Another gravity wave detected by LIGO

Please consider donating to Behind the Black, by giving either a one-time contribution or a regular subscription, as outlined in the tip jar to the right. Your support will allow me to continue covering science and culture as I have for the past twenty years, independent and free from any outside influence.

The LIGO gravitational wave detector has detected its second gravitational wave, thought to come from the merger of two black holes.

The new observation came at 3:38.53 Coordinated Universal Time on 26 December 2015—late on Christmas day at LIGO’s detectors in Livingston, Louisiana, and Hanford, Washington. As in the first event, the detectors sensed an oscillating stretching of space-time, the signal, according to Einstein’s 
general theory of relativity, of massive objects in violent motion. Computer modeling indicated that its source was two black holes spiraling together about 1.4 billion light-years away. (LIGO researchers had seen a weaker signal on 12 October 2015 that may be a third black hole merger.)

Note the last sentence in the quote above. They might have had a third detection, but are uncertain enough to have not claimed it as one.


  • wodun

    The sensitivity on these LIGO systems is remarkable. That they think they sensed a gravitational wave but can’t say for sure shows just how small the potential wave was. The LIGO facilities offer tours and anyone traveling near one should check their websites to see if a tour is available.

  • Frank

    The frequency of these events suggests that black hole mergers are relatively common occurrences.

  • The creation of black holes themselves are relatively common. Gamma Ray Bursts (GRBs) are thought to signal their creation, and these occur routinely about once per day.

  • Max

    I’m still skeptical. The first event was a 5.1 Sigma (a five Sigma and below does not register)

    The machine is so sensitive, that it can detect a distortion 10,000 times smaller than a proton. (?) How is this possible? Do they compensate for vibrating Atoms in molecules? The electrons in the laserbeam are individually nearly 8000 times larger than this.
    (They could measure the size of quarks/gluons… )
    The original article says,” if we could measure the distance between our Sun and the nearest star Alpha Centauri, this machine could measure a difference down to the width of a human hair”. (That’s unbelievable.)

    The entire event occurred in 2/10 of a second. (is it possible to merge such massive objects in so little time?)

    Speaking of time, inside the event horizon of a black hole, not only does space warp, but time warps to the extent that it nearly Stops…
    Head on collision could take centuries…
    Scientists are still debating how gravity can warp the space and time not even letting light escape and yet gravity itself seems unaffected. A photon has mass, gravity it seems does not. This is why light speed is limited because of this mass?

  • LocalFluff

    They calculated an expected 2 to 400 detections per year after the first one. You know how astronomers use numbers differently than ordinary people, it wouldn’t do for a weather forecast. I thought when I saw Kip Thorne, who has been at this since he was a student, at that press conference, that he already had more of them up his sleeve.

    Talking about Nobel prizes, as we obviously do, wouldn’t it be a great idea for a new space enthusiast billionaire to donate money for new Nobel prizes dedicated to astronomy, to planetary science and to rocket science? And to finance the extension of the prizes to more than three per branch a year. LIGO papers published begin with entire pages of the physicists involved. A hundred years ago three were plenty, Einstein wrote all his papers alone. Now huge organizations of abstract specialists are required to achieve breakthroughs in natural sciences.

    Economics was added half a century after Alfred Nobel’s testament, financed by the Swedish central bank, and (macro) economics is not even a science, or an obviously failed one at best. Edvin Hubble, the discoverer of extragalactic space and the expansion of spacetime, never got a Nobel prize although he lived decades after his paradogm shifting discoveries. The motivation was: “Astronomy is not physics!” Astronomy was then still conservatively viewed as a branch of mathematics, almost. Little more than celestial mechanics, the art of calculating the positions of dots in the sky. Einstein got his Nobel prize for the photoelectric effect because it could be studied in a lab down here. The Nobel proze is such a great motovational force for the top scientists that it should be very attractive to build upon it, without devaluing its prestige. Three in physics per year is too small anyway. Individuals should win it, not organizations. It is after all only individuals who do the job, an organization is nothing without them

  • Edward

    LocalFluff wrote: “Individuals should win it, not organizations.”

    I agree completely. The intent of the prize is to encourage those receiving it to go on to ever more discoveries. Double winners are rare, but that they exist demonstrates the value of this prize and its intent.

    An organization will have more income than the value of the prize, so the incentive is largely lost on the organization (e.g. the IPCC). The value of the prize to most organizations is that they are the ones who have the laureates — not the prizes. Universities and countries brag about the number of laureates they have (whether they did the work there or they came later does not matter so much, e.g. Einstein counted as a laureate in Germany, the US, and at Princeton). The university I graduated from gave special parking spaces to its laureates.

    The downside to handing out too many prizes, however, is that it waters down the professional and social value of the prize. On the other hand, the academies should try hard to assure that those who are most responsible for each discovery gets appropriate credit and laurels, even if that is more than three people; it seems that they increased from two to three, in the 1930s, so an increase is reasonable. The winners’ organizations can do the rest (e.g. give them special parking spaces).

  • wayne

    Interesting update on the LISA Pathfinder Mission from last week:
    –apparently set-up is going better than expected.

    Max: There’s techie-data in the notice, you would appreciate, as to the sensitivity they intend to get in space.

    As for getting a precise location of the source’s; I believe I read recently–with 2 detectors they can figure out a relative location with huge error bars & ideally need 3 data points to triangulate a location that means anything.

    JPL & The Perimeter Institute have some lengthy video on gravitational waves, LIGO, and space-based detectors.

  • LocalFluff

    Maybe a silver Nobel prize could be introduced, financed by donors who themselves are prominently successful in their field like Alfred Nobel was. So that up to three get today’s prize as it is, but hundreds would get a medal and shake the hand of that stupid king too. Changing the tradition would kill the magic, but it might be extended to honor more of all those who made tremedous controbutions to science. An update every hundred years or so could be healthy even for traditions.

    They seem surprised that it turned out to be somewhat easier than they had expected. Black holes are larger than expected, making bigger waves in our spacetime. And their machines incredibly work just great. And more detectors are planned, and I think investments in this are being greatly accelerated now that is no longer a theoretical pipe dream. Spacetime itself is unstoppably waving through us, this is beyond materia, it’s fantastic.

  • Edward

    Hmm… Interesting thought of having two levels of prize. The lower level may have similar status as an Oscar Nominee in the film industry. An acknowledgement of contribution to a great discovery.

    However, I would not be inclined to assign a Nobel Silver Prize winner his own parking spot, unless I didn’t have any Gold Prize winners at my (hypothetical) facility or campus.

Leave a Reply

Your email address will not be published. Required fields are marked *