Gravitational Waves Discovered

[Bomb#20]

So, strain of 10^-7 is what would happen to an earth at that distance. But does earth like material not couple efficiently with the wave? Is spacetime strained a lot more?

Back of the envelope classical mechanics approximations, on a planet 1 AU from the black holes, assume a spherical cow. I make it roughly 10¹³ eV delivered as a gravity wave to each atom in the cow: vastly more energy than needed to not only vaporize the cow but strip every electron from its nucleus. But what that wave actually does to an atom is move each of its electrons on the order of 1/10,000,000 of the way toward or away from the next allowed orbit. This would add to the atom on the order of 10^-13 eV, not even close to enough to ionize the atom. So, to my I-am-not-a-physicist eye, it seems the coupling efficiency can't be more than about 10^-26.

 

[repoman]

So, imagine that LIGO detects a signal that the scientists see as predicted from a core-collapse supernova and that neutrinos are also picked up at places like Super Kamiokande. Putting both of this signals together will be very informative.

Does anyone have a prediction on how the GW and neutrino signals will come in relative to one another according to the current model?

 

[repoman]

So, I saw a video where a scientist (who works on the mirrors) said the merged black hole had 4 solar mass equivalent rotational energy (a Kerr black hole), from I assume not much to begin with.

So is that 4 solar masses of energy part of the final 62 solar masses or accounted for separately? I did a rough newtonian estimate that bringing the black holes from a far distance would convert ~4-5 solar masses of potential energy to kinetic energy.

 

[repoman]

From the new thread on neutrinos I got reminded that seeing a gravitational wave from a core collapse supernova and also neutrinos and finally the light, they could get better bounds on neutrino velocity.

Would Supernova 1987A have been detected by LIGO?

 

[Underseer]

There was a peep about this a few weeks ago, that maybe this happened. I remember reading about this facility back in the late 90s and was so disappointed that we'd have to wait to see what it detected. Nothing!

Then they upgraded it and this is a huge observation, a wildly absurd one, to measure waves so unimaginably small. To put it in simple terms, gravitational waves are really fucking small. Smaller than the IQ of a Trump supporter!

My only question is, what do we gain from this observation. Do we need a bunch more to suss them out? Can we tell the source direction?

To be precise, the intelligence of a Trump supporter has never been empirically verified, only indirectly assumed.

Socialist! Why do you hate America?

 

[fromderinside]

To be precise, the intelligence of a Trump supporter has never been empirically verified, only indirectly assumed.

Socialist! Why do you hate America?

Underseer are you sure you want to use opinion as a basis for empiricism?

 

[repoman]

Was just watching a documentary about looking for evidence of gravitational waves in the B-mode of the CMB form the BICEP-2 experiment. Turned out that our own galactic dust may have been all the signal.

http://arstechnica.com/science/2014/09/gravity-wave-evidence-disappears-into-dust/

So, is another way that inflationary era gravitational waves can be detected? Are they are too faint to be seen directly?

 

[lpetrich]

So, is another way that inflationary era gravitational waves can be detected? Are they are too faint to be seen directly?

There are some planned and recently-started experiments for doing so ( List of cosmic microwave background experiments), but I'd have to hunt them down to learn more about them, like how good their B-mode detection would be.

 

[repoman]

But it looks like B-mode detection will be hard or maybe impossible because of the dust. So will a souped up and/or a space based version of LIGO be able to directly detect the relic gravitational waves? That or some other method besides B-mode.

 

[rjh01]

Was just watching a documentary about looking for evidence of gravitational waves in the B-mode of the CMB form the BICEP-2 experiment. Turned out that our own galactic dust may have been all the signal.

http://arstechnica.com/science/2014/09/gravity-wave-evidence-disappears-into-dust/

So, is another way that inflationary era gravitational waves can be detected? Are they are too faint to be seen directly?

Please note that this article is dated Sep 23, 2014. It has nothing to do with the article in the OP.

 

[repoman]

Was just watching a documentary about looking for evidence of gravitational waves in the B-mode of the CMB form the BICEP-2 experiment. Turned out that our own galactic dust may have been all the signal.

http://arstechnica.com/science/2014/09/gravity-wave-evidence-disappears-into-dust/

So, is another way that inflationary era gravitational waves can be detected? Are they are too faint to be seen directly?

Please note that this article is dated Sep 23, 2014. It has nothing to do with the article in the OP.

Oh yes, I know. This is a totally different thing than finding discrete gravitational waves from black hole collision. I just was keeping on the topic of gravitational waves.

If I read it right, the b-modes are polarizations from the inflationary era where quantum fluctuations of gravity (gravitational waves?) that got blown up similar to the way that fluctuations in the CMB were blown up. The slight (1 in 100,000) differences in the CMB would only make sense if the universe was very much smaller at that point.

But, I guess I don't know if ANY gravitational waves from the inflationary era can be detected now, or what is the farthest back g-waves can be detected. B-modes are supposed to be a proxy for quantum fluctuations in density during that era, right? The types of fluctuations that also would make a g-wave?