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Space Science

Gravitational Waves May Have Been Detected In 1987 221

KentuckyFC writes "In 1987, a physicist called Joe Weber claimed to have detected gravitational waves at the same time that other scientists spotted a supernova called SN1987A. His claims were largely ignored because of calculations showing that gravitational waves could not be strong enough to be picked up by Weber's equipment, a set of giant aluminium cylinders designed to vibrate as the waves passed by. But these calculations were based on first order effects in the way spacetime can be distorted. Now a new analysis shows that second order effects can enhance gravitational waves by four orders of magnitude, but only when certain asymmetries are present. It turns out that SN1987A possesses just the right kind of asymmetries to make this enhancement possible because the supernova wasn't entirely spherical. Which means that Weber, who died in 2000, may have been the first to see gravitational waves after all."
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Gravitational Waves May Have Been Detected In 1987

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  • Honor (Score:5, Funny)

    by AKAImBatman ( 238306 ) * <{akaimbatman} {at} {}> on Wednesday March 04, 2009 @03:21PM (#27067907) Homepage Journal

    Gravity waves? I thought they'd never be observed! Impeller Drive [], here we come! Now all we need is to prove hyperspace as a viable means of travel and invent Warshawski sails. :-P

    (Joking aside, this is great news! Gravity waves have been one of the most difficult aspects of relativistic physics to pin down.)

    • Re:Honor (Score:5, Insightful)

      by dk90406 ( 797452 ) on Wednesday March 04, 2009 @03:40PM (#27068143)
      This is not great news. This is (great) speculative news. It is interesting and inspires hope, but I seriously doubt that the scientific community will accept this as proof.
      We are talking '87 and there are too many unknowns in the experimental setup, that no-one can clarify now. Did a truck drive by here in '87?
      • Re:Honor (Score:4, Insightful)

        by Brian Gordon ( 987471 ) on Wednesday March 04, 2009 @03:56PM (#27068369)
        The problem is that you can't exactly reproduce a supernova..
      • I saw the setup (Score:5, Interesting)

        by io333 ( 574963 ) on Wednesday March 04, 2009 @09:47PM (#27072607)

        I saw the setup in the winter of late 1986. It was deep (many levels) under the physics department's machine shop, deep underground, at the University of Maryland & you had to go down several ladders to get there. It was hanging from the ceiling, big giant (I thought hollow, but apparently solid) cylinders of what looked like aluminum, hanging from thin wires. Does anyone know if it is still there?

    • Re: (Score:3, Interesting)

      by rpjs ( 126615 )

      But if this Weber (Joe) detected the gravity waves at the same time as SN1987A lit up, the Honorverse has a major problem as that Weber (David) assumed that gravity waves would be FTL.

      • As I recall, only the grav waves traveling through hyperspace were FTL. So grav waves could be read by sensors at superluminal velocities, but the impeller drive functioned on the light-speed grav waves. I think. :-P

      • Re: (Score:3, Insightful)

        by Anonymous Coward
        and at what speed do you presume the light emmited from this supernova made its way to earth, if they arrive at the same time, they are both going at a speed they should be going
      • Re: (Score:3, Interesting)

        Gravity waves arriving at the same time as light seems to raise a whole lot of questions to me.

        For a start it means gravity affects itself in the same way it bends and affects light. As light travels away from a gravity well it's redshifted, bringing it down to a lower energy state. Light can also be focused by a gravity well (gravitational lensing). Since gravity arrived at the same time it can also do all these things to itself. So why aren't we seeing a whole lot of unpredicted gravitational anomolies
        • by hitmark ( 640295 )

          could it be that he didn't detect the first wave? or am i totally of target?

          i'm envisioning something like ripples in a pond after a rock is thrown in.

          basically the star going nova yanks at the gravity "fabric", and said "fabric" then vibrates for a while, setting of weaker and weaker waves as the nearby masses acts as "shock absorbers".

          and it could be that said wave action plays tricks on the light, as it has to deal with the changes in the gravity...

          so, maybe the light from the nova was carried on a wave

        • Re: (Score:3, Insightful)

          by DM9290 ( 797337 )

          It also raises the question: if light waves can't escape a black hole then why can gravitational waves?

          indeed. one would almost think light and gravity waves are not the same kind of thing.

  • FTFS (Score:2, Funny)

    by Anonymous Coward
    In 1987, a physicist called Joe Weber...

    So, what was his real name? Also, editors, the last statement of your summary is a sentence fragment. Please fix this.

    • Re: (Score:3, Funny)

      by elrous0 ( 869638 ) *
      Actually, you're wrong. There is clearly supposed to be an "and" before "claimed." The physicist who called Joe just wishes to stay anonymous at this time.
    • I used to be a grammar nazi. Then I dated someone who spoke English as her second language (after French). Such an experience will thoroughly train you to suppress your nazi tendencies. Trust me.

  • Dude, (Score:5, Funny)

    by OneSmartFellow ( 716217 ) on Wednesday March 04, 2009 @03:25PM (#27067959)
    ...where's my surfboard ? I'm totally stoked, I want to be the first to ride a gravity wave, that'd be, like really heavy, man !
    • Re:Dude, (Score:4, Funny)

      by boarder8925 ( 714555 ) <> on Wednesday March 04, 2009 @04:17PM (#27068657) Homepage
      There's that word again. "Heavy." Why are things so heavy in the future? Is there a problem with the earth's gravitational pull?
      • Re:Dude, (Score:4, Funny)

        by linzeal ( 197905 ) on Wednesday March 04, 2009 @04:30PM (#27068807) Homepage Journal
        Americans importing half of the solar systems foodstuffs have grown so large that the average city block in the 20th century barely contains the girth of one 5000 ton Homo Americanus Gigantus. This displacement of mass has caused a localized gravitational disturbance in the curvature of spacetime large enough that places like the former state of Texas are now 200 feet below the 2000 BCE sea level. If it wasn't for the mile high tall walls with lasers on them surrounding the US to keep out aliens it would be completely underwater except for parts of Colorado.
  • Nobel prize (Score:5, Interesting)

    by Alain Williams ( 2972 ) <> on Wednesday March 04, 2009 @03:26PM (#27067969) Homepage
    Can this be awarded posthumously ?
  • Waves? (Score:5, Funny)

    by imajinarie ( 1057148 ) on Wednesday March 04, 2009 @03:36PM (#27068089)
    And here I was always convinced they were Gravity Particles.
  • How much (Score:5, Insightful)

    by MyLongNickName ( 822545 ) on Wednesday March 04, 2009 @03:37PM (#27068105) Journal

    How much does it have to suck to die, with your observations being discredited, and your claims laughed at? Then a decade later, the scientific community goes "oops, you were right".

    And now, in Slashdot's infinite wisdom, I am required to wait five minutes between posts.

    • Re:How much (Score:4, Informative)

      by paiute ( 550198 ) on Wednesday March 04, 2009 @03:44PM (#27068215)

      How much does it have to suck to die, with your observations being discredited, and your claims laughed at? Then a decade later, the scientific community goes "oops, you were right".

      This guy had a carrier shot out from under him. I don't think the naysaying of a bunch of geek theorists bothered him much.

    • Re:How much (Score:4, Funny)

      by Anonymous Coward on Wednesday March 04, 2009 @03:45PM (#27068231)
      I'm sure glad you didn't die during those five minutes. I mean, how much does it have to suck to die, with your post being discredited, and your claims laughed at? Then a decade later, the Slashdot community goes "Oops, you were right" with a +5 Insightful.
    • Re: (Score:2, Insightful)

      by Em Emalb ( 452530 )

      Probably doesn't suck at all for this guy, I'm sure he doesn't care at all. Maybe his family and friends, but he probably doesn't care one bit.

      • Now, Slashdot is a US based site, but I'd guess you don't have to be so cautious among as...

        You can safely say "almost certainly".

    • Ask Alfred Wegener [].
      • Ask Alfred Wegener.

        Bah, just ask me!

        I invent the time machine, but die before getting credit because some corporation sent an assassin back in time..hold on, there's the doorbell.



      • by Sanat ( 702 )

        What a brave man this Mr. Wegener was.

        His theory on continental drift was pretty accurate, but like Weber he never got the credit.

        Back in 1952 I was in the 3rd grade (Ohio) and remember Mrs. Beard the teacher showing us a pull down map on the world in geography class. I raised my hand and said "Look Mrs Beard... if you push all of the continents together they fit together like a puzzle... she said "Sanat, don't be ridiculous, that is the stupidest thing I have ever heard."

        Seeing patterns is one of the best

    • by Kjella ( 173770 )

      How much does it have to suck to die, with your observations being discredited, and your claims laughed at? Then a decade later, the scientific community goes "oops, you were right".

      Isn't that what they say about great artists too? IMO it's just bullshit to soothe the 99% who'll remain utterly insignificant after their death too, but it's not like scientists are the only ones not to be understood by their contemporaries.

    • by MBCook ( 132727 )

      Hopefully not too much.

      If I die before my Hambuger Earmuffs are finished thought, I may get the opportunity to find out though.

      *glaven* warm ears...

    • Re: (Score:3, Interesting)

      by east coast ( 590680 )
      As a scientist, I would find it a far better thing to have my claims proven correct after my death than to have them declared correct in my lifetime only to be discredited later due to lazy peer review.

      Science should be a marathon, not a sprint.
    • Re:How much (Score:5, Informative)

      by JustinOpinion ( 1246824 ) on Wednesday March 04, 2009 @04:36PM (#27068867)

      Then a decade later, the scientific community goes "oops, you were right".

      Hm. But this raises an interesting question. Was he actually right?

      Let's assume for the moment that TFA is correct, that higher-order terms can enhance gravity waves and that this is the case for SN1987A. So Weber's measurements in 1987 contained a valid signature of a gravity wave.

      In a sense, then, he did detect gravity waves. And so he was right in saying "I detected gravity waves". However, he may have been right for the wrong reasons. Science works by interpreting data, and convincing others that your interpretation is correct. Weber was not able to do so. He was not able to convince others because he couldn't provide a way to connect the magnitude of the signal in his measurements to the available theory.

      Now, if he had done what the present scientists have done, and demonstrate that the higher-order terms make gravity waves detectable in his apparatus, then he might have been able to convince his colleagues. Then he would really have been right (and for the right reasons). But he didn't (as far as I can tell). He incorrectly said "gravity waves, as described by these theories/equations, have been measured on my instrument"... which is wrong.

      Some of you may think I'm just splitting hairs or something. But it's important because in science being right is not about randomly guessing the right answer... it's about providing a robust argument based on repeatable measurements. In science, happening upon the right answer using the wrong logic isn't really considered a good thing. As an extreme analogy, imagine that I am trying to predict when the next volcanic eruption will be, and I come up with a complicated theory based on tides. Then I correctly predict an eruption. A few years later some smarter guys come along and create a really great theory that predicts volcanic eruptions, and show that it is really based on magma flow... and that I was just lucky to have predicted the eruption. Was I "right" in my prediction?

      • Re: (Score:2, Informative)

        by poopdeville ( 841677 )

        That depends on whether there's any causal link between the tide and magma flow. (There is)

      • Re: (Score:3, Insightful)

        by ShakaUVM ( 157947 )

        In a sense, then, he did detect gravity waves. And so he was right in saying "I detected gravity waves". However, he may have been right for the wrong reasons. Science works by interpreting data, and convincing others that your interpretation is correct.
        Not necessarily. There's different things under the title of science, and one of them is black-box science, when you're investigating something that you don't know the slightest thing about, and seeing what happens. We don't know exactly how gravity waves sh

        • > We don't know exactly how gravity waves should behave...

          That isn't exactly true. General Relativity predicts exactly how they should behave. However, computing the amplitude for a real event such as an asymmetric supernova is very difficult, and in Weber's day they settled for approximations such as assuming symmetry. Thus they had reason to suspect there was a small chance that their calculations were wrong and Weber's measurements right.

      • But it was known that the calculations were approximations.

    • by shma ( 863063 )

      How much does it have to suck to die, with your observations being discredited, and your claims laughed at? Then a decade later, the scientific community goes "oops, you were right".

      You obviously didn't read the actual paper. This is in no way a rigorous theoretical argument that Weber saw gravitational waves. It's nothing more than a rough order of magnitude calculation. A second look should be taken, but we should not start handing out posthumous awards right away.

      And who was laughing at him? Weber was regarded as a pioneer of gravitational wave experiments. You can find a discussion of his work in standard textbooks. You seem to assume that anyone who doesn't succeed in every one

      • by khallow ( 566160 )

        The most telling part of the paper comes at the end: "It would also be necessary to check that the predictions of this proposal do not violate the absence of observed gravitational waves from other sources." To me, this 10^4 enhancement factor is probably enough that we'd have seen GW from a variety of sources by now in our more sophisticated detectors (which are interferometers, and are unrelated to Weber's setup), which leads me to be dubious about the claims of enhancement.

        But I gather those aren't as sensitive to the second order effects in question, right?

        • by shma ( 863063 )

          But I gather those aren't as sensitive to the second order effects in question, right?

          Wrong. The supposed 10^4 enhancement factor is in the magnitude of the GW waves and would be seen by any detector.

    • by jamesh ( 87723 )

      Then a decade later, the scientific community goes "oops, you were right".

      In further news, a sharp jump in gravity waves being detected since this new discovery was announced have now been determined to have been caused by Joe Weber rapidly spinning in his grave.

    • Re: (Score:3, Insightful)

      by mog007 ( 677810 )

      What more could a scientist hope for? You're ostracized your entire life, and after you're dead and forgotten, your research comes back to the forefront and people realize you were onto something.

      Surely Copernicus and Galileo would be psyched to be part of the group who resurrected the concept of science. What about Darwin? Darwin's ideas were good, but not good enough. He had a mechanism for evolution, but no way of allowing the mutations to be passed on. With the synthesis of genetics, Darwin's name

  • Gravity model (Score:3, Interesting)

    by cyberchondriac ( 456626 ) on Wednesday March 04, 2009 @04:04PM (#27068493) Journal
    One thing I've never liked about the current popular gravity model, you know, the one they discuss on discovery channel, usually for a cosmology special, where they discuss how gravity distorts space-time, and then you get to see a CGI animation of a large ball on a rubber like grid -drawn as a 2 dimensional analogy- and the ball is pushing down on the grid, making an indentation in it, and another, smaller, ball starts circling the bigger ball, eventually falling in towards the larger ball..
    Isn't that like using gravity to explain the effect of gravity?
    • Re:Gravity model (Score:4, Insightful)

      by tylersoze ( 789256 ) on Wednesday March 04, 2009 @04:25PM (#27068727)

      It's only a very crude analogy. In reality, it's both space *and* time that are being distorted. Gravity causes all the "straight lines" (geodesics) in space-time to become curved. So the Earth orbits around the Sun and a thrown ball follows a parabolic arc because it's actually a "straight line" in space-time that gravity has curved just like a Great Circle on the Earth is a "straight line" (i.e. the shortest distance between two points) with respect to the surface of the Earth.

      • Re: (Score:3, Informative)

        It's only a very crude analogy.

        That's a good point, and it should be elaborated as the proper response
        to cyberchondriac.

        cyberchondriac identifies the grid-bent-by-balls as "the current popular
        gravity model". It is in fact a popular model, which I remember from
        watching PBS even as far back as the 1970s. The good thing about this
        model is that it allows one to visualize how a mass both distorts space
        and moves in response to the distortion caused by another object. But
        its goodness as a model of gravity ends there, in part due to

    • Not really. (Score:3, Informative)

      by AltGrendel ( 175092 )
      They're showing it in two dimensions, when it's actually happening in four. Try and think about that, but be careful. Your head might explode.
      • They're showing it in three dimensions. We humans can visualize up to 3 very well. Adding another gets complex.
        • Actually you could probably visualize a simple case of one dimension motion with a traditional 2D space-time diagram (1 spatial + 1 time dimension) and curve that into three dimensions. You could at least visualize why a dropped ball would accelerate downwards along a straight line. Starting at 0 velocity (a straight line upwards along the t-axis) that "straight line" would start to curve in the direction of gravitational source, which translates into an increasing velocity (the slope of the curve).

      • Re: (Score:3, Informative)

        by tylersoze ( 789256 )

        It's even worse than that. To visualize a curved 4-dimensional space you'd need 5 dimensions to embed it in. Not to mention the fact that time is a different type of dimension so distances are measured differently in space-time. t^2 - x^2 (or "proper time", the time a object would experience traveling along that line) instead of pythagorean x^2 + y^2. So the distance between all points along a light cone is 0 and every outside is imaginary!

    • It's not trying to explain, it's an analogy that gives an example of how distortion in topology can affect motion.

      The reason they use it in pop science programs is it's hard to visualize 4 dimensions of curvature.

    • Well if it's a CGI animation, then you're not really using gravity, you're just using fancy rendering. But ignoring that technicality, it's not really that much different than using a substance made out of molecules to build a scale model of a molecule. You're just using what's available to you in order to make a simplified model. There's not any easy and intuitive way to represent some aspects of physics in a manner that relates directly to the normal human experience of the universe. So you have to make

    • and then you get to see a CGI animation of a large ball on a rubber like grid -drawn as a 2 dimensional analogy

      Actually, it's a four dimensional analogy.

      You have your x/y dimensions (forwards/backwards,left/right) as noormal, but they have flattened the z (up/down) as it's not important for the visualization. Now, instead of there being an up/down they have used that axis to show gravity.

      Trying to draw something in four dimensions and hoping that the audience watching the show will make heads or tails of it would be like trying to nail jelly to a tree.

    • Re:Gravity model (Score:4, Interesting)

      by Chris Burke ( 6130 ) on Wednesday March 04, 2009 @05:46PM (#27069845) Homepage

      Isn't that like using gravity to explain the effect of gravity?

      Sure, but it's just an analogy. It's not supposed to explain why masses warp space-time, only to show how a mass causing space-time to warp gives rise to effect we call gravity. In the analogy, the curvature of the space-time sheet is caused by gravity pulling downward on a ball to create the curve. In the reality the analogy is supposed to represent, the curvature of space-time is gravity. The analogy just gives you an easy way to ignore the "why" that theory can't answer, so you can focus on understanding the effect.

      If it makes you feel better, you can just ignore the gravity-pulling-the-balls-down part of the analogy, and replace it with a simple assumption that a ball on the sheet causes the sheet to bend, and that other balls tend to move towards "low" spots in the sheet, with no explanation for why this happens.

    • by bonch ( 38532 )

      It's just a convenient visual model to explain the idea of gravity distorting space-time.

  • by stoolpigeon ( 454276 ) * <bittercode@gmail> on Wednesday March 04, 2009 @04:04PM (#27068495) Homepage Journal

    it was the pure amazement of my high school teachers that I was graduating. I was pretty shocked too.

  • using my tin foil hat.
  • Poor guy (Score:3, Interesting)

    by markov_chain ( 202465 ) on Wednesday March 04, 2009 @04:29PM (#27068785) Homepage

    What are they going to name the gravity SI unit, Webers? Right...

  • Why wouldn't you say Joe Weber discovered this, instead of some random physicist? Is his name Joe Weber or is that just what people called him?

    I don't know anyone else named Joe Weber so you would not have to say Joe Weber the physicist to clarify either, although I appreciate the additional information. I would have said maybe a dog called Joe or a robot called Joe, but it sounds awkward and a bit insulting talking about people.

    Me, I'm a poster called b4dc0d3r - you don't know if this is a person or mach

  • Some more info (Score:5, Interesting)

    by photonic ( 584757 ) on Wednesday March 04, 2009 @05:12PM (#27069285)
    I don't know the fine details of Weber's experiments, but I believe his 2 meter metal bar [] was operating at room temperature, so he was severely limited by thermal noise. His claimed strain sensitivity (delta L / L) was on the order of 1e-16. There are currently a small number of resonant bars operational which are kept at just a few Kelvin. They reach a sensitivity around 1e-21 in a narrow band and have not measured anything during the last ~5 years, so Weber's claim is highly unlikely. I am involved with one of the big [] interferometric [] detectors [], which use vacuum tubes of several kilometers and reach sensitivities at the 1e-22 level over a broad bandwidth. If the astrophysical models are right we should be able to detect something within the next 5 years.

    As already mentioned in a previous comment, the article is somewhat speculative and it is a little bit late to verify the experiment. The standard accepted practice for claiming the detection of a GW is to observe the event with at least 2 detectors which are separated far enough to not measure the same external disturbances (but preferably 3 or more spread around the world so that you can do proper triangulation of the source). One single glitch might be a cosmic ray, lightning, dust falling before your detector, an earthquake, an instrumental error, anything. We see more of those than we like. One glitch measured at different observatories within the time it takes to travel at lightspeed (a few ms) at different observatories around the world might give you a nobel prize.

    One book that is high on my 'to read' list is Gravity's shadow [], which supposedly describes not only Weber's experiments, but also its reception by the scientific community and the eventual downfall of Weber's reputation.

    • Re: (Score:2, Insightful)

      "eventual downfall of Weber's reputation."

      I think this type of thinking is a problem with the scientific community. It prevents people from admitting mistakes and moving on. If someones hypothesis is wrong that shouldn't be the end of their reputation. It doesn't necessarily make them a bad scientist and shouldn't be mean the ruination of their careers and the destruction of their reputation. Whats important is the process. Its quite possible that with limited data two different possible hypotheses cou

      • Re: (Score:3, Insightful)

        by mbone ( 558574 )

        It's when you don't admit that you are wrong that your reputation suffers.

  • by Anonymous Coward on Wednesday March 04, 2009 @07:45PM (#27071417)

    Since I work in gravitational wave physics, I read this article with great interest when I saw it. I'm afraid, the arguments are far from compelling. Some of the many problems:
    1) The proposal for the calculation of the energy content of the gravitational wave is speculative at best. There is no agreed upon quantity for the energy of spacetime curvature, as the author himself points out.
    2) The only calculation of the claimed non-linear enhancement seems to be in a paper which is cited by title and author only - there is no way to find and read the paper which this calculation was supposed to be in.
    3) There seems to be some confusion between cylindrical gravitational waves and cylindrical gravitational wave sources. His method using approximate lie symmetries would correspond to the symmetry of the spacetime - ie the matter. I don't believe there is any way to produce cylindrical (or spherical) gravitational waves since you need a time-varying mass quadrupole to create them. Axisymmetric sources do not produce such waves. In short, there are exact (non-linear) solutions to the Einstein equations with no sources that have a gravitational wave-like nature, but they are not the solutions you get for (linear) gravitational waves from sources, and it is misleading to confuse them.
    4) His supposition that 10% asphericity of the source is somehow related to a gravitational wave which is 90% spherical and 10% cylindrical is just bizarre. The gravitational waves from a rotating ellipsoid which has a 0.1 asphericity (assuming it is rotating about one of it's minor axes, since if it was rotating about the major axis it would be axisymmetric and give of no gravitational waves) is not really like an exact spherical wave or an exact cylindrical wave solution.

    So, all told, this is still very early and very speculative. The safe money at this point is still that Weber (who had other irreproducable "detections") did not see a gravitational wave. While the non-linear nature of gravity would in principle allow for some sort of self-amplification, there has been to my knowledge no paper that claims to show this kind of amplification by four orders of magnitude available to view, let alone verified by other calculations or observations. Until something like that is available, this is at best speculation and hype, not science.

  • by MillionthMonkey ( 240664 ) on Wednesday March 04, 2009 @07:57PM (#27071521)

    I remember because I was alive in 1987 and I felt it too when it happened. It was just as that star was exploding as a matter of fact. But it was hard to notice and you had to be paying really close attention. I take a lot of mind-altering drugs so I was able to sit still and concentrate on the physics.

    Basically gravitational waves have a quadrupole moment so you feel your ears move apart slightly and your face contracting vertically. Then your face expands vertically as your ears move together. This happens a bunch of times and the effect is very slight- just a few femtometers- so you might not notice. But once you feel that cool wind of neutrinos flowing up from the floor and blowing through your hair, that should be a fairly obvious hint that a star is exploding somewhere and deserving of your attention.

  • I don't think so. (Score:4, Interesting)

    by mbone ( 558574 ) on Wednesday March 04, 2009 @08:33PM (#27071893)

    I don't like to speak ill of the dead, so I will leave it at that.

  • Joe Weber (Score:4, Interesting)

    by rotenberry ( 3487 ) on Thursday March 05, 2009 @11:22AM (#27077353)

    In 1980 I met with Joe Weber at the Jet Propulsion Lab.

    He had been reducing the noise in his experiment over the decades was still confident that the disturbances he was recording were gravitational waves.

    Rather that being bitter about the 20 years of skepticism concerning his experiment, he was upbeat and optimistic. He understood that the theorists claimed that he could not possibly being seeing gravitational waves, but, as he told me, "You are not going to see them if you don't look!"

    The reason he was at JPL was that John Anderson, Frank Estabrook, and Hugo Walquist conducted searches for gravitational waves using high precision spacecraft tracking during the 1970s and continue to search to this day.

Things equal to nothing else are equal to each other.