NASA has found more than 5,000 planets outside of our solar system

NASA has discovered more than 5,000 planets outside of our solar system – but so far, Earth is the only one that appears to have the right conditions for human life.

NASA said it has confirmed 5,005 exoplanets – or planets outside of our solar system. Most are in a very small region outside of our galaxy, the Milky Way. And by "small," NASA means within thousands of light-years. One light year is 5.88 trillion miles. 

The closest known exoplanet to Earth, Proxima Centauri b, is about four light-years away.