# Can someone explain me gravity?

Another question:
Would Meissner’s frog experience G-forces if rapidly accelerated?

Unless there’s something special about Meissner’s frog (is there another thread this is referencing?) then yes the frog experiences G-forces. The frog, and anything else, experiences G-forces if accelerated at all, it doesn’t have to be rapid but the greater the acceleration the greater the G-forces.

I think the OP is talking about experiments where a live frog is levitated by magnetic fields employing - there’s a bit about it on the Wiki page about magnetic levitation:
http://en.wikipedia.org/wiki/Magnetic_levitation

The magnetic levitation isn’t making gravity go away, it’s just adding forces that happen to balance it out - add some more forces and the frog will feel it.

Can someone explain me gravity?

No such thing as gravity - the Earth sucks.

Jeffy from the Family Circus has pretty much explained gravity

The magnetically levitating frog (or anything else) would experience G-forces in the direction of travel, barring the device isn’t compensating for the acceleration. It would then disrupt the fine balance the magnetism is performing, and the frog wouldn’t levitate anymore.

Gravity is a property of mass. The more mass you have, the greater the gravity. The greater the gravity, the more it warps space-time around it, thereby curving anything else with mass in its field toward, around or into it.

The levitated frog experiences gravity, just like you do when you’re standing on the floor. If the frog is fat, his belly still sags. You are held up by the electromagnetic force of the floor on your feet. The frog is held up by the magnetic field. Both of you will experience g-forces when accelerated.

Newton explained gravity as a universal force between all objects, whose strength is proportional to the product of the objects masses and inversely proportional to the their separation distance. Einstein’s theory of general relativity refined Newton’s theory and explained gravity as the result of curvature in the four dimensions of space and time. A fundamental tenet of Einstein’s theory is the “equivalence principal,” which holds that gravitational force is equivalent to acceleration, thus if the frog accelerates, it experiences g-forces.

To explain all of this in detail would take far more words than practical for this column, but there are many good resources on the Internet.

I believe I made an error, gravity effects massless particles too, like photons.

No such thing as gravity. Its Intelligent Falling.

I really could not read the whole article. The laws of Physics happen - period. Written laws may change, though.

Einstein predicted the speed of gravity to be what is now measured, that is the speed of light. Can you tell me why not slower/faster?

I’m not so sure about the sagging belly. Magnetic levitation is different from most methods of support, in that it acts on water molecules throughout the body of the frog. Since frogs, like all living things, are mostly water, this provides a very uniformly-distributed force. The net effect is that, if the frog were accelerated, provided that the magnetic field were adjusted to compensate, it should have much less effect on the frog than most accelerations.

Consider a typical case where high acceleration does cause damage, like when the ground accelerates you at the end of a long fall. The reason that causes damage is that the bits of you that hit the ground stop moving immediately, but the internal bits of you, and the external parts on the other side, keep on moving for a little while. It’s the fact that different parts of you have different accelerations that causes problems, not the acceleration per se. But with the levitating frog, all parts of it do have close to the same acceleration.

Quoth komolono:

The simplest answer is that that’s the only speed that exists in the Universe. All other speeds depend on your reference frame, but gravity, as described by Einstein, doesn’t have any particular reference frame, so whenever a speed shows up, there’s only one speed it could be.

Good point, my bad.

[quote=“Chronos, post:11, topic:550314”]

Now, if you move the magnet the frog moves - yes? This should be easily tested. Could this be another form of transportation in the future? Let the sorry Maglex-frog earn it’s name in history!

Has it really been measured? I thought that was still a huge technical challenge?

It sounds like the OP just read some article on gravity, which might have mentioned a measurement of the speed of gravity, and which prompted this thread… But he forgot to include a link to the article he read. Hopefully he’ll be back to tell us.

[quote=“komolono, post:13, topic:550314”]

I’m pretty sure the magnetic force on the frog only acts in the direction pointing from the magnet to the frog. So if you move the magnet forward, the frog will fall as soon as the magnet is not directly beneath it (and the frog will even be pushed backward a little).

Interesting, my chair is doing the exact same thing at this moment.

Why aren’t there any tides of moon dust?

I thank you for now - I’m sorry I couldn’t find the document about the speed of gravity. It was late last year or early this year on a printed media. Propably one of those popular science magazines with great graphics. There was something about a space probe and Einstein being right. I didn’t find anything similar on the Net.
Neither Moondust nor moonshine make tidal waves on the Moon. The locked orbit sort of makes the Moon a tidal wave of the Earth - says JeffJo.

The only one I can think of recently (aside from a Jupiter/star transit from a few years back) would be Gravity Probe B. The Jupiter/star experiment had a thread in GQ though I can’t find it now.