Robittybob1

From the paper So 3 solar masses of energy are radiated into space and that mass is reflected in the reduced mass of the merged BH. This is all happening in the last fraction of a second (0.3 sec??). As they get closer the frequency rises "signal sweeps upwards in frequency from 35 to 250 Hz" From the graph in that time that occurs all in 8 cycles. Can anyone tell me where this mass comes from?

Well if anyone can explain "Aberration and the Speed of Gravity" by S. Carlip you are most welcome to give a simple version of it so we can all read the paper with a bit more understanding. Thanks ∗

If the speed of sound in a vacuum is "c" maybe that is what we are talking about but once again I have never heard that said before either. (Can you give me a clue as to where this idea "speed of sound in a vacuum" came from please? )

If you get a way to explain it in words (rather simply) or by analogy please let me know. I was NOT attempting to hijack the other thread but genuinely queried how you knew gravity propagated at the speed of light. Well my understanding of gravity wave might be wrong but I understood it to represent the energy released that ultimately allows the two orbiting bodies to merge. It is doing something completely different to gravity. Gravity would keep the two bodies at exactly the same distance, but the Gravitational Radiation (G-Rad) takes away the orbital energy and the orbit decays. How those two ideas link I can't quite comprehend.

I can only see one fault in what you are saying so far and that is if gravitational waves have energy does the bending of spacetime require energy too? I have heard that if it did the whole Universe would have run down to nothing by now. So gravity and gravitational waves are different things, so the speed of one does not imply the speed of the other. I wanted proof that is all. They might be the same speed and maybe aberration of gravity explains it but I wasn't able to comprehend it. Thanks I'd appreciate that.

That is what was claimed and I had tried to comprehend that years ago too and didn't seem gel with it. Maybe this time I will get it. Does it seem right to you? So would you use the same claims in your own arguments? What is it saying in very simple terms do you know? How would you explain it to a skeptic like myself? Maybe if I understood it the behaviour of the binary pulsar makes sense as well.

It was the idea like discussed in the short video #1, that orbiting objects needed the full strength of the gravitational field to maintain an orbit. The Sun is moving through space around the galaxy, it is always moving, so does the Sun's gravitation need updating continually?Can this be done in time to keep the Earth in orbit? I know the Earth orbits the Sun, I don't doubt that, but just question how the G field seems to update quicker than the time it takes light to come from the Sun. In the video he says they used the information from the binary pulsar to show the speed of gravity was "c". I don't recall that myself. I know it showed that the rate of orbital decay matched the theory on the production of gravitational waves, but I can't remember that being used as the proof of the speed of gravity.

I have never questioned the speed of gravitational waves, for they are energy of some sort, but what about gravity? Mordred said it travels at the speed of light and I asked for proof of that. It was his link that introduced the idea that others had not accepted this as a fact. Now I followed up on the person mentioned "Astronomer Thomas Van Flandern" but I wasn't convinced by him either, but it was from my own attempt to understand the orbits of the binary that made me wonder if it is possible to have gravity bending spacetime at the speed of light. OK it could have been just my calculations were in error but it looked too slow. It has been something bugging me for some years now.

All I want is proof that gravity acts at the speed of light. Until that is done without any doubt why is it wrong to question this?

I never said it would be easy.

I presume that is some sort of joke? The LHC could up the power and produce 2 mini black holes. In fact you don't even need the BHs to go through the slits at the same time, that should make it a little easier and not to mention safer! Pop science covered some of the safety aspects e.g. "The safety of the LHC" http://press.web.cern.ch/backgrounders/safety-lhc PS: I'm not certain if your reasoning is right for isn't it the wave or particle that goes through the slits rather than the BH. The energy released in the merger of massive objects is in the form of gravitational waves rather than BHs. This might help us understand BHs better for where does that energy come from? Did something come out of a BH? Did the mass of the BHs reduce when the E=MC^2 formula is applied?

Those lectures (OP videos) are complete BS.

I would like to get away from that rubber sheet analogy, for it only works if there is a reason for the ball to fall down the slopes. Will we get destructive interference of gravity waves too! Gravity waves through the double slit experiment! Quantum Gravitation theory! exciting stuff .... a lot of hard work for some budding scientist.

Thanks for that Strange.

So is there nothing telling anything any more but just that each point in space has a stress energy momentum tensor (SEMT)? Is that limitation built into the equation? Does it have to be information transferred? Like could each test particle know its own SEMT? Like in the Milky Way galaxy billions of stars all moving around how is that information handled if it is dependent on information exchange? It gets worse than that to for every photon and neutrino also affect the SEMT. I just can't get my head around the complexity.

So were they virtually no distance apart (merged=singularities touched) or was that when their event horizons touched. What is "merged" in physical terms? for when one of the singularities go beyond the other's event horizon I suppose the concept of information going out is stopped. Did the gravitational wave terminate abruptly as that would suggest for the two singularities could take forever to fully merge (doesn't time stop at the EH?)

I could understand most of that except the sentence "Essentially it is the stress tensor that tells space how to curve." That telling bit is that limited to the speed of light too?

I have started another thread exploring what a gravitational wave is http://www.scienceforums.net/topic/93485-what-is-a-gravitational-wave/so you could explain it there is you like. Those 2 BHs must have been orbiting at an extreme frequency. Did that frequency increase as they got closer or not?

Can you measure something that is not material? Well please tell me what you mean by not material?

Gravitational waves have been measured but what are they measuring? Like we have 2 black holes orbiting each other ..... their orbit decays so they unite. That loss of energy required to have this orbital decay is .... Can we say gravity and gravitational waves are the same? Can someone fill in my lack of understanding of this phenomenon and complete those sentences?

Well my wishes may come true yet and someone will explain it fully on another thread. So you are saying that the strength of the gravity wave is the measurement of the strength of gravitational field. (I tend not to get too involved with gravity lately so I'm behind the times as to what the gravitational waves are actually measuring.) I understand that the measurements were measured at different times on the Earth and that confirmed gravitational waves traveled at the speed of light.

The article in the 3rd link ends in this quote I don't know if you have ever tried to prove it yourself but I am skeptical of anyone saying gravity acts at the speed of light. I haven't got all the figures at my fingertips but with that binary pulsar 1913+16 it seemed impossible to understand how they could orbit each other if their gravitational field was established at the speed of light. I spent a lot of time on this and I am none the wiser but it defies the imagination if you say it is propagated at the speed of light. I had presented my workings on another forum but I never got a satisfactory answer from anyone except to be told it needed to be worked out by relativity, something I wasn't able to do. But the bodies are not going anywhere near the speed of light, so why weren't Newtonian physics good enough (even for a good estimation). I would love to be shown it properly. With the Sun in the center of the SS it is easier to see how there maybe the correctly curved spacetime for the Earth to move onto but when there were two centers as in the binary what existed moments before was not good enough for now, so how did that signal come across the vast distance of the space between them in time to keep them gravitationally bound? I never understood it.

has this been proven? If they could see the two black holes combining at the same time as the gravity waves being detected that would be a wonderful proof of that.

this was one of your helpful posts. ...break complex operations into managable portions.... very helpful thanks.

Those first three links did not work. Please if you could give me the title I'll see if I can locate them. That was a good thread! "Can anything fall into the Sun?" I see the P-R drag was discussed there too. http://www.scienceforums.net/topic/88734-can-anything-fall-into-the-sun/page-2#entry865556 This was a good link to the paper on "Planet-disk interaction and orbital evolution" http://arxiv.org/pdf/1203.1184v2.pdf Thanks for the links Mordred.