LIGO's colleagues in Italy, Virgo, should hold an event at the same moment, i.e. 16:30 Central European Time. This should also be webcast – and there are hints that these people will actually be at CERN, not in Italy, and the webcast will actually be aired via webcast.cern.ch, too.
But you should already bookmark this YouTube page on the NSF channel where webcast will start in 29 hours. See also an NSF press release.Incidentally, the arXiv already boasts a theory paper about the first black hole mergers detected by LIGO. ;-) It seems clear to me that they pretend to be ignorant of some numbers that they actually know.
Our latest blog post on LIGO has 12,000 views so far (and 1,000+ Facebook likes LOL) and there are lots of other responses by the media to the tomorrow's event that is gaining the official status these days. An unusually intelligent article written by David Castelvecchi appeared in Nature:
Castelvecchi mentions six (a number he translates as 5 into Arabic numerals LOL; update: DC fixed it) physical phenomena that the gravitational wave detection may clarify:
- Certainty about black holes' existence
- Speed of gravitational waves
- Mountains on neutron stars (maybe)
- Cosmic strings (maybe)
- Events igniting supernova explosions (maybe)
- New measurements of the Universe's accelerated expansion (maybe)
At least since the 1960s or so (when Wheeler coined the catchy term "black holes"), it was rather implausible to suggest that black holes didn't exist – the mastery of the theory as well as the emerging experimental evidence got way too strong more than half a century ago. But you may still find lots of people, e.g. the 2005 TRF guest blogger George Chapline, who like to say that black holes don't actually exist.
Tomorrow, these suggestions will probably become really-really indefensible (so far they were only "really indefensible"). The agreement between the gravitational waves predicted from the black holes' inspiral+merger+ringdown by general relativity, and those observed, will be so precise (despite its dependence on the events in extreme conditions where all the nonlinearities of GR matter intensely) that people suggesting that there is any large mistake in the general relativistic description of these black hole phenomena will probably drop out of the fringes of science.
Lots of questions about black holes – especially about their quantum behavior – will remain murky or open. String theorists' research of quantum properties of black holes will continue pretty much independently of the LIGO discovery. But the black holes' macroscopic behavior may be almost as accessible as the Moon's surface.
A one-minute video: LIGO - What is a Gravitational Wave? from Kai Staats on Vimeo. A 20-minute video is here.
There are many special characteristics of black holes. They're the simplest, most determined and smooth, astrophysical (by size) objects in Nature macroscopically. Because of the no-hair theorem and their general uniqueness, they carry the minimum amount of "personality" macroscopically. On the other hand, they carry the maximum amount of microscopic, quantum information (or entropy) in them – relatively to all objects of the same size. Their density calculated from the mass and the event horizon radius is "maximal" among all the objects; but the local density of matter is "minimal" (basically zero) among all astrophysical bodies. And so on.
Black holes, the 21st century theoretical physicist's favorite laboratories, are queens of the extremes.
This is why the black hole merger, if it is announced tomorrow, will be one of the strongest methods to confirm what we believe about a theory, in this case general relativity. One more confirmation will become possible if and when LIGO/Virgo detects an event that may also be seen optically. If an event will be both "seen" and "heard" (the verb we should use for the detection by gravitational wave astronomy – the similarities between regular sound signals and the LIGO signal is hard to overlook and the 2 LIGO detectors really behave as 2 ears, even when it comes to the way how they estimate the location of the source etc.), we should be able to verify that the speed of the gravitational waves is the same as the speed of light in the vacuum, \(c\). I am confident that it's the case. Even relatively small deviations would be rather shocking from my viewpoint because the Lorentz symmetry would have to be broken (perhaps spontaneously) in some way.
Einstein's memorial in Washington D.C. Will they bring the man to the National Press Club? ;-)
But then there is another, perhaps even more important motivation for the experiments. We also want to learn new things – answers to questions that we're genuinely uncertain about.
Castelvecchi has mentioned four possible discoveries that may be made with the gravitational wave detectors in the future: rugged neutron stars, cosmic strings, events that ignite supernova explosions, and new methods to measure the expansion of the Universe.
The mountains on neutron stars sound both "sufficiently unexciting" for me – as well as probably "too weak signals". Neutrons stars, like black holes, may merge and the emitted waves could be just a little bit weaker than the gravitational waves from the black hole mergers. But these 10-kilometer neutron stars may also have 1-millimeter "mountains" on them and the spinning involving such inhomogeneities is predicted to emit gravitational waves, too. I just feel that those must be extremely weak – unless the neutron star is extremely close, of course. And when it's close and the "waves from the neutron mountains" are strong enough, I have no idea how I would distinguish this signal from many other sources.
Similarly, I have no idea what to do with the "causes of the supernova explosions". If there isn't a good enough candidate for the gravitational waves that would be associated with a given possible phenomenon that ignites the common supernova explosion, I have no idea how one could search for it or extract any useful information. There may be an agreement in the timing between an optically observed supernova explosion, and a gravitational wave burst, but will we be able to reverse-engineer the gravitational wave signal and learn something about the interior of the supernova star?