The Search for Gravitational Waves
Regardless of what will or will not be announced on Thursday, I thought it would be worth sharing this nice colloquium talk by Dr Alan Weinstein of Caltech about the search for gravitational waves, featuring the Laser Interferometric Gravitational-wave Observatory (LIGO). I’ve picked this not only because it’s a nice and comprehensive overview, but also that Professor Weinstein doesn’t call them gravity waves!
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In the Dark 
February 8, 2016 at 3:13 pm
I’m currently reading “Gravity’s Ghost and Big Dog” by Henry Collins, about the GW experimental process. I don’t know if you came across Collins during your time at Cardiff. I would be interested to hear what you thought if you had. He seems to have written quite a bit about the GW community.
http://www.amazon.co.uk/Gravitys-Ghost-Big-Dog-Twenty-First/dp/022605229X
February 8, 2016 at 3:15 pm
That should have been Harry Collins.
February 8, 2016 at 3:18 pm
Yes, I have met him. He’s a sociologist.
February 9, 2016 at 3:20 am
It was called the Big Dog in part because the initial sky localization of that faked signal back in 2010 put it in Canis Major.
February 9, 2016 at 3:26 am
Alan is also a pretty awesome person, beyond being a fantastic scientist.
February 9, 2016 at 2:15 pm
And an engaging lecturer too. I just finished watching the video, and now looking for more.
February 9, 2016 at 11:51 am
Thanks.
Someone on Twitter had recommended this tutorial from your old haunt.
http://www.astro.cardiff.ac.uk/research/gravity/tutorial/?page=4blackholecollisions
February 9, 2016 at 2:23 pm
49 hours to go…
February 9, 2016 at 4:28 pm
Surprising the rumors are so specific considering how closed the analysis is supposed to be.
February 10, 2016 at 11:15 am
If you are on the team and you want the news out then you leak it to friends rather than tweet it yourself. Whether you should is an amusing discussion.
February 10, 2016 at 11:16 am
If you are on the team then you leak it to friends, of course; although whether you should is another matter.
February 10, 2016 at 1:01 pm
Hehe… I was (am) considering this possibility as well. 😀 Sort of like a false signal injected to test the team’s ability to hold a secret.
February 10, 2016 at 10:32 pm
Is LIGO shielded from photons having the same frequencies as the gravitational waves to be measured?
February 11, 2016 at 9:52 am
The graviton is spin-2 and can only be detected via quadrupole effects. LIGO is set to compensate for lower n-pole effects due to spin-1 particles.
February 14, 2016 at 4:50 am
I have read a lot about Ligo but I never read about how this compensation works. The thing is, in my theory, particles falling into a black holes (which is a five dimensional ring) will spiral around one side of the ring before merging with it. This should produce gravitational waves. The 2 dipoles from the black hole are suppressed because its oscillations are too small relative to us. But the momentum must be conserved, being reciprocal for the black hole and the particle, it’s total is near zero so we are left with two beams of photons in opposite direction and perpendicular to the spin for very specific reasons I won’t elaborate here, related to the fifth dimension. This is what is observed. My most constrained model limit the black hole spin between 0.5 and 1/squareroot(2) (about 0.707).
February 14, 2016 at 10:00 am
corrections:
‘The dipole from the black hole is suppressed’ not ‘the 2 dipoles’
‘ two beams of photons in opposite direction and perpendicular to the rotation’ not the spin
My most constrained model limit the black hole spin between 0.5 and 0.707 in any case.
My model is based on a deterministic Quantum theory, so the ring is real and the gravity is suppressed in the middle plane so photons can only be ejected from the inside at a perpendicular direction because gravity is not suppressed in the outside plane.
The linear mass is the Planck mass divided by 2pi, a constant!
Thus, a gas would produce a sharp beam while a star falling into the black hole would produce a more diffuse beam due to perturbations.
http://www.nasa.gov/topics/universe/features/black-hole-symmetry.html
February 10, 2016 at 10:45 pm
If no, then I won’t be surprised to learn of a positive detection.
Wavelength is approx.. 3 millions km: very difficult to shield!
February 10, 2016 at 10:52 pm
30 000 km not 3 million km.
February 10, 2016 at 11:28 pm
Again, I’ve made a mistake… it is 3000 km…
Only the earth could potentially shield it.
It is impossible at this point to differentiate GW from photons…
Seriously, gravitational waves are very difficult to merge with QM. That’s why we need the graviton. Photons are the way to go unless proved wrong.