A is correct. And that’s aside of the „must read before“ request (hint) given, as it’s already a well known - non arguable fact - that our solar system (or any similar for that matter) would be instable after already -300 Mio. years (so we would not exist to discuss).

Emmanouil Markoulakis You are asking about the speed with which the effect of the Sun suddenly disappearing, would radiate outwards, cancelling the gravitational field. I can't see any way at all how we could know the answer to this, and I certainly wouldn't assume it was the speed of light. There is no reason at all to assume it would be the speed of light.

Then you talk about the speed of gravity. Presumably you are referring to this same speed, as in the speed with which changes propagate through a gravitational field.

There is an equivalent question for a sink in a pool of water. The water is flowing out through the sink, and there is a radial velocity field. Then we stop the sink and a pressure wave radiates outwards from the sink, stopping the flow. So there are different speeds involved. There is the flow speed, which will depend on a radial function of the distance from the sink. And there is the speed of the pressure wave that arises when we stop the sink.

But as for the Sun suddenly being stopped, I see no way how we could know the speed of the pressure wave that would radiate outwards afterwards. We have neither theory nor data.

The Earth will be released from the grip of the Sun's gravity after 8 minutes and 20 seconds.

Sky Darmos You are assuming, without any foundation whatsoever, that changes in a gravitational field are transmitted through the field at the speed of light.

Gravity has the speed of light. That is proven by many pieces of evidence. One of them being gravitational waves.

Sky Darmos No experiment has ever been performed that measures the speed of propagation of changes in a gravitational field.

Gravitational waves and the corresponding optical events arrived at the same time, proving that the speed is the same.

Sky Darmos The thing that you are referring to as a gravitational wave would not have been the same thing as a transmission of changes in a gravitational field. What was detected at LIGO was in fact a disturbance in the electromagnetic wave carrying medium. If I recall correctly, the explosion that caused it had angular momentum at the source. So what was observed at LIGO was simply a pulse of EM radiation. It wasn't a gravitational wave at all.

A pulse of EM radiation does not cause length fluctuations in large lasers. Also, we know that gravitational waves are real because of the orbit decay of the Taylor pulsars. Trying to deny all evidence is not helpful.

Sky Darmos Nobody denied the physical verified experimental result of interferometer path length changes in the 10^-18m range - a stunning scientific achievement indeed. But that has nothing to do with speed of gravity.

Some gravitational waves were observed together with optical signals that arrived simultaneously.

Sky Darmos The problem seems to be that you can't properly define what a gravitational wave is, or why it should affect a path length. Nobody is denying the experimental results, but the issue centres on the physical interpretation. There was obviously some kind of disturbance propagated at the speed of light, but that is the speed of EM waves and it has got nothing to do with gravity.

Gravitational waves are very well defined.

Sky Darmos You say that gravitational waves are very well defined. I can tell you that the deeper physical nature of electromagnetic waves is not even well defined.

So, I'd like to hear your description of gravitational waves. Let's start at the source where the explosion occurred. Did this have an effect on the surrounding gravitational field? What kind of an effect?

Sky Darmos Assuming that the two black holes spiralled into each other, causing the observation in 2015, and that three Earth solar masses of energy where emitted from the collision, then whatever propagated outwards from that collision is very probably what LIGO detected. But there is no basis upon which to label it a gravitational wave. Whatever it was, it travelled at the speed of light and it propagated through the EM wave-carrying medium. Meanwhile, you seem to think this was not an electromagnetic pulse because you think EM waves don't affect distance along their path.

What we do know however is, that the so-called 4D space-time continuum is the EM wave-carrying medium, and that there was some kind of distortion in this medium that was picked up at LIGO.

Unfortunately, though, all official attempts to put the "gravitational" label on this pulse, are justified within the strict confines of Einstein's theories of relativity which give no recognition to the existence of an elastic EM wave-carrying medium. Therefore, neither do they allow an interpretation based on a density ripple in the propagation medium that would briefly alter the travel time of the lasers in the interferometers.

The logic of relativity is being used by LIGO tautologically to prove itself.

But there is no explanation for whatever happened at LIGO that could possibly involve gravity. The 4D space-time continuum is the electromagnetic medium. It is not the gravity medium.

Dear Sky Darmos ,

Quote:"Some gravitational waves were observed together with optical signals that arrived simultaneously." - Please read the suggested paper of Van Flandern et al. first. You missed the whole point and argument of this question as asked to you also by @Rupert Sheldrake that the "speed of gravitational waves is not the same as the speed of gravity"!! Actually, gravitational waves are not gravity.

David Tombe: you are surprisingly reluctant to admit the existence of gravitational waves, a quantitative prediction of general relativity which predicts a propagating distorsion of the space-time metric. Vacuum is not

an "EM wave carrying medium", it is vacuum, through which all kinds of particles (photons included) or waves can propagate. Going from particles to waves, is indeed a delicate matter, which is not yet solved for gravitation.

I'm not doubting that LIGO detected some kind of energy pulse which came from the collision. But I have heard no explanation of this pulse that would connect it to gravity.

Also, I am quite satisfied that the so-called 4D space-time is in fact the electromagnetic medium, and that gravity acts on it, but that it is not the medium that is the cause of gravity.

I'm told that this pulse had a transverse oscillation which rotated ninety degrees every cycle. Nobody has explained how this would work in the spherically expanding wavefront.

On the other hand, such a description has got all the hallmarks of an electromagnetic effect, because a magnetic field is tensile along the lines and pressurized at right-angle to the lines. Hence, a pressure pulse through a magnetic field would be accompanied by a tension pulse at right-angles to it.

So, I'm waiting for supporters of gravitational waves to provide a more detailed explanation of the nature of the displacement, how it was generated by two collapsing black holes, and how the energy was transported at the speed of light.

Dear Frederick David Tombe ,

Van Flandern et al. says inside the question linked paper and PFD link that gravitational waves are actually observed as or indistinguishable from very low frequency (i.e. large wavelength) EM radio waves.

Let me remind here that the formation of matter-mass is classically and fundamentally an effect of quantum electrodynamics and Electromagnetism at the macroscale and not because gravity.

Meaning any EM wave passing through a mass will interfere with the EM field of the mass creating a matter wave inside this mass and causing the same exact wobbling effect vibration in this mass to the one caused allegedly by a gravitational wave spacetime wobbling.

The problem is, that many people take gravitational waves as being conceptually synonymous with gravity which could be no more farther from the truth. Actually, the connection of gravitational waves with gravity is even less relevant to the relation of water surface waves on sea with the sea itself.

Kind Regards,

Emmanouil

I urge anyone to thoroughly read the linked paper pdf inside the question above. IMHO, it is one of the most important physics papers written in the last 20 years or more.

Emmanouil Markoulakis I would say that Van Flandern was probably correct in saying that the pulse detected by LIGO in 2015 was a low frequency radio wave.

At the end of the day, the Lorentz transformation from which the 4D-space-time concept arises, is entirely an electromagnetic process. The involvement of gravity is only a superimposition which comes afterwards.

Notice that none of the defenders of gravitational waves here have been able to step forward and describe them, and explain how they are connected to gravity.

Emmanouil Frederick David Tombe MarkoulakisEmmanouil Markoulakis

A completely theoretical question. How do you want to make the sun disappear? The correct answer is C. The result depends on the spell you use ;-)