Amazing to consider what we didn’t know less than a hundred years ago. Via PBS:
On December 30, 1924, Hubble announced the discovery of a Cepheid, or variable star, in the Andromeda Nebulae. Since the work of Henrietta Leavitt had made it possible to calculate the distance to Cepheids, he calculated that this Cepheid was much further away than anyone had thought and that therefore the nebulae was not a gaseous cloud inside our galaxy, like so many nebulae, but in fact, a galaxy of stars just like the Milky Way. Only much further away. Until now, people believed that the only thing existing ouside the Milky Way were the Magellanic Clouds. The Universe was much bigger than had been previously presumed.
If you’re curious to see what the famous telescope named after him has been up to lately, check out: Hubble Sets an Eye on the Dawn of Time.
Here’s a video of Hubble’s work found on YouTube: