What kind of exoplanets are out there?
Even though they’re far away, we can deduce important properties of exoplanets, like their size, mass, orbit, temperature and composition. They exhibit a fascinating variety.
The gravitational force between an exoplanet and its parent star reveals the mass of the planet. The amount of light it blocks out when it crosses the face of the star reveals its size. Together, mass and size tell us about a planet’s composition. From its orbital period, astronomers can calculate the distance between the planet and its parent star. This also tells us the planet’s average temperature. So, we know quite a lot about exoplanets. We’ve also learned that they can be very different from the planets in our own Solar System.
Our Solar System is not the only one. Most stars in the Universe have planets, too — there are billions of them. But they can be very different from the eight planets that orbit our Sun.