5
votes
1answer
173 views

What is the likelihood of a long-period comet impact?

I always see lots of information about asteroid impacts, but very little is said about comet impacts. As I see, a long period comet impact is much more dangerous because a) we wouldn't have time to ...
8
votes
1answer
56 views

Why does the debris from comets and former comets hang around so long?

So tonight's Quatrantids shower got me thinking. Why does the debris from comets and former comets hang around so long? Each year the earth sweeps through the region of space that the comet went ...
10
votes
1answer
4k views

What are the facts that allow accepting the Oort cloud theory?

I admit without any fact that the Oort cloud (comet reservoir) should exist, and it seems to be accepted by far by the large majority of astronomers. But it is still a theory without any direct ...
11
votes
1answer
5k views

How does a comet form?

As the title explains, How does a comet form? What are the elements, what is a comet composed of? Why didn't they become part of planets, moons or asteroids?