Indicate your 1st, 2nd and 3rd preferences and return in class on 1/27.

The following descriptions are meant to be illustrative.  The exact material
to be covered is limited only by the creativity and resourcefulness of the
presenter and some slight conservatism on the part of the instructor. 

Feel free to negotiate whole new topics by calling or emailing Doc R. before
1/26 or negotiate details after your assignments have been made.

___  Mar 10 .  Two related topics.  There are a variety of searches going on
worldwide for objects with the potential to collide with Earth in the future.
A second series of design efforts is exploring what could be done to protect us
if a large Earth impactor was discovered. This presentation will explore the
background and current status of these efforts.

___ Mar 24  Again, two topics.  We tend to view any major change as catastrophic,
but the Earth has endured a number of such major changes in the biosphere, the
sum of all living things.  The presentation will summarize what is known about
these changes over billions of years, and also discuss the current rate of biosphere
change.  Under what conditions can life exist elsewhere in the Universe?  What
does this mean for the possiblities of life elsewhere, given the best of our astronomical
knowledge?

___ Mar 31.  Perhaps we can avoid catastrophes by learning from other civilizations
on other planets.  Or perhaps, if catastrophes are inevitable here on Earth, we should
just move!  This week's presenters will explore the Search for Extraterrestrial
Intelligence and the possibilities for life on and colonization of other worlds. (but not search
for other planets).

___ Apr. 7.  Explosive events abound in the Universe, releasing potential lethal
amounts and forms of energy, if you're unfortunate enough to be within shooting
distance.  This week's presenters will explore the dangers from nearby supernovae
and the recently discovered even more energetic gamma-ray bursts.

___ Apr 14.  Perhaps the threat will come from aliens. This week we will look at
the myth and folklore around alien invasions (past, present and future) and some
of the thinking about whether these would be benign or malevolent.

___ Apr 21.  What if?  There are a variety of seemingly "natural" phenomena, without
which life on Earth would be very different than it is today, or perhaps might not
even exist.  This week we will explore cosmic catastrophes that *didn't* happen, such
as the Moon not existing, the Earth's tilt being different,  the Earth having a smaller
mass, etc.  Presenters will begin with the book "What if the Moon Didn't Exist?" by
Neil Comins.

___ Apr 28 . People seem to be natural worriers, and see signs in the sky of good and
bad tidings.  This week we will explore the pseudo-scientific claims of astrology and
disaster-bringing alignment of planets.