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uscitizen
08-16-2006, 12:43 PM
http://www.dbeat.com/28/

Damocles
08-16-2006, 12:50 PM
I like the 56 hour weekend...

OrnotBitwise
08-16-2006, 12:53 PM
Hey, they're 1.4 million years ahead of their time. That's impressive

Brent
08-16-2006, 01:09 PM
Currently, the distance between the earth and the moon is increasing. However, in about 7 billion years the moon's orbit will begin to shrink, moving ever closer to earth. Eventually this will slow the rotation of the earth to approximately 60 days. How would you like a 1440-hour day? ;)

This, of course, will never happen because the sun will enter the red giant phase in about 4 billion years, engulfing the earth in the process.

uscitizen
08-16-2006, 01:14 PM
Oh well I won't be here to see the end. I wonder what our national debt will be by the end ?

OrnotBitwise
08-16-2006, 01:17 PM
Oh well I won't be here to see the end. I wonder what our national debt will be by the end ?
But if you can last only 1.4 million years you'll have your 28 hour day. ;)

And you can stop worrying about the national debt. There won't be any nations by that time. The Morlocks will control everything.

uscitizen
08-16-2006, 01:21 PM
LOL
That was a very cool movie, esp for it's time.
Well govts and such lasting that long I will leave up to Brent to decide :)

Brent
08-16-2006, 01:21 PM
I do not see how the day will be 28 hours long in 1.4 million years. What would be slowing down our rotation? Certainly not the moon, as it will be approximately 42 kilometers farther away from the earth at that time.

OrnotBitwise
08-16-2006, 01:26 PM
I do not see how the day will be 28 hours long in 1.4 million years. What would be slowing down our rotation? Certainly not the moon, as it will be approximately 42 kilometers farther away from the earth at that time.
Yes, it's the moon. More correctly, we're losing angular momentum as the moon moves further away. What, you thought it was moving for free? Ain't no free rides in this universe.

Conversely, the days were much shorter millions of years ago, when the moon was much closer. About 16 hours long during the Permian, for example. We know this both from the physics and because of corroborating evidence in tidal rhythmites (sp?).

That 1.4 million year figure was a quickie calc though. My memory said that the days are getting longer by about one second per century. I didn't check it but just ran with it. I could be way off.

Brent
08-16-2006, 01:59 PM
The distance between the earth and the moon is increasing by 3 centimeters per year.

3 x 1,400,000 = 4,200,000
/ 100 = 42,000 Meters
/ 1000 = 42 Kilometers.

Or am I missing something?

Damocles
08-16-2006, 02:03 PM
This means that the Earth still rotates faster than the Moon travels around it. This creates a tidal bulge in the Earth surface that pulls the Moon while it makes it's travels. This causes accelleration which causes the moon to spiral away from the Earth... At the same time the Moon pulls on the bulge on the surface of the Earth creating a deceleration on the Earth... So, at some point the speed of rotation will match the speed of orbit... This will begin the slowdown of the Moon rather than accelleration and the moon will begin to creep toward the Earth. Of course, right about that time both will be swallowed by the Sun as it expands burning Helium rather than Hydrogen...

klaatu
08-16-2006, 02:21 PM
I like the thought of getting rid of Mondays ...

Damo ..did that last post create a bulge on the side of your head? ;)

Damocles
08-16-2006, 02:22 PM
I like the thought of getting rid of Mondays ...

Damo ..did that last post create a bulge on the side of your head? ;)
No, but I had to borrow a bit of brain matter from a colleague...

OrnotBitwise
08-16-2006, 02:41 PM
The distance between the earth and the moon is increasing by 3 centimeters per year.

3 x 1,400,000 = 4,200,000
/ 100 = 42,000 Meters
/ 1000 = 42 Kilometers.

Or am I missing something?
You're only missing the effect that has on the Earth's rotation. 42 klicks doesn't sound like a lot but it takes an enormous amount of energy to move a mass the size of the moon that far. That energy has to come from somewhere. As Damo explains, it comes from the angular momentum of the Earth: the Earth's rotation slows . . . and the day therefore gets longer.

Brent
08-17-2006, 12:16 AM
You're only missing the effect that has on the Earth's rotation. 42 klicks doesn't sound like a lot but it takes an enormous amount of energy to move a mass the size of the moon that far. That energy has to come from somewhere. As Damo explains, it comes from the angular momentum of the Earth: the Earth's rotation slows . . . and the day therefore gets longer.

I understand now. Thanks :)