Answer:
A galaxy is a system of solar systems and other stars. Galaxies, like solar systems, are held together by gravity. In galaxies, the solar systems are separated by vast sections of mostly empty space. The galaxy that contains the Earth and its solar system is called the Milky Way. This galaxy is thought to contain more than 200 billion different stars. Solar systems orbit around their galaxies just as planets orbit around their suns. It takes the Earth's solar system roughly 200 to 250 million years to complete its orbit.