A naive person I deal with says that the Spin of an planetary object... ?
919025
Let's clear up our terms a little bit.\n\nGravity only generally occurs between things of mass.  And it is pretty much independant of what the mass is doing.  And I say pretty much because there are things that can create or destroy mass... but in a general sense it all comes down to the mass.\n\nNow, as astronomical bodies form, they tend to get a spin.  Because of the conservation of angular momentum, things that suck up more mass tend to have more spin than others.  These are, however, tendancies, NOT necessities.\n\nCase in point - the Earth.  Because of the tides, the spin of the Earth is slowing down.  We used to have twelve-hour days millions and millions of years ago, but now they're twice as long.  Has this affected the force of gravity?  Not a bit.  The same mass is present, and it's causing the same amount of gravity.\n\nWhat your friend may be confused by is what is sometimes called centrifugal force (a physicist would probably just call it inertia, though).  Although gravity pulls us down to the centre of the Earth, the motion of spin carries us away from the centre, counteracting gravity.  This means if you take a tool to measure gravity near the equator, you'll get a lower reading then you will when you measure it at the axis.  The force of gravity hasn't changed at all, but the spin is creating another force that is mitigating gravity's effects.  On Earth, this force is pretty small, but it's concievable that it could amount to a huge amount on a fast-enough spinning object... say, a space station with almost no gravity, but which was spinning fast to simulate gravity but pulling out instead of in.\n\nSo in a literal sense, you are completely right.  Gravity has ONLY to do with mass (well, mass and distance).  In a squishier sense, your friend is sort of right, in that spin can change the APPARENT force of gravity in local areas and that objects with large gravities also tend to have large spins.\n\nHope that helps!
308954
After the Earth formed and all the component asteroids and other proto-planetary debris coalesced the residual spin from the collisions left us spinning counter-clockwise.  Were there to be another collision, a series of collisions, or close interaction with some super-massive object (i.e. black hole, brown dwarf, etc.) with enough momentum or gravity to retard, stop or reverse our rotation, it could definitely do so.  Venus is an example of a planet in a retrograde rotation (probably because some massive impact reversed its spin), so it is definitely possible...hell, Uranus spins almost 90 degrees out of alignment with the orbital plane.  Most planets in our solar system spin in relatively the same direction, and that is likely to be the case in most systems in the universe, but it is by no means set in stone.
340001
The earth turns with respect to the motion of force which was placed upon it with in the vacuum of space, and also with respect to the vacuum of space there is no friction to slow it down, therefor it shall continue to spin forever if it's motion is uninterrupted, or unaltered by another matter energy object of aether large size, or fast speed impacting it with direct respect to the angle of the interaction.\n\nas for your second question the axis is the center point at which the spin turns, and is therefore recognized by us with respect to the earths motion spin as the axis, and if the motion and direction of spin were changed tomorrow to be perpendicular of that which it is today, then the new axis would be perceived tomorrow as existing at some point at which we recognize the equator today.
644044
Why does it always spiral the same direction?\n\nIt *doesn't*.\n\nTry the experiment in your bathtub.  It can go either way.\n\nSome people mentioned the "coriolis effect", but for\nsomething as small as a bathtub, this effect is *tiny*.\n\nThe last references below describes experiments where (with\nvery careful controls) this effect was demonstrated, but\nfor most of our experiences, we're seeing other local\neffects (ie. residual currents in the water).  The\nexperimenters literally had to let the water sit for *days*\nin order to let the residual currents die down so that they\nwouldn't overwhelm the vanishingly small coriolis effect.\n\n[By the way, the coriolis effect is *not* vanishingly\nsmall for something *really big* -- like a weather\nsystem.  In that situation, there is a significant\ndifference in the speed (due to the earth's rotation)\nof the portion farthest from the equator vs. the \nportion closest to the equator.]
266432
This is tricky without a particular formula to derive. The master of this was Richard Feynmann. Try his Six Easy Pieces. His lectures on the motion of the planets and his autobiographies are fun easy reading.\n"Surely You're Joking Mr Feynmann"  is the first.\nThe Physics Lecture series are classic physics books.
265349
"have you ever seen a compass dance before"? that would be my guess. it would just spin around
475479
here's my guess --\nthat these particles are somehow "connected" . that they do not violate casuality (this one is proveable) or locality....somehow.
69231
An elderly lady who believed that the world was a flat disk carried on the back of a giant turtle was asked what she believed was below the turtle. Her answer went something like: "you can't trick me, young man, it's turtles all the way down".\n\nAll the way down to where? The question was meaningless to the old lady.
1179134
It would be so helpful if, when providing proof of something, there was actually a whit of truth to what you have to say.  Not only is most of what you've said untrue, it simply doesn't make sense.\n\nHowever, not being one to just say that and not back it up.\n\n1)  A planet sized comet wouldn't be generating a large magnetic field because comets are made of ice and (mostly carbonaceous) dust, two things which are most notably not magnetic.\n\n2)  No scientist worth his salt yet has indicated there's any evidence of massive "plasma scarring" on the surface of Mars, and if one did, it would be from plasma hitting the surface of Mars.  While the Sun and other stars are made out of the stuff, comets completely lack it and magnets don't create it, even if one magnetic field comes into alignment with another one, which brings us to...\n\n3)  Mars has no significant magnetic field.  It has a few magnetic patches on it where there is probably quite a bit of iron concentrated, but it's not magnetic in the least (as a whole planet, in the fashion of, say, the Earth).  It has no magnetic poles, either... and since you can't demagnetize an object with another magnetic field, it couldn't have ended up that way because another magnet "stripped off" it's magnetic field, and in any case you've said Mars absorbed all the energy... so it should be absolutely glowing on the magnetic front, and it isn't.\n\nSo, your theory is that an object which we know has no significant magnetic field (Mars) and an object which we know cannot have a magnetic field (a comet) got together and flipped magnetic poles which didn't exist when you said this event took place, in this massive magnetic tango that produced a product it could not have produced (plasma), that literally fired right through Mars like a gun and, even though it shot straight through the core from one non-existent magnetic pole through the other, didn't destroy the planet from the inside out, but left it completely in tact and just burned off the northern hemisphere, totally defying just about every one of the Laws of Physics God created the Universe to run on because, perfect being that He is, He was too incompetent to get it right the first time and needed to make a trial run which, as a compassionate and merciful God, He decided to burn to a crisp and roast alive every living thing on rather than allow to live on in peace once it had served His purposes, because He just didn't feel bothered to have them around any more.\n\nYou're right.  That's a freaking miracle.\n\n\nP.S.-- Craters naturally fill in from the center out because the edges of the crater are protected by the wall, leaving the center of the crater where dust can be most easily blown and settle, and there are dust storms on Mars.  Also, cooling cracks are very regular things, as the contracting matter pulls evenly away from the weakest point, most often causing the split to be very even and straight.  There's nothing about those features on Mars (or the shield volcanoes, for that matter) we haven't seen happen endless times on Earth-- and directly witnessed in other planetary bodies in the Solar System, which is why we know what made them.\n\nEdit:  All right, let's do this.  First, as for comets:\n\nhttp://www.windows.ucar.edu/cgi-bin/tour_def/comets/comets.html\n\nhttp://www.solarviews.com/eng/comet.htm\n\nhttp://solarsystem.nasa.gov/planets/profile.cfm?Object=Comets&Display=Kids\n\nEveryone from the sixth grade on but you seemed to learn in science class what comets were made of, and most of us quite a bit sooner.  They're made out of ICE and DUST.  Because of the severely black color of them and our analysis of the gases in the comet's coma (you know, that big gas cloud you see around the comet that, oddly, is made out of ice and dust), we're pretty darned sure a lot of that dust contains CARBON, so they're made
788812
Uh-oh. Prepare for a spinning head!\n:-)
324477
point to an object and say what it is called?\n\nthere is a blind gentlemen (since birth) that nasa has hired sometime ago to investigate how to communicate/unscramble an incomming alien message. perhaps, he would be the best one to answer this question. unfortunatly i don't recall his name.
638122
That's human nature. We never want to be wrong so we always spin things to fit our preconceived notions instead of looking at something objectively. \n\nI am including Theists and Atheists in this as well
359195
All planets are tilted, just not to that extreme...   It is more than likely that it had a close encounter with a large object in its past.  But what the crap do you mean that it moves sidewards?  Its in a relatively normal orbit, how does it move sideways?  I think a more interesting question is why does Venus spin clockwise?
1159975
No.  I think it can be generalized that humans judge motion in two ways.  First, a physical reaction; feeling a car on the road, or wind in your face.  Second, a visual reference; such as trees buzzing past or a familiar landmark getting closer.\n\nSince there is no "atmosphere" to speak of in orbit (at least not what we'd consider an atmosphere anyway), there is nothing physical to oppose his motion.  Therefore, from his perspective, he is just sitting there.  Also, since the shuttle that he's tethered to is also moving at the same speed, it doesn't appear to move either (unless of course the astronaut is moving toward, away from, or parallel to the ship somehow).  Regardless, with no frame of reference, there is no sensation of motion.\n\nWell, what about the Earth?  Surely that is a frame of reference.  Well, yes and no.  Sure, one could look at the rotating Earth below them and get some sense of how fast they were moving.  However, anyone who has taken a road trip and has been driving towards a mountain range (i.e. driving across Nebraska towards the Rockies) knows that something that far away and that large can fool the senses into believing that you've stopped.  Therefore, I would (and this is an opinion) discount the Earth as a frame of reference.
838226
i think this person is trying to say that science (physics) and religion (10 commandments) are opposing forces and that while most people order their world around science, this person prefers to use religion...now why they think the 2 can't coexist is beyond me
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?
998322
Lets make an enormous assumption to fill in the gaps.\nYou have a thing on a string of length L and spin it round at a certain rate of rotation. Keeping the rate of roataion what would the tangential velocity of the thing be if the string was shortened to L/2?\nIn this case the tangential velocity (= the radius x the angular velocity) will also halve.