Observation of Gravitational Waves from a Binary Black Hole Merger

[gary]

Observation of Gravitational Waves from a Binary Black Hole Merger
B. P. Abbott et al. (LIGO Scientific Collaboration and Virgo Collaboration)
Phys. Rev. Lett. 116, 061102 – Published 11 February 2016

Originally Posted by B. P. Abbott et al., LIGO Scientific Collaboration and Virgo Collaboration

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave
Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in
frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0 × 10−21. It matches the waveform
predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the
resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a
false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater
than 5.1σ.

Originally Posted by B. P. Abbott et al., LIGO Scientific Collaboration and Virgo Collaboration

These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct
detection of gravitational waves and the first observation of a binary black hole merger.

Abstract -
https://journals.aps.org/prl/abstrac...ett.116.061102

Full paper in PDF available under Creative Commons License -
https://journals.aps.org/prl/pdf/10....ett.116.061102

[Shiraz (Ray)]

goodness me....what a time to be alive. Thanks for posting.

so the merger resulted in three solar masses of energy being converted to gravitational waves....in a fraction of a second. And it is all as GR predicted - how extraordinary.

seems like black hole mergers make spacetime go "boing".

I wonder what the "black holes don't exist" brigade will do now.! http://www.huffingtonpost.com.au/ent...tion=australia

[gary]

Originally Posted by Shiraz

goodness me....what a time to be alive.

Hi Ray,

A great time to be alive indeed.

Ponder the fact that the black hole merger took place at a time
a billion years ago where we were still single cell organisms and
starting to evolve into multi-cell organisms.

The gravitational waves emanated across space at the speed of light and
by the time they reached Earth on Monday September 14th 2015 we
had evolved to the point we could detect them.

[Dave2042 (Dave)]

I gather that a particular aspect of this is that the observed signal shows that all the waves (at different frequencies) traveled at the same speed (c). This rules out a bunch of 'exotic' variants of GR.

Neat.

[glend (Glen)]

Originally Posted by Dave2042

I gather that a particular aspect of this is that the observed signal shows that all the waves (at different frequencies) traveled at the same speed (c). This rules out a bunch of 'exotic' variants of GR.

Neat.

I believe that the researchers will be exploring all possibilities of exotic variants in decades to come in 'gravitational astronomy'. Unlike light they don't seem to reflect or lense but travel right through things. If the ones observed from the binary blackhole merger took one billion years to get to us, where are all the others, there should be massive numbers of waves moving through space/time in all directions.

I can just hear people ringing work and using a gravitational wave passing through them to excuse all sorts of things - the ulimate excuse.

[Bendy (Ben)]

Originally Posted by gary

Hi Ray,

A great time to be alive indeed.

Ponder the fact that the black hole merger took place at a time
a billion years ago where we were still single cell organisms and
starting to evolve into multi-cell organisms.

The gravitational waves emanated across space at the speed of light and
by the time they reached Earth on Monday September 14th 2015 we
had evolved to the point we could detect them.

Nicely put Gary, certainly gave me pause.

I love the following aspect of the discovery:

"The violent event temporarily radiated more energy — in the form of gravitational waves — than all the stars in the observable Universe emitted as light in the same amount of time."

http://www.nature.com/news/einstein-...t-last-1.19361

[Shiraz (Ray)]

nice simulation video here (and an an audio representation of the actual signal)http://www.huffingtonpost.com.au/ent...tion=australia

[Eratosthenes (Peter)]

Can the researchers identify the source/direction of these very faint gravitational waves? Is it a "cumulative" wave?

Very important discovery - perfect example of how the scientific method works - the interplay between theory/mathematics and experiment/observation

A huge number of scientists, research groups and institutions have been involved in the LIGO project. (e.g Lots of Russian input which spans several decades).

[gary]

Originally Posted by Eratosthenes

Can the researchers identify the source/direction of these very faint gravitational waves?

There were only two interferometers active at the time, one in
Louisiana and one in Washington state.

The Virgo interferometer was offline at the time undergoing an upgrade.

As discussed in the press conference, with only two interferometers the
source could only be narrowed down to a relatively large region, somewhere
in the direction of the Large Magellanic Cloud but 1.3 billion light years
away.

Probability contour plot here -
https://www.ligo.caltech.edu/image/ligo20160211b

Originally Posted by LIGO Caltech

In the future, when additional gravitational-wave detectors are up and running, scientists will be able to pinpoint more precisely the locations and sources of signals.

Originally Posted by Eratosthenes

Is it a "cumulative" wave?

The video of the press conference includes a supercomputer
animation of the black hole merger and graphically shows the nature
of the disturbance that created the ripple in space-time.

[silv (Annette)]

a "ripple in space time" for "a fraction of a second".

was it the low sensitivity of the 2 Ligo that shortened the measurable wave to so incredibly ... short?
I mean, 2 black holes marrying each other - that's surely a major BAM in gravity, no?
bigger than, say, a super nova?

""The violent event temporarily radiated more energy — in the form of gravitational waves — than all the stars in the observable Universe emitted as light in the same amount of time.""

both wave forms travel at speed of light but gravitational observable offspring is only 10 miliseconds? whereas last year's big super nova had a peak plateau of several days....

and if all this IS indeed so - and the 2nd LIGO, necessary to have proof, only came online 2 days before the ripple hit - that's also very incredible.

plus afterwards, nothing else worth mentioning up to January when the first observation phase ended. ... incredible.

Did Einstein throw the dice for this one?

[silv (Annette)]

Shiraz,
I guess there is a reason for peer reviewed papers, eh?
And also a reason for papers without such quality control :p

[Eratosthenes (Peter)]

wasn't a Nobel prize awarded in the 1990s (1993 or 1994?) for ground breaking work on gravitational waves?

This measurement needs to be validated by repeated detection and hopefully verified by another device in another part of the world.

Gravitational waves exist theoretically, and are a rational consequence of intense matter/energy interactions, but obviously are difficult to detect due to their faintness and minute amplitudes.

Looks like the next generation of LIGO detectors might get funding - perhaps increase the length of the evacuated tube to 6km or more. (remember, the initial funding for the LIGO detector was fought for vigorously and almost didnt get approved). One of these simple experiments but performed on ridiculously large scale looking for minute shifts in laser beam measurements. I hope they allowed for the trucks zooming on the nearby freeway or the odd earth tremor.

Just when you thought that the pathetic corporatised Scientific community, with its trivial pursuit of technological advancements approved by Wall Street short term junkies was plunging deeper and deeper into its sticky abyss of ignorance, it sneaks in some fundamental research like the LIGO experiment or the LHC search for the Higgs Boson. we are definitely wiser as a result of their results.

Who would have thunk it? Well done Kip, the gang and the Russian freak scientists in Moscow

[Eratosthenes (Peter)]

Originally Posted by silv

Shiraz,
I guess there is a reason for peer reviewed papers, eh?
And also a reason for papers without such quality control :p

Scientists are very crafty when releasing news to the public prior to having it validated by the peer review process in the scientific journal system.

The purpose of Symposiums, seminars and other informal society meetings and gatherings offer plenty of opportunity to flesh out any issues with measurements and conclusions etc. These measurements after all, when not carried out a few weeks ago. IMO for the big guns to release the news, albeit with some caution, says to me that gravitational waves have indeed been detected but require validation and verification.

I am grateful that Scientists are finally dragging themselves out of the corporate pit of commercialisation and decontaminating their profession from the stench of their ignorant fear and corporate sell out.

Great to see. there is hope for science after all

[xelasnave]

Why is the signal so short. The merger of objects of the masses involved shows up for only a split second if I read correctly.
I expect the answer can be found using GR but can anyone give an explanation.

Well having found GWs can they conclude GR has delivered its prediction and so stop spending money on GWs and channel funds to something even more exciting.

What benefits will acrue by pursuing GW research or having absolutely established GWs exist where does that take us.

Congratulations to those involved.

[silv (Annette)]

Why is the signal so short.

yes, please, why so short?

[multiweb (Marc)]

Originally Posted by Shiraz

nice simulation video here (and an an audio representation of the actual signal)http://www.huffingtonpost.com.au/ent...tion=australia

Cool video. Explains it well.

[silv (Annette)]

as to the benefit of GW: it determines which of the several current assumptions of the universe "type" are wrong, which are somewhat wrong and which are a bit right.
http://www.scientificamerican.com/ar...ational-waves/

or maybe that only applies to the ones still around from the bigbang. I dunno. dang I wish I had some form of scientific education. in the universe of my brain, every minute particle of understood stuff floats around unattached to and unaware of the next particle. it's utter chaos.

[Eratosthenes (Peter)]

Originally Posted by xelasnave

Why is the signal so short. The merger of objects of the masses involved shows up for only a split second if I read correctly.
I expect the answer can be found using GR but can anyone give an explanation.

Well having found GWs can they conclude GR has delivered its prediction and so stop spending money on GWs and channel funds to something even more exciting.

What benefits will acrue by pursuing GW research or having absolutely established GWs exist where does that take us.

Congratulations to those involved.

a novel way of "observing" the universe is potentially possible now.

A gravitational wave scope/detector

it may be able to detect objects and/or phenomena that are currently not understood or observable in any way.

very exciting times ahead if GW detectors and methods can be constructed with enhanced sensitivity and accuracy.

The scientific community should take one big theoretical/experimental bow today - it's the way science should function in this pathetically corporatised and casino stock market world. Scientists and decision makers should exhibit courage and imagination when performing their professional duties otherwise the stench of their pathetic craft will remain

[anthony.tony]

http://www.nature.com/news/gravitational-waves-1.19321 - Some good info from Nature Magazine -- Tony.

[sjastro]

Originally Posted by xelasnave

Why is the signal so short. The merger of objects of the masses involved shows up for only a split second if I read correctly.
I expect the answer can be found using GR but can anyone give an explanation.

Congratulations to those involved.

Alex,

The signal is short only because it fell within the detection limits of LIGO.

Giving a GR free explanation, gravitational waves are produced by the orbital decay of binary systems around a centre of mass.
The power radiated by a gravitational wave increases steadily as the objects approach the centre and rotate faster. There is a substantial increase in power in the very final stage leading to collision.
In the case of binaries being Black Holes there is no collision but a merger, the increase is even greater leading to a "spike" in the gravitational wave emission strong enough to be detected by LIGO.

Interestingly being a non linear theory GR is next to useless in describing the interactions between objects of similar mass, gravitational waves are an exception as has been recently shown.

Steven