if there were two identical earth's, would one spin up and the other down?
397558
not if they're identical.
424875
No, but it would be neat if it did. Reversals happen very rarely and take hundreds of years to complete.
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.
420139
Not unless the wind carries it because whilst the earth is spinning around rapidly, so is everything on it. If this were not the case, and a person jumped straight up into the air they would shoot of in a direction and this doesnt happen
606294
If they were in the same place and time, 'same' mathematically, they would fall at same speed.\n\nIf they were in different places or time, the forces exert on them may be different e.g. the moon which cause tides, and the gravitational acceleration 'g' is different from place to place.\n\nMy answer is different, coz' I am not a physicist but an engineer. I take everything into account. Of course, there are many forces beside gravitation and air resistant.\n\n"No air resistant" doesn't mean that there is only gravity. Besides, gravity different from place to place.
431091
It is because of the Earth's rotation.
613637
NO.\nTechnically speaking if you travel on the earth in on a single vector you would not end up in the same place because in order to do so you would be constantly changing your vector. Technically speaking.
280629
We would never FEEL it rotate because it acts directly opposite to gravity. The only way we would feel it it if it CHANGED in velocity.
753758
the question really should be, 'which direction is the earth spinning if you look at it from (insert place here)?'\n\nit all depends on your frame of reference. and your direction of reference. and your size of reference.
825744
I think you meant to say that the people were running forward, not in place.  If they were running in place, nothing changes.\n\nOtherwise, assuming that an average person has a mass of 70kg.  That means that all the people have a combined mass of about 70*6.4*10^9 = 448*10^9 kg.  The earths mass is approximately 6*10^24 kg.  That means that all of the peoples mass is only 0.00000000000007466667 of the earths mass.  Using the conservation of angular momentum with:\nm = moment of inertia of people\nM= moment of inertia of earth\nw_1 = angular velocity of earth with people standing still\nw_p = angular velocity of FORWARD running people\nw_e = angular velocity of earth while people are running \n\nw_1*(m+M) = w_e*M + w_p*m\n\nso by the conservation of angular momentum you can see that you would effect the rotation of earth.  However m compared to M is essentially zero, as mentioned before (mass is in a way related to ineria) so setting m = 0, you get:\n\nw_1*(m+M) = w_e*M + w_p*m\nw_1M = w_e*M\nw_1 = w_e\n\nThe effect that this would have is practically none so no you will not change the direction but, yes you do slow the earth down a tiny, tiny, minuscule amount.
131841
The seasons would be far milder. There probably still would be some seasonal variations because the earth is not always the same distance from the sun.\n\nAlso, it should be noted that even if the axis of rotation was oriented to be normal to the ecliptic, there is still a 435 day period Chandler Wobble to the earth's axis, caused by redistribution of mass on the earth's surface (and presumably within the earth as well) and the conservation of angular momentum.
932837
forces are opposite and equal, otherwise you would change speed/direction.
328856
Time is unconnected to the Earth.  The only immediately noticeable differences between normal Earth and a backward rotating Earth (NOT counting the moment during which the Earth stops spinning) is that water will circulate in the opposite direction in the ocean, counterclockwise instead of clockwise, and storms will rotate across the Earth in a different directional tendency.
914874
yes if it is spinning on its own axis as it moves.  This is called Spin Angular Momentum
51113
Yes. It's only true that the chances of any two snowflakes being identical are extremely low, and nobody's checking and cross-referencing them all to see.\n\nIf two identical seed particles took two identical journeys to the ground, you'd have two identical snowflakes. There's no mystical law stopping this from happening apart from the sheer weight of different possibilities available.
467215
Spin relative to what?\n\nThe spin of the Earth about its own axis causes day and night but only because the spin is not synchronised with the orbit of the axis around the sun.  Mercury spins once on its axis for every orbit and so always has the same face to the sun.  It could be said in this case that Mercury does not spin, but that is only relative to the orbit of Mercury.\n\nImagine a frame of reference that is fixed in space like the grid lines on a map.  If a planet did not spin on its axis relative to this reference, then it would have a day/night cycle that took one orbit to complete (this would be one year for the Earth).\n\nIt is also believed that the spin of the Earth contributes to the generation of the magnetic field, so if the spinning stopped or slowed (relative to any reference) we could loose the magnetic field and thus be exposed to higher radiation levels from the sun.
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.