Generally stars are in the one galaxy. However, it is possible for galaxies to collide or merge, so in those instances it can change.
No, there are more massive galaxies with stars in them.
A "Galaxy"
All stars visible with the naked eye are in the same Galaxy. Our galaxy, the Milky Way.
A galaxy is by a definition a group of stars. If there were no stars it could not be a galaxy.
Every galaxy contains stars, if that's what you mean. "Galaxy" means "big bunch of stars". No stars ===> no galaxy.
Halo stars are usually very old stars that do no orbit the centre of the Galaxy the same way that our Sun or other stars in a galaxy. Rather, they travel in elliptical orbits, which often take them well outside the plane of the Galaxy.
there all made of the same thing
Elliptical Galaxy The Elliptical Galaxy has mostly old stars and blue stars are new stars.
The sun is a star but the sun is a star but it is the only one in our galaxy, the milky way.
Venus is in our solar system and so it is in the same galaxy as we are. We are in the Milky Way galaxy, as are all the stars that you can see.
Bellatrix is in the same galaxy that we are in: the Milky Way. All the stars you see at night are in the Milky Way.
andrometa. it is the biggest galaxy near the milky way it is the same age same shape but has many more stars