26
votes
4answers
2k views

Why are there no asteroids or meteoroids with relativistic speeds?

Cosmic rays can have energies going into the $10^{20}$ eV domain. Asteroids and meteoroids originating in the solar system are probably limited in their speed because they all started out from the ...
0
votes
2answers
30 views

Ways to spot a comet or asteroid?

How do we spot a comet or asteroid if it does not emit light or pass infront of an object which emits light? And if such an object would be on a crash course with our planet how early would we be ...
7
votes
5answers
3k views

What are the differences between Comet versus Asteroid versus Meteoroid versus Meteor versus Meteorite?

What are the differences between comet versus asteroid versus meteoroid versus meteor versus meteorite in practical terms?