#1
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The moon
Does anybody have any info on how far the moon is moving away from the earth each year and how this figure would have changed over time. ------ D. Haas "Consistency requires you be as ignorant today as you were a year ago." Bernard Berenson |
#2
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The moon
On Sun, 03 Aug 2003 20:30:40 GMT, David Haas wrote:
Does anybody have any info on how far the moon is moving away from the earth each year and how this figure would have changed over time. I'm sure I read somewhere it was something like an inch or two per year (or 100 years?). And that eventually it would become free from earths attraction and fly off into space. At which time the earth wouldn't be a good place to be. Perhaps someone else will be able to add some facts to this explanation, I'm going on memory and don't claim to be very knowledgeable on this subject. Andrew Do you need a handyman service? Check out our web site at http://www.handymac.co.uk |
#3
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The moon
On Sun, 03 Aug 2003 22:05:12 +0100, Andrew McKay
wrote: On Sun, 03 Aug 2003 20:30:40 GMT, David Haas wrote: Does anybody have any info on how far the moon is moving away from the earth each year and how this figure would have changed over time. I'm sure I read somewhere it was something like an inch or two per year (or 100 years?). And that eventually it would become free from earths attraction and fly off into space. At which time the earth wouldn't be a good place to be. .... Andrew Do you need a handyman service? Check out our web site at http://www.handymac.co.uk Moon is receeding from Earth at a speed of 37mm per year (about an inch and a half). Moon is currently 371 167 kM from Earth but in five billions years, when the Sun will turn to a red SuperGiant, Moon will have moved away by 185 000 kM for a total of 556 167 kM. This is not a big difference. Moon will never be free from Earth, everythings will be vaporised long before that... Sleep well! Benoît Morrissette... |
#4
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The moon
Some have suggested, I think, that as it moves away the stresses will
make the moon shatter into a ring like Saturn's. Is this correct? The bigger problem is the effect of tidal forces which give momentum to the moon - to slow down the moon's receding we could for example build a huge barrage across the Pacific to reduce the loss of momentum... [This was in a Disacovery programme on TV not so long ago.] Benoit Morrissette wrote: On Sun, 03 Aug 2003 22:05:12 +0100, Andrew McKay wrote: On Sun, 03 Aug 2003 20:30:40 GMT, David Haas wrote: Does anybody have any info on how far the moon is moving away from the earth each year and how this figure would have changed over time. I'm sure I read somewhere it was something like an inch or two per year (or 100 years?). And that eventually it would become free from earths attraction and fly off into space. At which time the earth wouldn't be a good place to be. ... Andrew Do you need a handyman service? Check out our web site at http://www.handymac.co.uk Moon is receeding from Earth at a speed of 37mm per year (about an inch and a half). Moon is currently 371 167 kM from Earth but in five billions years, when the Sun will turn to a red SuperGiant, Moon will have moved away by 185 000 kM for a total of 556 167 kM. This is not a big difference. Moon will never be free from Earth, everythings will be vaporised long before that... Sleep well! Benoît Morrissette... |
#5
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The moon
"Carusus" wrote in message
... Some have suggested, I think, that as it moves away the stresses will make the moon shatter into a ring like Saturn's. Is this correct? It could break up if it approached closer, within the Roche Limit. It's perfectly safe (from breakup due to tidal stress) as it recedes. |
#6
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The moon
David Haas wrote in message ...
Does anybody have any info on how far the moon is moving away from the earth each year and how this figure would have changed over time. ------ D. Haas "Consistency requires you be as ignorant today as you were a year ago." Bernard Berenson In the context of refuting one of the many invalid "young earth" arguments, there's some good information at http://www.talkorigins.org/faqs/moonrec.html The moon is receding at about an inch and a half per year. This is faster than its average recession over time. It's faster today because of the mechanism of recession... Basically, the earth's rotation is slowing slightly thanks to tidal force from the moon. The rotational energy has to go someplace: that someplace is into the moon's orbit. When you put energy into an orbit, you raise it. The biggest reason the tides slow the earth is that the earth's oceans bulge toward and away from the moon, and this bulge slams into the eastern edge of each continent as the earth spins. This produces a drag on the earth's rotation. During a significant fraction of Earth's history, there was only one big continent. During those times, each tidal bulge hits an eastern coastline only once per day. Currently, however, we have two north-pole-to-south-pole continental masses, meaning that the tidal bulges hit the eastern coastlines twice each day, and the drag effect of this particular process is more or less twice what it has historically most often been. |
#7
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The moon
Carusus wrote in alt.astronomy:
Some have suggested, I think, that as it moves ....closer, not... away the stresses will make the moon shatter into a ring like Saturn's. Is this correct? Here's two on the Roche Limit: http://pegasus.phast.umass.edu/a100/handouts/roche.html http://zebu.uoregon.edu/~js/glossary/roche_limit.html -- CeeBee Uxbridge: "By God, sir, I've lost my leg!" Wellington: "By God, sir, so you have!" Google CeeBee @ www.geocities.com/ceebee_2 |
#8
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Is that correct? Surely the total momentum of the wavefronts will remain
the same? eyelessgame wrote: David Haas wrote in message ... Does anybody have any info on how far the moon is moving away from the earth each year and how this figure would have changed over time. ------ D. Haas "Consistency requires you be as ignorant today as you were a year ago." Bernard Berenson In the context of refuting one of the many invalid "young earth" arguments, there's some good information at http://www.talkorigins.org/faqs/moonrec.html The moon is receding at about an inch and a half per year. This is faster than its average recession over time. It's faster today because of the mechanism of recession... Basically, the earth's rotation is slowing slightly thanks to tidal force from the moon. The rotational energy has to go someplace: that someplace is into the moon's orbit. When you put energy into an orbit, you raise it. The biggest reason the tides slow the earth is that the earth's oceans bulge toward and away from the moon, and this bulge slams into the eastern edge of each continent as the earth spins. This produces a drag on the earth's rotation. During a significant fraction of Earth's history, there was only one big continent. During those times, each tidal bulge hits an eastern coastline only once per day. Currently, however, we have two north-pole-to-south-pole continental masses, meaning that the tidal bulges hit the eastern coastlines twice each day, and the drag effect of this particular process is more or less twice what it has historically most often been. |
#9
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Is that correct? Surely the total momentum of the wavefronts will remain
the same? eyelessgame wrote: David Haas wrote in message ... Does anybody have any info on how far the moon is moving away from the earth each year and how this figure would have changed over time. ------ D. Haas "Consistency requires you be as ignorant today as you were a year ago." Bernard Berenson In the context of refuting one of the many invalid "young earth" arguments, there's some good information at http://www.talkorigins.org/faqs/moonrec.html The moon is receding at about an inch and a half per year. This is faster than its average recession over time. It's faster today because of the mechanism of recession... Basically, the earth's rotation is slowing slightly thanks to tidal force from the moon. The rotational energy has to go someplace: that someplace is into the moon's orbit. When you put energy into an orbit, you raise it. The biggest reason the tides slow the earth is that the earth's oceans bulge toward and away from the moon, and this bulge slams into the eastern edge of each continent as the earth spins. This produces a drag on the earth's rotation. During a significant fraction of Earth's history, there was only one big continent. During those times, each tidal bulge hits an eastern coastline only once per day. Currently, however, we have two north-pole-to-south-pole continental masses, meaning that the tidal bulges hit the eastern coastlines twice each day, and the drag effect of this particular process is more or less twice what it has historically most often been. |
#10
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"Carusus" wrote in message
... Is that correct? Surely the total momentum of the wavefronts will remain the same? Friction on the continental shelves dissipates energy as heat. |
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