earth is rotating at a speed of about 1100 miles per hour. If our planet suddenly stopped rotating the atmosphere would still be in motion at that speed. The atmosphere would be moving so fast it would literally pick up the land masses that are not anchored to bedrock, this would mean rocks, soil, trees, buildings, people and animals. All would be swept up into the atmosphere. Also one side of the earth will always be covered in darkness whilst the other is facing the sun. What if it slowly decreased speed? Would a non rotating earth be able to maintain it's atmosphere and magnetic field? As far as I know our magnetic field is caused by the earth's metallic core rotating (It has some weird witchcraft metal particles that generate our magnetic field), If that one stopped rotating as well, we would be fucked indeed. The atmosphere would stay here because gravity makes sure the air doesn't escape. EDIT: Lukenukem, check my edited post, may clear up things. The magnetic field of the Earth is generated by a dynamo effect that involves its rotation. If the Earth stopped rotating, the magnetic field would no longer be regenerated. There would be no more 'northern lights' and so would our protection from cosmic rays and other high-energy particles. Losing this protection would cause serious health issues to us and Hundy