Quote from: ChrisWilson68 on 02/18/2016 10:48 am...New experimental results that are a surprise are much more useful to get us to understand things we didn't understand before. The LIGO results aren't a surprise. They're the opposite. We turned over another rock and found exactly what we expected. We'll keep turning over rocks, looking for surprises, and the LIGO hardware might yet help us find surprises under different rocks, but so far, no surprises, and no help toward new physics.There are four natural forces in the Universe. Electromagnetic, Strong Nuclear, Weak Nuclear, and Gravitational. Humans currently have a fairly decent mastery of the Electromagnetic force, some mastery of the strong and weak nuclear forces, though incomplete (commonplace power generating fusion reactors are still in development), and absolutely no control and limited knowledge of Gravitational. Throughout our history we were not able to harness any of these without first gaining a more or less complete understanding of what they actually were, and how they worked in nature. To any extent, even limited use such as a nuclear weapon. My point here was that the only shred of hope mankind will ever have of trying to master Gravity is to gain a total and full understanding of how it works in nature, and working backwards from there. That historically, is how we have gotten this far, up until now. This doesn't mean it is ultimately, or will ultimately be possible to actually gain any control over gravity under the processes by which this Universe operates, all it means is that you 100% can't without first understanding the natural force in its normal domain. THAT to me is why experiments and programs like this one, and this discovery, are so important. The more we know about the natural state the better equipped we become, if there is ever a chance of manipulating it.
...New experimental results that are a surprise are much more useful to get us to understand things we didn't understand before. The LIGO results aren't a surprise. They're the opposite. We turned over another rock and found exactly what we expected. We'll keep turning over rocks, looking for surprises, and the LIGO hardware might yet help us find surprises under different rocks, but so far, no surprises, and no help toward new physics.
Finally, let me mention N=8 supergravity. This theory was invented by Eugene Cremmer and Bernard Julia in the late 1970s, with other important contributions from Bernard deWit and Hermann Nicolai, Joel Scherk and others. When superstring theory had its 1984 revolution, N=8 supergravity was quickly pronounced dead — because string theory was manifestly free of all ultraviolet divergences, and how could any point-particle theory dare to make that claim? However, it never received a proper burial. At that time, it was generally thought that N=8 supergravity would diverge at three loops, but no-one could do a full calculation past one loop. With the unitarity method, we could get to two loops in 1998 (with Zvi, Dave Dunbar, Maxim Perelstein and Joel Rozowsky), to three loops in 2007 (with Zvi, David, John Joseph Carrasco, Henrik Johansson and Radu Roiban), and to four loops in 2009. We still have found no direct sign of a divergence in N=8 supergravity, although the conventional wisdom has retreated from a first divergence at three loops to a first one at seven or eight loops. Zvi, John Joseph, Henrik and Radu are pushing ahead to five loops, which will also give important indications about seven loops. A first divergence at even the seven loop order would be the smallest infinity known to man…
in the work of Zvi, Dixon and friends for which they won the Sakurai prize N=8 supergravity does not lead to ultraviolet divergences so far as has been calculated which may be as many as five loops so far. http://www.preposterousuniverse.com/blog/2013/10/03/guest-post-lance-dixon-on-calculating-amplitudes/QuoteFinally, let me mention N=8 supergravity. This theory was invented by Eugene Cremmer and Bernard Julia in the late 1970s, with other important contributions from Bernard deWit and Hermann Nicolai, Joel Scherk and others. When superstring theory had its 1984 revolution, N=8 supergravity was quickly pronounced dead — because string theory was manifestly free of all ultraviolet divergences, and how could any point-particle theory dare to make that claim? However, it never received a proper burial. At that time, it was generally thought that N=8 supergravity would diverge at three loops, but no-one could do a full calculation past one loop. With the unitarity method, we could get to two loops in 1998 (with Zvi, Dave Dunbar, Maxim Perelstein and Joel Rozowsky), to three loops in 2007 (with Zvi, David, John Joseph Carrasco, Henrik Johansson and Radu Roiban), and to four loops in 2009. We still have found no direct sign of a divergence in N=8 supergravity, although the conventional wisdom has retreated from a first divergence at three loops to a first one at seven or eight loops. Zvi, John Joseph, Henrik and Radu are pushing ahead to five loops, which will also give important indications about seven loops. A first divergence at even the seven loop order would be the smallest infinity known to man…
There isn't a lack of theories that could fully describe quantum gravity either, string theory is a very natural and beautiful self-consistent candidate.The actual issue is not really that we lack theoretical understanding, but rather that our current approximative description of the universe is so ridiculously accurate that we're struggling to build experiments that can actually falsify it and give us pointers on which possible candidate theory is the most accurate extension.
Right, I was considering a mention of SUSY and how it makes everything so much simpler, but left it at a brief mention of string theory, which provably has no UV divergences and requires SUSY for fermions. SUSY is a very natural geometric idea which can in a way be viewed as just a stronger form of conservation of momentum (since the simplest form essentially boils down to introducing a pair of spinor charges whose anticommutator is the momentum, and positing that both charges are conserved, not just their anticommutator).Sadly we don't yet have experimental evidence for SUSY, and it is not at all obvious that we will obtain it within our lifetimes. However its simplicity and the fact that it makes so many things simpler means that it is imho overwhelmingly likely that we will find it at some point.
PRIZE IN FUNDAMENTAL PHYSICS AWARDED FOR DETECTION OF GRAVITATIONAL WAVES 100 YEARS AFTER ALBERT EINSTEIN PREDICTED THEIR EXISTENCESelection Committee of previous Breakthrough Prize winners recognizes contributors to experiment recording waves from two black holes colliding over a billion light years away$3 million prize shared between LIGO founders Ronald W. P. Drever, Kip S. Thorne and Rainer Weiss and 1012 contributors to the discoveryhttps://breakthroughprize.org/News/32
I don't think it works out to much each.
The Special Breakthrough Prize can be conferred at any time in recognition of an extraordinary scientific achievement. The $3 million award will be shared between two groups of laureates: the three founders of the Laser Interferometer Gravitational-Wave Observatory (LIGO), who will each equally share $1 million; and 1012 contributors to the experiment, who will each equally share $2 million.
This simple cosmic song may not be the only music these gravitational-wave emitters are capable of producing. At the American Physical Society April Meeting, held April 16 to 19 in Salt Lake City, Niels Warburton, a postdoctoral fellow at the MIT Kavli Institute, discussed simulations showing what kind of gravitational-wave "song" should be produced by collisions involving black holes that spin faster and are significantly larger than those that have been detected by LIGO.
The two black holes that LIGO observed merged together and produced a "chirp" — that is, the frequency of the signal rose steadily, then was cut off abruptly when the two objects combined. But Warburton and his colleagues showed that fast-spinning black holes create a signal that reaches a peak frequency, and then starts to lower in frequency, before fading out."Instead of chirping, you get this kind of singing sound from the black hole," Warburton said. "It'll rise, it won't get cut off, it'll sing, and then it's quiet at the end.""[It's] a completely different gravitational-wave signature … than what was detected [by LIGO]," he said. If a gravitational-wave detector picked up a signal that looked like the one the researchers' model describes, "you would know you were looking at a gargantuan system, something that is rotating extremely close to the maximum," he said.This runs contrary to what scientists expected from a merger involving a very fast-spinning black hole, according to Jolyon Bloomfield, a lecturer at MIT, who presented research at the same press conference."It was certainly very unexpected to see something that didn't chirp," Bloomfield said, when asked during the press conference what he thought of the results. "Every template that we've seen so far … has had this beautiful, chirping feature, and we just assumed that [if we] make [the spin of the black hole] bigger … it chirps bigger. But this is quite interesting work that says no, the chirp actually goes away. Something else is happening here."
“Our signal is consistent with both the formation of a black hole and a horizonless object – we just can’t tell,” says B. S. Sathyaprakash of Cardiff University, UK, who is part of the LIGO team. But if we can detect larger black holes merging, or a pair that is closer to us, it should settle the matter, he says. “That’s when we can conclusively say if the late-time signal is consistent with the merged object being a black hole or some other exotic object.”Ultimately, the black hole explanation is likely to win out, but it is worth double-checking, says Pani. “As scientists, we try to play the devil’s advocate and not believe in paradigms without observational evidence.”
June 23, 2016Russian physicists create a high-precision 'quantum ruler'Physicists from the Russian Quantum Center (RQC), MIPT, the Lebedev Physical Institute, and L'Institut d'Optique (Palaiseau, France) have devised a method for creating a special quantum entangled state. This state enables producing a high-precision ruler capable of measuring large distances to an accuracy of billionths of a metre. The results of the study have been published in Nature Communications.
Now that gravitational waves have been detected, theoreticians have been furiously speculating about what we might learn from our gravitational wave observatories. Now that we have a couple of observed black hole collisions under our belt, it is time to consider what we might study. There's some speculation that, depending on the sort of physics at play, the event horizon of a black hole might be studied through gravitational waves.For this to work, the gravitational wave signal has to change depending on what type of black holes are merging. A recent paper in Physical Review Letters indicates that, unfortunately, reality will probably not cooperate.
http://www.centauri-dreams.org/?p=25605The "Dyson Slingshot"Two neutron stars, each with a diameter of 20 kilometers and a mass of one solar mass — and a combined orbital period of 0.005 seconds — would provide a departure velocity of 0.27 c
Criticism for NASA.Rainer Weiss laments NASA’s decision to pull of the space-based gravitational wave observatory LISA, and praises Europe’s determination to ‘go it alone’ with the eLISA mission and LISA Pathfinder. But he hopes for a new collaboration.@DrStuClark Gravitational Waves sound like Radiohead's Planet Telex intro, from album The Bends. #spookyhttps://mobile.twitter.com/ClickConsultLtd/status/697819704732291072?ref_src=twsrc%5Etfwfinal question of the webcast press conference is whether LIGO has seen other signals. Gonzalez answers very carefully placing the emphasis back on the signal announced today. As she finishes one of her fellow panellists quips ‘that didn’t even sound rehearsed’.Hmmm. What should we make of that?
In addition, both parties introduced the respective gravitational wave detection plans and agreed that there is a cooperation possibility in this area.