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anonymoussome
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Why do we see the near side of the moon only??
Why do we see the near side of the moon only?Why not the far side??
Why do we see the near side of the moon only?Why not the far side??
russ_watters said:The moon is tidally locked to the earth. The same forces that cause our tides cause the moon to rotate once per revolution.
Yes, except in both cases, they rotate in the same direction.fakrudeen said:unlike 24 hours and 365 days for earth, for moon periods of spin and orbit are roughly the same and are in opposite directions. [think of a ball rolling on the floor and at the same time rotating in opposite direction]
No historical accident is necessary. Tidal friction is like applying the brakes on your car. It is a very real friction force that slows the rotation.rbj said:so, i s'pose some historical accident, the angular velocity of rotation of the moon is very close to the angular velocity of revolution about the Earth (ignoring the fact that both are revolving around the Sun together). now, i would not expect these two angular velocities to be sooo exactly equal that, over thousands of years, no relative turning motion would be detected. it's like with a continuous random variable, say a spinner, the probability of the spinner pointer landing precisely at 20o is zero (as opposed to the probability of the spinner landing between 20o and 21o which is not zero).
Tidal friction is literally generated by the changing tides. It is perhaps easiest to understand with the flowing of water in and out of a bay. With any fluid flow, there is an associated viscous fluid friction that dissipates energy and generates heat. But the same force also kneads the Earth and moon like a ball of dough, deforming the actual bodies themselves. This deformation is not perfectly elastic, and thus generates energy.so, somehow the angular velocity got close enough, what torque applied to the planet acts as a control system with negative feedback to keep the same side facing us?
russ_watters said:No historical accident is necessary. Tidal friction is like applying the brakes on your car. It is a very real friction force that slows the rotation. Tidal friction is literally generated by the changing tides. It is perhaps easiest to understand with the flowing of water in and out of a bay. With any fluid flow, there is an associated viscous fluid friction that dissipates energy and generates heat.
But the same force also kneads the Earth and moon like a ball of dough, deforming the actual bodies themselves. This deformation is not perfectly elastic, and thus generates energy.
Wallace said:There is some info on Wiki under 'Tidal Locking' if you are interested.
russ_watters said:Yes, except in both cases, they rotate in the same direction.
Chronos said:Wallace gave the long and short of it.
I'm actually not exactly sure what you mean by this, but the easiest way to see it is with a top-down view of the solar system. Most bodies both rotate and revolve counterclockwise.fakrudeen said:I meant if orbital motion is to your left [as seen from Earth lying face up looking at the moon], moon should rotate to right. To an Earth observer aren't they in opposite directions?
anonymoussome said:I also learned that Earth's rotation is slowing down due to tidal friction, this means that the orbits would have to distance themselves further.
Isn't moons attraction and the torque it provides enough to speed up the earth??
anonymoussome said:I also learned that Earth's rotation is slowing down due to tidal friction, this means that the orbits would have to distance themselves further.
Isn't moons attraction and the torque it provides enough to speed up the earth??
anonymoussome said:I also learned that Earth's rotation is slowing down due to tidal friction, this means that the orbits would have to distance themselves further.
Isn't moons attraction and the torque it provides enough to speed up the earth??
Holocene said:For the experts, is it safe to say that IF the sun lasted forever, all the material in the solar system would eventually be pulled into the Sun?
Wallace said:Not at all, there is no reason that the orbits of the planets should decay over time.
Ulysees said:In fact they should do the opposite. The sun has an equatorial bulge due to its rotation, therefore we should get something similar to the moon getting slowly further from the earth.
No, the Earth itself has a tidal bulge, like kneading some dough with your hands.Ulysees said:Tidal lock implies there would be no lock if the Earth had no sea?
In fact, the moon does have a tidal bulge.But then the moon has no equatorial bulge or ocean.
The moon's rotation and orbit around the Earth are synchronized, which means that it takes the same amount of time for the moon to rotate on its axis as it does for it to orbit around the Earth. This results in the same side of the moon always facing towards the Earth, making the near side the only side visible from Earth.
The synchronous rotation of the moon is due to tidal forces between the Earth and the moon. These forces have gradually slowed down the moon's rotation, causing it to become locked in its current position.
No, we cannot see the far side of the moon from Earth. However, spacecrafts and satellites have been able to capture images of the far side of the moon.
Yes, there are several differences between the near and far sides of the moon. The near side has a thinner crust and a larger concentration of maria (dark, smooth areas) compared to the far side. The far side also has more craters and a thicker crust.
Yes, the term for this phenomenon is called tidal locking or synchronous rotation.