(Submitted April 17, 1998)
I would like to know about the history in brief about the discovery of
galaxies in the Universe. If this seems to be a lengthly question please
give me references.
Immanuel Kant, who was a famous philosopher, was the first to
suggest around 1755 that the spiral nebulae were island universes.
Prior to this century there was no distinction made between the things
that today we call nebulae, such as the star forming region in Orion or
the crab, which are luminous gas clouds within our galaxy, and other
galaxies. This is exemplified in the Curtis Shapley debate of 1920.
You can read about how this was resolved and other related topics at:
I hope this helps,
for 'Ask an Astrophysicist'