In 1920, astronomers Harlow Shapley and Heber Curtis held a Great Debate. Shapley argued that the spiral nebulae were small ...

Curtis argued that the spiral nebulas were galaxies in their own right, but said that the Milky Way was only 10,000 light years across. Shapley argued the opposite. Hubble enters the fray Edwin ...

Since Hubble’s launch, astronomers have discovered over 1 trillion galaxies, but Andromeda stands out as the closest and most ...

Around 13.7 billion years ago, something collapsed. It fell outward into the nothingness that stretched in every direction, ...

Sagittarius A* is the supermassive black hole at the center of our home Milky Way galaxy. It has a mass equal to billions of suns and has an accretion disk made up of gas and dust surrounding it.

The Hubble Space Telescope is helping scientists ... You could fit our entire Milky Way galaxy between them and still have room to spare. At 250,000 light-years across, the Bullseye itself is ...

Hubble makes his mark Edwin Hubble was young and ambitious ... His measurements marked the end of the Great Debate about the Milky Way’s size and the nature of the nebulae.