Up until the mid 1990s, astronomers didn't know for certain if there were any planets outside of our own solar system. But ever since the first exoplanet was discovered, it’s been increasingly clear that our Sun isn’t the only one in the universe with a handful of planets orbiting it.
Over the last three decades, astronomers have confirmed 5,557 exoplanets in the universe. While that already seems like a high number of exoplanets, scientists actually believe that the universe is teeming with trillions of them. Makes sense, given a single galaxy can contain billions of stars and there are an estimated two trillion galaxies. The problem is that exoplanets are still relatively hard to find.
