Robittybob1

That is a bit different to the situation you were talking about in http://www.scienceforums.net/topic/94222-what-difference-does-it-make-if-the-schwarzschild-radii-touch/page-6#entry914745 where there was a merger and a change in the mass.

But there is a mass beyond the EH. But I'm not sure that BH mass has gravity for that would be information coming through the EH. But wasn't that the whole point of BHs they had mass and gravity. Can we say there is mass beyond the EH? It is not important whether it is at a singularity.

What! I thought the EH was calculated from the mass via the Schwarzschild radius formula. How is one going to see the radius of the event horizon otherwise. Have I missed something? What were the steps? [As an aside: with all the discussion on the BH we've been having I can read the papers put out by LIGO Team and just about know what they mean now. Thanks for the help Mordred and Strange and others of course, but you two in particular.]

Let me get this straight - the mass of a BH is beyond the event horizon isn't it? Its back to school for me if it isn't.

The ringdown wave pattern could be analysed. Important clues are there for those that know what to look for http://www.scienceforums.net/topic/94060-what-is-the-best-3d-description-of-gravitational-waves/?p=913986).

That was what I was thinking, but I'm sure Mordred wouldn't agree. I don't know enough to assist in this discussion, but it seems an interesting topic.

I didn't know that. There are plenty of drawings of accretion disks and polar jets but not much discussion. With the mass of the accretion disk close to a BH would that mass affect the shape of the event horizon? The accretion disc drawings seem enormous compared to the size of the BH. It seems surprising when we talk of the EHs touching when the accretion disks could be very significant too. I'll have to check the LIGO paper on GW150914 to see what they say about the accretion disks.

Those accretion jets - you asked a question about them. Do they just involve surface effects?

This still seems to be a very good question if the words "Schwarzschild radius" is exchanged for the "event horizon" If the mass of a BH is at the singularity what difference does it make if the event horizons touch when they merge? The word "touch" needs to be more scientific too maybe we should say "overlap" If the mass of a black hole is at the singularity what difference does it make if the event horizons overlap when black holes merge? Did we find the answer? Wouldn't the inertia of that mass have some bearing on this happening? Like two orbiting objects don't just fall toward each other. You have to lose momentum to allow that to happen. It was a good point though. +1 That is the big question that I see a lot of people are asking. How can we prove this?

Have you tried hanging it upside down? Is the current set up with the mass below the spring?

Mordred are you talking to me when you say "I have no idea why you would have difficulty in understanding that the tensors involve scalar and vector field strength at each coordinate."? Who is that "you"? Personally I do have difficulty. Let's put some numbers on these symbols.

Surely it must. If you can see a 3D structure you use that to deduce something about the source of that structure. The wave comes from the binary and has 2 wavefronts per orbit. We all know this from multiple discussions. I am sorry if you thought I "was asking how a sine wave gives you successive wave fronts". That to me has never been an issue. It is the question "Does anyone have an idea of the description of a 3D gravitational wave at a distance from the binary?" that is the purpose of the thread. there are the 1D views and the 2D descriptions but we wanted the 3D picture. Could you say what post number that was please?

They go hand in hand. If you can describe the 3D nature you will understand how the GWs are generated.

"Successive wave fronts" they are what you feel at a distance from the source. In my case whether I use the spinning garden sprinkler or two masses rotated in a water tank I get successive wavefronts at a distance. So I haven't changed the topic.

That is a thought experiment of a wave tank. Two spherical masses linked and rotated. All of the GW animations show a similar pattern so why would you need it again? You need frequency for spheres as well. So how does your picture of spherical waves use that frequency to produce two waves per rotation? Now this is true: So neither of us can use those equations to describe the nature of the source. Which is what I have been saying all along (last 2-3 pages at least). That is the purpose of the thread - to understand the generator of these waves. We must be using the same generator - a BBH? Should we limit our discussion down to just a 10,000 km radius?

they describe its abilities: They give a low rate but describe it as a volume. Is that per minute or hour? A rate would need a time factor surely.

Is it possible to put values on the GR terms so we can check those statements?

The height (amplitude) of the wave depends on distance, time and "the angle of the observer". Let's define angle of observer. I take the to be the angle of the orbital plane to the observer, and that angle isn't going to change whether the wave generator is a point source or a line between two bodies. A point source will give off waves that if looked at from a 2D perspective are circles (and I think if and if only if the point source pulsates. A line between the two massive bodies rotated will produce 2 waves per rotation and the waves will be a spiral. The equations give the amplitude of the wave at distant point in space "R" from the source. It is sinusoidal in nature because of the succession of wave crests coming from the generator. How do you get the barycenter (your point source) to produce a succession of waves. The small r term only makes sense if the are two bodies in binary orbit. #59 for r is derived from the omega equation. If it was a point source what difference would the r term make? Obviously the omega has a bearing on the frequency of the wave fronts, but how do you get successive wavefronts from a point source?

Was it? I can't recall that. Time to recap the thread if I'm starting to forget.

We might have to look at that in another thread. It doesn't seem right for there would have to be some mechanism to replenish the energy on the outside if that was the case.

Look at post 89 as well please.

There was another section of the results in http://arxiv.org/pdf/1506.00560.pdf Page 4/9 I took that to mean that the inside of a BH "is not as predicted by GR" in other words it is not a singularity. Could it be something new? Particles above the EH moving with extreme velocity around a spinning BH and the EH changes shape. What happens to the particles? There is a Caltech/Cornell simulation YT "Merging black holes, falling spacetime, and gravitational waves" starts at 58 secs. .

OK but once you have particles you are not going to get them to move at the speed of light, so you get a separation of the geometry with the radiation and fields able to move at the speed of light but not the particles, They will move but not as far and as fast. If the EH had a wave in it, will the particles move in and out of the EH? Like a ship in a wave. The boat will remain practically in the same place but the wave will pass along the ship. The wave could even go over the sides of the ship (resistance to inertia).

Would you use the pebble analogy to describe the production of GWs? I have always likened it to the waves of water from a two head rotating garden sprinkler. But that too was only a 2D description and I was trying to develop the 3D description.

That would depend on the wave generator. If you threw a pebble into the water you would get rings from one point but it soon fades away. There so many situations really. I have never denied that at one point in space e.g. at the LIGO that you wouldn't get a "sinusoidal oscillation. Pulsing." You would get the same pulsing from spherical and spiral 3D structure but those that go for the spherical have to have a pulsating source. In other words you would have to say the source of the GWs is pulsing, and I haven't seen it described that way. Would you say the source is pulsating?