AdmiralGT

While I never got to know you that well personally Xeno, I can truly say that you are an inspirational person. Other than that, I don't know really what to say...

This effect would eventually lead to a "month" and a "day" being the same length, meaning the Moon would be in a Geostationary orbit.

and erm...how long will that take?

by the way, did you guys know the magnetic north and south pole are going to switch around? i believe it will happen soon...


...erm, no not soon but it's already affecting satellites
http://www.impactlab...=...le&sid=3672

anyway, i have a theory: could it be possible that the fact that the magnetic poles are close to the geographic poles, be a sheer coincidence? that they were somewhere on the equator a long time ago, but not when humans invented compasses and stuff?

Billions of years, at which point the Sun would have gone Nova and probably destroyed the Earth/significantly changed it's orbit.

As for the magnetic poles, they settle near the geographical poles due to the rotation of the Earth, since the liquid core of the earth is thought to cause our magnetic field, the rotation of the Earth is the main cause of the poles. However, other effects cause the poles to shift in time, which takes hundreds of years. And yes, we are due a shift in the poles, sometime in the next few millenia.

Sorry to um... drop the ball on you. But even without aerodynamic friction, yes even in a vacuum, the ball still loses energy. The reason is similar to what happens when an electric charge is moved around: it radiates some of its energy in the form of electromagnetic waves. So what if you move mass around? Exactly, gravity waves. This energy loss is absolutely tiny, but nonetheless it does exist. It causes the earth's rotation to slow down each day. So, eventually, after billions of years maybe, the ball will come to a complete stop relative to earth. That is, assuming the sun doesn't blow it up first.

Out into space. And it would move other bodies that have mass around a tiny bit.

Honestly, it's nothing weird. Just imagine I have a positive electric charge in a tube. It can move freely around the tube, but can't go out of it. Now, I take a negative charge in my hand, and move it up and down along the outside of the tube. The laws of electromagnetism say that the positive charge will be attracted by the negative one, and will move up and down with it.

Now, imagine that negative charge again, but this time moving up and down extremely fast: a million times a second or even more. Again, it's obvious that anything near it will start moving up and down just as fast (albeit not as much). However, as you may know, an oscillating electric field (as is the case here) is manifested as electromagnetic waves. And we all know those carry energy, and in this case in the form of radio waves. But this must mean that this oscillating charge slowly loses energy just by radiating energy away from it in the form of waves. So even if there is no friction, the fact that it's moving up and down leads to energy loss by itself, and therefore causes it to slow down and asymptotically come to a stop.

The exact same thing happens to the ball, except that the energy it radiates is not electromagnetic, but gravitational.

Analogies are fantastic, however, in this case, their use is misguided. While electromagnetic waves do propagate from oscillation electrical charges, the same cannot be said for an oscillating mass. The electromagnetic (essentially part of the electroweak) force behaves very differently to the gravitational force. The theory of graviational waves or gravitons is only hypothetical and is only described by String Theory and has a lot of trouble at high energies in the Standard Model.

And this "gravity wave" is not the reason why the rotation of the Earth slows. The rotation of the Earth slows while the rotation of the Moon increases. This is caused by Tidal Acceleration, whereby tides caused by the Moon are "dragged" forward by the rotation of the Earth. This causes Torque to occur, accelerating the Moon and decelerating the Earth. This effect would eventually lead to a "month" and a "day" being the same length, meaning the Moon would be in a Geostationary orbit.

If there is no air resistance ie in a vacuum, the ball will experience Simple Harmonic Motion (it will osciallate between point A and B)
If there is air resistance, the ball will experience Damped Harmonic Motion (it will osciallate, however, each time the point where it changes direction will get closer and closer to the centre of the Earth until it eventually comes to rest at the centre).

Oh, and if you like, you can argue with my 4 year physics degree, but, I assume you will not.

If anyone wishes to add me to their friend's list, my in-game name, is unsurprisingly, AdmiralGT.