when we discovered that there were other galaxies?

Question

does anyone have any proof that any other person in history had mentioned this idea?

or was it found in this 20th century that we have more than the one we live in.

Answer 1

It wasn't proved until the 1920s, when Hubble discovered a Cepheid variable star in what we now call the Andromeda Galaxy. But the idea wasn't completely new. In fact, I believe Immanual Kant was one of the first to put forth the idea of "island universes" long before there was much evidence for galaxies. It was more of a philosophical idea than a scientific one, however.

Answer 2

I recall that earlier than the 20th century, some "stars" were smudgy when viewed through a telescope. As early as the 1750's it was proposed that other galaxies existed.

These stars were eventually surmised to be clusters of stars outside of our milky way. It wasn't until the 1920's that evidence was obtained.

Answer 3

I think it's a "modern find." The only ones who speculated on it where people like Nostrodamus.Nobody believed, and charged them with Hearesay.They were shunned and persicuted and even killed, because they had no proof, they only believed ii it.
There was a documentary on T.V. a few years ago called "The Chariots Of The Gods."
It had cave drawings of men in space helmets, and other star configurations, it talked about the speculation of how and why those land markings of spiders and other pictures, that are so huge, you can only see them from a plane, may have origenated.
It was a good food for thought documentary.

Answer 4

It was recognized barely fifty years ago. Until then, astronomers didn't realize that some of what they see in the sky represents whole other galaxies, galaxy clusters and galactic super-clusters. They didn't even know until the middle of the Twentieth Century that stars emit radio waves - that was the beginning of radio astronomy.

Answer 5

Seimerth is spot on. The Shapely-Curtiss debate settled the question of the nebula back in 1920.

Answer 6

Look into Edwin Hubble and the pioneers that used photography plates in telescope observatories.

Answer 7

stars were mearly lights in the sky. no one ever thought that some of those were acutually galaxies.