A galaxy is a gigantic mass of stars and other heavenly bodies. They are bound together by gravity and whirl through space at tremendous speeds. The galaxy we live in is callled the Milkay Way but there are billions of other galaxies in space.
Galaxies have different shapes.
Many are sprial shaped. They look like slowly turning giant pinwheels. Other galaxies are shaped like a football. The stars in the center of an ellipse are packed closely together. Still other galaxies have irregular shapes with random groupings of stars.