... Closeup of Antennae Galaxy Collision . ... When two galaxies collide, however, the stars that compose them usually do not. This is because galaxies are mostly empty space and, however bright, stars only take up only a small amount of that space. Welcome to Planet Earth . ... Welcome to Planet Earth, the third planet from a star named the Sun. ... It is visible as the black indentation to the red emission nebula seen just to the right of center of the above photograph. ...