At the turn of the 21st century, a new age of galactic discovery began.
Through the latest telescopes on land and in space, astronomers began to a Wealth of planets outside our solar system, called exoplanets. In our Milky Way, scientists have confirmed over 4,480 exoplanets, with thousands of other candidates. Some are probably rocky worlds. Many belong to a class of planets called “super-Earths,” orbs two to ten times as massive as our mild blue world. Others are gas…