Raymond Pierrehumbert
University of Chicago
The variety of planetary environments revealed by the growing catalog
of extrasolar planet discoveries challenges conventional notions of
habitability, as do new discoveries about the history of planets in
our own Solar System. Can planets in highly eccentric orbits
be habitable? Can a tide-locked planet be habitable? What does
the spectrum of red M-dwarf sunlight do to the runaway greenhouse
phenomenon? Could a Jupiter or Uranus in a Earthlike orbit have
an oceanic habitable layer? If a planet with an ocean falls into
a Snowball state, can it ever defrost? Can the habitable zone
be extended to arbitrarily large distances from the planet's star
simply by adding ever greater quantities of a greenhouse gas
to the planet's atmosphere?
I will review some recent developments
in the physics of planetary climate which have a bearing on these questions,
using the Gliese 581 system as a source of examples. I will
touch briefly on geochemical cycles and the time-span of habitability as well.
Friday, May 29, 2008 at 4:00 PM
Room L211, Technological Institute
Refreshments are served at 3:30 PM
