What makes the earth keep spinning?

Question

or any planet,

Answer 1

your finger.

Answer 2

Inertia.

Answer 3

Gravity.

Answer 4

Inertia - basically, there's nothing to STOP it from spinning, and a body in motion tends to stay in motion.

Answer 5

The TC @ the top of the list got it. However, it is been said by many that the fact that Chuck Norris is walking around on the planet keeps it spinning. :)

Answer 6

momentum. any object in motion will stay in motion until acted upon.

Answer 7

when the earth was formed from the sun it started spinning.but as there is no opposing force in the space,it went on spinning due to its inertia of motion.

Answer 8

Superman is on a treadmill that is positioned exactly on the equator.

Answer 9

Conservation of angular momentum.  It is slowing a little as the moon recedes.

Answer 10

candy..

Answer 11

Inertia is the tendancy for an object in motion to stay in motion and an object at rest to stay at rest. The more massive an object is, the more inertia it has.

The fact that the earth continues to rotate is not really a question. What started it rotating or what factors might stop it is an interesting one.

Answer 12

Short answer: conservation of angular momentum.

Longer answer: there is very little friction to slow down the spinning.  The planets are in the vacuum of outer space in orbit around the sun (you can think of an orbit as always falling at the sun, but always missing) and there are very few forces to oppose the spin of the planets.

There are some opposing forces though.  Outer space is not a perfect vacuum, and so the earth does encounter a small amount of resistance as it orbits and spins.  The earth is also pushed away from the sun by the force of sunlight (photons have momentum; they transfer it to the earth when they bounce off or are absorbed; then there's the solar wind).  The spin of planets on their own axes is resisted very slightly by forces of tide.

So for example Mercury (closest to the sun, therefore highest tidal forces)  spins only once on its axis for each orbit about the sun.  Mercury thus always keeps the same face to the sun.  It used to have more spin, but the greater tidal forces on Mercury have already reduced its spin to the stable configuration.

Likewise the Moon spins once per orbit.  The moon exerts tidal forces on the Earth, and the Earth, being much more massive, exerts larger tidal forces on the Moon.  The result is that the Moon now always keeps the same face towards the Earth (the stable configuration).  

Just as the Moon lost its spin to Earth tidal forces, the Earth is slowly losing spin to solar tidal forces, so days are slowly getting longer (on the order of 1 or 2 milliseconds per century).

So the long answer is that the earth only seems to keep spinning because you have been observing it for such a short time.  If you wait a billion or so years you'll notice it is slowing down!

Answer 13

all the fat people give it momentum and keep it spinning lol

Answer 14

No friction to slow it down...