Exoplanets are planets located outside our solar system and orbiting other stars. Scientists only began actively discovering them in the late 20th century, and since then it has become clear that the universe is incredibly dense — practically infinite in number by human standards. Hundreds of billions of exoplanets may exist in our Milky Way Galaxy alone, and hundreds of billions of galaxies in the universe as well. These worlds include giant gas planets, molten lava worlds, icy deserts, ocean p

Neptune Core