1 Billion Years ago, Earth Days Were Shorter

And they will become shorter again!

This information comes from a chain having four or five oral links. Should we refuse to accept it? And a huge bank of other critical information which we may never get othrwise?

Best Wishes

There is no mention of "oral links" in the article, let alone "four or five of them". Can you please explain your statement?

Maybe the links refer to something not in the article, of a more religiously apocalyptic nature? Or maybe...the man in the moon.

Best Wishes to All

Thanks guest (#3). You are right. This is from another source which has not been introduced nor proved acceptable in this forum yet.

Somebody in ths forum has proved on energy considereations that it is possible.

As a corollory, if this source is correct, man will survive on this earth to see a much shorter day, of the order of a few hours by our clock.

Best wishes to All.

This may be true, but this has nothing to do with tidal forces. If you look at the rotation of the Earth, you will see that It does not rotate about the center of Earth. I wish I could show you a picture but I cannot right now. But the centrifugal forces that are excerted on the ocean's, from the rotation of the Earth, are the main cause of the tides. Once I figure out my computer, I will attach a picture of what I am talking about.

Strictly speaking, the Moon does not orbit the Earth. Rather both bodies orbit a common "barycenter" - the system's center of gravity, more or less. Ocean tides are the result of both gravitational effects *and* centrifical force, in combination - not just one or the other. There are also so-called 'earth (or 'land) tides,' as well as 'moon tides', where in each case the body undergoes a slight gravitational deformation such that the major axis of the deformation is on a line connecting the centers of mass of the two bodies. The most obvious result of moon tides is the Moon's odd habit of always presenting the same face to the Earth. Gravitational resonance, as this is called, is due to the Moon's having lost rotational energy as heat, sometime in its past, produced by the continually-moving gravitational deformation with respect to the Moon's frame of reference. Earlier in its history the Moon's rotational rate was higher than it is today and it did not always present the same face to the Earth. The rotational rate gradually slowed due to deformation losses until the deformation became stationary. Similar energy losses due to a moving deformation explain why Jupiter's moon Io is so hot and volcanic. But in Io's case the deformation moves much more rapidly and it is far more pronounced due to Io's close proximity to massive Jupiter. Our Moon's rotational rate has slowed to the point where it exactly matches the orbital period. The Moon is still gravitationally deformed, of course, but the deformation no longer moves and no longer dissipates rotational energy.<p>In contrast, the Earth is still losing energy in this way and so its rotational rate continues to decelerate. The tides add their contribution, to be sure, but as the Moon's example makes quite clear, this slowdown occurs regardless of whether there are ocean tides or not. So, yes, Earth's days are getting longer - and my birthday will be slightly later this year. I can hardly wait. --Europium

This is what I was trying to get at earlier. I do appologize though, I am a student and it was my birthday. I was not saying that the Earth's days are not getting shorter, but only that the longer days are not caused by the moon. If this does not make anymore sense, I do applogize again, as I am "celebrating my birthday" once again.

I do, however, like this forum. Keep posting interesting things.

Guest writes: "I was not saying that the Earth's days are not getting shorter, but only that the longer days are not caused by the moon."--------- *That* actually had not occurred to me at all and I apologize for my reply having conveyed this impression.---------- Guest writes: "If this does not make anymore sense, I do applogize again, as I am "celebrating my birthday" once again."-----Happy birthday, Guest! Your post made perfect sense, actually. I hope my reply was likewise. Take care, Europium.