Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v15_0/v15no056.txt

Internet Message Format | 1993-07-13 | 35KB

Date: Sat,  1 Aug 92 05:00:02
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #056
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat,  1 Aug 92       Volume 15 : Issue 056

Today's Topics:
                         Bio-matter clumping
                     Calendar and Zodiak (3 msgs)
                         ET's, life in space
                        ETs and Radio (2 msgs)
                            Geotail launch
     Martino's lunar suicide (was Re: message from Space Digest)
         O.G. want us to hear them! (was Re: ET's and Radio)
                             Odds of Life
          ReEe: aA 12 mile tether that gernerates 5000v?
                         Red-blooded ET's :)
                            Space position
     Trekglow brighter than sci.space (was Re: Star Trek Realism)
                       trivial self-replication
                     What about the time ? (ETI)

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

Date: Thu, 30 Jul 1992 23:24:46 -0400
From: David O Hunt <[e-mail]>
Subject: Bio-matter clumping
Newsgroups: sci.space

There's a theory, jokingly called the "Open-Faced Sandwich Theory of Life"
in which colloidal particles of clay act as congrgating surfaces for organic
molcules.  Such an affinity has been demonstrated in a lab, and would go
far in explaining how organics ended up near each other...

The theory goes on to state that the byproducts of many reactions are
fatty acids, the stuff of membranes, which would form little domes over
the reacting proteins/genetic materials.  Eventually they get shaken off
or just cut loose in some other fashion.
David Hunt - Graduate Slave | My mind is my own.          | Towards both a
Mechanical Engineering      | So are my ideas & opinions. | Palestinian and
Carnegie Mellon University  | <<<Use Golden Rule v2.0>>>  | Jewish homeland!
============================================================================
Email:  [e-mail]            Working towards my "Piled Higher and Deeper"

Democracy is based on the theory that the people know what they want...and
they deserve to get it - GOOD AND HARD!

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

Date: Fri, 31 Jul 1992 03:55:15 GMT
From: Dave Tholen <[e-mail]>
Subject: Calendar and Zodiak
Newsgroups: sci.space

Adam R. Brody writes:

> I was just reading that the Earth precesses at a period of 26000 yrs.
> This means that over the past 2000 years, we have precessed about
> 30 degrees or one month.  If the vernal equinox was in March back then,
> how do we account for the missing (or extra) month in our calendar?
> To reiterate, the vernal equinox is occurring 2000/26000 sooner than when
> it occurred 2000 years ago in a solar system coordinate system.  In another
> 2000 years, will spring star in February, or do we account for precession
> somehow in the calendar?

The vernal equinox was in Aries back then, now in Pisces.  The vernal
equinox changes constellations, but it doesn't change months, because
we have cleverly chosen the length of the calendar year to be the tropical
year, not the sidereal year.  The length of the tropical year includes
the effects of precession.  Of course, back then the true length of the
tropical year wasn't known accurately, hence the calendar reform that
replaced the Julian calendar with the Gregorian calendar, otherwise the
vernal equinox would have drifted out of March.  It's a fascinating
story, much too long to go into too much detail here.

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

Date: 31 Jul 92 04:01:16 GMT
From: Dave Tholen <[e-mail]>
Subject: Calendar and Zodiak
Newsgroups: sci.space

George Hastings writes:

> To make up the VERY small difference due to precession, as well
> as to adjust for the slowing of the Earth's rotation due to
> tidal drag of the oceans (caused by the moon's gravitation),
> from time to time they declare "leap-seconds" there was one
> this year.

Yes, leap seconds are used to correct for irregular rotation, but
they are not used to correct for precession.

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

Date: 31 Jul 92 04:11:02 GMT
From: Dave Tholen <[e-mail]>
Subject: Calendar and Zodiak
Newsgroups: sci.space

Gary Coffman writes:

> There wasn't a March 2000 years ago. The calender we use is a modern
> invention of the 17th century. When the Gregorian calendar was rationalized,
> we lost a week, and renters rejoiced and landlords cried. Precession is not
> figured into the calendar. Unless someone rationalizes the calendar again,
> the seasons will precess across the months. The Chinese calendar, and the
> Jewish calendar now have the new year occurring on dates other than Jan 1.
> That's because both calendars are old enough to have precessed a bit.
> Besides, it's midwinter now, in the southern hemisphere. Which one stands
> on it's head?

The month of March did exist prior to the 17th century, but not in all
calendars.  Precession is figured into the calendar.  The seasons will
not precess across the months.  I'm no expert on the Chinese calendar,
but I believe it is based on the Moon, not the Sun, so a comparison with
a solar calendar isn't entirely appropriate, but I doubt the new year
differs from January 1 because of precession.

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

Date: Fri, 31 Jul 92 11:49:11 BST
From: [e-mail]
Subject: ET's, life in space

> remember, we not only need self-replication, we need non-trivial
> self-replication.)
>


You seem to have a hangup with this "non-trivial". If you stay with
that you have a tautology.

The whole point many people are making is that the difference between
life and non-life (as we define it) is at somepoint where the
"trivial" chemical replication becomes complex enough to be definable
as your "non-trivial" replication.

The point is that competition between forms takes on different
meanings depending on the environment and the nature of the forms. A
chemical form that is more efficient in utilizing energy and it's
environment (which may well be a sea of chemicals produced by itself
and others) to replicate itself will dominate. The lack of a membrane
is meaningless in an environment where no one else has one. But the
first ones to utilize it will "break" the "social contract" :-) and
wipe the oceans with the ones who don't have it. Until that time the
fact that organisms are leaking material to their surroundings is not
significant. And since their surroundings will most likely be their
progeny, it might even be a bit of an advantage. And if a parasite
evolves, it will be forced to extinction along with the "host" if it
is too good at the job.

There were two very early sets of mass extinctions on the way to
modern life. The first occured when the initial soup of chemicals was
used up by more competitive organisms, probably by developing your
cell membranes or by utilizing certain clays as an initial structure.
The second occured when some truely nasty bug learned how to produce
energy directly from sunlight and gave off a terribly poisonous,
highly oxidative gas that proceeded to chemically burn the very rocks
and very nearly wipe out most of the previously existing anaerobic
life: Oxygen. This event is recorded in the rocks as the end of the
formation of the Banded Irons.

There just doesn't appear to be any point at which you need to point
to say "and then a miracle occurs". The steps aren't all known, and
the actual ones that occured on Earth may never be known: there is
more than one way to skin a cat, and therre is probably more than one
way to evolve chemistry into "non-trivial" life.

Chemistry for the formation of membranes has been demonstrated in the
lab with no need for recourse to life.

Another point of interest. It has LONG been known that the ribosomes
are from an ENTIRELY separate evolutionary strain. They don't even
use the same genetic code. Eukaryotic cells are nothing but a
symbiotic relationship between independant organisms. It is thought
that even some of the different organells may have originated from
different organisms that formed a "colony" inside a membrane, to
their mutual benefit, and then proceeded to evolve into closer and
closer dependance.

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

Date: 30 Jul 92 22:05:44 GMT
From: Gary Coffman <ke4zv!gary>
Subject: ETs and Radio
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>Now subtract out all Population II stars, no heavy elements like iron,
>
>Some of them might have enough for a small planetary system.

I mentioned iron for two reasons. First, it's necessary for oxygen
transport via the blood. Second, and this is opinion, it's needed
for the planet to have a significant magnetic field to redirect energetic
radiation from the planetary surface. Now iron is the result of supernova
explosions. Population II stars formed *before* supernovas became common
enough to supply heavy elements.

>
>>and subtract out all multiple star systems, no stable planetary orbits,
>
>I'm told this doesn't look like as big a problem as was once thought.

??? Let me put it another way, stable orbits in the liquid water zone.

>>subtract out all systems that don't have a planet in the liquid water zone,
>
>This is where we get into real guesswork.  Note, though, that the liquid-
>water zone is wider than we once thought -- Mars would have liquid water
>if it was bigger.  (The idea that the "habitable zone" is very narrow and
>Earth has just happened to stay in it has been discredited.)

The potential liquid water zone of a G star like ours is roughly from
near Venus orbit to somewhat beyond Mars orbit given specially designed
planets in the various places. Now on the solar system scale, that's a
small range of distances.

>>subtract out all planets not at the correct stage of planetary evolution,
>>ours is
>>billions of years old while conditions for life are a much smaller fraction
>
>Really?  Please elaborate.  All you really need is liquid-water temperatures
>and adequate materials.  The major changes in our planetary conditions over
>the last few billion years have pretty well all been due to the presence of
>life.  (The idea that Earth had a lucky escape from being another Venus has
>also been discredited -- Earth's oceans would still be liquid even if it
>had Venus's load of atmospheric CO2 today.)

What I'm saying is that the accretion process, the remelt, the second
cooling, and finally the out gassing of water vapor and methane that
formed the primordial atmosphere took about 1/3 the life of the solar
system to occur. (At least according to popular theories of planetary
formation) The great extinction, due to oxygen liberation, took another
4 billion years, before oxygen based life became dominant. I think we
can safely assume that intelligent life would require the energetics
only possible to oxygen breathers.

>>... now subtract out all the systems where life hasn't evolved from
>>primitive forms to advanced forms, life has existed on this planet for
>>a long time, humans much less so, etc.
>
>But add in the potential for life to take faster routes than ours.  Some
>of the dinosaurs might well have evolved intelligence if their history
>hadn't been cut short a bit too early, and several other species on Earth
>are not impossibly far from intelligence.  This is getting pretty far into
>guesswork again, though.

At best that shaves only 60 million years off the timescale of billions.

>>who've thought about the question say that there are perhaps 50 systems
>>in the galaxy that may have life as we know it.
>
>References, please.  There have certainly been *much* higher estimates too.

One of Sagan's books quoted this figure. There have been other estimates
in the thousands to millions for our galaxy, but the factors I listed
above weed that number down dramatically. One of the greatest unknowns
is whether life bearing planets naturally evolve intelligent creatures,
or whether that's a rare accident. We don't have any data to support
either position very well.

>Also, why insist on it being life as we know it?

Because we wouldn't recognize any other kind. Any lifeform not based on
carbon chemistry would be very strange indeed.

>The only argument against extraterrestrial life/intelligence that strikes
>*me* as being particularly telling is the Fermi Paradox:  if they're out
>there, why didn't they colonize this planet long before we evolved?

Assume Einstein is right. Interstellar flight takes longer than the
time available since the Universe began to visit all the stars. Or,
we are the *first* technological civilization to evolve in the galaxy.
Or, technological civilizations self destruct.

Gary

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

Date: 30 Jul 92 22:34:24 GMT
From: Gary Coffman <ke4zv!gary>
Subject: ETs and Radio
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (russell wallace) writes:
>In <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>>In article <[e-mail]> [e-mail] (russell wallace) writes:
>>>Given that for evolution of life to start, a simple living organism must
>>>come together from amino acids etc. by accident; and that for any
>>>complex structure to fall together by accident is extremely improbable;
>>>then it looks pretty much like the odds against life appearing on any
>>>one planet could easily be more than 10^1000 to 1 against, and the
>>>number of planets in the visible universe is only about 10^22.
>
>>When you place hydrogen and oxygen together in a 2:1 ratio and provide
>>an energy source, what happens? Blooey! Every time? Yes, every time.
>>That's the way it is with life chemicals, there is nothing accidental
>>about their combination.  It's just basic organic chemistry at work.
>>We have very good evidence that the primordial chemical mixtures of
>>early planetary bodies contain the proper precursor compounds and
>>elements in abundance. We know that solar UV and electrical discharges,
>>lightning, will supply the necessary energy. We've done it in a test tube.
>>We haven't yet made the step to the enclosed cell, but with 10^23 precursor
>>molecules in every cubic meter, the combination is bound to occur.
>
>Yes, I realize that amino acids are bound to form under the appropriate
>conditions. However, those amino acids are no more likely to
>spontaneously assemble into a life form than 10^6 transistors placed in
>a box and shuffled around are to assemble themselves into a working
>computer.

But you are still making a flawed assumption. The carbon chemistry of
complex organic molecules *dictates* that they must react in such a
way as to form self replicating structures. Once that happens, the
self replicators quickly dominate all other processes. The only way
you can view life as an accident is if you view the chemical laws
as an accident. Given the laws of carbon chemistry, life *must* result
when conditions meet certain criteria of temperature, pressure, precursors,
and energetics. Given the intial conditions on Earth, life *had* to
form. There was no way the chemical laws could be broken any more than
light can travel faster than 300,000 m/s in vacuum.

The result of *evolution* to the current human form is much less certain.
That's the result of trillions of chance combinations of life being weeded
by selective pressure. It's far more certain that *some* form of intelligent
life would evolve and *call* itself human in whatever language it developed.
And it's absolute certainty that *complex* lifeforms would evolve since they
have a demonstrated higher survival probability than simple forms.

Creationists invariably choose to misunderstand carbon chemistry so that
they can say life *by chance* is absurd. But life is not by chance. If
there's a place for a god, it's in formulating the basic chemical and
physical laws that *demand* that life arise.

Gary

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

Date: 30 Jul 92 19:55:21 GMT
From: Keith Stein <[e-mail]>
Subject: Geotail launch
Newsgroups: sci.space

Yes GEOTAIL was successful, no problems.

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

Date: 31 Jul 92 09:24:42 GMT
From: "Frederick A. Ringwald" <[e-mail]>
Subject: Martino's lunar suicide (was Re: message from Space Digest)
Newsgroups: sci.space

Shoot, guys, why bother with a pound of anything? Why not open up a
vent valve and let all the air out?

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

Date: 31 Jul 92 08:21:36 GMT
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: O.G. want us to hear them! (was Re: ET's and Radio)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] writes:
[Dale dropped the attribution on this quote:]
>> If life really is somewhat rare, the place to look for ET signals
>> is from
>> distant galaxies, broadcast by pan-galactic supercivilizations.
>
> Although we'd better look for the odd laser that happens to be
> pointing at us. Or maybe look for a source of modulated neutrinos. Or
> maybe start opening worm holes in the Plank-scale froth to see what
> the latest news is. The chances that advanced civilizations are
> spewing vast amounts of energy into the void in order to transfer a
> few Giga bits bits from point A to bit strains credulity to the
> breaking point.

Dale, recall that the "classic" Morrison-Cocconi version of SETI
search assumes the Other Guys are intentionally beaming radio signals
at our planet, in the hope that young, technologically primitive
civilizations will be searching for such beacons (or at least doing
radio astronomy).   Obviously they could continue to do this long
after their own technology had passed the 20th-century stage.

Your last sentence implies that terrestrial SETI researchers are
fools.  I don't think so.

If I had paid more attention to the details of modern SETI searches,
I would know whether they hope to detect signals *not* intended for or
aimed at us.  But at a minimum, they should still be searching for
intentional signals.   Others on the Net could tell us more.

(Hope summer in Belfast is treating you well, and the songwriting
thing was fruitful!)

Bill Higgins                           | Every so often, Innumeracy
Fermi National Accelerator Laboratory  | strikes.  Out of all Americans,
Bitnet:     [e-mail]        | a lot suffer from it.  But
Internet:  [e-mail]       | we can win the fight against
SPAN/Hepnet:      43011::HIGGINS       | Innumeracy with your help.
                                       | All it takes is a few pennies a day.

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

Date: Thu, 30 Jul 1992 21:15:29 -0400
From: David O Hunt <[e-mail]>
Subject: Odds of Life
Newsgroups: sci.space

IF (big if) one assumes that the probablilty of life arising on earth is
so small that it couldn't happen, then there are only 2 possiblities
for our existance:

1)  That life arrived from another place (accidentally or purposefully)

2)  That "God" created us

About 1) - this only delays talk, as SOMEwhere down the line life had to
arise spontaneously...kinda like the "turtles all the way down [to what?]"
argument.
About 2) - If we assume that the odds are impossibly small for life to
have arisen anywhere, then this proves "God's" existence.

But wait!  We've proven something that can't be proven.  And so God
vanishes in a puff of logic (with apologies to D. Adams).

Ergo, we aren't alive at all!  :P



David Hunt - Graduate Slave | My mind is my own.          | Towards both a
Mechanical Engineering      | So are my ideas & opinions. | Palestinian and
Carnegie Mellon University  | <<<Use Golden Rule v2.0>>>  | Jewish homeland!
============================================================================
Email:  [e-mail]            Working towards my "Piled Higher and Deeper"

Cthulhu for President!  Stop voting for the lesser evil!

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

Date: 31 Jul 92 05:40:58 GMT
From: ryan korniloff <[e-mail]>
Subject: ReEe: aA 12 mile tether that gernerates 5000v?
Newsgroups: sci.space

>Path: mnemosyne.cs.du.edu!uunet!olivea!tymix!rael!filfeit
>From: [e-mail] (Fil Feit)
>Newsgroups: sci.space
>Subject: A 12 mile tether that generates 5000v?
>Message-ID: <[e-mail]>
>Date: 30 Jul 92 19:10:32 GMT
>Sender: [e-mail]
>Reply-To: [e-mail]
>Organization: Sun Microsystems
>Lines: 14
>Nntp-Posting-Host: rael
>
>Hi all.
>
>Can someone explain how that works?  I saw reference to this on the AP
>wire, and they must think this is perfectly normal, since no-one is
>bothering to explain it.
>
>Is there an article on this some kind soul can direct me towards?
>
>Thanks,
>
>--f2
>----------------------------------
>  Hey, Mother Earth, won't you bring me back down,
>  safely to the sea?

The 5000 volts are induced by the Earth's magnetic field as the spacecraft
orbits. The same principle in using magnets to enduce a voltage when you
pass a magnet through a coil of wire.


     -- Ryan Korniloff
     -- [e-mail]

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

Date: Thu, 30 Jul 1992 23:19:59 -0400
From: David O Hunt <[e-mail]>
Subject: Red-blooded ET's :)
Newsgroups: sci.space

> I mentioned iron for two reasons. First, it's necessary for oxygen
> transport via the blood. Second, and this is opinion, it's needed
> for the planet to have a significant magnetic field to redirect energetic
> radiation from the planetary surface. Now iron is the result of supernova
> explosions. Population II stars formed *before* supernovas became common
> enough to supply heavy elements.

I'll buy the iron argument about magnetic fields, though I think that
some other light metal might work...I'm admittedly ignorant about geomagnetics,
but isn't it the currents in the core rather than the composition of
the core?

As to requiring iron to carry oxygen - NONESENSE!  Spock did it with
copper!  :)  Seriously, the horseshoe crab has _copper_ based blood.
Magnesium, among other light metals, could also work (don't know the
exact energetics, alas...shouldn't have slept through chem! :)  And
why do we assume it must be a _metal_ carrying the oxygen - there are
non-metals with oxygen-affinity.

> The great extinction, due to oxygen liberation, took another
> 4 billion years, before oxygen based life became dominant. I think we
> can safely assume that intelligent life would require the energetics
> only possible to oxygen breathers.

What about other bi-elemental gasses?  Cl2 may be too energetic, but we
can't assume not...the main problem I see to this is the relative
abundances of the elements.  Perhaps N2?

> >Also, why insist on it being life as we know it?
>
> Because we wouldn't recognize any other kind. Any lifeform not based on
> carbon chemistry would be very strange indeed.
>
> Gary
Maybe, maybe not.  We may not understand its biology, but a lithium
skeleton lying on the ground of an extra-solar planet might be a clue.

And I highly suspect, given numerous examples of convergent evolution on
earth, that similar structures would evolve elsewhere.



David Hunt - Graduate Slave | My mind is my own.          | Towards both a
Mechanical Engineering      | So are my ideas & opinions. | Palestinian and
Carnegie Mellon University  | <<<Use Golden Rule v2.0>>>  | Jewish homeland!
============================================================================
Email:  [e-mail]            Working towards my "Piled Higher and Deeper"

Democracy is based on the theory that the people know what they want...and
they deserve to get it - GOOD AND HARD!

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

Date: Fri, 31 Jul 1992 05:53:55 GMT
From: Felix Finch <[e-mail]>
Subject: Space position
Newsgroups: sci.space

>>>>> John Roberts said:

> Actually, it's an ongoing problem for the US. As Japan comes to own more and
> more of the US, it has an increasing ability to influence US politics and
> policies.

I'll be more impressed by your paranoia when you worry more about
Britain (which owns more of the US than Japan) or The Netherlands
(which owns more per capita).  Of course, you'll probably be more
impressed by my statistics when I can give references, but I like
the trade-off :-).

--

            ... _._. ._ ._. . _._. ._. ___ .__ ._. . .__. ._ .. ._.
   Felix Finch, scarecrow repairer / [e-mail] / uunet!crowfix!felix

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

Date: 31 Jul 92 07:39:38 GMT
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: Trekglow brighter than sci.space (was Re: Star Trek Realism)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Kevin Hanna) writes:
> [e-mail]  writes:
>> When the ship is streaming through space, stars moving past
>> at several per second, how is it that the ship is steadily lit from one
>> side?  What is the source for this light?
>
> The light comes from the Enterprise's running lights reflecting
> off the hull of the observer's  ship.  Geez!  :-)

Hmm, r-to-the-fourth dependence, times geometry of camera ship, times
reflectivity of camera ship...  seems like we should be seeing some REALLY
bright lights shining toward us from the *Enterprise* if Kevin Hanna's theory
is right.

Well, maybe the camera ship is covered with Scotchlite.  And we can't rule out
that it's really *big*...

Disclaimer & apology:  I am aware that there are newsgroups and
mailing lists devoted to discussion of *Star Trek*.  However, I never
read 'em, so I would have missed this thread if it had been conducted
there. Take heart-- this thread will damp out soon and we will return
you to chatter about the "real thing" again.

As food for thought, here are the Usenet Arbitron statistics for May 1992
posted by Brian Reid ([e-mail]):

        +-- Estimated total number of people who read the group, worldwide.
        |     +-- Actual number of readers in sampled population
        |     |     +-- Propagation: how many sites receive this group at all
        |     |     |      +-- Recent traffic (messages per month)
        |     |     |      |      +-- Recent traffic (kilobytes per month)
        |     |     |      |      |      +-- Crossposting percentage
        |     |     |      |      |      |    +-- Cost ratio: $US/month/rdr
        |     |     |      |      |      |    |      +-- Share: % of newsrders
        |     |     |      |      |      |    |      |   who read this group.
        V     V     V      V      V      V    V      V
  45  94000  2023   82%   834  1744.8    13%  0.04   4.1%  sci.space
  83  77000  1661   81%   857  2424.9    12%  0.06   3.3%  sci.astro
 119  65000  1415   76%    10    43.2     0%  0.00   2.9%  rec.arts.startrek.info
 146  59000  1282   63%    81   186.4    36%  0.00   2.6%  rec.arts.startrek
 195  51000  1098   80%   294   507.6     3%  0.02   2.2%  sci.space.shuttle
 245  46000   995   58%  1725  3570.2     4%  0.11   2.0%  rec.arts.startrek.current
 280  43000   923   58%  1101  2942.5    11%  0.10   1.9%  rec.arts.startrek.misc
 390  36000   768   60%   220  1064.5     0%  0.04   1.5%  sci.space.news
 437  33000   709   57%   461  1043.9     4%  0.04   1.4%  rec.arts.startrek.tech
 464  31000   681   58%   191  1561.4     5%  0.07   1.4%  alt.startrek.creative
 526  28000   609   57%   108   214.4    32%  0.01   1.2%  rec.arts.startrek.fandom
 959  13000   272   55%   118   318.5    11%  0.03   0.5%  talk.politics.space

Totals (ignoring crossposting):

*Trek*-related messages:   3977
Space-related messages:    2323

*Trek*-related volume:     9562.5 kbytes
Space-related volume:      6060.3 kbytes

*Trek*/space ratio
by message:                1.712
by volume:                 1.578

Oh, well, I think we're still beating out alt.tv.simpsons.

     O~~*           /_) ' / /   /_/ '  ,   ,  ' ,_  _           \|/
   - ~ -~~~~~~~~~~~/_) / / /   / / / (_) (_) / / / _\~~~~~~~~~~~zap!
 /       \                          (_) (_)                    / | \
 |       |     Bill Higgins   Fermi National Accelerator Laboratory
 \       /     Bitnet:     [e-mail]
   -   -       Internet:  [e-mail]
     ~         SPAN/Hepnet:      43011::HIGGINS

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

Date: Fri, 31 Jul 1992 05:11:54 GMT
From: russell wallace <[e-mail]>
Subject: trivial self-replication
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Tom) writes:


>>>Simple molecules in solution can reproduce
>>>themselves, given favorable conditions.  RNA, in particular, does this.
>>>Not well, and not quickly, by itself... but it does do it.

>>Again, if it is replicating by itself, it is performing *trivial*
>>self-reproduction, because it is not carrying any genetic information.

>So what if it isn't carrying genetic information?  Self-replication is
>self-replication.  Evolution will favor more complex forms, and eventually
>it won't be 'trivial' anymore.  BTW, what is the definition of 'trivial'
>in this context?  And no, evolution does not require DNA.  In this context
>(usually called chemical evolution) it is just the process by which those
>structures that replicate (whether 'trivially' or not) come to dominate.

Basically the problem with not having genetic information is that that
chemical substance which tends to form most easily and be most
persistent will certainly come to be the most abundant, but unless it
has a blueprint for its own construction, which can be mutated to create
a more complex version of the substance, this is a dead end. This is why
reproduction without genetic information is termed "trivial".

>>If the only machinery required is the stuff floating around all over the
>>place (free amino acids etc.) then you have trivial self-reproduction
>>which does not count, because even if RNA can replicate in this context,
>>it is trivial self-reproduction because the RNA does not have or need
>>any genetic information.

>By what standards are you deciding that it 'doesn't count'?  If it can be
>demonstrated (as I think it has, both in my own studies and in the
>synopses offered here of late) that life processes can arise on their
>own, without the infamous hidden watchmaker, or without the improbable
>'protien of the Ninth Configuration', then what exactly, does 'not
>counting' mean?  That we aren't here?  Ps- it's been mentioned already,
>but RNA doesn't need genetic material, because it IS genetic material.
>If we could talk to a piece of DNA, it might say that we existed for IT.

Well, by "not counting", I meant that that wouldn't get you any closer
to cracking the key problem, of forming something capable of non-trivial
self-reproduction (see above for the reason why you need non-trivial
self-reproduction).

However, it has been suggested that a strand of RNA can act as an
enzyme, its activity being determined by the sequence of bases; and that
as such it can moderate its own replication, and produce protein enzymes
which can assist with this process. If it could work, this would seem
the most promising way to solve the problem, because then the RNA
strand would be doubling as blueprint AND machinery, thereby solving the
problem of requiring the two to form together. Does anyone know exactly
how far the research on this has got (i.e. what capabilities of RNA in
this area have been demonstrated)?

>Aaaaand, as long as you have such a great handle on the defintion of life...

>1)  Are viruses alive?  They reproduce non-trivially (by what I can get
>    of your defintion from context)

A virus by itself is not alive because it does not reproduce
non-trivially or indeed at all (it has the blueprint, but lacks most of
the machinery). I would be inclined to say that a virus is somewhat akin
to a computer virus, having a sort of pseudo-life.

>2)  If humans built self-sufficient space colonies, would it mean that
>     Gaia (the entire biosphere) had reproduced?  Evolved?

>3)  Is human culture, as a whole, an organism?  It feeds, makes wastes,
>    evolves, etc...

Hmmm... these are interesting questions :-). I think proponents of the
Gaia hypothesis would say yes to 2), perhaps with some justification;
and there's a book a read a while ago called "Bionomics" in which the
author draws parallels between human culture and an ecosystem; which
would seem to be an argument in favour of 3).

--
"To summarize the summary of the summary: people are a problem"
Russell Wallace, Trinity College, Dublin
[e-mail]

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

Date: 31 Jul 92 09:33:15 GMT
From: B Johnson <[e-mail]>
Subject: What about the time ? (ETI)
Newsgroups: sci.space

I've been reading about this ETI question, and it seems to centre on whether
or not these amino acids etc. can spontaneously join. To me it seems
unlikely.

However one question that seems to be ignored is the length of time that
the intelligence would hang around for.
Take earth as an example...
Universe created circa 15 billion years ago
Earth formed circa 5 billion years ago
Projected sun-life another 5 billion years. ie at max we have 5B years to
find out how to leave, where to go and how to get there.
Man emerges circa several thousand years ago (controversy on this point
but safe to say less than a million.
Takes most of that time to develop up to the industrial revolution.
Only been able to fly 89 years (excepting ballons), leave the atmosphere
about 30 years. Radio telescopes etc used for trying to find ETI all
developed this centuary.

Projected stay on earth ? Considering Ozone, CO2, over population,
desertification, exhaustion of natural resources etc etc we seem to
have a few problems. (ps lets not leave out Nuclear war ?). Now
assuming we manage to solve these problems (and we probably will
one way or another ) the question is how close did we come ? and how
often ? to destroying ourselves ?

OK so for life to be out there it has to have developed in a similar
timescale - if we want to hear it, it has to have broadcast xx years
ago, to get here conveniently in time for us to develop the tech. to
listen. Then they have to survive long enough for the message to get
here, and for us to do something about it. What do we do ? E-Mail
back ??? Plug them into INTERNET ??

Now here's the crux. Even if we discover "life exists *there*"
do we believe in travel at speeds faster than light. And
disbelieve all the wacko time effects Albert E. would have us
believe. Yes ? No ? So does it matter even if they were there.
Does it affect us ??

Bruce
<[e-mail]>

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End of Space Digest Volume 15 : Issue 056
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