| MadSci Network: Astronomy |
Hi Bill,
If the Earth were to stop spinning abruptly, it would certainly be a major disaster, but nothing would go flying into space. The Earth's gravity prevents this from happening now, and would keep doing so.
One measure of the strength of a planet's gravity is its escape velocity. This is the speed at which you must move in order to escape from the gravity of the planet. The escape velocity of the Earth is 11 kilometer per second.
If the Earth were to instantaneously stop spinning, then everything on it (including us) would keep moving at the the speed with which the Earth underneath us had been spinning. The fastest speed would be at the equator, where objects would move at 0.5 kilometers per second, fast enough to wreak havoc, but not fast enough to escape the Earth's gravity.
If, in fact, the Earth were rotating at 11 km/s, then it's own gravity could not hold it together. In that case, objects at the surface would fly off into space even with the Earth spinning.