
Until 1990, no one could say for certain that planets existed beyond our solar system. Today, thanks to unprecedented advancements in technology, astronomers have found more than 5,000 of these exoplanets. Some are Earth-sized, some orbit a sun-like star, and some are rocky rather...

Until 1990, no one could say for certain that planets existed beyond our solar system. Today, thanks to unprecedented advancements in technology, astronomers have found more than 5,000 of these exoplanets. Some are Earth-sized, some orbit a sun-like star, and some are rocky rather...