Exoplanets are all those planets that are outside our solar system. For a long time, we didn’t know much about other planets. They are simply too small on a cosmic scale to see with simple telescopes. Only since 1995 have we had the technology to detect planets outside our own star system.

Since then, telescopes have been increasingly improved, and the Kepler Space Telescope was the first telescope dedicated solely to the search for exoplanets from 2009 to 2018. Today, we know for sure of the existence of about 5,000 exoplanets, and more are being discovered every year.

There are probably several billion planets throughout the Milky Way, and about 300,000,000 of them may resemble Earth.