Lecture of the Week: Cosmology and Life
- From: "Wirt Atmar" <atmar@xxxxxxxxxxxxxxxxx>
- Date: Thu, 7 Sep 2006 00:43:32 -0400 (EDT)
The Evolutionary Biology Lecture of the Week for September 4, 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 sixteenth and final lecture in a summer-long series on the
new science of astrobiology.
=====================================
September 4, 2006
Part XVI: Astrobiology
Cosmology and Life
Mario Livio
Space Telescope Science Institute, Baltimore
37 min.
"A universe that came from nothing in the big bang will disappear into
nothing at the big crunch. Its glorious few zillion years of existence
not even a memory."
- Paul Davies (introducer of this talk)
Mario Livio says that he was asked just a few days before he gave this
lecture, "Is this going to be just a short version of the Bible?" He
said that he answered no, but it is a talk beginning at the beginning
of time.
If we were to rewrite the Book of Genesis, based on our current
understanding of cosmology, it would go much like this:
In the beginning was the Bang, and the Bang was good, but it was
without form. As time progressed, small ripples in the fabric of the
Bang precipitated mass and energy out of the stuff of the Bang, but the
stuff of the Bang itself was without substance. From the Bang came the
Void, and the Void was dark, but from the precipitation of the Bang,
hydrogen - and a very little helium and a miniscule amount of lithium
- filled the Void. This was the periodic table for the first few
hundred million years.
Nature then said, "Let there be light," and there was light. The
almost imperceptible ripples of the Bang grew and amalgamated to the
point of accreting large spinning things, composed of almost nothing
but hydrogen, and from these large spinning things the first galaxies
of stars formed. The force of gravity collapsed pockets of this
hydrogen gas, and as those pockets collapsed, they self-ignited into
the fire of thermonuclear fusion. As these first stars were born, grew
and died, they consumed their primordial hydrogen, elevating it into
the upper elements of the periodic table through proton-proton fusion,
but the energies of these first stars were weak too. Iron was the most
complex element that was formed in these early stars.
This was the time of giant stars, and when their fuel was
exhausted and they could exist no longer, many of the stars died the
cataclysmic deaths of supernovae, and from this cataclysm, the
remaining higher elements of the naturally occurring elements were
born.
The first generation stars begat the second generation stars, and
in turn, the second generation stars begat the third, and with each
generation, "metallicity" increased, and Nature said that "metallicity"
was good. The new generation of stars were born for the first time with
chemically complex protoplanetary accretion discs. From these accretion
discs, planets, with all of their elemental complexities and
high-volume volatiles, were formed for the first time.
Covalently bound molecules formed in this abundance, centered on
the bottom rungs of the periodic table in the fourth group, and from
these covalent molecules, hydrocarbons, nitrates and carbohydrates
bountifully flowed. The precusor molecules of life were now everywhere,
and that abundance too was good, and Nature said, "Let there be life,"
and there was life.
The text above is not meant to be irreverant. Rather it is merely a
reasonably accurate recitation of our present understanding of the
genesis of the Universe, written in an older idiom.
The rate of increase in our understanding of the origin of Universe has
simply been astounding over the last century, with most of that advance
occuring in the last 40 years. We know now the age of the Universe to
three decimal places, 13.7 billion years, because of the recent results
of Wilkinson Anisotropy Probe. Clearly, these and other findings in
cosmology have direct and obvious implications for our understanding
the emergence of life in the universe. But there remains an enormous
amount we don't yet fathom. The greatest mysteries appear to lie ahead
of us.
Mario Livio speaks to these points in his talk, suggesting that
carbon-based life became possible only ~7 billion years ago. He
specifically addresses these questions:
o the requirements for carbon-based life and their dependencies on
the values of physical constants
o the inflationary model and its implication for the existence of
a "multiverse" of universes
o the nature of dark energy, as well as we understand it, or are
mystified by it, and its relation to anthropic considerations
o the possibility of time-varying constants in nature
o the question of the potential rarity of intelligent life
=====================================
.
- Prev by Date: Re: Neanderthal vs Cro-Magnon
- Next by Date: Re: The long neck of the giraffe: a just-so story
- Previous by thread: HOX: Chromosome spatial order corresponds to axis gene-expression order?
- Next by thread: Paper: Gene Transposition as a Cause of Hybrid Sterility in Drosophila
- Index(es):
Relevant Pages
|
