If all the planets were formed by the same processes wouldn't they spin at the same speed if their masses were the same?
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No, because the planets rotation rates and rotation directions were determined by the masses and accelerations of the bodies that they collided with while the Solar System was forming.
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It is unlikely since there is no law which dictates ther rate of a planet's spin.
You can hang a ball from a thread and give it any rate of spin you desire and nothing unexpected will occur, The same is true for planets; however, you would get a displacement of the ocean water and the equatorial bulge will increase or decrease as one would expect.
For example the Moon could be speeded up or slowed down by one or two hours each day and no ill effects will be experienced. It is interesting to note that if the Moon' s rate of spin were changed , either slowing or speeding, it would then be possible to see the Moon slowly spin and to view the entire surface .
You can hang a ball from a thread and give it any rate of spin you desire and nothing unexpected will occur, The same is true for planets; however, you would get a displacement of the ocean water and the equatorial bulge will increase or decrease as one would expect.
For example the Moon could be speeded up or slowed down by one or two hours each day and no ill effects will be experienced. It is interesting to note that if the Moon' s rate of spin were changed , either slowing or speeding, it would then be possible to see the Moon slowly spin and to view the entire surface .
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No...
Take Venus and Earth - they're both about the same mass, about the same size... Venus actually rotates *backwards* - it's day is longer than it's year.
Probably the initial mass of the planet was spinning at certain rate, and it accumulated mass as it grew from the debris during the formation of the solar system. Impacts with larger rocks and planetoids added or reduced the speed of that rotation.
Again, look at Earth - we got clobbered by a mass about the size of Mars, which formed our moon. That impact spun our planet so our day was about 9 hours long, and knocked our axis to 23.5 degrees from the plane of our orbit.
Take Venus and Earth - they're both about the same mass, about the same size... Venus actually rotates *backwards* - it's day is longer than it's year.
Probably the initial mass of the planet was spinning at certain rate, and it accumulated mass as it grew from the debris during the formation of the solar system. Impacts with larger rocks and planetoids added or reduced the speed of that rotation.
Again, look at Earth - we got clobbered by a mass about the size of Mars, which formed our moon. That impact spun our planet so our day was about 9 hours long, and knocked our axis to 23.5 degrees from the plane of our orbit.
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No. Their orbital speed is determined simply by the length of orbit. Planets nearer the Sun complete an orbit much faster than those farther away.
Axial rotation, which produces the planet's "day", is not related to mass. Mars is much, much smaller than Earth, yet it's day is virtually the same length as an Earth day. Venus is roughly the same size and mass as the Earth, yet it's day is radically shorter.
Axial rotation, which produces the planet's "day", is not related to mass. Mars is much, much smaller than Earth, yet it's day is virtually the same length as an Earth day. Venus is roughly the same size and mass as the Earth, yet it's day is radically shorter.
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spin and rotate are not the same in a stickier sense. spinning about its axis is not even applicable to all planets, rotating around the sun or stars depends on the distance away it is from the sun or star. speed of rotation and the distance it is from the sun is very critical to maintain or remain in orbit.
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Only if they were the same distance from planetary object they are orbiting. The further an object is from an orbital the less speed they need to stay in orbit.