The "Intelligent Falling" Theory

[ParadigmShifter]

Well the convincing part of that paper to me is that if gravity propogated at the speed of light then it would be impossible for black holes to exert a gravitational influence.

It is different to the "rubber sheet" analogy of space-time since the rubber sheet made of matter does in fact have a speed of propogation (equal to the speed of sound in rubber I believe), a lot slower than light-speed.

 

[ParadigmShifter]

But if you moved an electromagnet to the same point and turned the magnet on it would propogate at light speed would it not? Since both are forms of electromagnetic radiation?

 

[Fugitive Sisyphus]

Apparently gravity does, and gravity waves is not equivalent to gravity.

The strongest argument is that in order to accurately determine the position and movements of objects in space, you have to take into accounts their real positions in an instant t - not their future positions. In other words, you have to postulate that gravity is instantaneous.

If you try to calculate orbits by applying a delaying effect to gravity (saying it can not go faster than the speed of light) it is impossible to get the correct results.
Also it is impossible to have stable orbits if you postulate that gravity propagates no faster than the speed of light.

From what I have learned gravity works at the same speed light does. I am not an expert on the matter but I do not know why stable orbits would be impossible without instantaneous gravity.

 

[Masquerouge]

From what I have learned gravity works at the same speed light does. I am not an expert on the matter but I do not know why stable orbits would be impossible without instantaneous gravity.

I remember being taught that nothing is faster than the speed of light AND that gravity is instantaneous which used to annoy me to no end (and which is why I remember it)

Anyhow:

Yet, anyone with a computer and orbit computation or numerical integration software can verify the consequences of introducing a delay into gravitational interactions. The effect on computed orbits is usually disastrous because conservation of angular momentum is destroyed. Expressed less technically by Sir Arthur Eddington, this means: “If the Sun attracts Jupiter towards its present position S, and Jupiter attracts the Sun towards its present position J, the two forces are in the same line and balance. But if the Sun attracts Jupiter toward its previous position S’, and Jupiter attracts the Sun towards its previous position J’, when the force of attraction started out to cross the gulf, then the two forces give a couple. This couple will tend to increase the angular momentum of the system, and, acting cumulatively, will soon cause an appreciable change of period, disagreeing with observations if the speed is at all comparable with that of light.” (Eddington, 1920, p. 94)

 

[ParadigmShifter]

Here's another link arguing that the speed of gravity is equal to c...

http://math.ucr.edu/home/baez/physics/Relativity/GR/grav_speed.html

Some things can of course travel faster than light, such as shadows of objects (however, a shadow is not a physical object). I think quantum particles can tunnel at faster than light speeds too.

I am not an expert on any of this btw. I'm a maths person. The original link was the first page googling for "speed of gravity".

 

[Masquerouge]

Here's another link arguing that the speed of gravity is equal to c...

http://math.ucr.edu/home/baez/physics/Relativity/GR/grav_speed.html

Some things can of course travel faster than light, such as shadows of objects (however, a shadow is not a physical object). I think quantum particles can tunnel at faster than light speeds too.

I am not an expert on any of this btw. I'm a maths person. The original link was the first page googling for "speed of gravity".

Darn. Just when I thought I understood your first link

 

[brennan]

But if you moved an electromagnet to the same point and turned the magnet on it would propogate at light speed would it not? Since both are forms of electromagnetic radiation?

Yes, but the field from the first magnet would still be there. So you would see 'instantaneous' action at the electromagnet (which is sitting in an EM field when it is switched on) and delayed action at the magnet (which has to wait for the change in EM field caused by activation of the electromagnet to reach it).

Beware making obvious arguments about black holes, they are complicated phenomena. Recall that Hawking proved that they evaporate through the (impossible) emission of radiation? If you say that at the moment of formation of an event horizon the space around a BH becomes unaware of the presence of said BH, recall that time is standing still at the BH itself due to infinite time dilation. Thus the BH has already effectively shot off to the end of time anyway. Damn these things are confusing.

 

[ParadigmShifter]

I thought Hawking Radiation was caused by particles/atoms at the cusp of the event horizon being split apart by the gravity differential?

 

[Masquerouge]

I thought Hawking Radiation was caused by particles/atoms at the cusp of the event horizon being split apart by the gravity differential?

IIRC it was caused by a particle and an antiparticle spontaneously appearing out of the vacuum right at the even horizon and one falling under the event horizon and the other not.

 

[brennan]

Correct, but the net effect is that energy within the event horizon leaks out.

 

[The Yankee]

Before this gets too far, I feel I need to again remind people that "Creationist" does not automatically mean belief in a 6,000 year old Earth. Those are "Young Earth Creationists."

Let's not ball up everyone together now, okay?

But it's more fun that way!

 

[Fugitive Sisyphus]

I remember being taught that nothing is faster than the speed of light AND that gravity is instantaneous which used to annoy me to no end (and which is why I remember it)

Anyhow:

I read some more on the subject. It seems that there is no consensus on the actual speed of gravity. I suggest we blow up the sun to check if the world gets dark first or if we get flung out into space first.

 

[Masquerouge]

I read some more on the subject. It seems that there is no consensus on the actual speed of gravity. I suggest we blow up the sun to check if the world gets dark first or if we get flung out into space first.

the only way to do science!

 

[BasketCase]

Proof that Intelligence is not responsible for gravity:

If things fall because God is pushing them downwards, every now and then God would screw up. And so every once in a while objects would go flying off in random directions for no apparent reason.

This does not happen. The only infallible forces in the Universe are those NOT powered by Intelligence: those forces that act as a result of physical laws and mathematical equations. Two plus two always equals four.

 

[Chandrasekhar]

Proof that Intelligence is not responsible for gravity:

If things fall because God is pushing them downwards, every now and then God would screw up. And so every once in a while objects would go flying off in random directions for no apparent reason.

This does not happen. The only infallible forces in the Universe are those NOT powered by Intelligence: those forces that act as a result of physical laws and mathematical equations. Two plus two always equals four.

I take it you're not familiar with the theory of "Intelligent Mathematics"?

 

[Elrohir]

Proof that Intelligence is not responsible for gravity:

If things fall because God is pushing them downwards, every now and then God would screw up. And so every once in a while objects would go flying off in random directions for no apparent reason.

This does not happen. The only infallible forces in the Universe are those NOT powered by Intelligence: those forces that act as a result of physical laws and mathematical equations. Two plus two always equals four.

Ah - but what if He's PULLING them downwards? What then?!


What?

 

[History_Buff]

*Quotes the above source at you*:

That quote is desribing GR's explanation of how gravity must act, and is not a stipulation of the article itself.

That link is a bit misleading actually, having skimmed through it. It tries to suggest that gravity acts instantaneously, rather than with a LS delay, but I rather think the same results would be expected if you represented a gravitational field as space-time geometry without resorting to instantaneous effects. Guess what relativity does?

Actually it doesn't suggest gravity is instantaneous, it suggest that gravity propagates 200 Million times faster than the speed of light.

 

[frob2900]

According to General Relativity, gravity travels at the speed of light, in the sense that if one objects shifts position, the change in the gravitational field will propagate outward at the speed of light.

It is impossible to transmit information faster than the speed of light by using gravity.

@Masquerouge:
You were probably taught that gravity is instant because you studied gravity in a Newtonian physics course. Then when you took a special relativity/electromagnetism course they told you that the speed of light is the fastest speed possible.

Many teachers are like that. They can compartmentalize the universe into small courses in which it works completely different from every other course

 

[Erik Mesoy]

I will now undercut the "theory" of gravitation by showing that the gravitationists have a contradiction that they cannot resolve! Bwahahaha!

Not only are they contradicting one another, but both positions are wrong.

If gravity moves slower than instantaneous, we get "couple" effects where things go out of orbit. But we're still in orbit.

But if gravity moves faster than light, we can use it to transmit information by putting up a gravity detector and moving some heavy lead balls around. Which would lead to sending information back in time, which doesn't work either, because of paradice. (Plural of paradox. )

Hence, since there's no speed gravity can move at, an intelligent pusher must be responsible! Hallelujah!

*falls over laughing*

 

[frob2900]

If gravity moves slower than instantaneous, we get "couple" effects where things go out of orbit. But we're still in orbit.

...

Hence, since there's no speed gravity can move at, an intelligent pusher must be responsible! Hallelujah!

You must be kidding?

You proved nothing. The reduction of General Relativity to Newtonian mechanics in the regime of planetary orbits is well understood and the calculations have been done to many decimal places.

With computers you can even run the simulations at home.

If you want references I can post links to several good GR books on amazon.