Thoughts On GW150914

Mike Hewson
Mike Hewson
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RE: Do they? This is

Do they? This is counter-intuitive.

Yes they do and it is ! :-)

A contra-rotating pair has delayed merger compared with a co-rotating pair. Define here the first moment of merger as that observed distantly by the touching of the horizons.

It seems this is generically true for vortices in all manner of circumstances. I think I understand the reasoning in those other cases ( eg. airflow turbulence from wings ) but I am struggling to give a clean and simple explanation here. This is why I prefaced this series of posts with :

I would like to subsequently explain these things in a basic manner ! Let us see how I fare ..... :-)

I may of course fail.

Currently I am worried about whether it is valid at all to relate ( the same line of logic of ) vortex merging to black hole mergers. In some of those other scenarios it is a conclusion reached a posteriori ie. after some modelling, numerical simulation or measurements, and not with some natural or intuitive expectation. What is common is that all the systems are highly non-linear and thus the difficulty in teasing these conclusions out. Certainly in the volume b/w the merging black holes we are well out of linear approximations to the GR equations, and thus my earlier reasoning/analysis may not be relevant at all .... :-)

Cheers, Mike.

( edit ) FWIW : I am transported back to childhood watching my Mum use a 'double beater combo' to whip cream. This was hand cranked and constructed so that the paddles would contra-rotate. Being an inquisitive lad, then after licking them clean of cream I would clean the beaters in water in the sink and watch what happened. If you stirred really fast you could generate a rooster tail ! :-)

( edit ) This is almost exactly the device I refer to :

... you could of course reverse the direction that you wind the crank but either way the paddles would go around in opposite senses.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

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RE: ... seem to avoid


... seem to avoid each other in between ?

When you say avoid, you mean they lack of circular shape at their close point ?

My thinking, and it intuitive so all bets off, about why they are not round went like this.

The more massive the black hole the larger the apparent "hole", and the more it can bend light.

The black hole is located at the centre and the blackness is because there in no feasible path light can take (from behind) without falling into the black hole.

In reverse, i fired a laser beam back at the black area, it would fall into the black hole.

However a even bigger meaner black hole comes by to save the beam, and drags it away, and the beam is saved. Between the BHs a safe pleasant oasis exists (until inter-galactic oblivion in a few seconds time) and light is not bent so much around that area. So one side bends more than the other so it is not round any more.

I don't know if that means the event horizons are still spherical, or what we see is distorted.

I have not seen a good example of what a (pair of) black hole would do to say a big chess board behind them, with each tile the same colour say green and a a clock on each tile.

Do the tiles go redder, can we see all the tiles, are the tiles the right way up, are some clocks behind?

Edit: i have seen a diagram of a neutron star, and because of gravity you can see the north and south pole simultaneously.

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Mike, Very good reading


Very good reading thanks, and all the better for the good detail and thoughtful consequences...

One tangential thought:

Could there be the effects found in the light data recorded by Keplar or in the s@h radio data showing the distortions of binary systems where there is black hole occultation?

(Given time and distortion effects, might we 'see' recursive occlusions[+] where a binary black hole system 'sees' itself coming? :-P [*])

A re-read is needed... Later :-)

Keep searchin',

For those in the UK: "Recursive Occlusions" was the name of a Doctor Who episode set on Castrovalva :-)

OK... So, implausible from our vantage point and even if so, the number of photons to be seen would be too few to be recognized but...

Detailed sky surveys can note the Einstein ring distortion. For another search, could we use the general background noise of the CMB or hydrogen emissions or cosmic noise to note 'holes' or 'eddies' in the view? ...

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