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 ...

In the heart of our Milky Way galaxy, two gigantic "bubbles" extend roughly 50,000 light-years above and below the galactic ...

Hubble revealed a universe of galaxies that existed beyond ours — but he couldn't have done it without a little help.

In the 1920s, astronomers thought that the Milky Way was the entire universe. Hubble's discovery revealed a much bigger ...

But what of smaller astronomical bodies, like the Large Magellanic Cloud, a dwarf satellite galaxy that is expected to collide with the Milky Way in 2.4 billion years? Nobody is quite sure whether ...

Observations show Andromeda has a more active star formation history than the Milky Way, potentially due to a past galactic collision. NASA recently released images of the Andromeda galaxy ...