IIUC, the Moon is tidally locked to the Earth because it was initially a bit molten and due to Earth's gravity was an elongated ball shape, not quite a sphere. Then it cooled down and solidified that way. The tug of gravity keeps the Moon's bulge pointed toward us, braking the rotation of the Earth, transferring the angular momentum to the Moon which makes it move farther away. It tugs the oceans, too, but I think that effect is smaller.
An Earth-Earth system with rounder planets wouldn't have to be tidally locked, I think. Even so, the oceans on both planets would still make tidal drag on both planets so the lost angular velocity, conserving angular momentum, would mean they'd still pull farther away from each other. On Sunday, February 23, 2014 2:14:40 PM UTC-6, [email protected] wrote: > > I was just trying to imagine the effect two equal oceans, one on each > objechave? The ocean puts a heavy brake on the rotation of Earth and has > already tidally locked the moon. But what tidal drag went both .ways? Would > the planets start moving toward eachother, or pull further away? > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
