Asteroids that orbit close to the Earth inevitably cause us some anxiety due to the even remote possibility of a collision.

In 1920, astronomers Harlow Shapley and Heber Curtis held a Great Debate. Shapley argued that the spiral nebulae were small and in the Milky Way, while Curtis took a more radical position that they ...

"The idea that they can somehow obliterate these sources is dead wrong — scientists in general and astronomers in particular ...

Predictions are uncertain, but the solar system may be pushed farther from the galactic core or even ejected entirely from the new galaxy.

Centaurus A: NGC 5128 is a galaxy in constellation Centaurus, discovered in 1826 by Scottish astronomer James Dunlop. Messier ...