Barbarian. I said nothing about a non rotational earth. I said a situation where the tidal bulge was not displaced from the straight line of the moon. I realize that is only possible in a non rotating earth but i was making a point. I was saying that if the bulge was instantaneous created where the rotation did not displace it, the friction of crashing against the continents would still be there and would dissipate has heat without slowing down the earths rotation. Its a hypothetical to make a point.
toldailytopic: How old is the earth?
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Yes radiometric dating of meteorites show 4.6 billion years. But this assumes a constant rate of decay. Atomic time does not match time kept by motion of the sun and planets. Its taking the orbits of planets and other satellites longer and longer when measured against atomic time. Atomic time is slowing down. Decay rates are slowing down. If this deceleration is inversely exponential, that solves the 4.6 billion years down to less than 7000 years.
The point is, if the Earth was not rotating, there would be no tidal forces pushing on the continents. The tides would be stationary. The energy being removed as heat comes from the kinetic energy of the rotating earth. That's why it's slowing down.
You will get no heat from potential gravitational energy. An object two feet off the ground does not produce heat because it's higher than an object on the ground.
Has to to with the conversion of kinetic energy to heat. Potential gravitational energy is not converted to heat.
The heat is due to lost kinetic energy of the rotating Earth. That's why the tides slow it down.
Tidal friction is not a factor in moon recession. Or if you want to include tidal effects in the model you cannot pick and choose which tides you look at and ignore the rest.
Barbarian observes:
Has to to with the conversion of kinetic energy to heat. Potential gravitational energy is not converted to heat.
The heat is due to lost kinetic energy of the rotating Earth. That's why the tides slow it down.
Physics shows that it is:
Lecture 20: Tides
Key Ideas
Tides are caused by differences in the gravitational pulls of the Moon and Sun between near and far sides of the Earth.
* Earth's Tidal Bulge
* Spring & Neap Tides
Tidal Effects in the Earth-Moon System:
* Tidal Locking of the Moon
* Tidal Braking slowing the Earth's Rotation
* Lunar Recession (increasing size of the Moon's orbit)
Lecture notes Ohio State Astronomy course
Didn't you read what I wrote? All the tides count. C'mon, Stipe; you just look foolish trying to deny what it is.
Has to to with the conversion of kinetic energy to heat. Potential gravitational energy is not converted to heat.
The heat is due to lost kinetic energy of the rotating Earth. That's why the tides slow it down.
Physics shows that it is:
Lecture 20: Tides
Key Ideas
Tides are caused by differences in the gravitational pulls of the Moon and Sun between near and far sides of the Earth.
* Earth's Tidal Bulge
* Spring & Neap Tides
Tidal Effects in the Earth-Moon System:
* Tidal Locking of the Moon
* Tidal Braking slowing the Earth's Rotation
* Lunar Recession (increasing size of the Moon's orbit)
Lecture notes Ohio State Astronomy course
Didn't you read what I wrote? All the tides count. C'mon, Stipe; you just look foolish trying to deny what it is.
student_ad_x
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Around 6000 years, give or take a few :chuckle:
God created a mature universe and a mature earth. :cheers:
Then the friction generated is all conserved within the earth. :idunno:
You cannot say that friction within the earth slows the earth's rotation. That's like insisting you can speed up a sailboat you're standing in by blowing on the sails. If the earth started scraping against something extraterrestrial then you'd have a point, but earth's rotation is slowed, not by friction, but by the altered gravitational environment generated mostly by the water on earth being so affected by the moon.
I'm afraid all your sources are either describing some terrestrial effect that does not need to worry about moon recession or else they're just plain wrong.
Friction has nothing to do with the moon's recession.
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Then the friction generated is all conserved within the earth.
Friction caused by tidal forces do. See the above from the astronomy people at Ohio State.
Not unless the Moon is sitting on the Earth. Wind moves sailboats, because the energy is not generated by a fan on the boat. You're back to that thing about cooling your house by opening your refrigerator. Won't work that way, unless you put the coils outside the house. Sort of like the Moon being off the Earth. This shouldn't be that hard for you, Stipe.
The heat generated by the moon's gravity (tidal forces) comes from the reduced kinetic energy of the Earth's rotation. Energy doesn't magically appear, Stipe. It has to come from something.
I can believe astrophysicists (and the physics of force and motion) or I can believe, um, an English teacher, is it?
Not much of a choice, really.
The rotational angular momentum of the Earth decreases and consequently the length of the day increases. The net tide raised on Earth by the Moon is dragged ahead of the Moon by Earth's much faster rotation. Tidal friction is required to drag and maintain the bulge ahead of the Moon, and it dissipates the excess energy of the exchange of rotational and orbital energy between the Earth and Moon as heat. If the friction and heat dissipation were not present, the Moon's gravitational force on the tidal bulge would rapidly (within two days) bring the tide back into synchronization with the Moon, and the Moon would no longer recede.
http://en.wikipedia.org/wiki/Tidal_acceleration
Give it up, Stipe. You're just making yourself look more and more foolish.
Friction caused by tidal forces do. See the above from the astronomy people at Ohio State.
Not unless the Moon is sitting on the Earth. Wind moves sailboats, because the energy is not generated by a fan on the boat. You're back to that thing about cooling your house by opening your refrigerator. Won't work that way, unless you put the coils outside the house. Sort of like the Moon being off the Earth. This shouldn't be that hard for you, Stipe.
The heat generated by the moon's gravity (tidal forces) comes from the reduced kinetic energy of the Earth's rotation. Energy doesn't magically appear, Stipe. It has to come from something.
I can believe astrophysicists (and the physics of force and motion) or I can believe, um, an English teacher, is it?
Not much of a choice, really.
The rotational angular momentum of the Earth decreases and consequently the length of the day increases. The net tide raised on Earth by the Moon is dragged ahead of the Moon by Earth's much faster rotation. Tidal friction is required to drag and maintain the bulge ahead of the Moon, and it dissipates the excess energy of the exchange of rotational and orbital energy between the Earth and Moon as heat. If the friction and heat dissipation were not present, the Moon's gravitational force on the tidal bulge would rapidly (within two days) bring the tide back into synchronization with the Moon, and the Moon would no longer recede.
http://en.wikipedia.org/wiki/Tidal_acceleration
Give it up, Stipe. You're just making yourself look more and more foolish.
Let me explain this to you as simply as I can.
The moon affects the entire mass of the earth and its rotation. It does that by attracting the nearside tidal bulge that is generated almost entirely by the earth's abundant liquid water. This attraction slows the near side tidal bulge on the earth more than the far side bulge is accelerated providing a net brake force applied to the earth's rotation. This effect would play out regardless of the degree of internal friction experienced on earth. Thus the friction generated is irrelevant when considering the earth's slowing rotation. Similarly the friction generated is irrelevant when considering the recession rate of the moon. The only factor that is relevant is the size of the tidal bulge. More bulge = more mass for the moon to attract = faster slowing of the earth = faster recession of the moon. Friction doesn't
factor.
Can you explain your ideas in concise form?
In fact wave crashing isnt even due to tides. The waves crash at all times of the day. they are due to currents. The tides simply raise the sea level which brings water up further on the beach. You have the water rising over a 24 period. This is not hitting the beach with force. it is simply water rising by the force of gravity. which does not have an angular velocity to it.
XitStrategy
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And bible code says some really funny things about American Idol, but all that proves is that blatant misuse of something adds nothing to its value on either side.
XitStrategy
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You can't "figure out" how old the Earth is, but you can use all of the available evidence to arrive at an acceptable number. You won't find agreement between all of the evidence, but inaccuracies can be removed by first excluding things that are inconclusive or vary wildly from any normalized trend.Have we figured out how old the earth is yet?
Just checking.
For example, studying the digestion of wheat in rabbits that have been carbon dated to the 3rd Millennium BC might throw a wrench into the works, so you might have to consider either excluding all carbon dating results, or at the very least check that the study used carbon dating within parameters that produce viable results.
You could of course use evidence inferred from the bible, but you would have to exclude the history of beer - not because it skewed the results, but who wants to drink a beverage that is older than the Earth!
It does. The issue is that because the oceans are both fluid and massive, friction of the tides is almost entirely responsible for the slowing of the Earth' rotation. The tides of the atmosphere are also fluid, but they have so little mass that it doesn't do much. Likewise, the rock of the Earth is quite massive, but so inflexible that it doesn't affect the rotation much, either.
I understand you want us to believe that. You might even believe it yourself. But there is that problem of physics. The forces generated by the movement of the Earth under the tidal bulge, draw energy from the Earth's rotation, slowing it.
C'mon Stipe, you've come a long way from your original belief here; just go a bit further, and you're home. Remember your example of the person standing on the deck of a sailboat, blowing on the sail?
It won't work because of the friction of that person's feet on the deck. You can't get a torque like that without friction. And that what the torque on the Earth is. The Earth moves under the tidal bulge, and the friction from that movement is the energy lost by the Earth and gained by the Moon.
Think.
No. The Earth moves under the tidal bulge. The water rotates with the Earth, but the bulge does not. Think of water waves coming ashore. The waves travel to the shore, but the water does not. Does that help?
Tides have ZERO friction barbarian. The fluidity and mass of the ocean has no bearing friction experienced when waves crash on a beach.. Those waves are generated by currents that are independent of the earths rotation. The tide does not move horizontally. It moves up and down. The position of this moving up and down does change with the position of the moon but there is still no horizontal movement of water.
You say the earth moves underneath the tidal bulge barbarian. It only does so in a positional sense. The bulge is nothing more than an area of heightened sea level. As the earth moves under this bulge, earth is not moving underneath a body of water. What is actually happening is that as the earth and water move together at the same velocity, any particular location will pass by an area that will elevate the already moving water.
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