guy@slu70.UUCP (03/28/86)
In article <215@pyramid.UUCP>, dan@pyramid.UUCP (Danial Carl Sobotta) writes: > > WRONG!! :-) The reason that the earth's rotation is slowing down is > because of all that air friction. The reason its revolution rate around the > sun is slowing down is 'cause of friction through ether. So what's gonna > happen is we'll have a 25-hour day at the same time we have melted polar ice > caps. It's all true, I thought of it myself!! Just on the off chance that this posting is serious or that it might be taken seriously. The length of the day has changed, as has the length of a lunar month. This is due to the fact that the finite viscosity of the earth's interior causes the tidal bulge to be slightly ahead of the earth moon axis. The net effect is to transfer angular momentum from the earth to the moon. This causes a increase in the length of the day and an increase in the earth-moon distance. Measurements of Devonian corals (340 my) show a 22 hr day. Consult a general reference such as Garland (Introduction to Geophysics) for more details and references. There *are* small fluctuations (short term) due to air friction, primarily caused by transfers of air masses with the change of the seasons. These do not cause, for obvious reasons, any long term change. Just a shuffling of angular momentum between the earth and atmosphere.