Outside of our own Solar System, we now know of many exoplanets orbiting other stars. Exoplanets around Sun-like stars were first detected in the 1990s, and since then, thousands are on their way to being confirmed thanks to new telescopes and instruments. In fact, the Kepler space telescope and other planet-hunting telescopes have helped astronomers confirm that planets are common, with perhaps hundreds of billions of exoplanets in the Milky Way Galaxy alone, and something like 10²² planets in the observable Universe. Although astronomers can most easily detect large planets in close-in orbits — gas giants that are often heated to searing temperatures by their parent stars — many smaller planets that may be rocky like Earth have been found, some of which are in Earth-like orbits around Sun-like stars.