|Primary Terrain||Cultivated lawns, Cities|
|Notable Species||Green Humanoids|
It is not currently known whether the "51" means it is the 51st planet within a given set of cataloging or whether it is the 51st planet in a given planetary system, or possibly a reference to the infamous military test site, 'Area 51', although it is more likely the former as the name if it was a planetary system would indicate that the System itself would be known as "Planet", which is unlikely. It is home to a distinctly humanoid species of bipedal, sapient race of extraterrestrials.
This planet has gravity, atmosphere and temperature similar to Earth, at least similar enough so that Humans can survive there. The plants are very similar to Earth plants, but the animals are quite different. There are native fish and lizards with a single eye, and a domesticated Xenomorph breed which is kept by the natives as pets. The natives of this planet have green skin, and antennae. Their brains also have small antennae and they are able to survive fairly well after having the brain removed. Their society is similar to the USA in the 1950s.
On Planet 51, it rains rocks. Planet 51, when seen from space, has well developed rings. At some point it must have had a satellite that passed within the Roche limit  and disintegrated. The rocks are likely meteorite falls from the rings.
- General Grawl
- Professor Kipple
- The name "Planet 51" is a reference to Area 51.
- The name "Planet 51" is also a reference to the 50's time period.