Descriptive Astronomy: PHY 101

Here's a study guide for Tuesday's final exam (Preble 335, 8:00-10:00 a.m.).

General
 

Fix online	Views of the Solar System
The Nine Planets	Windows to the Universe

Extrasolar Planets

• Planetary systems form from protoplanetary disks, or "proplyds."  You can tell that they're flattened disks when they happen to be viewed edge-on.
• Here are some methods for finding extrasolar planets (turn on your sound).
• A Scientific American article discusses an extrasolar planetary system discovered in 1999.
  (Larger versions of the diagrams can be viewed here.)
• In 2000, a planet was confirmed as real when it was caught transiting its parent star -- and the next year we were even able to study its atmosphere
  (Here's a cool animation of this evaporating planet and its atmosphere's spectrum)
• We recently found a planetary system similar to our own by measuring how the planets' gravitational fields affect the light of a background star: gravitational microlensing
• OK, so we find an Earthlike planet with an Earthlike orbit around a Sunlike star: What do we look for to check for life on that planet?
• Optional:

• In 2006 an almost Earth-sized planet was found via gravitational microlensing.  (Don't sweat the details.)
• In order to have life, a planet must not only be the right size but also the right distance from the right kind of parent star.  That is, different kinds of star have different habitable zones in which life could form -- or at least could most easily form.
• Life as we know it is far more likely to exist on small (Earthlike) planets than on the large extrasolar planets discovered to date.  Some future planet searches will use a technique called nulling interferometry to find such planets.  (Here's the figure that goes with that article, in case you missed it.)

Headstart on Next Week

Good luck with your finals!

Links from previous weeks are here

-- and don't forget the future!  Here are the requirements for your final paper

For enlightening fun, take a look at the Astronomy Picture of the Day

You're always welcome to send me feedback about the course.

Descriptive Astronomy has been brought to you by Chris Magri and The University of Maine at Farmington

URL: http://academic.umf.maine.edu/~magri/phy101/