This creates a "comet shower" lasting of order 1 million years,
during which the Earth is much more  (10x) likely to be hit by
a comet than usual.

    The existence of Nemesis was proposed to account for a
26 million year periodicity in the fossil extinction record,
combined with strong evidence that at least one extinction
(the Cretaceous-Tertiary, 65 Myears ago) was caused by some sort
of large-body impact).
The periodicity (with some changes in best-fit timing) remains statistically
significant after several years of (often very skeptical) analysis;
the most recent results involve tracking the extinction rate for
some 10,000 genuses (originally only a few hundred families were
tracked).  The theory made several predictions, notably that
impact craters would also be found to be concentrated at
regular time intervals, and that multiple impacts would occur at
each extinction, spread over of order 1 Myear.
(since, if at least one impact
occurs on each "pass", the "average" number of impacts must be
greater than one).


    The known orbital period gives the size of the orbit:
the major axis of the orbit is 2.7 light years.  The requirement
to go through the Oort cloud gives a
"most probable" ellipticity of about 0.7, as I recall.
Passing stars "frequently" (every few Myear) come closer than
the companion to the sun, but they have relatively high
velocity (they're not bound to the Sun) and do not strongly
perturb either the companion or the comet cloud.  Over
about 1 billion years, though, they would be expected to
disrupt such a weakly bound pair; this means that either the
companion was only captured ~1 Gyear ago or (more likely) it
used to be closer in and has been kicked out to its current
distance in the last ~1 Gyear.

>> What kind of star is it?
>It is a mythical star.
>> Is it visible through a telescope?
>No.

    The companion star has a mass between approximately
.01 and .1 solar masses.  Smaller and it would require a very unlikely
orbit to produce the postulated effects; larger and it would be
too conspicuous an object to have been overlooked so far.  This
makes it a "brown dwarf", probably too small to have significant
fusion going on, and too cold (surface temperature below 2000 degrees)
to produce significant visible light, though it should be
a fairly bright infrared source.  It might, however, be bright
enough to look like a very dim red star; as such it would
be (at first look) indistinguishable from numerous red dwarfs and
particularly from much more distant red giant stars.  UC Berkeley
is still running a search that will inspect all catalogued faint red stars in
the northern hemisphere looking for "parallax" -- evidence that
the star is close, because it moves against the background.
However, a failure of this search will not rule out a companion,
just prove that it is not a) bright in the visible and b) in the
northern hemisphere.  Note that there is no a priori reason for the companion
to lie in the plane of the solar system; it could be anywhere in the sky.


The Nemesis hypothesis is indeed "just" a hypothesis, in that there
is no direct confirmation.  The two predictions above, however, have
certainly not been disproved, and there is some evidence in their
favor -- some periodicity in the handful of well-dated craters, and
some evidence for multiple impacts at the major extinctions, including
evidence for _both_ ocean and land impacts at the CT boundary.
Currently no other theory accounts as well for periodicity of either
extinctions or craters, or for multiple impacts.

>
>>  Was this just a trendy theory that got tossed out after a while?
>
>Yes.
>
 No, absolutely not.  It is a speculative theory, but one which
has some support and no contradictory evidence.

>>     My wife's sixth-grade students want to know...
>
>Teach them the difference between theory and observation, and you'll do
>them a life-long favor.
>

    Agreed.  But make sure they neither accept theories as fact
_nor_ dismiss them as falsehoods.

>--
>Ed Nather
>Astronomy Dept, U of Texas @ Austin

Jordin Kare
Special Projects Group, LLNL
-formerly at- U. C. Berkeley/ Lawrence Berkeley Labs.

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

Date: 19 May 89 12:45:30 GMT
From: mcvax!ukc!etive![e-mail]  (D Murphy)
Subject: Re: Andromeda Strain

In article <[e-mail]> [e-mail] writes:
>
>    By the way, I do think it is possible that an extraterrestrial bug
>    could cause problems on earth, although very unlikely. ~rI am thinking
>    that something couldevolve to live in an incredibly harsh and spartan
>    extraterrestrial environment by being able to extract energy from
>    almost any kind of molecule.  }iConsider 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.
>
>    Chris Eliot

This comment perhaps shouldn't be here - but in support of the above there
is a terrestrial equivalent (New Jersey'll hate this, creeping alt.sex
into sci.space :-)). I read once that syphillis (and perhaps one or 2 other
`venereal' diseases were at one time indigenous to certain parts of Africa
where they grew outside the body in warm, moist conditions. Upon being
inadvertently taken to Europe they were only able to survive in areas of
the body which were 1. Accessible from the outside, 2. Warm and damp and
3. Not full of nasty enzymes which would try to digest the organisms.


Murff....

JANET: [e-mail]      Internet: [e-mail]
       [e-mail]-a             [e-mail]
       [e-mail]        [e-mail]
D.J. Murphy     *Artificial* intelligence ?  Evidently.....

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

Date: 19 May 89 18:10:53 GMT
From: hpfcdc!hpfcdj![e-mail]  (Bob Myers)
Subject: Re: citizens in space -- risk silliness

>>... If the costs were trivial,
>>United Airlines would be offering LEO as a tourist attraction, and you'd just
>>be faced with a stack of liability waivers to sign before you got aboard.

>It's not that simple any more, in the US in particular.  Getting sworn
>statements from your passengers that they understand the risks and are
>taking them voluntarily will *not* protect you from the lawyers if
>something -- anything -- goes wrong.  It may provide useful ammunition
>for the enormously-expensive court battle, but it won't avert it.

Still irrelevant, Henry; I claim that if the costs were trivial, SOMEBODY
would be offering a "tourist ride"; the fact that this is not happening
means that we cannot yet ignore cost in the "ordinary citizen in space"
question, which was my original point.


Bob Myers            | "Man will occasionally stumble over the truth, but
{the known universe} |  most of the time he will pick himself up and continue."
!hplabs!hpfcla!myers |                        - Winston Churchill

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

Date: 20 May 89 16:06:09 GMT
From: aramis.rutgers.edu!paul.rutgers.edu![e-mail]  (Steve Masticola)
Subject: Ballistic parachutes (was: Giotto)

Bob Gray writes:

> Giotto isn't carrying enough fuel to slow down as it passes
> the Earth (You can't just put on the brakes you know :->).

Maybe you can put on the brakes. IF Giotto survives, and can be
steered to the vicinity of Earth, could it use the upper atmosphere to
brake into LEO or permanent orbit, without melting itself in the
process? If so, it might be possible to recover nonvolatile comet
remnants from the wreckage at a later date. I believe the term for
this maneuver is "ballistic parachuting."

- Steve ([e-mail])

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

Date: 21 May 89 08:11:17 GMT
From: shelby!Portia!hanauma![e-mail]  (Joe Dellinger)
Subject: Re: Andromeda Strain

In article <[e-mail]> [e-mail] writes:
>    Now imagine one that grew
>    much more rapidly in a suitable environment, say inside the lungs.

Interesting idea. I think this would pretty much happen with regular Earth
bugs, except for our immune system actively preventing it (isn't this what
actually kills most AIDS patients, in fact?). So the question is, how
specific to Earth-based life are the methods our immune system uses to
recognize and zap interlopers? Could we imagine some nasty alien bug which
likes warm, moist, carbon-rich environments as energy sources, is not very
picky about what it eats, and which our immune system doesn't even see or
can't even scratch? (Finally, a posting to sci.space within Henry's nominal
field of expertise?!)
\    /\    /\    /\/\/\/\/\/\/\.-.-.-.-.......___________
 \  /  \  /  \  /Dept of Geophysics, Stanford University \/\/\.-.-....___
  \/    \/    \/Joe Dellinger [e-mail]  apple!hanauma!joe\/\.-._

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

Date: Sun, 21 May 1989 19:03-EDT
From: [e-mail]
Subject: Re: SPACE Digest V9 #432

> In fact, not one person responded to my original posting with an
> argument in favor of the manned space program.

The answer is that the group is bored silly by this topic. It was
beaten to death with a dead heron only a few months ago. If you are
truly interested, go back through the last few years of archives of
Space Digest. You will find enough discussion to not only put you to
sleep, but to put you into a very deep coma.

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

Date: Sun, 21 May 1989 20:40-EDT
From: [e-mail]
Subject: Re: SPACE Digest V9 #443

> It is not at all clear whether this method would work, though, since
> the projectile might just go through without stopping.

I have my doubts about this statement. Fusion all occurs at the core,
and energy is transported between various layers in convection cells.
There are also acoustic waves that generate some of the cell pattern at
the surface. A body going through the sun would massively disrupt what
is currently a very stable situation. I don't think I would want to be
anywhere in the neighborhood when the experiment was tried.

I have no idea what would happen. I doubt anyone else does either.

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

End of SPACE Digest V9 #454
*******************