Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Ice Age vs. Now.

Does the Earth rotate at the same rate when encased in ice during the height of an Ice Age as it does when the bulk of it's water is liquid and always in motion?

share|cite|improve this question
One presumes not simply because the moment of inertia will be different on account of the ice being (on average) higher than the oceans; but though the quantities of water involved are staggeringly collossal on the human scale, how you tried a BoTE calculation of what fraction of the Earth moment of inertia is bound up in the oceans? – dmckee Jan 24 '13 at 3:57
Reference:… – Kyle Oman Jan 24 '13 at 18:43
up vote 3 down vote accepted

Yes, the growth of continental glaciers can change the earth's rotation.

The length of a day can vary by a measurable amounts (microseconds) over periods of days or weeks. The motion of ordinary weather systems in the atmosphere can change the length of a day. Because the growth of glaciers during an ice age would load the continents with ice and change sea level, they would effect even greater changes to the earth's angular inertia, and even larger changes to the length of day.

share|cite|improve this answer
The tides will change, too. With less water to slosh around, the earth will transfer rotational energy to the moon more slowly. The moon's rate of outspiraling from the earth, and the rate of slowdown of the day, will probably decrease modestly. – Will Cross Jan 24 '13 at 19:52

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.