- #1
neo143
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Why the Earth keeps on spinning?
In summary: Over time, the two particles will become more and more tightly bound together, until they form a new body - in this case, the Earth.
- #2
Doc Al
Mentor
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- 2,219
Because it has rotational inertia. 
It's just Newton's 1st law applied to the rotational motion of a solid object. (In other words: It doesn't need a reason to keep spinning--that's what things do. But it would need a reason (a torque) to change its spinning.)
It's just Newton's 1st law applied to the rotational motion of a solid object. (In other words: It doesn't need a reason to keep spinning--that's what things do. But it would need a reason (a torque) to change its spinning.)- #3
neo143
- 29
- 0
What about friction due to atmosphere??
- #4
Danger
Gold Member
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Atmospheres are part of the planets that they're associated with, and as a basic rule rotate with them. There's nothing in space for the atmosphere to drag against. Winds are 'internal' phenomena of the system, caused by convection, and aren't reflective of the planet's motion.
- #5
vaishakh
- 334
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Better the question-What initiated the Earth to be in a state of spinning? Why did Earth start rotating around its axis when it was formed? Can anyone here clear my doubt?
- #6
DaveC426913
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The coalescence of matter into a body will conserve the angular momentum of its individual parts. The Earth did not "start rotating", the Earth was a cloud of particles, rocks and gas, in a loose orbit around a cloud of particles rocks and gas that was to become the Sun and the rest of the Solar System. It was already rotating before it formed.
Where does the rotation come from in the first place?
1] Take two particles in empty space.
2] Give them each a random velocity in a random direction.
3] Place them close enough so that they gravitationally interact.
4] When they eventually collide, they will not exactly cancel each others' motion out (There is only a single, astronomically small chance of this happening - it requires both particles to collide with each other in a direct line, with no tangential motion relative to each other i.e. they were on a collision course to begin with). So, when they collide, they will stick together. They will retain any residual tangential motion that doesn't completely cancel out. This effect is cumulative.
Where does the rotation come from in the first place?
1] Take two particles in empty space.
2] Give them each a random velocity in a random direction.
3] Place them close enough so that they gravitationally interact.
4] When they eventually collide, they will not exactly cancel each others' motion out (There is only a single, astronomically small chance of this happening - it requires both particles to collide with each other in a direct line, with no tangential motion relative to each other i.e. they were on a collision course to begin with). So, when they collide, they will stick together. They will retain any residual tangential motion that doesn't completely cancel out. This effect is cumulative.
1. Why does the Earth spin?
The Earth spins because of its initial rotation when it was formed and the force of gravity. As the Earth was forming, the materials that made it up were moving in different directions. As these materials came together, their movements combined to give the Earth its initial spin. This spin has been maintained by the force of gravity pulling on the Earth's mass.
2. How fast does the Earth spin?
The Earth spins at a speed of approximately 1,000 miles per hour at the equator. This speed decreases as you move towards the poles. The Earth completes one full rotation on its axis in 24 hours, creating our day and night cycle.
3. What would happen if the Earth stopped spinning?
If the Earth suddenly stopped spinning, it would have devastating effects on our planet. The atmosphere and oceans would continue to move at the Earth's previous speed, causing catastrophic storms and extreme weather patterns. The lack of rotation would also affect the Earth's magnetic field, leading to increased exposure to solar radiation. Additionally, the change in centrifugal force would cause the Earth to become more oblong, resulting in changes to our seasons and climates.
4. Is the Earth's spin constant?
No, the Earth's spin is not constant. It is affected by various factors such as the gravitational pull of the Moon and Sun, the movement of the Earth's molten core, and the changes in the Earth's surface due to tectonic plate movement. However, these changes are very small and do not have a significant impact on our daily lives.
5. Will the Earth ever stop spinning?
It is highly unlikely that the Earth will ever stop spinning. As mentioned earlier, the Earth's spin is maintained by the force of gravity, and there is no known force strong enough to stop it. Some scientists predict that the Earth's rotation will gradually slow down over millions of years, but it will not completely stop.
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