Comet/atronomy questions?

Question

I saw a movie, "Deep Impact" and I have a few questions.

1. Are comets as bright as stars?
2. Do comets display a rapid-fire series of events? If so, is it in a short period of time?
3. How fast do comets move?
4. Could any spacecraft catch up with a comet?
5. What is an orion engine?
6. What color are comets?
7. Can comets vent? (does it happen when the sun rises over a certain spot?)
8. Do comets glide silently?

Answer 1

Hi.
1) Usually when they get close to the Sun.
2) Sometimes, but it depends on the spin rate.
3) Just above or just below the escape velocity of the Sun.
4) Yes. Giotto did catch up with Halley's Comet.
5) You must mean ion engine. http://www.thespacesite.com/space_electric_propulsion.html
6) Usually various shades of gray.
7) Yes, that is what makes the tail.
8) No. their sound should include particle hitting each other, gas shooting of of the surface, creaks internally due to stress, etc. But that sound cannot pass through a vacuum.

Answer 2

I think I speak for everyone when I say do your own ******* homework. If it's not homework:

1.no
2.sometimes
3.Depends, very fast though
4. They have a couple of times
5. Forgot what one is.
6.Depends what you mean, which way an how fast they move.
7. They could.
8. Since there is nothing for the sound to travel through, no.