Lecture of the Week: Part II: Astrobiology

I have enclosed below the same note that I posted on ECOLOG-L regarding
this week's lecture, but it would seem to be just as appropriate to
sci.astro.research:

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This week's lecture is given by Geoff Marcy, someone you've perhaps
never heard of, but only proving once again that you can only be famous
if people at least first know your name.

Nonetheless, Marcy has discovered more planets than Galileo ever dreamt
of, and as a result of his and his colleagues extraordinary work, he
recently shared the $1 million Shaw Prize. The Shaw Prize was
extablished by the Hong Kong businessman, Sir Run Run Shaw, to create
awards equivalent to the Nobel Prize, but in those areas of
investigation where no Nobel Prize exist: biology, astronomy and
mathematics. The Shaw Prize has been awarded for only two years now, and
Marcy, along with Michel Mayor of the Geneva Observatory, were awarded
the prize in astronomy last year.

Although the subject of Marcy's talk is nominally astronomy, it is also
hardcore biology, even if it is at a very primitive state. Geology was
the science that informed and transformed evolutionary thought during
Darwin's time. Comparative planetology will do the same during ours. The
questions that will dominate this coming century a (i) is life
inevitable?, (ii) is it fragile?, and (iii) to what degree does the
evolution of complex life depend on the good fortune of specific
planetary configurations in remote solar systems?

I've written before that I've always found it discouraging that people
so readily say that biology (or ecology) has no laws. It's simply not
true, even though Marcy says much the same thing in this lecture. When
we do find life on other worlds, it will almost certainly be true that
its biochemistry will be different than our terrestrial biochemistries,
perhaps anchored in a different part of the periodic table, and almost
certainly using a completely different information-bearing schema than
DNA/RNA. It will however inevitably still be subject to Darwinian
selective constraints, and thus must exhibit all of the "laws" and
constraints that we see in the ecological patterns we find here on
Earth: logistic curves, predator-prey population cycles, competitive
exclusions, niche partitioning, species-area curves, nestedness, and so on.

Ecology studies the grand patterns of life, not the minutia, and those
patterns should be common throughout the universe, wherever life exists.

Wirt Atmar


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The Evolutionary Biology Lecture of the Week for May 29, 2006 is now
available at:

http://aics-research.com/lotw/

The talks center primarily around evolutionary biology, in all of its
aspects: cosmology, astronomy, planetology, geology, astrobiology,
ecology, ethology, biogeography, phylogenetics and evolutionary biology
itself, and are presented at a professional level, that of one scientist
talking to another. All of the talks were recorded live at conferences.

This is the second lecture in a summer-long series on the new science of
astrobiology.

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May 29, 2006

Part II: Astrobiology

Exoplanets, Yellowstone, & the Prospects for Alien Life
Geoff Marcy, University of California, Berkeley
52 min.

"It will be especially interesting to see whether it is astronomy
that absorbs biology, or the other way around."
-- Fred Hoyle (1915-2001)

The beginnings of formal Western science can be traced back to a single
point in time: the life and work of Copernicus (1473-1543). His major
work, De revolutionibus orbium coelestium, was published in the year of
his death, after more than three decades of thought. "The Copernican
Principle" is the philosophical statement that no "special" observers
need or should be proposed to explain our position in the heavens.

Bruno, in 1584, explained the principle in this fashion:

"Thus the earth no more than any other world is at the centre; and
no points constitute definite determined poles of space for our earth,
just as she herself is not a definite and determined pole to any other
point of the ether, or of the world space; and the same is true of all
other bodies. From various points of view these may all be regarded
either as centres, or as points on the circumference, as poles, or
zeniths and so forth. Thus the earth is not in the centre of the
universe; it is central only to our own surrounding space."

Although we have greatly expanded the reach of the idea, we still
conduct our science by this same principle: that the laws of physics and
chemistry are the same everywhere, and we now call the general thought
the "Principle of Mediocrity."

If this is so -- and after 400 years of observation and investigation,
we have no reason to doubt it -- then we cannot believe that there is
anything special about the Earth or the life that inhabits it. If one
earth exists, then there must be many.

The first extrasolar planet was discovered in 1995 by Michel Mayor and
Didier Queloz of the Geneva Observatory, but we deeply believed in the
existence of these planets long before their recent discoveries.

Mayor and Queloz's finding was soon confirmed by the team of Marcy,
Butler, Fischer and Vogt and then greatly expanded upon. Marcy and
colleagues have since discovered more than 110 planets. But in the
intervening years since 1995, we have been surprised by the diversity of
the types of solar systems we've found.

In September 2005, Geoff Marcy and Michel Mayor were awarded the $1
million Shaw Prize for their revolutionary discoveries. In referencing
his award, Marcy said:

"We now know that other planetary systems exist, but that their
diversity renders our solar system just one type of many. The odd
orbital shapes caused by the gravitational scattering of planets by
other planets makes our solar system relatively peaceful by comparison.
Perhaps life owes its existence here on Earth to the fortuitous,
delicate arrangement of the planets in our system."

What does this imply for the prospects of other life in the universe? We
truly don't yet know. The detection of other Earth-like planets remains
beyond our current technologies, but as you will hear in the coming
lectures, that may soon change.

Marcy, like almost everyone else at the moment, expects that bacterial
life should be common in the universe, but he is quite pessimistic about
the presence of technological, "intelligent" life anywhere near us.
Every observation of the night sky for the last two hundred years has
been one more negative affirmation its nearby absence.

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