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Pondering Gravitational Waves

“Einstein would be beaming,” said National Science Foundation director France Córdova as she began this morning’s news conference announcing the discovery of gravitational waves. I can hardly disagree, because we have in this discovery yet another confirmation of the reality of General Relativity. Caltech’s Kip Thorne, who discussed black hole mergers way back in 1994 in his book Black Holes and Time Warps, said at the same news conference that Einstein must have been frustrated by the lack of available technologies to detect the gravitational waves his theory predicted, a lack that it took a century to remedy with the LIGO collaboration.

Thorne believes that if he had been armed with the right tools, Einstein himself would have made the detection. But of course the tools weren’t there. Somehow that thought produced an odd echo of the very decade of General Relativity’s emergence, one that shows how much GR changed the nature of our view of the universe. It was in 1911, just four years before Einstein published GR, that Hugo Gernsback started talking about gravitational waves. The future editor of Amazing Stories, the first true science fiction magazine, Gernsback published his novel Ralph 124C 41+ in 1911, in a magazine called Modern Electrics.

Here’s how, in the era just before General Relativity, Gernsback handled gravitational waves, as our hero Ralph ponders his latest device:

It was known that certain high frequency currents would set up an interference with the gravitational waves, for it had been found in the first part of our century that gravitation was indeed a wave form, the same as light waves, or radio waves. When this interference between the two waves, namely, the gravitational waves and the electrical waves was discovered, it was found that a metallic screen charged by electric high frequency waves would indeed nullify gravitation to a certain extent…

And so on. Gernsback did his best (and at all too great a length), but how could his predictive powers have coped with gravitational waves? After all, his era was used to dealing with electromagnetic phenomena. General Relativity would stipulate a gravitational radiation which, like the electrical waves he mentioned, travels through space at the speed of light. But gravitational waves are themselves distortions — ripples — in spacetime itself. Finding gravitational waves means we have found yet another successful test of General Relativity in a kind of radiation different from any Gernsback could have imagined.

At Last, the Discovery

As fluctuations of expanding and contracting spacetime, we can think of gravitational waves as the movement of squeezed and stretched space. Accelerating bodies should produce these ripples, but only the largest events — a supernova explosion, a pair of infalling neutron stars, or even the collision between two black holes — should be sufficient to produce waves we can detect. The Laser Interferometer Gravitational-Wave Observatory (LIGO) experiment has been looking for these waves for more than a decade, with an upgraded Advanced LIGO in place since last September and far more sensitive than its predecessor.


Image: An aerial view of the Laser Interferometer Gravitational-wave Observatory (LIGO) detector in Hanford, Washington. LIGO has two detectors: one in Livingston, Louisiana and the other in Hanford. LIGO is funded by NSF; Caltech and MIT conceived, built and operate the laboratories. Credit: LIGO Laboratory

LIGO has been searching for gravitational waves since 2002, involving the work of some 1000 scientists. Its laser interferometer apparatus, installed at stations in Hanford, Washington and Livingston, Louisiana, takes advantage of the fact that a passing gravitational wave should change the apparatus itself, shrinking or expanding the space between two objects.

A single laser beam is split into two, with the twin beams being sent on different paths perpendicular to each other down vacuum channels four kilometers long, bouncing off mirrors in the process and eventually recombining, still aligned. A gravitational wave passing through the experiment should be able to change the distance of the two paths, meaning that the beams are no longer in alignment — they no longer cancel each other out. The changes amount to no more than a tiny fraction of the width of an atomic nucleus but they have proven detectable.

A Date to Remember

Now we know that the first gravitational waves were detected on September 14, 2015 at 5:51 a.m. EDT (09:51 UTC) at both LIGO sites. The amalgamation of a black hole 36 times the mass of our Sun and another of 29 times solar mass has evidently created a Kerr black hole (one that is spinning) of 62 solar masses. The missing 3 solar masses are thought to have been converted into energy and released as gravitational waves in a fraction of a second, with a peak power output, according to this NSF news release, about 50 times that of the whole visible universe. The Livingston detector recorded the event 7 milliseconds before Hanford picked it up.

The two black holes collided some 1.3 billion years ago, in an area of the sky that can be only imprecisely determined because we have no more than the two detecting sites. Nonetheless, Gabriela Gonzalez (LSU), a spokesperson for the LIGO collaboration, was able to point to the southern sky in the region of the Large Magellanic Cloud. Bear in mind that we have help on the way — the Italian VIRGO interferometer, which will come close to LIGO sensitivity later this year, and detectors in progress at the Japanese Kamioka Gravitational Wave Detector (KAGRA) and another detector in the works at LIGO-India (which could be operational by 2022). And remember that the Laser Interferometer Space Antenna (LISA) Pathfinder, launched in December, has now reached L1.


Image: Simulation of two merging black holes in front of the Milky Way. Scientists said the Sept. 14 event was so intense that in the moment before the colliding black holes swallowed each other, they emitted more energy than the rest of the universe combined. Credit: SXS Collaboration.

Toward a New Astronomy

We are, in other words, about to enter the era of gravitational wave astronomy. We’ve already learned as of this LIGO detection that binary black holes do exist, and that they can merge. A proven method of detecting gravitational waves should lead to our learning the signatures of different astronomical phenomena. Just how different is hard to ascertain, because as the oft-made comparison with Galileo’s first instrument reminds us, unexpected things turn up whenever we start looking with new tools. Gravitational waves provide us with a way of seeing into the earliest moments of the universe. And they’re certainly our way into violent processes like black hole and neutron star mergers and supernova explosions. Thus we move beyond electromagnetic wavelengths — visible light, X-rays, infrared — into a new era.

“At optical wavelengths,” Kip Thorne told the news conference, “we can see the universe as a calm place, like looking at the ocean on a quiet day. But on September 14, all that changed. Now we see an ocean of crashing waves, as black holes create a violent storm in the fabric of space and time.” Thorne went on to speak of the kind of detections that will be possible as gravitational wave astronomy advances, including not only the black holes, neutron stars and supernovae previously mentioned, but the possible detection of cosmic strings reaching across the cosmos, created by the process of inflation in the earliest moments of the universe.

“With this discovery,” adds Thorne, “we humans are embarking on a marvelous new quest: the quest to explore the warped side of the universe — objects and phenomena that are made from warped spacetime. Colliding black holes and gravitational waves are our first beautiful examples.”

The temporal distance between Gernsback’s first novel and Einstein’s General Relativity was four years. The distance between GR and gravitational wave detection was a century, a span of time in which the foundations of General Relativity have become part of the fabric of basic scientific literacy. A useful thought experiment is to put ourselves back in that pre-GR era and ponder just how dramatic the conceptual change that Einstein wrought must have been.

An Antiquarian Thought Experiment

Hugo Gernsback (1884–1967) magazine publisher

The thought experiment is a way of seeing how preconceptions can be overturned dramatically, which is why I sometimes return to creaky old stories like Gernsback’s Ralph 124C 41+. It’s a famous novel in the annals of science fiction but only a turgid read. Brian Aldiss once described it as a “tawdry illiterate tale,” and its author evidently viewed its plot as little more than an on-ramp for his real purpose, describing futuristic technical marvels.

Gernsback was no Einstein, but then, who was? He was an inventor, a publisher with a large stable of magazines whose contributions to science fiction were large enough to have resulted in the annual Hugo awards being named for him. He was also famous for paying his writers very low fees (H. P. Lovecraft would call him ‘Hugo the Rat’). Few science fiction fans today have read Ralph 124C 41+, but that early 20th Century gusto for sweeping predictions about technology drew impetus from the book, energizing the nascent but energetic genre.

Image: Portrait of magazine publisher Hugo Gernsback(1884–1967) by Fabian Bachrach (1917–2010). Credit: Wikimedia Commons.

Today’s science fiction, with all its sub-genres, takes General Relativity as a starting point for what comes next even as it continues to poke at how the theory might be extended in ways useful both to science and to plot. It’s just possible that we’ll find something through gravitational wave astronomy within the next hundred years that is as wildly out of kilter with current thinking as General Relativity was in its day. We didn’t abandon Newtonian physics when we moved on to GR, we simply placed it in a wider context. Open a new portal into the universe and things happen. We can only wonder what science — and science fiction — will look like a century from now.

Today’s paper is “Observation of Gravitational Waves from a Binary Black Hole Merger,” Physical Review Letters 116 (11 February 2016) 061102 (full text). See also this useful backgrounder from the American Physical Society’s online journal Physics : Berti, “Viewpoint: The First Sounds of Merging Black Holes,” (full text).


Comments on this entry are closed.

  • Horatio Trobinson February 11, 2016, 14:40

    And with that, Gravitational Interferometry was born.

  • Ron S February 11, 2016, 15:17

    “Thorne believes that if he had been armed with the right tools, Einstein himself would have made the detection. But of course the tools weren’t there.”

    If this is what Thorned said he’s being overly romantic. First, Einstein wasn’t much of an experimenter. He probably would not have even been much use as an adviser since he was not an observational astronomer.

    Second, there have been mavericks trying to detect gravitational waves for a long time. Not so much cranks, but experimental physicists hoping to get lucky. Early on that was somewhat reasonable since we knew little about events in the cosmos that stood a chance of being detectable at all.

    It’s with modern astrophysics and cosmology that the statistics of distance and frequency of a variety of emission events has been firmly pinned down. That told us the probability of detection of events over a time interval and the required instrument sensitivity and selectivity. Without that hard won knowledge LIGO would never have been built.

    The detection was expected (that is, probable) and very, very welcome. It is a fantastic accomplishment. As Paul says, this will spur further investment now that we know we can detect gravitational waves. Good times ahead.

  • Andrew Higgins February 11, 2016, 16:01

    The sign of a great breakthrough in science is that an outsider can actually read the paper: The discovery is so monumental, it can be described in simple language rather than couched in a lot of jargon. This paper certainly meets that criterion: I can understand almost every work (which is almost never happens in Phys. Rev. Letters for me.)

    Also, we should all be happy to see the pioneering work of our hero, Robert L. Forward, cited right there in the Introduction!

  • ljk February 11, 2016, 16:59

    Links to key papers on this historic event:


  • Hiro February 11, 2016, 17:08

    Greg Egan wrote a SF novel re-building GR from different point of view. However, Diaspora will dominate all our attention later in this century, the dark little secret has been hiding there for quite some time.

    • Michael Spencer February 13, 2016, 8:16

      Which novel are you referring to please?

      • Hiro February 13, 2016, 21:30

        *…re-formulating GR…

        The name of that sf novel is Incandescence, not a normal sf novel that is usually read.

        • Adam February 15, 2016, 23:30

          “Incandescence” doesn’t involve any new physics, but describes how aliens might learn about GR via experiments in a high curvature environment. I think you mean a different novel.

          • Hiro February 20, 2016, 18:14

            You meant that novel about the Riemannian universe with the metric signature (+,+,+,+) right? I read it somewhere about the possibility of the stability in the space with the lowest nontrivial neutral signature (+,+,-,-); but they must be some weird connected twistor surfaces under some restrictions.

  • Jim Strom February 11, 2016, 17:41

    A great day for science. Now, how will the LIGO technique be extended for every day scientific observations?

  • lepton February 11, 2016, 17:54

    It is exciting times indeed.

    LISA pathfinder is on the way to L1, hope it verifies all the technologies are ready.
    Wish new powerful instruments follows and opens a new era to understand the cosmos.


  • Eric Hughes February 11, 2016, 18:05

    I am struck by unbelievably violent this is. Not merely because of size, although that’s impressive, but because of the mass-to-energy conversion fraction. In this process, around 5% of the initial mass ends up as energy. In fission and fusion processes, you’re down in the few parts per thousand, a whole order of magnitude weaker.

    The mind boggles.

  • Al Jackson February 11, 2016, 18:08

    Robert Forward was one of Joe Weber’s graduate students and got his doctorate under Weber with a dissertation called Detectors for Dynamic Gravitational Fields. Joe Weber was the great pioneer of gravitational wave detection. Weber used a Guggenheim Fellowship to study under John Wheeler at Princeton. Wheeler almost highhandedly revived interest in General Relativity in the 1950’s and went on to produce almost every major GR theorist for the rest of the 2th century.

    The 100 anniversary of General Relativity was last November and December in lectures given by Einstein in 1915. The 100th anniversary of the first paper on GR was in 1916 so this is timely!

  • Andrew Palfreyman February 11, 2016, 18:20

    I am all a-tingle today with this news, announcing as it does the birth of a new era of investigative science. It is a day for the history books. Three quick comments:
    1. Not only can we now expect to investigate the details of inspiralling massive objects and cosmic strings (if they’re there), but also dark matter too. We can also look forward to direct observations of the pre-CMB universe itself.
    2. The USA pulled out of LISA funding a few years back, leaving Europe with the watered-down eLISA. I sense the mood is for the USA to jump back in and make LISA the system as originally intended. That would be wonderful.
    3. There is a proposal to build a table-top grav wave detector with the potential of sensitivity 4 orders better than aLIGO. You can read about it here

  • Al Jackson February 11, 2016, 18:27

    One notes that Henri Poincaré beat Gernsback by 5 years in predicting gravitational waves in :

    Poincaré, Henri , “Sur la dynamique de l’électron”,
    Comptes-rendus des séances de l’Académie des sciences
    140, 5 Juin, 1905, pp. 1504- 1508.

    I have no idea if Gernsback knew about this.

  • H. Floyd February 11, 2016, 19:31

    On that exhilarating topic of discovery and awareness:

    “Thorne went on to speak of the kind of detections that will be possible as gravitational wave astronomy advances, including… cosmic strings reaching across the cosmos, created by the process of inflation in the earliest moments of the universe.”

    Is Dr. Thorne talking about experimental validation of String theory? I’d always understood that that, all by itself, would have seismic implications for human awareness. Even for the 99.9% of us who will never understand it.

    At least two more informative posts here anticipating that moment:

    An Extragalactic Probe of String Theory (Feb. 13, 2006)

    Tantalizing Evidence for Cosmic Strings (Jul. 18, 2005)

    • Mr Spock February 12, 2016, 22:01

      The strings he’s referring to are cosmic megastructures that were created during inflation and reach from one end of the universe to the other. I don’t believe they have anything to do with string theory, which falls under quantum physics, not astrophysics.

  • John Walker February 11, 2016, 19:35

    The first illustration in the article identifies the site as Livingston, Louisiana. I think this is actually the Hanford, Washington site. Livingston is in the middle of a forest with clearings for the interferometer beam tubes.

  • Project Studio February 11, 2016, 21:33

    An exciting empirical result that will continue to challenge our conceptual framework of mass and energy. I was surprised at the loss of mass in the black hole merger … gravitational waves have no equivalent energy transference particle … there is no carrier medium (either) in which to store a potential energy … where did the lost mass-energy go? … Could the energy in a gravitational wave somehow be tapped? … Or has the conservation principle broken down
    Wonderful an thought provoking.

    • Ron S February 12, 2016, 10:45

      The energy went into the gravitational waves. That’s what was detected, and what LIGO was designed to detect. It’s analogous to radiation from a supernova or a GRB, and violated no conservation law. Being in the vicinity of this BH merger event would be as fatal as being near a supernova.

      The radiation is expected due to the asymmetry of the merging masses, and can be calculated quite precisely. “Bumps” that don’t fit within the new event horizon are expelled.

      • Project Studio February 12, 2016, 11:26

        I’m still wondering. A supernova or GRB radiates electromagnetic gamma rays. That is electromagnetic radiation. LIGO interferometry detected a space-time distortion, not electromagnetic radiation. Is there an imaginable way to extract the potential energy of an oscillation in space-time? If not, how do we know it is there? I find this question interesting to think about.

        Did LIGO also measure EM radiation coincident with the gravitational space-time waves? Is that where the missing mass bumps went?

        • Michael Spencer February 13, 2016, 8:18

          An intriguing question emblematic I think more of just how little we know about the universe. We’ve made a step towards explaining baryonic matter, yes, but the Universe holds far more secrets, most of which we cannot even imagine. Yet.

      • Mr Spock February 12, 2016, 22:11

        In what way would not be lethal, though (assuming one was far enough away to not be in danger of falling into the black holes)? I was under tge impression that there would be no EM radiation emitted by this type of merger. Say you were at a relatively safe distance in a spaceship observing what was happening. Would you see anything? Wouldn’t the gravitational waves just warp space around you (and in you) and pass through you harmlessly? It’s hard to imagine two massive objects like this merging in such a catastrophic way without some type of titanic explosion.

        • Ron S February 13, 2016, 11:09

          No EM. However any objects in the vicinity would be shredded by the intense and rapidly oscillating gravitational gradient. This is somewhat like the tidal forces that tear matter apart when falling toward the center of a black hole.

          The radiated gravitational energy is immense, as stated in the paper and this article.

          • Project Studio February 13, 2016, 20:47

            Still not sure – the gravitational waves are expanding and contracting the space-time cyclically – but there is no acceleration of any objects caught in that cycle. The ‘objects’ caught in the gravitational waves are not moving in space at all, it is the space that is ‘doing the moving.’ (I’m thinking by way of analogy with an Alcubierre warp, where the ship inside the warp feels no acceleration.)
            So no acceleration, no force. No force, no shredding.
            Is my model oversimplifying?

            • Volucris February 14, 2016, 15:55

              AFAIU there can still be tidal forces: if the passing gravitational wave is about to compress space between head and tail of your 100m long spaceship to 90m inside a few milliseconds, either the head and tail of your spaceship will manage to accelerate to new points that are 100m apart (force = mass*acceleration i.e. the spaceship will feel compression) in those milliseconds, or the spaceship will be violently crushed to 10m shorter version of itself. Yes, definitely shredding.

              • Project Studio February 14, 2016, 20:39

                I don’t see the case of the ship accelerating to maintain a 100m length (which reminds me of a relativistic thought experiment).
                If the gravitational wave is momentarily shrinking space-time, the distance between elementary components (electrons, quarks, whatever) of the ship is decreasing, but those elementary components are not being accelerated through space to accomplish this.
                Given a great enough amplitude, I suppose that an object that an non-homogeneity of fundamental forces – electro-magnetic/strong/weak – could manifest from a such ‘big rip’ leading to degenerate matter or even vacuum decay. Wild speculation. But that wouldn’t be a result of acceleration or the the spaghetti-fication force of gravity gradient.

                • Volucris February 15, 2016, 2:50

                  You are missing the point that the passing gravitational wave does not change *other* laws of physics: i.e. suppose you have a spring that applies 10N force if it’s compressed 1cm, and passing gravitational wave quickly shortens the distance between the 2 ends of the spring 1cm. The spring still works the way it always did, and there is now 10N spring force trying to accelerate the 2 ends to their former distance. It’s not the gravity causing the acceleration, it’s the spring :-)

                  • Mark Zambelli February 15, 2016, 10:37

                    My concern with this is when you say…

                    “passing gravitational wave quickly shortens the distance between the 2 ends of the spring”

                    … but, in your frame of reference, spacetime is ‘compressed’ rather than shortened… ie your ruler is also compressed and measures no change in length. Also, the gravitational wave would pass at ‘c’, much faster than the forces acting on the spring. LIGO measures the relative change in length along two perpendicular distances in spacetime, else it would never detect anything.

            • Michael February 15, 2016, 10:27

              Gravity waves carry energy which is equivalent to mass therefore there will be an interacting with objects in the way and they will be moving waves at c. Space-time will undergo oscillations in dimensions due to the passing of these waves and energy could be generated in masses via friction i.e. in Stars. If the stars are close enough to the event they will undergo changes in shape that could be detected by changes in neutrino output as the star undergoes heating. The GW’s and neutrino generation should go hand-in-hand.

              Here is an image of the largest known black hole, its a biggy!


      • Sean Robert Meaney February 14, 2016, 23:45

        Its not real gravity. G=m×a. Gravity is an attractive force caused by acceleration of the mass. If there were waves of varying attraction due to gravity it would be because the mass is accelerating and decelerating. I have concluded that mass is a standing wave propped up by a force pulling at the centre simultaneously as it pulls toward the centre. That means somehow we only experience half a force that generates matter. It also puts a question mark over what we consider gravity.

        • Denver February 15, 2016, 12:56

          There is no “attractive force” or “pull”, only curved space-time (or so they tell me).

  • Sean Robert Meaney February 12, 2016, 3:01

    All well and great that ‘gravity waves’ are a distortion of space time but ‘gravity’ would be an force of cyclically varying attraction.

  • J. Jason Wentworth February 12, 2016, 4:59

    Today engineer Dr. Travis Taylor, the host of the “Rocket City Rednecks” TV show on National Geographic’s TV channel, was interviewed concerning this discovery, and he discussed its possible ramifications for space travel:

    While the engineering will take some time to catch up with the science, he said that this means that anti-gravity propulsion and, *just* maybe, superluminal (FTL) interstellar travel are possible. (Also, if the Higgs Boson’s effects could be controlled so as to reduce a starship’s mass to zero–don’t ask me how this might be done!–voyages of any duration should be possible with immortal, never-aging crews traveling *AT* the speed of light, just like photons, for which time doesn’t pass.)

    • Hiro February 12, 2016, 19:42

      No thanks, the possibility of vacuum instability is too high in this case. Playing around with different variations of quantum vacua doesn’t help increasing the life span of anyone.

      • J. Jason Wentworth February 13, 2016, 1:04

        Even Dr. Taylor said that “some time” could be decades or centuries, but he said that gravity manipulation (negation or amplification of it) is now, in principle, possible. Also:

        Quite detailed anti-gravity propulsion system concepts have been developed (a 1981 issue–I forget which month it was–of “Science Digest” magazine had a cover article titled “Antigravity Starships: Engineers Unveil Their Plans”). Most of them depended upon the anticipated future ability (which we’ve now just reached) to detect local gravity waves, and then (which we haven’t achieved yet) produce identical waves that would cancel them out. Two of the designs involved doing this in such a way as to cause the toroidal device (and the ship it was attached to) to vanish from one point in space-time and instantly reappear at another, at an arbitrary distance away. The engineer who developed them stressed that accurate knowledge of the gravity wave “fabric” of space-time would be necessary in order to go where and when one wanted to go (and no less importantly, return to *this* where and when). In addition:

        Another design in the article (and depicted on the cover), developed by Stephan Alzofon (if memory serves), used a 2-dimensional array of symmetrically-arranged iron and aluminum panels (this assembly looked like a “2-D” double-convex lens), which would be hit with high-frequency (as regards their frequency *variations*) microwaves while the panel array was immersed in a ship-produced electromagnetic field. This process would produce short-lived virtual particles, which would enable the device to produce thrust without ejecting any mass. (Since such a device [Arthur C. Clarke speculated that anti-gravity devices of this sort might be possible] requires the input of energy in order to produce thrust, it wouldn’t violate any of the conservation laws, any more than a magsail or an M2P2 propulsion system does.) We shouldn’t abandon rockets and sails yet, but other, faster methods for crossing space may eventually become possible as a result of the detection of gravitational waves.

        • Hiro February 13, 2016, 21:35

          “…… if the Higgs Boson’s effects could be controlled so as to reduce a starship’s mass to zero…..”

          We live in the region of meta-stability, any unreasonable manipulating the numerical value of the Higgs field is easy leading to the abyss of darkness.

          • Michael February 18, 2016, 3:14

            I doubt changing a local field will have an ‘ice nine’ effect on the rest of the universe! If we could reduce the Higgs field in front of a ship i.e. reduce the ships inertia, and return it to normal behind it say sort of like a zip effect it would allow higher velocities to obtained for less fuel. Answers and solutions on a postcard please…

            • Hiro February 20, 2016, 18:27

              It’s more like expanding and replacing any meta-stable vacuum. Dr. Coleman wrote several papers about this particular topic in the late 70s and early 80s. Any extreme distortion of the Higgs field would increase the probability of vacuum decay.

              • Hiro February 20, 2016, 18:42

                Starting from the paper “Gravitational effects on and of vacuum decay” as a basic step, then replacing the classical scalar field with the Higgs field and compute the functional. The full result is a nasty pde instead of an ode, I guess some numerical approximation would give you reasonable result. Of course, there are some advanced methods (from several dozens of paper) to do this, but I stop paying my attention after reading the words “eternal inflation”.

  • Giulio Prisco February 12, 2016, 5:13

    Yesterday I and thousands of viewers around the world watched live the LIGO press conference on gravitational waves detection from black hole fusion event. The young take the Internet for granted but for us oldies the ability to watch live science history in the making is still awesome.

    Those who missed the press conference can watch a recording here:

    Gravitational waves are no surprise – they are predicted by Einstein’s General Relativity. The importance of the LIGO result is that now we have the technology for gravitational wave astronomy. The measured results match the results of supercomputer solutions of Einstein’s field equations, which confirms the accuracy of both Einstein’s equations and laser interferometry technology for gravitational waves detection. As they said in the press conference, new detection technologies always result in unexpected findings sooner or later.

    I’m wondering how many zillions of sentient beings died as a result of the black hole fusion event (ref. Greg Egan’s Diaspora).

  • Giulio Prisco February 12, 2016, 8:09

    This is evidently Nobel Prize material and I wonder who’ll get the Nobel. Gonzalez? Reitze? Weiss? All? I wonder if Thorne has a chance as a LIGO Project co-founder. I am very fond of Thorne’s textbook “Gravitation” and his popular science books “Black Holes and Time Warps: Einstein’s Outrageous Legacy” and “The Science of Interstellar” – a great science book and a much needed bridge between physics and entertainment.

    • Robert February 17, 2016, 13:36

      How about the taxpayers who built the facilities.

  • Harry R Ray February 12, 2016, 10:17

    Confused as usual. I thought that the only way information can escape from a black hole is via Hawking Radiation. Three suns worth of MASS seems like A WHOLE LOT OF INFORMATION TO ME! Can anyone help me out here?

    • Michael February 12, 2016, 11:18

      The energy transfer only occurs in our version of the universe i.e. our side of the event horizon.

      • H. Floyd February 12, 2016, 13:13

        Really glad someone else asked that first. If the constituents to the collision were themselves black holes, how did any energy transfer occur outside their event horizons, or the event horizon of the merged black hole?

        What I’ve been telling myself is, based on some of Kip Thorne’s interview comments (linked), energy from a black hole can exist outside the horizon in the form of perturbed spacetime, and at the merger of two black holes, some of their combined energy erupts away as spacetime distortion: http://www.space.com/17086-bizarre-black-holes-kip-thorne-interview.html

        And no, I would not trust my inferences about that, either. Anyone clarify?

        • Project Studio February 12, 2016, 21:34

          Thanks for the link.

          • Harry R Ray February 14, 2016, 14:37

            OK, correct me if I am wrong again, but does this mean that we have ALSO CONFIRMED the existance of ALTERNATE(although not necessarily PARALLEL)UNIVERSES? Our “version” having 3 solar masses LESS than the Black Holes’ “version” would seem to be a VIOLATION of the conservation of energy, otherwise.

    • Michael February 12, 2016, 23:53

      The BH’s had orbital energy or potential energy (information) that was dissipated via gravity waves and a mind blowing amount at that. I wonder what the first galactic central BH’s energy dissipation levels were, they are measured in the billions of solar masses and must have had a profound effect on the formation of galaxies!

      I am amazed at how quickly the combination died down, the whole event was over in milliseconds. We could if given advanced warning have a SGF telescope to view a merger but they are very, very rare.

    • Mark Zambelli February 15, 2016, 10:25

      Harry, I’d suggest that the 3 solar masses of energy was ‘dumped’ into the fabric of spacetime to set that wobbling. The energy would be completely incoherent and random and therefore would carry no information therfore circumventing any conservation issues.

      • Michael February 16, 2016, 3:31

        See this is where GR and QM are at odds, QM implies no information is lost but GR is indicating a loss or so it seems, it may just be so mixed up that just trying to sort it out changes the outcome much like in QM. GR describes the large scale very well and QM the small scale very well, they just don’t get on together though.

        We badly need to know what Space-Time is, is it a sea of gravitons or a foamy sea of transient energy-particles or a sea of field particles no one knows? Einstein once stated that space-time has properties, may be once we learn more about GW’s we will know more about the fabric of ST.

      • Harry R Ray February 17, 2016, 10:52

        What I meant to say was, one “version”(OURS) has a COMBINED mass of only 62 solar-masses, whereas ANOTHER “version”(THE COMBINED BLACK HOLES’) STILL has the ORIGINAL solar mass of 65! THEORIES suggest that the regions INSIDE THE EVENT HORIZONS of Black Holes are INDEED separate universes, with different physical PROPERTIES(i.e. masses) but not necessarily different physical LAWS! Conversion of mass to gravitational waves was REQUIRED to provide this “difference”, which was NEVER PROVEN until NOW!

        • Michael February 19, 2016, 14:31

          ‘What I meant to say was, one “version”(OURS) has a COMBINED mass of only 62 solar-masses, whereas ANOTHER “version”(THE COMBINED BLACK HOLES’) STILL has the ORIGINAL solar mass of 65!’

          It was some of the orbital energy that was released as gravity waves, no material or energy can escape the black hole not even light.

          ‘THEORIES suggest that the regions INSIDE THE EVENT HORIZONS of Black Holes are INDEED separate universes, with different physical PROPERTIES(i.e. masses) but not necessarily different physical LAWS!’

          For all intensive purposes they are separate from our universe but it is not one I would like to visit. Maybe there is a point when a large enough mass gets together to rupture space-time and begin another universe but it has no been calculated as we don’t fully understand what space-time is. I suspect that more research will be carried out because of this important finding, GW’s, which I am sure will shed light on the mysteries of the universe in greater depth.

  • Al Jackson February 12, 2016, 12:00

    An interesting aspect is that the signal fits modeling to the Kerr solution for a rotating black hole.. This is the first detection of a Kerr BH too!

  • Al Jackson February 12, 2016, 12:05

    Also as far as I know this is the first verification of the full blown 10 coupled nonlinear partial differential equations of General Relativity.

    • Project Studio February 12, 2016, 21:59

      Yes I think that further study will lead to precise verification of particular Eigenfunction solutions of General Relativity field theory, and discovery of small discrepancies in other cases. The discrepancies will be by far the more valuable findings as they will help take GR theory further and may suggest unexpected practical applications.

      @Joy: With expensive mega instruments pushing the frontier of research, the scientific method’s requirement of independently reproducible results breaks down if only one such instrument exists. We can keep doing the research but we can’t properly call the conclusions scientific,or the findings knowledge.
      One thing I like about this indication of the likelihood of gravitational waves, is it makes the universe our laboratory for study of relativistic gravitational phenomena. I think these kinds of studies based on gravitational waves will provide a relatively economical way to probe early the universe and high energy interactions in the cosmos.

  • Harold February 12, 2016, 12:07

    Would we expect to see gravitational wave interference patterns?

  • Harry R Ray February 12, 2016, 12:13

    Advanced VIRGO will come on-line soon. Then we should able to REALLY triangulate and get more precice positions! The reason I mention this,is; now that gravitational waves have been proven to REALLY exist, could ET’s COMMUNICATE with them, and if so, What Kardashev classificaton would they be? Could anyone help me out here? A REPEATING signal from a small region of sky would be a REAL MIND_BLOWER!

  • Al Jackson February 12, 2016, 15:13

    @Harry R Ray

    If they can manipulate ~30 solar mass black holes with ease, then I would Kardashev aleph null!

    • Harry R Ray February 17, 2016, 11:41

      Apparently these HYPOTHETICAL Kardashev Aleph Nulls(i.e. GREATER than III, I assume) could ALSO ENTER THIS NEWLY FORMED Black Hole because it IS a Kerr Black Hole! Read “Cauchy-horizon Singularity inside perturbed Kerr black holes.” by Lior M Burko et al.

      • Harry R Ray February 17, 2016, 11:45

        Sorry, I meant …..ENTER THIS NEWLY FORMED Black Hole WITHOUT being spagettified…

        • Michael February 19, 2016, 14:37

          The tidal forces around very large black holes is not strong enough to tear you apart on passing over the EH. But eventually you will get nearer the centre where tidal shear will.

  • Joy February 12, 2016, 15:45

    I do believe in gravity waves, but not because of LIGO. The binary pulsar work of Hulse and Taylor in 1974 – which could be replicated by anyone with access to a radio telescope – proved that gravitational waves exist. But concerning LIGO, there is no way that I find this UNCONFIRMED OBSERVATION to constitute a discovery.

    Ok, I am officially a fossil. My face palm reaction to the type of journalism surrounding the LIGO announcement may not even be understandable by the post modern reader. To put it bluntly, there has not been a discovery of anything here. The LIGO team has announced an observation. The observation of this one off irreproducible event by a single instrument is not and can not be anything more. Just as Kepler planets need to be confirmed by another instrument, nothing out of LIGO can rise to the level of discovery until it is confirmed by another independent gravitational observatory. And no, the two ends of LIGO don’t count, it is one instrument.

    For what it is worth, I do believe the observation to be legitimate, at least at a 50% confidence limit. Why so cynical? I have over 40 years of experience with biomedical literature, of which about half is known to be wrong. This is not just my opinion. From Lancet editor Richard Horton, “much of the
    scientific literature, perhaps half, may simply be untrue.” Or over in the states at NEJM from longtime editor Marcia Angell: “it is simply no longer possible to believe much of the clinical research that is published, or to rely on the judgment of trusted physicians or authoritative medical guidelines. I take no pleasure in this conclusion, which I reached slowly and reluctantly over my two decades as an editor of The New England Journal of Medicine”

    Why is so much of what is published wrong? In biomedicine, part of the blame is poor use of statistics by biologists and physicians. Part of it is outright fraud by individual researchers – which I witnessed at both Stanford and Caltech. But, the largest contributor to bad medical science is the vested interests of big pharma to get the results they want. If researcher A can’t find a way to make experimental drug X look good, the research will never see the light of day. The drug company will try again with researcher B. Every adult in the field knows how the game is played. If you want to get paid you have to be a team player.

    How does this relate to physics? Humans are what we are in any field. LIGO has been a very expensive project. Without results, LISA might never be funded. How many careers hang in the balance, administrators as well as physicists. Not to mention many engineering contractors and subcontractors. Literally nearly a thousand scientific careers are at stake and in the future billions of dollars. Amongst all of those people 1% would be sociopaths as in any group of humans. Is it possible that someone would be unscrupulous enough to load a software worm into both ends of LIGO to simulate a detection? Oh yeah baby.

    • J. Jason Wentworth February 13, 2016, 1:23

      Joy, I am–despite my interest and excitement at this announcement–with you, because the data certainly are, and in all areas of science. The biologist Dr. Rupert Sheldrake (who is involved in research on controversial concepts such as morphic fields and morphic resonance, which are connected with the forms of living things and imply other phenomena) has written in detail about the surprising amount of fraud that has occurred and still occurs in all fields of science, for the reasons that you mentioned. Also:

      Since what was observed by LIGO can’t be reproduced in a laboratory, only numerous similar observations of other such astronomical events can prove that gravitational waves exist and can now be detected. This has usually been the case in astronomy, where only by observing large samples of objects of various types (stars, planets, asteroids, comets, and galaxies) can hypotheses, theories, and ultimately laws be determined.

    • Eniac February 13, 2016, 17:02

      Joy’s observation about mistaken, and occasionally outright fraudulent, publication in medical research are not to be trifled with, but I would have to call them a red herring with respect to the present work.

      1) The signal was already theoretically predicted to look exactly as it did, and 2) the instrument was designed to make its detection likely, plus 3) the signal was detected in two duplicate instruments. The three of these circumstances together put the reality of this observation beyond reasonable doubt, for me, anyway.

      No doubt, also, that further signals will be observed on a regular basis and we will know exactly whether they come from colliding neutron stars or black holes, and what masses they were. We’ll build statistics and learn a lot of details about the universe. We’ll also hear signals we can’t readily explain and try to get behind how they might have been generated. Good old fashioned astronomy, but starting from scratch in a completely new observational channel. These are exciting times!

      • Eniac February 13, 2016, 17:07

        Let me also just mention that the editorial staff of Phys. Rev. Letters and its reviewers apparently share my feelings and not Joy’s, which should also count for something.

        • J. Jason Wentworth February 14, 2016, 7:07

          I think they did detect gravitational waves, but a few more such detections (which shouldn’t be terribly difficult or too long in coming) will absolutely clinch the LIGO team’s case.

          • Harry R Ray February 14, 2016, 14:26

            Rumor has it that they have four more detections, but ONLY at the 3-4 sigma level. At this rate they should have DOZENS by October, which is also RUMORED to when their NEXT announcement will be.

  • Robert February 12, 2016, 15:54

    When they announced the Higgs they said that it looked like a Higgs but needed more data. And that discovery has some doubters in the field today.
    So, though it may look like what they expect from a gravity wave, I wonder how likely it is that it may be something else? I mean, after spending so much money and investing the careers of hundreds of scientists, aren’t they highly incentivized to interpret any signal as a true gravity wave?

    Shouldn’t we wait for a few years as data is accumulated, certainly before awarding any prizes.

    • Eniac February 13, 2016, 17:20

      This is much clearer than the Higgs. The Higgs was a simple bump above the noise in a spectrum, with a very involved and complex explanation, plus at least some room in theory that it might not exist at all, or at an energy outside of the range of detection.

      This is a complex signal that has a relatively simple explanation, and there wasn’t really much doubt in the field that it would occur and that the instrument, as designed, would detect it. Most interestingly, there is only one Higgs boson, but there will be many, many distinct signals to be observed by LIGO and its successors.

    • Eniac February 13, 2016, 17:22

      Oh, and if you know anything about Nobel prizes, you need not fear that one will be awarded prematurely. It can take many decades.

  • Rob Henry February 13, 2016, 1:11

    After hearing this news, I must ask two questions
    1 ) What would be the effect of such a merger in our own galaxy, say at 1,300 ly, or a million times closer. Would such waves of a trillion times that power have any effect on our planet or life on it?
    2) What if two million solar mass black holes merged in a galactic centre. If the process scaled up, that would release 100,000 stellar masses of energy. Even at our distance from the core, it would deliver a hundred times as much gravitational energy as we receive sunlight, in a single day (or should that be 2000 times as much within an hour?). Would that have any effect, or would it pass unnoticed?

    • Eniac February 13, 2016, 16:45

      On 2), assuming that some non-negligible fraction of the energy probably goes into gamma rays, I would think that that might be enough to cause some damage in the upper reaches of the atmosphere. I doubt that enough would get through to directly affect life on the exposed half of the Earth’s land surface. I have no idea if the gravitational waves would be noticeable or not at this power level.

      On 1), assuming your calculations on 2) are correct, this case would be about a 100 times weaker than 2) and should not be very noticeable at all. It would be a heck of a GRB, but you wouldn’t notice it without an instrument. Maybe a lightning-like flash in the sky if it happens to be night time.

      I doubt gravitational waves would have as much impact as gamma rays of the same power, since they aren’t easily absorbed. Still, it is a really interesting question. Perhaps it would be just enough to actually hear the chirp, as it deforms the matter around us…

    • Hiro February 13, 2016, 21:40

      Well, Mr. Egan had to cook up some reasonable effects for his Diaspora. It also gives another answer to the famous question “where is everyone?”.

  • Michael February 13, 2016, 10:54

    Since there has been no melding of quantum mechanics with relativity at the moment, each describes their domain very well, there is the possibility in fact more likely a more fundamental equational description of both as one. I believe unless we know what space time is we are going to have a hard time of it.

    It is as if the omnipotent one created relativity to cover up their addiction to gambling with dice!

  • Dave February 13, 2016, 10:58

    Since this was predicted 100 years ago, has theoretical work been assuming the existence of gravitational waves for a long time? If so, does this announcement truly herald something new, or simply confirm an assumption? Not to take away from the excitement, but is there a community of theoreticians who did not believe in gravitational waves and whose work is now suspect?

    • Eniac February 13, 2016, 16:20

      Correct me if I am wrong, but I think the current state of physics is such that experimentalists are so much behind theory (a century in this particular case) that what you are asking for has not happened in a really long time, and certainly not in this instance.

      As I understand, the chirp that was heard was exactly as expected and its prediction was precise enough to calculate the mass of the two holes to a better precision across 1.2 billion light years than we can measure the masses of nearby exoplanets….

      • Michael Spencer February 14, 2016, 8:46

        “experimentalists are so much behind theory”

        In the case of string theory that is certainly true. On the other hand the case can be made that there have been no real breakthroughs in physics for decades. Even the discovery of the background radiation (1967, I think) was confirmation of theory (and a very big piece of the puzzle indeed).

        I suppose that if string theory develops into something that can actually make predictions many decades will pass before confirmation.

  • Trey Franklin February 13, 2016, 12:23

    Your first aerial image is incorrectly labeled (the state of Louisiana is densely forested and humid!) The above image is the Hanford Observatory in Washington state.

    • Paul Gilster February 13, 2016, 14:05

      Meant to fix that before, as others have noticed. Will take care of it right away. Thanks.

  • spaceman February 13, 2016, 19:33

    Skepticism is an indispensable part of good science: extraordinary claims require extraordinary evidence. However, I must admit that I find some of the skepticism expressed in this forum over the LIGO observation of GWs to be trite, cheap, and questionable in and of itself.

    First of all, these momentous results were peer-reviewed and subjected to an incredibly high degree of rigorous scrutiny over a period of many months; furthermore, there are already indications that additional observations of gravitational waves have been made since the September 14, 2015 event. Just because you have experience in one scientific field like, say, bio-medical research does not necessarily mean that you are qualified to critique the intricacies of GW detection in any meaningful way. One person I knew made it a point to nay-say essentially every big result in astronomy that came out since at least the middle of the 20th century. He said he was ‘losing faith’ in modern physics as a whole because by that time (~2007) the Higgs particle, gravitational waves, and dark matter had not been detected. Apparently, cosmologists and physicists are damned if they do and damned if they don’t! At this point many very smart QUALIFIED people would say that two out of these three phenomena have successfully been ferreted out beyond a reasonable doubt. Are the skeptics truly qualified in the sense that those doing the questioning have a professional level understanding? Are they, honestly, qualified in the sense of having a truly substantive understanding the complex physics, mathematics, and engineering of LIGO at least on par with Kip Thorne? How many people in the physics/astronomy community are there who are expressing a high degree of skepticism in the LIGO results?

    Skepticism based on sociological critiques of science are a dime a dozen. Obviously, scientists are people too with hidden biases in their thinking that can affect both the construction of experiments and the interpretation of experimental data, and the use of statistics. But this works both ways– just like it is possible to engage in group-think in terms of confirmation, let us not forget that it is every bit as possible to jump on the skepticism bandwagon (e.g. the numerous critics of evolution and climate science). Food for thought: perhaps some of the critics of LIGO and other scientific endeavors have some of their own biases as well, like the guy I mentioned in the previous paragraph. He was so dead-set in his contention that “Einstein was wrong” and “modern physics is broken” that any amount of evidence that did not confirm his skeptical critique he would refer to as “trash.” Yes, people believe what they want to believe, including those who are perpetually skeptical. It is possible to skeptical of the skeptic, I should add. Actually, one of the skeptics of LIGO in this forum has already shown an uncivil attitude toward researchers, calling the recent paper by Lineweaver and Chopra “rubbish.” The use of borderline aggressive, certainly pejorative terms like “rubbish” to describe other people’s scholarship is certainly suggestive of a hidden bias.

    I once knew a leftist critic of science who said at a dinner party that “modern medicine was no better than going to see a Witch-doctor in the jungle.” Low and behold, I came to find out that a few months later that she rushed straight to the best doctors in the city when the health of one of her loved one’s started to fail rather than booking a flight to the amazon. NOT to say that indigenous knowledge isn’t valuable, but it was very revealing to see how quickly her cheap skepticism dissolved when push came to shove. FYI: her ailing relative was successfully treated and recovered: oh yeah baby!

    • Ron S February 13, 2016, 22:32


    • Mark Zambelli February 15, 2016, 10:54


    • Eniac February 15, 2016, 11:35

      Well said.

    • Robert February 16, 2016, 14:06

      Essentially you are making an argument that only ‘qualified’ people have a right to be skeptical of such a discovery, that is, only those vested in the highly refined paradigm they are trying to prove.

      It was pointed out to me that this data was ‘fit’ by computer to a scenario that would match the pulse. Is there any independent data that these two black holes existed and had the masses claimed in the paper? Are they just what the researchers claimed ‘must’ be the case?

      Because a vast amount of money was spent build these facilities to search for gravitational waves, with only theoretical backing, there is a strong motive to find something that justifies their existence. Just like the occasional ‘breakthroughs’ in fusion which come whenever they want more money to continue their careers.

      What mathematical form are GR predicted waves, longitudinal, transverse? What structure, if any, do they possess? Are they composed of gravitons? Are they truly waves or merely disturbances in the spacetime continuum? What does that mean?

      What exactly did Einstein predict and does this match that prediction?

      These are certainly a lot of question one can ask. The informed public must hold the scientific community to a higher standard when their money is at stake and not simply be told ‘trust us, were smarter than you are, you aren’t qualified to question us’.

      BTW, one of the ways many scientists insulate themselves from criticism is to ridicule anyone suggesting they might in fact be wrong.

      • Ron S February 17, 2016, 11:24

        There is a difference between informed skepticism and scattering ‘doubt’ bombs all around. From your questions I strongly suspect that your understanding of GR, gravitational waves and LIGO could be improved. I suggest you first learn about these subjects. A good selection of the papers associated with the discovery can be found at the following URL, at the end of the list. Many of the earlier papers might also be helpful to you. None of these will teach you the subject but I think they are sufficiently clearly written that you can gain a level of understanding to allay your doubts. They describe the instruments, noise management, signal processing, trigger criteria, numerical models and much more.


        I have been skimming some of these papers and reading several in depth. It’s been very enlightening.

        • Robert February 17, 2016, 15:10

          Thanks for the link to papers. Your suggestion that I would not ask such questions if only my knowledge were improved fits very well my arguments about how such fields are conveniently insulated from criticism.

          • Ron S February 18, 2016, 0:08

            Insulated? I’m just an anonymous blog commenter like you. I made a suggestion. You rejected it. Maybe someone else will answer your questions. The time I can spend on this subject is spent on reading the papers.

  • Joy February 14, 2016, 3:03

    Whatever guys. I remember quite well being hated on for several months at Centauri Dreams in 2011-2012 as a skeptic of the Italian superluminal neutrino announcement. I also recall no apologies from the FTL dreamers when the OPERA team finally admitted their error and retracted the result. No worries, I have a tough skin and don’t care. Wanting to believe might be ok for Fox Mulder, but is the death of science.
    I am not surprised at all that most completely missed my main point here. Science is about results confirmed by independent sources, anything less falls short of scientific proof. This is analogous to understanding the difference between a hypothesis and a theory – which unfortunately has also been lost to many post modern scientists.
    (I will allow that paths to personal knowledge quite outside the scientific method might exist. In fiction Hamlet met his father’s ghost on the battlements and accurately learned that Claudius was his father’s killer. But Hamlet himself did not consider such a source reliable enough to act upon and spent the rest of the play trying to confirm the information offered by the ghost by independent means. In thinking this way, Hamlet was thinking critically, which in the age of Wikipedia and Google is a dying art.)
    Internal review (which failed at OPERA – internal skeptics were suppressed) and peer review (which often fails for a host of reasons) are not enough.
    If the Chinese build their own gravity wave detector and in a decade both LIGO and the Chinese detector team detect the same event, that would be a confirmed discovery. Just 29 years ago we experienced such an event with the three site neutrino observatory detections of SN1987A, so such things can happen. Until that happens with gravity waves, my gravity wave champagne bottle will remain corked.

    • Ron S February 14, 2016, 14:24

      A waste of perfectly good champagne. Skepticism is fine, but to accuse others of elementary failures of critical thinking, and to do so without evidence, is not. Your condescension reflects poorly on you. In any case your latest comment is better than the conspiracy theory you earlier invented and shared.

      I have read the paper and have been following LIGO at a fairly deep technical level for years out of personal interest. Although I am not a physicist I have an advanced science degree and have done professional work in signal processing and analysis. I am reasonably convinced that they’ve done what they said they’ve done, though certainly not totally convinced. There is more work to be done. On that point, I believe, most would agree.

    • tesh February 15, 2016, 4:52

      As per your train of thought, the discovery of the Higgs particle also falls short of a discovery…

      I get that you would like independent confirmation of these observations but you can hardly expect us to build multiple LHCs, LIGOs (of which there are at lest two I believe) and other grand instruments. Their costs are not insignificant and I guess that when they build these mega-insturments, they have some pretty smart people doing the numbers (engineering wise, data management/pipelines and on whether the whole thing will deliver).

      This definitely not my field as I’m a biologist by trade. In my experience, at some point objective reasoning goes out of the window when it comes to science and especially when it comes to judging other peoples science. For me, I believe them but as with most people (I guess), it will only settle into full belief upon more observations (pretty soon I think), as other instruments come online (in the months and years to come) and upon our ability to manipulate them (decades and centuries ahead).

      Exciting time indeed.

      • Robert February 16, 2016, 14:53

        I think the problem here is less about the measurement and more about the interpretation.

    • Eniac February 15, 2016, 11:47

      “Whatever guys. I remember quite well being hated on for several months at Centauri Dreams in 2011-2012 as a skeptic of the Italian superluminal neutrino announcement.” I suggest you go back to those discussions, and you will find you were not alone, then. You and many of the more reasonable members of this forum pretty much agreed in their scepticism. You will also remember (absent selective memory) that the experimenter’s claims themselves were extremely tentative, that time.

      Enough said. This is very different than the neutrino incident, and if you cannot see that you belong in the “crackpot section” of this forum.

      • Rob Henry February 15, 2016, 15:28

        Selective memory impacts all humans. A slip-up does not a crackpot make.

        • Michael February 16, 2016, 15:47


          • Eniac February 17, 2016, 1:05

            I should not have used the c-word. What I meant to express is that equating the superluminal neutrino fiasco with this expected confirmation of well-established physics is absolutely ludicrous.

      • Robert February 16, 2016, 15:18

        Our modern scientific paradigms are so highly refined and it is all too easy to want to label anyone who challenges them as a ‘crackpot’. In fact, I’ve seen certain well known critics define being a crackpot as challenging basic paradigms that are considered ‘settled science’.

        Consider a hypothetical extraterrestrial civilization. If they were somewhat comparable to us now, the probability that their science would look exactly like ours, the same concepts, the same mathematical models, the same type of physics language must be astronomically small. Surely some of our scientists would look at their models and, if they didn’t know where they came from, might label them ‘crackpot’.

        It’s an accident of history that we have the exact, highly refined models we have. It should not be assumed they are the best or most accurate out of all
        possible historical scenarios. They should be constantly challenged.

        • Eniac February 17, 2016, 1:14

          “It’s an accident of history that we have the exact, highly refined models we have”

          I vehemently disagree. General relativity is simple and elegant, it is not “highly refined” at all. There isn’t any room for it to be different from what it is, which is why Einstein was able to derive it without any experimental data at all. It is absolutely not an “accident of history”.

          Consider a hypothetical extraterrestrial civilization. If they were somewhat comparable to us now, the probability that their prime numbers would be exactly the same as ours must be astronomically small.

          • Robert February 17, 2016, 13:29

            You are conflating pure mathematics and scientific models. But even math, who knows if concepts such as prime numbers would even have been discovered! Not all cultures or civilizations may have the interest in delving into pure theoretical mathematics and probably few would let their physics devolve into pure mathematics. It’s silly to think we have arrived at the best science possible at this stage in our development vs. comparable civilizations.

            • spaceman February 17, 2016, 18:42

              Yes, but most would also argue that we are currently far from being completely ignorant as to how nature works either, despite what many disgruntled internet pseudo-skeptics would like us to believe. It is not black and white: there are things that we currently understand about nature that will still be seen conceptually, hundreds of years from now, as they are seen today AND there will surely be other frameworks that will need to be revised or discarded as new discoveries are made. Both are true. However, the attitude I have seen expressed time and again on forums such as this one– often in a very condescending way— that modern science is broken by group think and we have no better an understanding of biology, chemistry, physics, and astronomy than we did 200 years ago is outright absurd and, frankly, grandiose and insulting.

              • Robert February 18, 2016, 13:47

                Well of course we know more facts than we did 200 years ago. There is a lot of experimental data. But it’s naive to believe that we basically nailed it. Some of the most fundamental ideas are being challenged including the supposed ‘supreme law of physics’, the Second Law of Thermodynamics.

                ‘Experimental Test of a Thermodynamic Paradox’
                D. P. Sheehan , D. J. Mallin, J. T. Garamella, W. F. Sheehan
                Foundations of Physics
                March 2014, Volume 44, Issue 3, pp 235-247
                First online: 14 March 2014

            • Eniac February 19, 2016, 12:36

              General gelativity is pure mathematics. That our universe seems to be following it to an extremely high degree of accuracy is an observation, but it is one that every other intelligent race in the same universe would inevitably also make.

              Some think that reality itself is pure mathematics (See: https://en.wikipedia.org/wiki/Mathematical_universe_hypothesis), a way of thinking that I am myself extremely attracted to. Again, in this case, any persistent intelligent race in this universe would eventually arrive at the one, correct description of it.

              It is obvious that we ourselves have not yet arrived at the complete description, since we have not quantized GR. We are missing at least one more piece of the puzzle. Still, just as Newtonian mechanics remains relevant in the face of GR, so will GR remain relevant in the face of quantum gravity, whatever form it will take.

              • Robert February 20, 2016, 15:16

                Well, I just don’t share your faith about the relationship between math and physics, about the necessity for quantum gravity or what a hypothetical alien science must look like.

              • Hiro February 20, 2016, 17:57

                It might be possible to test that interesting mathematical universe hypothesis, the theoretical side has already been done but the experimental side is completely different story and out of reach at this moment; it’s exactly like some lowly earthworms try to understand QM, the sad fact is that we are those earthworms!

          • Rob Henry February 18, 2016, 17:12

            It would be great to think that most of this work needs no more than the concept of GR itself. When they derived a new lower limit for the mass of a graviton, they must have gone way beyond the simple science that you expect to be universal. I, for one, would like to know what results rely on what paradigm, and the paradigm approach to science often hides that information from us, especially in modern physics. For that reason, I once contemplated ending every comment I made with ‘death to the paradigm approach to science’, but feared few would ever comprehend my meaning.

            • Eniac February 19, 2016, 12:40

              I think you made the correct decision… :-)

            • Robert February 23, 2016, 13:28

              It’s possible that there may be more than one mainstream view in future physics as suggested by the growing rift between string theorists and those who think that string theory have been a colonial waste of brainpower for decades.

              There could be different camps each centering around different approaches.

              • Robert February 24, 2016, 15:08

                Colossal waste of brain power. iPad like to change my words and I do not always notice.

  • Michael February 14, 2016, 3:42

    I am wondering if they can reverse ‘engineer’ the GW’s and determine how much of the energy was absorbed by the line of sight path. The wave should have interacted with matter and dark matter alike draining energy.

    Now if we ever get a solar gravity focus telescope we could train it on a binary neutron star system and we should get a more detailed view of GW’s.

    • Ron S February 17, 2016, 12:19

      The interaction cross-section is very, very weak. Of course that’s also a benefit in that GW allow observations that are invisible to EM.

  • Al Jackson February 14, 2016, 7:25

    Einstein never received a Nobel Prize for relativity, Special or General.
    Svante Arrhenius a Nobel laureate was member of the physics committee of the Swedish Academy. He considered Special Relativity unconfirmed experimentally even in the light of the Michelson-Morley experiment, a result at the time that was being muddled by one particular experiment by Dayton Miller. Mainly though it was the Swedish Academy’s unfavorable view of theoretical physics. Funny, Arrhenius was in favor of Einstein getting a Nobel for Brownian motion (deserved) but agreed with a Nobel for the photoelectric effect.
    To me the clincher for special relativity was Dirac’s theory of the electron. Combining special relativity with quantum mechanics predicted the positron , which was discovered. Dirac got a Nobel for his magic.
    Now John Bardeen, in modern times, got two Nobel’s in physics, so Einstein could have gotten one for SR but was not the way in those days.
    As for General Relativity I can see telling the Swedish Academy that one has to measure 1/1000 the diameter of a proton! Well in 1923!
    The Swedish Academy could go totally weird and award Einstein an ‘honorary Nobel’ for both SR and GR posthumously!
    I guess the exclusion of a posthumous medal is in the Nobel rules?

    • Ron S February 14, 2016, 14:34

      Their reluctance to award the prize for relativity (especially GR, as you say) in the early decades was reasonable since confirmation was lacking and its influence of the practice of physics was modest. At the time of Einstein’s death relativity wasn’t top of mind, with QM getting most of the attention. GR in particular only got seriously rolling in the 1960s when observational astronomy and attempts to unify GR and QM picked up, along with the experimental precision to routinely test some of GR’s predictions in the lab.

      Well, that is all before my time, but it is my understanding from reading history on this topic.

  • spaceman February 14, 2016, 13:05

    We have come quite far in our understanding of the Universe which is exciting, but it is equally exciting if not more exciting that there are still plenty of mysteries left for us to solve in the cosmological arena. Actually, there are more gravitational wave detectors in the planning and/or construction phase in Europe, Japan, and India. VIRGO in Europe, KAGRA in Japan, and LIGO-India. It will be a thrilling triumph of understanding if and when there is both a gravitational wave detection and an electromagnetic wave detection of the same extreme astrophysical event, such as a binary neutron star merger.

    Alas, like a broken record, I am sure there will still be armchair “skeptics” even when multiple detectors spot the same GW and there is simultaneous electromagnetic confirmation. The reason: as I said before, the internet is absolutely RIFE with trite, cheap, and questionable in and of itself “skepticism”. I have come to the conclusion that referring to these people as skeptics is really a euphemism. For some overreaching “skeptics”, cosmologists are damned if they do and damned if they don’t, and I have literally seen this pattern play out time and again among these folks both on this forum and others (e.g. universetoday.com). If a phenomenon continues to elude observational detection, then this is often cited as “proof” that modern physics has it all wrong (“Einstein is wrong” is what I most commonly see) and the scientific community is broken. Low and behold, if the very same phenomenon IS eventually detected through the painstaking hard work, technical/conceptual savvy, and patience of countless experts who are way more qualified than their armchair critics, then the detection must be a result of group think at work and, by the way, “of course” the theory is totally wrong anyway. Clearly, this type of fallacious thinking is not true skepticism. Give us a break!

  • Alex Tolley February 14, 2016, 16:15

    I personally find the Fig 1 in the paper showing the two signals from the 2 separated LIGO facilities quite compelling. The same signal was detected with a large distance between the facilities. While not impossible that this is a terrestrial signal, I’m confident that the team has investigated this possibility and that this has been ruled out.

    I’ll be interested to see how rapidly gravity wave detection evolves in sensitivity so that this becomes a useful tool for astronomy.

  • Randy Chung February 14, 2016, 17:27

    I wonder if we’ll ever hints about the singularities within the black holes when the black holes merge. For instance, just before the merger, I’d guess that the event horizons would be stretched toward each other, and perhaps right at the merger, the event horizon would be oval shaped and rotating.
    Do the gravitational waves come from a moving event horizon, or from the singularities? Would a rotating non-circular event horizon generate gravitational waves? Would two singularities in a merged black hole generate gravitational waves?

    • Michael February 15, 2016, 11:28

      ‘Do the gravitational waves come from a moving event horizon, or from the singularities? Would a rotating non-circular event horizon generate gravitational waves? Would two singularities in a merged black hole generate gravitational waves?’

      Only accelerating masses generate GW’s, with the ring down it appears that there is no addition GW’s when the ‘singularity’ merger event occurs. I am in the camp of there been no singularities, I am suspecting the surface tension of space-time holds up the immense masses preventing the physics ending event.

    • Al Jackson February 15, 2016, 13:28

      When two black holes collide the modeling does make a distinction between the event horizon and the central ‘singularity’. It’s the whole Shebang.
      These two BHs were rotating so they did not have ‘point’ singularities.
      What’s interesting is that the model and the observations have to fit together, and in this case it is to the 5 sigma level.
      This modeling can only be done on computers and that is a hell of a nonlinear modeling problem, really only solved in the last 10 years or so.
      So this also means the numerical modeling has been validated.
      Note the ‘singularities’ are in a region where the density is dominated by quantum effects and nobody has a model of this region , lucky it does not effect the observation, as far as we know.

      • Michael February 16, 2016, 16:04

        I wonder if the rotation was the in the same direction as they would tend to collide and slow the resulting BH’s rotation rate down, could shed light on where it came from ‘another galaxy’ may be.

        ‘Note the ‘singularities’ are in a region where the density is dominated by quantum effects and nobody has a model of this region , lucky it does not effect the observation, as far as we know.’

        Quantum effects would say the ‘singularity’ is there and not there, Schrödinger’s cat comes to mind, we simply do not have the equations to deal with the infinity issues. We need a new set of equations that govern the very, very small i.e. QM’s but they don’t get a handle on it yet. I suspect the hypothetical ‘graviton’ is having a supportive effect to prevent the ‘collapse’ of physics as we know it.

        • Ron S February 17, 2016, 12:22

          “Measuring systems with component spins misaligned with the orbital angular momentum is outside of the scope of this project. However, this study does include systems with component spins that are both aligned and antialigned with the orbital angular momenta, and we will evaluate the ability of aLIGO and AdV to distinguish such systems from one another.”

          http://arxiv.org/abs/1401.0939 (NINJA-2 Project)

  • PW February 14, 2016, 20:53

    Two black holes, combining at a whopping 60 solar masses, releasing energy at the merger brighter than the observable universe…changed the laser wavelength going out from the one bouncing back by…less than half of the width of a proton.
    Holy cow. No wonder no one ever recorded these things.
    It’s a stunning observation. A technical tour de force.
    Einstein is right again, right in ALL of his predictions of GR. The deepest insight into how mass curves spacetime. So totally correct! But, how exactly does that happen? How does mass tell the spacetime to curve? Einstein wasn’t a bit curious about that?
    Einstein had half of the picture, maybe less than half. Quantum gravity is still not explained and the two theories are not compatible. All of the cutting edge theorists have been String Theory guys. But is String Theory panning out? Many scientists are scoffing at it, predicting “everything”, so no need to predict anything.
    It’s a wonderful and difficult age to live in.

  • Robert February 15, 2016, 14:29

    Is this a true gravitational wave, with a field structure like an electromagnetic wave, or merely a pulse of a disturbance in spacetime?

    • Michael February 16, 2016, 7:20

      It is early days with GW’s but they should have all the trimmings of electromagnetic waves, interference patterns and dual particle/wave properties. It will be a huge difficulty to identify an individual graviton if even possible at all as they are theorised to be even less interacting than the neutrino!

      • Harry R Ray February 21, 2016, 14:17

        One of the MANY candidates for the POTENTIAL new LHC particle IS the graviton, but my gut instincts tell me that if this new particle IS confirmed, and it IS a gravitational force carrier, then it would be the MUCH HIGHER MASS SUPERSYMMETRY PARTICLE, the gravitino!

    • Al Jackson February 16, 2016, 9:39

      It has been shown that General Relativity can be constructed as a nonlinear classical field , see Feynman Lectures On Gravitation (2002). So the field and curvature formulations are equivalent.
      In the above Feynman book Feynman derives the GR field equations as a non-linear classical field, he was not the first to do so but it take until the 1950’s to this to be completed.
      Feynman in this book remarks that he is amazed that Einstein did this in 1915! Even tho the ideas behind it had been in the air since the time of Bernhard Riemann.

      • Robert February 16, 2016, 15:47

        But I was asking about the data, not some theoretical construct.

        • Al Jackson February 16, 2016, 17:13

          The data measures the theoretical construct.

          • Robert February 17, 2016, 13:35

            I do not see how the data, an extremely small shift in the path length of an interferometer, proves exactly what the pulse consisted of.

            • Michael February 19, 2016, 15:17

              They will have devices to eliminate as much as possible the likely suspects, and to coin a phrase.

              Chapter 1: “The Science of Deduction”

              Sherlock Holmes Quote

              ‘How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?’

              -The Sign of Four

            • Adam February 19, 2016, 16:58

              Only theory can tell you. Alternative theories are fine – if they actually make the same quantitative predictions of known observations. A browse through the physics arXive quickly reveals how many alternatives there are. The only “alternatives” that are rejected are those that “aren’t even wrong” – I.e. lacking in sufficient mathematical rigour to be able to make predictions with. Most armchair theorising falls into that basket.

  • Harry R Ray February 16, 2016, 10:49

    We MAY have the beast! Read “Fermi GBM Observations of LIGO Gravitational Wave event GW150914”, by Connaughton, Burns et al, currently up as Astro-ph#100 on http://www.voxcharta.org. CAVAET: Swift and Fermi LAT FAILED to detect ANYTHING, and Black Hole mergers are NOT SUPPOSED TO PRODUCE GRB’S OF ANY KIND!

    • Michael February 16, 2016, 20:11

      Their accretion discs could collide and emit enormous amounts of energy in the gamma ray range.

      • Harry R Ray February 17, 2016, 10:58

        Only if they are rotating in the OPPOSITE DIRECTION FROM ONE ANOTHER! That WOULD produce NEAR LIGHT-SPEED HITS!

        • Michael February 17, 2016, 15:48

          ‘Only if they are rotating in the OPPOSITE DIRECTION FROM ONE ANOTHER! That WOULD produce NEAR LIGHT-SPEED HITS!’

          It is the other way around, co-rotation implies maximum impact velocity and the impact velocity would be vey high.

          Even if they are anti-rotating the masses and debris distance would have to be very similar to prevent any reasonable collision energy which is much less likely.

  • Harry R Ray February 16, 2016, 15:15

    UPDATE: The Fermi GBM “detection” is now “most likely” just an artifact, since INTEGRAL ALSO FAILED to detect ANYTHING as well.

  • Rob Henry February 16, 2016, 20:15

    One more question for the experts what is the gain factor for gravitational waves at its minimum gravitational focus length from the Sun.
    I know that the answer for photons is 10^8, but these must skirt its disk giving a focal length of 550 AU. To communicate with another similar star we can use the gravitational focus of each for a gain factor of 10^16.

    For neutrinos and gravitational waves the focal line starts earlier. I believe that solar length is 110 AU for these. How does that effect the gain factor, and what would it have to be to contemplate far-future interstellar communication through gravitational waves.

    • Michael February 17, 2016, 4:06

      Light , neutrinos and gravity waves should move at the same velocity, c, having said that neutrinos are thought to have mass and so can’t be traveling at the speed of light. Perhaps neutrinos can travel less than the speed of light but they are so small they don’t interact with anything to slow them down.

      The focus point for light is ~550 AU, for neutrinos it is also ~550 AU but using the denser core it can be around ~19 AU, Uranus’s orbit.


      Gravity waves should have a similar profile to neutrinos as the denser core would bend them more than at the surface just as with neutrinos.

      • Rob Henry February 17, 2016, 18:16

        Thanks Michael. The possibility of 19 AU is a surprise! Unfortunately that paper doesn’t seem to address how that would effect the gain factor. Not even in a ballpark sense.

      • Michael February 20, 2016, 2:53

        It may be possible to roll a GW measuring device into a solar focus telescope system. If we had a few telescopes, say 3, that followed the bent rays towards the GFP in a triangular formation any waves could be detected by the change in the light beams length as GW pass, as well as use the resolution and magnification abilities of the sun. This system would be great in observing BH’s in their natural environments and neutron stars.

  • Adam February 17, 2016, 5:31

    The complaint that the GW observation hasn’t been laboratory replicated reminds me of the idiotic complaint that neutron stars can’t be replicated in laboratories and thus can’t be real. Astronomy is an observational science chiefly because most of the phenomena studied are impossible to replicate in verisimilitude inside a lab. Being sceptical of theory when its first applied to phenomena is regular scientific scepticism, but its ridiculous when a mountain of data exists. GWs have been intensively studied in detailed simulations – as intensively as the insides of the stars. That their phenomenological data is now catching up is fruition of that work.

    • spaceman February 17, 2016, 18:01

      Well said.

  • James Stilwell February 17, 2016, 21:40

    Is it silly to ask what space is expanding into? Is it silly to wonder what is empowering the light photon to keep traveling across the universe at light speed? And what exactly is the fabric of space anyway? Thank heavens everyone is long past this area of Centauri Dreams.

    • Al Jackson February 18, 2016, 15:56

      I once heard some answer the question:
      “What is the universe expanding into?”
      “The universe is expanding into time.”

      • Eniac February 19, 2016, 12:53

        But time and space are the same, both part of the universe. I think the correct answer is “nothing”.

        Or, in other words: It IS a silly question :-)

        In the same way that “What happens at the end of the world?” was when the world was thought to be flat.

    • Rob Henry February 19, 2016, 18:01

      You shouldn’t speak of the devil. To the mathematically minded it is natural make the assumption that spacetime is expanding into nothing at all, but now I can’t help thinking how to model it with spurious added dimensions. Aghh!

      • Michael February 20, 2016, 13:11

        Perhaps the nothingness is a sea of gravitons, a ‘particle liquid’ with surface tension upon which matter and energy are confined. A quantum fluctuation created a mass-energy release the ‘Universe’ that is spreading over the surface of this finite volume.

        I find it alarming that it would expand at an ever increasing velocity into nothingness, I am still stunned and so would Einstein and no one would dare tell Newton!

        Perhaps the universe from our point of view looks as if it is accelerating because it is ‘going over the horizon’ of this sphere. Eventually perhaps this expanding matter-energy will eventually collided on the ‘other side’ of this sphere collapsing into the interior to await the next ‘quantum fluctuation’.

        I prefer a cyclic Universe, it makes me feel more secure knowing it will all ‘Perhaps’ start again, but science has taught some very harsh lessons indeed!

        • Harry R Ray February 21, 2016, 14:21

          Dark ether!?

          • Michael February 26, 2016, 4:09

            I am thinking along the lines of a sphere of gravitons which have an enormous liking for each other and the surface of the sphere is where there is a leakage of field. The surface behaves as if it has surface tension because of the unequal graviton surface arrangement. It is this surface tension much like what happens in liquids that gives rise to our feeble gravitational constant on which matter and energy are largely confined. If we understand this arrangement of gravitons we could potentially manipulate space-time to our advantage.

  • ljk February 19, 2016, 11:00

    Good background on how the discovery of gravitational waves came about (hint, it was a long team effort):


  • Michael February 20, 2016, 14:15

    Here is a simulated merger of two BH’s,


    Further simulations,


    Imagine a GF telescope around one of these entities! you would see to the dawn of time and to the end of it in a very narrow region. These entities are the Alpha and the Omega of space and time.

  • Michael February 21, 2016, 10:20

    Neat site about LIGO, GW’s and BH’s,



    You can hear the sound the two BH’s would make merging, like a drop of water from a tap falling into a bowl of water!

  • Eniac February 22, 2016, 1:38

    No, sorry, the Nobel Prize is not awarded for financial contributions. That would be silly.