Expert: Jayendra Upadhye - 4/20/2005

Question
If the EArth stopped rotating would it effect the water on Earth? For example would it melt or freeze?

Have you worked for NASA? If so what did you do?  

Answer
Hi Colleen,
No I never worked for NASA!
(However if i ever did, i would have liked to work on their mars projects).

If the earth stopped rotating, we would have to look at it 2 ways.
1 - Gradual slowing down
2 - Rapid Catastrophic reversal / slow down

In the first case, we need not worry becasue the earth IS SLOWING DOWN gradually all the time, a few seconds at a time.(the leap second) due to the tidal coupling with the moon!
The moon as a consequence speeds up and gains altitude at 4 cm per year (moves away from earth). That is called the "recession rate" of the moon.

If the slowdown / reversal were catastrophic say due to a glancing blow by a very large body, the water would still try to continue its normal rotation due to its inertia.
Mechanical forces are more effectively "coupled" in solids than in liquids. So the earh could go about its sudden mischief faster than the liquid oceans!
This would result in a large relative motion between the two. A Tsunami of cosmic proportions would ERASE all life on the planet in a few moments! (The earth turns at 1500 kph from west to east at the equator, thus the tsunami would be supersonic!) Huge amounts of energy would be absorbed by the water in its turn and the havoc would be colossal.

The atmosphere would then do its own stuff and gales of 1000 kph would devastate what was left.

Quite a doomsday scene is it not?
Jayen