Rotation Rate and Thermal Balance
Date: Fall 2011
If Earth's rotation were to increase, would that have an affect on the general temperature of Earth? Would Earth get cooler since it would not have as much time to heat up the surface before it cools down again at night?
I am sorry to say you seem to have a critical error in your thinking.
Although the earth spinning faster would mean that any part of the
surface spends less time in the sun each day, it would also spend less
time in darkness before coming back into sunlight the next morning. In
other words, no matter what the speed of rotation, (and disregarding the
effects of polar tilt) half the time is spend in sunlight, and half in dark.
There may be other effects, such as an increase in general wind speeds,
and some loss of atmosphere from centrifugal forces.
An interesting and complex question!
According to work by several scientists, the earth spun faster and
had shorter days, when it was younger and has slowed down over the
last 400 million years or so. During that time, Earth's temperature
changed often and over a wide range. That tells us that, whatever
the speed of Earth's rotation does to temperature, other things are
far more important or powerful.
As a guess, I would say there would be no change. Shorter days
also mean shorter nights. Since the Earth loses a lot of heat at
night, I would think the less solar energy absorbed during the day
would be balanced by less energy being lost at night.
Sorry I cannot give you a more firm answer. Earth's temperature is
controlled by many factors that it is hard to measure just the
effect of the rotation.
R. W. Avakian
Click here to return to the Physics Archives
Update: June 2012