How Many Solar Systems Are There in the Universe?

many-solar-systems-universe Credit: NASA Goddard Space Flight Center/CC-BY 2.0

There are billions of stars, and no one knows how many solar systems there are. The Earth's galaxy, the Milky Way, is so large that it would take an object 100,000 years to cross it traveling at the speed of light.

The universe contains an estimated 100 trillion galaxies in the universe, including the Milky Way. The Milky Way contains at least 100 trillion stars, and each star has the possibility of having a solar system around it. The closest galaxy to the Milky Way is Andromeda; it is more than 2.3 million light years away though it can be seen with the human eye.