It's the last of the planets in our solar system, it's more than 30 times as far from the Sun as Earth is, Neptune is very similar to Uranus, it's made of a thick soup of water, ammonia, and methane over an Earth-sized with solid center, Neptune is the eighth planet in distance from the Sun, it is part of the so-called outer planets, and within these, it is one of the ice giants, and it is the first to be discovered thanks to mathematical predictions.