Comets
Part of Hall of the Universe.
Part of Hall of the Universe.
Comets are kilometer-size snowballs made of ice and dust. Trillions of them live beyond the orbit of Neptune. When a comet enters the inner solar system, sunlight evaporates its icy surface and solar energy blows back bright tails of gas and dust, extending millions of kilometers across interplanetary space.
The Great Comet Collision