NASA “Ask An Expert” Chat

Today, I participated in NASA’s “Ask An Expert” chat with Dr. Bill Cooke, the head of NASA’s Meteoroid Environment Office, about the study of asteroids, comets, and meteors. Since I was at school and couldn’t dedicate much time to the chat, I was only able to ask two questions:

Me: Do we know the chemical composition of comet Hartley 2’s jets?
Dr. Bill Cooke: Suspect they’re water vapor, carbon dioxide gas, mixed with dust – but don’t know for sure. We’ll have to wait for science team results.

Me: How many periodical comets (long- or short-period) are we aware of in the solar system?
Dr. Bill Cooke: Our periodic catalog now has well over 200.

If you’d like, you can download a full transcript here [PDF].
Or, you can view the official NASA transcript here.