|
September 4, 2006
Part XVI: Astrobiology
Cosmology and Life
Mario Livio
Space Telescope Science Institute, Baltimore
37 min. (slideshow requires QCShow Player)
Audio only (mp3 format)
View as a webpage (quicktime, real player) (notes)
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 Microwave 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:
- the requirements for carbon-based life and their dependencies on the values of physical constants
- the inflationary model and its implication for the existence of a "multiverse" of universes
- the nature of dark energy, as well as we understand it, or are mystified by it, and its relation to anthropic considerations
- the possibility of time-varying constants in nature
- the question of the potential rarity of intelligent life
[The sound quality for the first few slides is poor due to the use of a bad wireless microphone, but that is soon corrected.]
— Wirt Atmar
About the Speaker
Dr. Mario Livio is the Head of the Science Division at the Space Telescope Science Institute (STScI), the institute which conducts the scientific program of the Hubble Space Telescope. He received his Ph.D. in theoretical astrophysics from Tel Aviv University in Israel, was a professor in the Physics Department of the Technion-Israel Institute of technology from 1981 until 1991, and joined STScI in 1991. He has published over 300 scientific papers and received numerous awards for research and for excellence in teaching.
His interests span a broad range of topics in astrophysics, from cosmology to the emergence of intelligent life. Dr. Livio has done much fundamental work on the topic of accretion of mass onto black holes, neutron stars, and white dwarfs, as well as on the formation of black holes and the possibility to extract energy from them. During the past two years Dr. Livio's research focused on supernova explosions and their use in cosmology to determine the rate of expansion of the universe. In particular, he has shown that in spite of some uncertainties that still exist in theoretical models for supernovae, it is very likely that the recent findings that the expansion of our universe is accelerating are correct.
Subscribe to the Weekly Notice
If you wish to receive a weekly notice of the current lecture, please send a blank email to:
lectures@aics-research.com
Privacy Policy: Your email address will be shared with no one nor used for any purpose other than sending you the weekly lecture notice.
These Lectures are Sponsored by
AICS Research, Inc.
You can easily create lectures of equal quality yourself.
The internet has obvious promise for the dissemination of instructional material over very large distances and into remote corners of the world. To that end, AICS Research has created two products, QCShow, a freely-downloadable player, and QCShow Author, an inexpensive content authoring tool that produces FM-quality sound and full-screen HDTV-quality slideshows at very low bandwidths.
As an adjunct to that development process, for the past 30 months AICS Research has been recording the highest quality conferences in cosmology, astronomy, planetology, geology, astrobiology, ecology, behavior and evolutionary biology so that these presentations may be viewed by anyone anywhere in the world.
The QCShow Player was designed for both individual viewer and for the classroom, so that you may "team teach" with the lectures. Indeed, you may run the lecture through a classroom projector and your room's sound system and very closely recreate the lecture as it was first presented live, but now with the capacity to instantly pause the speaker and interpose your own commentary wherever you wish.
QCShow Author was similiarly designed to be as simple a mechanism as possible, allowing a single lecturer to create productions equal to the very best of educational television, but very quickly, and at astoundingly low costs.
Copyright Notice: AICS Research asserts no copyright over any of the lectures presented in this series. Whatever copyrights exist, they reside with the original authors. You have been given permission to save these lectures on your local machines if you wish, so long as they are not modified in any manner.
|
