Greeks and Romans called this the Milky Way. This band is actually made up of many stars and is part of our Galaxy. People had seen galaxies outside our own for a long time too but were not sure of their nature. For example the Andromeda Galaxy can just be seen by naked eye on a dark night. Messier was a French scientist in 18th century who was interested in comets.
Comets appear as little blurs in the sky when far away.
They move over time. We've only gained a proper appreciation for our Galaxy in the last 100 years. Today we will start to tell this story but first we need to talk about distance measurements. 3 units astronomers often use to describe distances. We are 8.5 Kpc from galactic center.