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Third Gravitational Wave Detected From Black-Hole Merger 3 Billion Light Years Away (bbc.com)
sycodon quotes a report from The New York Times (Warning: may be paywalled; alternate source): Astronomers said Thursday that they had felt space-time vibrations known as gravitational waves from the merger of a pair of mammoth black holes resulting in a pit of infinitely deep darkness weighing as much as 49 suns, some 3 billion light-years from here. This is the third black-hole smashup that astronomers have detected since they started keeping watch on the cosmos back in September 2015, with LIGO, the Laser Interferometer Gravitational-Wave Observatory. All of them are more massive than the black holes that astronomers had previously identified as the remnants of dead stars. The latest detection was made at 10:11 GMT on January 4, and is described in a paper accepted for publication in the journal Physical Review Letters. "The analysis suggests the two black holes that coalesced had starting masses that were just over 31 times and 19 times that of our Sun," reports BBC. "And when they finally came together, they produced a single object of a little under 49 solar masses. It means the unison radiated a simply colossal quantity of pure energy."
"I felt a minuscule disturbance in the gravitational force. I fear something terrible has happened."
What they "detected" was random noise. Nothing to see here.
They have two detectors now, one in Washington and the other in Louisiana. If they both trigger at nearly the same time, it's not random noise. This summer they'll add a third station in Pisa, Italy, which should not only help to collaborate the results, but also allow to triangulate the source.
The difference in distance to the event that caused the waves on different places on Earth is indeed much smaller than the measurement uncertainty of the distance, but the detectors are receiving the same waves with different delays, so the relative distance can be measured very precisely. In addition, the detectors are not equally sensitive to signals from all directions, so the relative amplitudes measured by different detectors provides some information too.
The waves travel at light speed. The earth is sufficiently big to give noticeable delta in detection times, which allows you to find the place in the sky where the source of the waves is, no matter how far the object.
A collision briefing putting out more power than the rest of the observable universe, wiping out who knows how many intelligent civilisations in an instant. Kind of puts the Trump thing in perspective, I suppose.
What makes you think the experiment depends on the gravitational constant being stable? What makes you think the folk at LIGO are waiting for you to explain the correlation/causation fallacy to them? What makes you think that gravitational waves are somehow linked to "electrical activity"? What makes you think that scientific projects with no immediate utility can survive without grants? What makes you think the entire purpose of science is to avoid doubt?
I have a lot of questions.
"pure energy" = anything other than the energy due to the rest mass of a particle. So kinetic energy, gravitational field energy, and electromagnetic field energy (including photons) are "pure energy". An electron is not a form of "pure energy". A proton isn't pure energy either (although strictly speaking, most of the mass of a proton is due to the energy in its gluon field, which really is pure energy by the definition I gave. But just ignore that.)
In the end, pure energy is just to distinguish between matter and everything else. There is no deep meaning behind it. Consider an atomic bomb explosion. The light, heat, and sound produced is pure energy. The fallout is not pure energy.
Simple - it turned into energy, via E=mc^2, in the form of gravitational waves. Yes, that's a colossal amount of energy, and it's the reason why we were actually able to detect it from here.
The missing mass was radiated away as waves in the gravitational field of the black holes. Think of it this way: when a black hole is static (relative to the total mean gravitational field of the rest of the observable universe) nothing much happens. If, somehow, a black hole were to start vibrating back and forth, it would be tugging at EVERYTHING, and moving EVERYTHING, back and forth. So the movement of the black hole is radiated out into movement of the universe, through dilations in space-time.
Now, every mass that moves does the same thing, but most masses are small enough that they don't much affect anything beyond a small distance. Black holes are big enough that they do have a measurable effect, even at enormous distances.
Think of the energy that gets released by an earthquake: it gets turned into shaking of big, massive things. That energy eventually turns into heat, but during the release: low-frequency shaking of things with great mass, mostly through semi-rigid coupling (which, ultimately, mostly means through electric fields). The same is happening with two black holes as they merge: they shed energy in the form of shaking everything else as they spiral inward.
At least that's as much as my non-physics-PhD head has been able to understand. I hope that someone who actually knows will be able to correct it.
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
Not sure, but you will find it on the Organic Aisle and it will cost twice as much as regular energy.
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
The distance can be derived from the combination of the amplitude and the degree of redshift of the signal. The direction can be extracted (to some extent) from the delay between the arrival times at the two detectors. When the third detector in Italy is added, they will be able to to pinpoint it to a spot on the sky.
M&A fees charged by Goldman Sachs.
Have gnu, will travel.
Ha! I am in no way as rabidly anti-Trump as some of the people around here, but even I have to ask "Which Trump thing?"
The likelihood of random noise creating a chirp consistent with a BH merger is very close to nil. The fact that two separate stations recorded the same chirp at the same time make this explanation very unlikely indeed.