Excellent subjective question

Immensely! 

First of course because they verify a prediction of General Relativity.

In the long run even more because they open a completely new window to observe the universe. And that through an effect which only falls off like 1/distance, instead of 1/distance2 like observations of various spectra of electromagnetic waves.

I guess some from this group will have to meet in Stockholm the coming December, or the next. The only worry may be that there for now is no independent observations of gravitational waves, but such will certainly come.

This is a bit like when the W and Z bosons was discovered at CERN in the mid-80's. They had been indirectly discovered before (in a way similar to gravitational waves from the Hulse-Taylor system), but Carlo Rubbia went straight away to Stockholm to collect a diploma.

@ Kåre Olaussen,

Could you please clarify if the amplitude or intensity falls as 1/r in the case of gravitational waves? For all other waves, amplitude is 1/r and intensity is 1/r^2.

The amplitude falls like 1/r, and the way they detect depends on amplitude.

Dear All,

 A few years ago,the BICEP2 experiment (see information below)  detected traces of gravitational waves in the CMB ,  which under certain caution, might confirms Guth's inflationary model.  It is mentioned that other methods of probing gravitational waves of the early universe will have to confirm this discovery.

Is the LIGO gravitational observatory has the capacity to probe that early universe?  What kind of gravitational signature is inflation supposed to have produced and what kind of inflation gravitational signal is supposed to be everywhere in the universe?

http://www.scientificamerican.com/article/gravity-waves-cmb-b-mode-polarization/

BICEP2 uses about 250 thumbnailsize polarization detectors to look for a difference in the CMB light from a small patch of sky coming through its telescope in two perpendicular orientations. The instrument collected data between January 2010 and December 2012 at the Amundsen–Scott South Pole Station, where the cold, dry air offers especially stable viewing conditions.

The Background Imaging of Cosmic Extragalactic Polarization 2 (BICEP2) experiment at the South Pole found a pattern called primordial B-mode polarization in the light left over from just after the big bang, known as the cosmic microwave background (CMB). This pattern, basically a curling in the polarization, or orientation, of the light, can be created only by gravitational waves produced by inflation. “It looks like a swirly pattern on the sky,” says Chao-Lin Kuo, a physicist at Stanford University, who designed the BICEP2 detector. “We’ve found the smoking gun evidence for inflation and we’ve also produced the first image of gravitational waves across the sky.”

Such a groundbreaking finding requires confirmation from other experiments to be truly believed, physicists say.

 The BICEP2 detectors found a surprisingly strong signal of B-mode polarization, giving them enough data to surpass the “5-sigma” statistical significance threshold for a true discovery. In fact, the researchers were so startled to see such a blaring signal in the data that they held off on publishing it for more than a year, looking for all possible alternative explanations for the pattern they found. Finally, when BICEP2’s successor at the same location, the Keck Array, came online and began showing the same result, the scientists felt confident. “That played a major role in convincing us this is something real,” Kuo says.

Dear Ales,

Thank you for the information.

extremely significant. with one nit. The upper range of GW frequencies is about 250 hertz, leaving out a lot of Black Hole physics. Still even with more information needed, it was magnificent work. But incomplete. Going up to at least 1000 Hertz will recover a lot more information about the black holes inquestion

There is a 5.1σ  statistical significance of the event detected by LIGO. By statistical significance we mean the following. We know that photo multiplier detector of LIGO is kept in a position where there is destructive interference (of light waves coming back from two 4 KM arms). There is no light falling on the detector in the absence of Gravitational Waves(GW). When GW sweeps through the interferometer, length of the arms are changed and detector is no longer at the exact position of destructive interference, it sees some light and then records it's intensity.

However even without GW, there is a statistical fluctuation of the lengths of the arms, shading a little light on the detector (however small). These are background events or background noise. If there are N observed events then one σ is √N. Therefore 5σ is 5√N. That is if the number of signal events is 5√N above number of background events, then the signal has a statistical significance of 5σ. Detected intensity is proportional to the number of detected photons.

If now, events of more than 5σ statistical significance are reported from two independent experiments then we call it a discovery. In that sense LIGO results pass through such a strict selection criterion.

General scientific significance is that it is the first scientific observation of a stellar-mass binary black hole system along with it's gravitational merger. This is also the first direct detection of GW.

Kåre> ...they open a completely new window to observe the universe.

... some from this group will have to meet in Stockholm the coming December, or the next.

Today I am quite happy with my predictions from February 2016 (although I forgot that the nomination deadline for the 2016 Nobel prize had already passed). As announced today, with GW170817 aka GRB170817A, the new window is demonstrated to be open, and the new field of multi-messenger astronomy has emerged.

At last and at least we use something else than Em Waves...

Good discussion

Excellent subjective question