Comet Tails Can Stretch For Hundreds Of Millions Of Miles
Comet tails form when comets are close to the sun. There are two kinds of tails: dust tails, formed from cometary debris, and ion tails. Ion tails always stretch away from the sun, because they consist of gas particles pushed by solar winds. These types of tails can be incredibly long—the ion tail on Comet Hyakutake measured about 580 million kilometers.
from Universe Today
Key Facts In This Video
In the 1500s, comets were discovered to be objects in space, rather than objects within Earth's atmosphere. (0:40)
Comets can have two types of tails: ion tails and dust tails. (1:21)
There isn't a clear distinction between comets and asteroids. (2:41)