why does the earth spin?
967123
It does! It is going slower and slower all the time, due to the gravitational drag of the moon. Eventually, there will be tidal lock, and the moon will be much further away. And you and I will be a billion years dead.\nSee, all this happens on a PLANETARY time scale. We can't perceive it, except with very very sensitive devices that have only become available fairly recently.\nAs to why it spins ... maybe its happy? \nNo no no. It spins because it retains the orbital movement from when it coalesced into a solid mass. At the core, there is a gravitational singularity, and all the matter that makes up our planet is/was in orbit around it, but reached equilibrium in the collapse, forming the "solid" planetary mass.\nWhat astronomers are only now coming to realize (having deduced that there is a lot more matter in the universe than is readily observable) is that there are gravitational singularities at the core of virtually every large-scale body - planets, stars, and galaxies. \nThe whole notion of planets "coalescing" WITHOUT such a singularity is absurd, even in a Newtonian universe.\nSo, if you dug a deep enough hole, you would find a hole. Neat-o, huh?
52855
It has to do with the direction the earth rotates on its axis. It rotates once every 24 hours. So, the direction it spins is the direction the sun passes by. The earth would have to completely stop and start to rotate in the opposite direction in order for the sun to rise in the west and set in the east. Hopefully that won't happen any time soon, because it would probably mess gravity all up.
20798
The Earth spins from west to east at about 900 mph. Looking from above the Earth's North Pole, the Earth rotates counter-clockwise around the Sun.
327144
Are you talking about rotation?  That is when the earth spins on it's own axis... You know how you spin a basketball on your finger?  That is called rotation.  It also revolves around the sun.  I think that all heavenly bodies have a rotation, and they all revolve around something else... everything in the universe is in constant motion.
736348
The Earth's rotation began as the matter, that came together to produce our planet, gradually increased and compressed upon itself.\n\nHave you ever seen a figure skater when they go into a spin?  Notice they spin faster when they pull in their arms and legs.\n\nSame effect.\n\nGravity is actually a property of mass.  \n\nGreater mass = Stronger gravity
448217
It goes back to when the solar system was formed.  The sun (and the planets, for that matter) were formed when a gigantic cloud of gas and dust collapsed.  When that cloud collapsed, it had something called 'angular momentum', which really just means that it was spinning a little bit.  When a large, slowly spinning thing collapses to something smaller, the rate of rotation speeds up (think about an ice skater that pulls her arms in...she spins up!).  Anyway, so now we have all this gas and dust in a disk that's orbiting the new Sun.  The dust eventually forms into planets.  As the dust collapses into new planets, the same thing happens, and the planets start spinning themselves.  So basically, the earth and moon and whatnot spin because of angular momentum.  I hope this made sense/helped!
168503
Finally, the gravitational pull between the Earth and Sun causes the Earth to travel around, or "orbit", the Sun at a velocity of 29.8 km/sec. At the same time, the Earth also turns on its axis causing the daily cycle of day and night. This "rotational velocity" is approximately .47 km/sec. That means that at the same time we're hurdling through space at nearly 67,000 mph, we're also spinning around in circles at over 1000 mph! Whew! Almost makes you dizzy, doesn't it?
859047
The earth's magnetism is a result of the fact that the core of the earth is liquid; as the earth spins around this liquid center, it creates polarity.
756076
One would think that while standing on a spinning Earth, you would feel lots of different angles of acceleration.  But this is not the case.  The fact that the Earth spins results in another force called the centrifugal force, which points in the direction away from the earth's axis of rotation.  It is greatest the farther you are away from the rotation axis (i.e. at the equator), and non-existent at the north and south poles.  \nHowever, even at the equator, this force is very tiny (only 0.3% of the \ngravitational force) - so you don't notice it at all.  The reason it is so small is simply that the Earth doesn't rotate fast enough.
998543
"how do we know the earth spins?"\n\n:  )
413242
The earth revolves around its axis and the reason we don’t feel it is because we live inside a bubble called the atmosphere and we’re moving along with it. It’s kinda like you in a car… you don’t feel your seat or CD case moving but they are.
112224
because it changes slowly, and also you don't feel the magnets on your frigde why would you feel the earth? :P
1157171
As Debster92 pointed out, there is no way to stop the Earth from spinning once it starts.\n\nAlso, and perhaps more importantly, there is absolutely no way to get it started again if it did stop.\n\nThe angular momentum imparted on the solar system as it coalesced out the primordial gas cloud is what causes all the planets to spin and rotate as they do today.  If one were to somehow stop a body from rotating, it would take tremendous energy to get it started again.
915719
Subatomic particles do not spin on their axis. What is called spin is actually a misnomer, given because it was originally thought that the only origin of the megnetic moment of the particles could be that they spin on their axis. In fact, spin magnetic moment arises naturally out of the Dirac equation (the relativistic form of the Schroedinger equation) with no rotation at all.\n\nThe Earth spins because the cloud of matter that it and the solar system condensed from was rotating, and angular momentum is conserved.
1007077
You are quite right (and others quite wrong) - centrifugal force is not real.\n\nCircular motion requires an inward (centripetal) force towards the centre of motion. Take that inward force away and object just carry on in a straight line with the velocity they had when the force was removed.\n\nNow for the spinning Earth think about where that force comes from. Its main source is gravity (think about it, it does not take a lot of force to pull bits of soil apart). And the force due to gravity at the surface of the Earth is more or less constant.\n\nBut at the equator, the force needed to keep the surface rotating and not flying into space is higher than it is at the poles, because the radius from the axis is larger. But the force or gravity is the same. So gravity can't hold things in quite as close. So the Earth tends to bulge in its middle.
805592
first: by world, do you mean earth? \nIf so, think about all things spinning, are they not always more or less round or oval shaped? Actually so is the earth. \nOn the other way,I think that by spinning, a lot of things get that shape. Especially as like the stars and planets, they tend not to be in a fully finish state. Ok, that is my answer but I am no astronom only a nurse... MC
1133398
That depends on where on Earth you are standing. At the poles, the Earth hardly spins at all, but as you travel towards the equator, the rotational speed picks up. This makes sense -- as the circumference of a circle increases, a single point along it has to travel faster to complete a revolution in the same amount of time. \n\nThe rotational speed of the Earth at the equator is about 1,038 miles per hour. The atmosphere at the equator is also slightly thicker due to rotation, and you weigh slightly less. At mid-latitudes, the speed of the Earth's rotation decreases to 700 to 900 miles per hour. \n\nIf the Earth were to stop spinning suddenly, the atmosphere would still be zipping along nicely at around 1,000 miles an hour. As a result, everything not attached to bedrock would pretty much be scoured clean. \n\nThe circumference of the Earth at the equator is 25,000 miles. The Earth rotates in about 24 hours. Therefore, if you were to hang above the surface of the Earth at the equator without moving, you would see 25,000 miles pass by in 24 hours, at a speed of 25000/24 or just over 1000 miles per hour. \n\nMultiply by cosine of your latitude to see how fast the Earth is rotating where you are. \n\nHope you get an A if you are doing a science project haha.  Or hope you learned something :)