Follow Slashdot stories on Twitter


Forgot your password?
Space Science

Initial Tests Fail To Find Gravitational Waves 553

eldavojohn writes that though gravitational waves are "predicted to exist by Einstein's Theory of General Relativity, the initial tests run by the Laser Interferometer Gravitational-Wave Observatory Scientific Collaboration (LIGO) failed to find anything. It doesn't disprove their existence although it does rule out a subset of string theory. From the article, 'For example, some models predict the existence of cosmic strings, which are loops in space-time that may have formed in the early universe and gotten stretched to large scales along with the expansion of the universe. These objects are thought to produce bursts of gravitational waves as they oscillate. Since no large-amplitude gravitational waves were found, cosmic strings, if they exist at all, must be smaller than some models predict.' The scientists working in Washington and Louisiana (in tandem to rule out flukes) will now move on to Advanced LIGO which will analyze a volume of space 1,000 times larger. If they don't find any gravitational waves in that experiment, the results will be more than unsettling to many theorists."
This discussion has been archived. No new comments can be posted.

Initial Tests Fail To Find Gravitational Waves

Comments Filter:
  • by genjix ( 959457 ) on Friday August 21, 2009 @08:02AM (#29144875)

    1. find contradiction in model
    2. modify model slightly for exceptions
    3. ??????
    4. PROFIT!!!

  • by Anonymous Coward on Friday August 21, 2009 @08:03AM (#29144883)
    That's how science works, yeah.
  • Success! (Score:5, Insightful)

    by benwiggy ( 1262536 ) on Friday August 21, 2009 @08:06AM (#29144899)
    An experiment is only a failure if you don't learn anything from it.
  • Re:Unsettling? (Score:3, Insightful)

    by Schiphol ( 1168667 ) on Friday August 21, 2009 @08:22AM (#29144993)
    > The worst, that could happen for a physicist, would be that the observations could be explained with GR.

    This kind of (extremely common) remarks strike me as frivolous. It is one thing to say that physicists enjoy being disproved, because this shows the length of the road ahead; it is another thing to say that physicists would hate to attain knowledge in one particular area or other. Science is in the business of securing truths, not in the business of idly advancing ever-refutable theories.
  • Re:Success! (Score:5, Insightful)

    by Thanshin ( 1188877 ) on Friday August 21, 2009 @08:26AM (#29145013)

    An experiment is only a failure if you don't learn anything from it.

    There are still degrees of success.

    I tend to consider it a failure if all I learned is: "I should wear fireproof clothes for all my pyrotechnical flamabilities experiments.

    Especially after the third time I learn the same lesson.

  • by ledow ( 319597 ) on Friday August 21, 2009 @08:30AM (#29145041) Homepage

    More like a cycle... observe, theorise, observe to check results, refine theory.

    In this case, this is exactly what's happened - the observations looks like they may not fit the theory perfectly - hence, once that's been double-checked, go back and revise the theory and try to find out why.

    If you don't test the theory, it's worthless. And if you posit a theory, only observation will definitively "prove" it. Science is about positing theories, observing results, and if they fit the theory - WONDERFUL... you just "predicted" part of the universe that nobody has before.

  • by Thanshin ( 1188877 ) on Friday August 21, 2009 @08:31AM (#29145049)

    Unless horses get so expensive and building carts so cheap you'd rather prepare a thouosand different carts just to be absolutely sure of which kind of horse you're going to invest all your effort trying to find.

  • by Shihar ( 153932 ) on Friday August 21, 2009 @08:37AM (#29145083)

    Not really. String theory is based on observations like any theory. You can observe things, see that it lines up with your theory, and you can falsify string theory. The problem with string theory, and the reason why people complain about it, is that most of its observations are also true of the boring old theories we have right now or true of other variations of string theory. People get a little annoyed when you come up with a dozen contradictory string theories and according to all known observations they could all be true and no one can figure out a way to disprove any of them shorting of lighting off a big bang.

  • Re:Success! (Score:3, Insightful)

    by clone53421 ( 1310749 ) on Friday August 21, 2009 @08:38AM (#29145105) Journal

    That's a valuable lesson, but that would indicate that the first two times were failures...

  • by Tenebrousedge ( 1226584 ) <(moc.liamg) (ta) (egdesuorbenet)> on Friday August 21, 2009 @08:42AM (#29145135)

    Intelligent Design has theories? What, if anything, does it predict? How could it be falsified?

    This is like that Babbage quote: I am not able rightly to comprehend the kind of confusion of ideas that could provoke such a question.

  • by FTWinston ( 1332785 ) on Friday August 21, 2009 @08:43AM (#29145141) Homepage
    Thats half-way there. Observe, then theorise, then make a prediction, and test that. The problem is that we have General Relativity and Quantum Mechanics, and both describe their own domains very well (the very large and very small, respectively) - but we have no way of combining the two into a single, unified theory.

    String theory in its various permutations could be (partial) theoretical solutions to this, but coming up with testable predictions of such theories (such as large-amplitude gravitational waves) is horrendously tricky. Indeed, some theories are pretty much untestable by definition - many string theories have been considered to come into this category.

    So we have our observation (GR and QM both work well, but are hard to unify), we have many predictions (string theories, etc), and now we have a test of many such theories in the form of this experiment.

    "Observe then theorise" is all well and good, but when you can't you can test predictions of your theory, its not worth much.
  • by damburger ( 981828 ) on Friday August 21, 2009 @08:47AM (#29145161)
    Whilst scientists, being human, sometimes form attachments to a particular theory, the failure to find predicted gravity waves can only possibly be good for physics. It is also an exciting time for physicists; failures of existing theories to explain observations provide the kind of mystery a scientist can make a name for himself or herself by solving.
  • by 4D6963 ( 933028 ) on Friday August 21, 2009 @09:05AM (#29145293)
    That's the wrong way to look at it, when you fail to detect something that SHOULD have been detected using what you used, that means that things just actually aren't quite as you expected them to be. Sure there still may be some be gravitational waves, but this proves that they're nothing like we thought/nowhere as strong, if they exist at all.
  • by Vellmont ( 569020 ) on Friday August 21, 2009 @09:07AM (#29145309) Homepage

    Now maybe the string theorists, such as Michio Kaku, will spend a little more time back at the drawing board and a little less time pretending to be Carl Sagan crossed with Alan Alda.

    I doubt it. There is no such thing as "String theory". It should be more accurately called "String Theories". It's like a multi-headed hydra that lives forever. Falsify one part of it and 3 other theories pop up to replace it.

    The only thing that can really kill String Theories is a experimentally verified competing theory that's unifies quantum mechanics and general relativity. Kill the body and the head will die.

  • by Shihar ( 153932 ) on Friday August 21, 2009 @09:21AM (#29145435)

    Intelligent Design has theories? What, if anything, does it predict?

    That is actually the wrong criticism of ID. ID can certainly predict things. If the 'designers' are a bunch of bored aliens that like to do anal probes, you could predict that the aliens will cause changes in animals DNA such that they tend towards having ass holes. If the FSM is the designer, than you will predict that creatures will be designed towards higher spaghetti creating lifeforms. If the designer is an all powerful omnipotent god that thinks beetles totally kick ass, you will predict that there will be a crap ton of beetles (which there in fact are).

    And hey, all of the above might very well be true.

    If someone wants to go out and try and prove it, more power to them. The issue is that ID is nothing more than an attempt by religious nuts to try and teach about baby Jesus in the schools. If there were people that were taking the 'study' of ID seriously, they would sit around designing experiments to catch whatever the mysterious force is that manipulates DNA to force evolution and create their spiffy designed universe. Further, when they pondered what the force was, they would have to constrain themselves to theories based upon real physics. This would handily rule out 'magic' and 'god juice'. If they want to show that the force is god juice, they then need to go ahead and reinvent physics to try and explain how the force of god juice works. At no point does 'magic', 'just cause', or 'humans can't understand because they are not Jesus' acceptable.

    The issue with ID is that science doesn't accept 'magic' as an answer. If you say a designer is forcing evolution, you need to go and figure out the force being used, and it either needs to conform to current theories or you need to find new ones that explain all observable events. This is what makes the ID folks nothing more than religious whack jobs. When Darwin declare that natural selection was the answer, people went to work figuring out how natural selection works and didn't just decide it was a magical force that just happens. They tore it apart by from a macroscopic level that studied how animals compete and co-opt, they tore it apart on the biological level understanding how cells reproduces, and they keep on drilling down until they are looking at atoms and figuring out how quantum affects influence evolution. At no point was anyone ever satisfied with 'magic' as the answer.

  • Re:They exist. (Score:4, Insightful)

    by aicrules ( 819392 ) on Friday August 21, 2009 @09:26AM (#29145471)
    Pretty much certain? Yes, a lot of observations have fit the theory of gravitational waves, but this one in particular went against it. The observation method may be flawed in some way, but it COULD mean that the other observed effects are actually attributable to something else. Whether flawed or not, this observation did not disprove or prove the existence and/or nature of gravitational waves. It only served to potentially better define them.
  • by maxwell demon ( 590494 ) on Friday August 21, 2009 @09:43AM (#29145609) Journal

    Even if science were to come to the conclusion that some theologians were right all the time (it's completely impossible that all of them are right, because they contradict each other), it would still be a great achievement, because the theologians only have their faith, while the scientists would in that case have scientific proof. Or, to remain in the picture, while the theologists have been brought to the peak, and just had to believe it's the peak they were told it is, the scientists know the way to the peak and can therefore be completely certain of being on the right one. And BTW, even for the theologians sitting on that peak it would be great news, because they then would finally have a good argument that they got to the right peak, and the other theologians sitting on the other peaks were wrong.

    However, it is more likely that when the scientists get over the final rock (assuming there is one), the'll find no theologian there, because those all sit on those lower peaks where it is much easier to get to.

  • by Anonymous Coward on Friday August 21, 2009 @09:56AM (#29145769)

    The problem of "negative" results, is that maybe you didn't detect something because it's actually not there, or maybe you just did your experiment wrong. Differentiating the two is non-trivial.

  • by Anonymous Coward on Friday August 21, 2009 @10:23AM (#29146005)

    Agreed. There's nothing more exciting that the ID debate. It never fails to change everyone's mind every time it comes up, and it's like so totally appropriate here.

    I don't really care if my neighbors think we sprouted like mushrooms from unicorn poop, as long as they don't try to force their beliefs on me, and I think they should have the right to teach their kids whatever they want and not be forced to....

    Oh! See! You tricked me into the debate....

  • by Abcd1234 ( 188840 ) on Friday August 21, 2009 @10:38AM (#29146135) Homepage

    You *are* aware that Dark Matter has been observed, right? Or did you just miss the announcement of the Bullet Cluster results (among others)? As for Dark Energy, that isn't really a theory, so much as an observation with no explanation. Specifically, the rate of expansion of the universe is increasing. This is a fact. *Why*, we don't know, so we just call it Dark Energy for now. It's a placeholder, nothing more.

    So please, take your trolls and go back into your basement, as it's pretty clear you don't really know what you're talking about.

  • Re:Unsettling? (Score:4, Insightful)

    by Attila Dimedici ( 1036002 ) on Friday August 21, 2009 @10:42AM (#29146165)

    . Science is in the business of securing truths, not in the business of idly advancing ever-refutable theories.

    I'm sorry, science is in the business of proving theories wrong. All current scientific theories are merely those that have yet to be proved wrong. They are extremely valuable in that they can be used to predict future behavior of the universe to a significant degree of confidence. However, scientific theories cannot be proven true, they can only be proven false.
    The great weakness of science is that people have a tendency to view theories that have been around for a long time and not proven false to be true. All it really means is that they are reliable predictors of the behavior of the universe insofar as our technology allows us to observer the behavior of the universe. Sometimes this means that they are good theories that are very useful (say General Relativity), other times it merely means that our technology has not yet reached the point where we can reliably test any of the theory's predictions (say the various String Theories).

  • by Abcd1234 ( 188840 ) on Friday August 21, 2009 @10:46AM (#29146209) Homepage

    That is actually the wrong criticism of ID. ID can certainly predict things.

    Quite correct, that is the wrong criticism. Unfortunately, yours is, too. The argument that "science doesn't accept 'magic' as an answer", and therefore ID isn't science is a circular one. ie, if ID is magic, then science doesn't accept magic, therefore ID isn't science. Well, yeah, duh, no kidding. Heck, technically, I think that might actually be "begging the question".

    No, the *real* problem with ID is that it isn't *falsifiable*. And this is specifically because any attempt to falsify the theory, by providing evidence which contradicts any "predictions", could easily be reinterpreted under the lens of "god did that, too". And if a theory can't be falsified, it simply isn't science.

  • Re:Linearization (Score:5, Insightful)

    by Brain-Fu ( 1274756 ) on Friday August 21, 2009 @10:55AM (#29146325) Homepage Journal

    Of course Einstein was wrong.

    He was, at best, as right as any human could have been given the evidence available at the time. If he was as true a scientist as the world portrays him, then he expected to have his model refined over time as new evidence comes to light, eventually being completely replaced by something much more accurate.

    Whatever new theory we build based on this new evidence will also be wrong, for the exact same reasons.

    But it will be right enough to be useful as a stepping-stone to an even righter theory. That is how science works, and that is also why find science zealots to be even more annoying than religious zealots have accepted as absolute truth a model that is just a stepping-stone, in direct contradiction of the very methods that they proclaim to be the ultimate determiners of truth.

  • Re:Hex (Score:2, Insightful)

    by rubycodez ( 864176 ) on Friday August 21, 2009 @11:00AM (#29146367)

    it's a particle that waves from a float in a parade

  • Come again? (Score:3, Insightful)

    by JSBiff ( 87824 ) on Friday August 21, 2009 @11:05AM (#29146423) Journal

    How does *failing* to find the thing which was predicted to exist by Einstein, prove Einstein right? Granted, they weren't *expecting* to see gravitational waves at this point, because they were only looking for waves which would have been at such a high magnitude that they weren't expected to exist *except by string theorists* because of part of string theory. So, that part of string theory was *dis-proved*, but Einstein's theory has not yet been proved correct (though they expect it will be 'soon' when they start looking for smaller magnitude waves).

    Anyhow, what's wrong with proving that our ideas about the natural universe are either correct or incorrect (or somewhere in between, in some cases)? You know, one never knows all the applications of scientific knowledge until long after that knowledge is obtained. Perhaps spending all this money now to do this science today, will lay the groundwork for very useful applications in the future? Perhaps the knowledge gained from these observatories will help us figure out how to make fusion work economically, or help us develop more advanced spacecraft, or even more advanced terrestrial vehicles? Or help us detect the aliens which are spying on us with advanced cloaking devices but can't hide their G-waves (ok, that last is mostly a joke, but one never knows)?

    Scientific knowledge is, in itself, largely useful - how much has our technology and economy, our health and standard of living, improved, because of scientific advances achieved in past centuries that are only now being put to great use?

  • Re:Linearization (Score:5, Insightful)

    by Idarubicin ( 579475 ) on Friday August 21, 2009 @11:06AM (#29146449) Journal

    and why do we think we can detect them this deep inside a Gravity well?

    honestly, looking for something like that needs to be outside the gravity well of the sun.

    There's a pebble on top of Mount Everest. Using my trusty ruler, I measure the pebble as being 1.3 inches tall.

    "Aha!", says my colleague. "Now we know that the top of the pebble is exactly 6 miles, 1.3 inches high!"

    "No, silly!", says my other colleague. "The only way that we can measure the height of the pebble precisely is by bringing it down to sea level! Being on a mountaintop confounds any precision measurement!"

    Oddly enough, the pebble turns out to be 1.3 inches tall. A most remarkable coincidence, I'm sure.

  • by dov_0 ( 1438253 ) on Friday August 21, 2009 @11:10AM (#29146491)
    In a field of grain, you can grow wheat, barley, rye or oats. It's still a field. ID is still an area that people study. It's a field. You may not agree with it. I may or may not agree with things that come out of it. That's fine. It's still a field of study. Get over it.
  • Re:Linearization (Score:5, Insightful)

    by clone53421 ( 1310749 ) on Friday August 21, 2009 @11:15AM (#29146563) Journal

    Here's the part that I find interesting. The whole gravity/space-time curvature is merely an abstraction of gravity into a new dimension.

    Ancient people's idea of gravity was simple. Stuff goes down.

    Then people figured out that the earth's surface is curved, and "down" didn't work anymore. The new theory of gravity said that stuff moves toward other stuff, and the earth is a big blob of stuff that all our little stuff moves toward. Kinda simple, but you don't have the nice, straight, linear sort of system. You've got a radial one, and other planets and stars have their own gravity fields that pull stuff toward them, and it's a bit more complex.

    So, with this notion of mass curving the surface of space/time in some higher dimension, we envision space/time as a sort of elastic surface. Mass sinks into the surface, and smaller mass will "roll" into the depression caused by the larger mass. Why does the "mass" roll downhill? Well, there's the kicker: this higher dimension apparently has its own sort of gravity, and, like the ancients' theory, it's nice and straight: it always goes down!

  • Re:Success! (Score:3, Insightful)

    by shadwstalkr ( 111149 ) on Friday August 21, 2009 @11:18AM (#29146593) Homepage

    Go talk to some older chemists about the days before strict lab safety. Days gone by were pretty exciting.

  • by dov_0 ( 1438253 ) on Friday August 21, 2009 @11:54AM (#29147141)

    That's very true, of course. But you can't grow wheat, barley, and Ford Pintos. I'm arguing that physics, philosophy, and automobile repair are fields of study, while ID is not. It is a platform. An agenda. It's like saying the people paid by the tobacco companies to falsify studies on the effects of tobacco smoke are conducting science. Apples to orangutans.

    At many levels, Evolutionism is an agenda as well. Why else would there be such a push to have it taught in schools?

  • Re:Linearization (Score:2, Insightful)

    by maxwell demon ( 590494 ) on Friday August 21, 2009 @11:57AM (#29147213) Journal

    Well, there's simply no point outside of the black hole in the absolute future of any point inside the black hole. In other words: There's no way anything could go which leads outside the horizon. You'd need superluminal speed to escape, but gravitational waves only go at the speed of light (and everything else goes at most as far, too).

    That's the "trick" of the event horizon: It's not exactly that a strong force keeps you from going out, it's just that there is no way out (at least no way you can follow).

  • by martyros ( 588782 ) on Friday August 21, 2009 @11:58AM (#29147223)

    The issue with ID is that science doesn't accept 'magic' as an answer.

    Here you have just given away that you start with the philosophical assumption of naturalism: that is, everything that is (or everything that affects the universe) happens inside the universe. There is not, cannot be, any supernatural. That's not a proof you have, it's an assumption that you start with. And that's fine, we all make assumptions (e.g., logic works), but it's better if you're honest about it.

    Let's try an analogy. Computers operate by rules, right? Everything in the computer can be defined by the state of its memory, registers, and disk (toss in whatever extra motherboard or micro-architectural state you want). How it transitions from one state to another depends only on what the state before it was, and any inputs into the system. The vast majority of those state transitions are 100% deterministic. (I know, I did my PhD thesis on this stuff.) Only a relatively small amount of input when you boot up determines whether you're playing Quake with friends or writing posts on Slashdot. In fact, for a running system overall, the less input needed to make the whole run smoothly the better designed it was.

    Now, suppose there were a self-aware program living in your computer, looking at the state of the system, and trying to determine if there were such things as these mysterious "users", and if so, how they affected the state of the system. All you know is "data"; you can't see the physical world. Since these mysterious "users" don't live in data, to you they're essentially super-natural. Now ask your question: How is it that these "users" affect data?

    If you do, you'll see that in this case "magic" (meaning, "something not described in the rules of the system") is an acceptable answer; in fact, "magic" is by definition the only answer. Users create the input from the keyboard, mouse, network, &c that feed into the system. Users really can decide which processes live and die; but what does that look like to a program? Some random data came in on a certain line which fed into a program, which when certain data hits inside a certain area on the screen (the "X" button on the upper right-hand-side of a window), the program sends a signal to another program which sends a signal to another program which tells it to exit. An atheist program might say those inputs were random, like states in quantum physics. Furthermore, really technical humans may have even more control: They can use in-circuit-emulators to directly change state on the CPU and use PCI bus devices hidden from the cpu to directly read and write memory. They can rewrite the register after an ADD instruction to make it look like it added 2 and 2 and got 5.

    People who believe in the Judeo-Christian God believes that God has that kind of access to the universe. If he can feed 5000 people from five loaves of bread and 2 fishes, turn water into wine, and come back from the dead, surely he can twiddle some DNA at key points in history. By definition, a "miracle" is a temporary suspension or contravention of the normal laws of the universe. And thus, by definition, the "force being used" may not be detectable or describable under the laws of physics, any more than changes a programmer makes using an in-circuit-emulator would be detectable or describable by a program inside the computer trying to determine if the universe consisted only of data, or if there was a "supernatural" outside of the data.

    Note that my point is not to defend any particular ID theories or people who promote them. I have a lot of biologist friends who are Christians, and think that the evidence pretty clearly supports the current scientific understanding of the development of life here on Earth. Believing that God can intervene in the natural world doesn't mean that you can't believe in and shouldn't look for natural laws and natural explanations for things. But your logic of "ID is bad because it will accept a supernatural explanation (i.e., magic)" isn't sound.

  • by lgw ( 121541 ) on Friday August 21, 2009 @12:20PM (#29147555) Journal

    Science studies that which is not "magic". A supernatural explanation may be true and it would still not be science. This is a necessary limit of science.

    However, even if the answer is "God did it", if God chooses to do things according to some set of rules (as most religions would have us believe), then those rules should be apparant from the patterns observable in the universe, and science should be able to deduce those rules.

    That is the point of science: to observe the patterns than events in our universe follow, and produce a set of rules -- a predictive model -- that explain those patterns. This approach only fails if there are effects in our observable universe with an arbitrary or random cause outside of it. Only a God who actually behaved in an arbitrary and random way would affect the predictive success of scientific models.

  • by KingMotley ( 944240 ) * on Friday August 21, 2009 @12:30PM (#29147701) Journal

    That isn't a valid argument. You could say the same thing about any subject. Such as:

    At many levels, Mathematics is an agenda as well. Why else would there be such a push to have it taught in schools?

    The simple answer is because evolutionism is actually based on scientific evidence. ID is simply a religion that is trying to make itself look scientific so it can be lobbied to be taught in public schools.

  • by SignalFreq ( 580297 ) on Friday August 21, 2009 @12:54PM (#29148021)

    A statistical test akin to testing for a biased coin would be sufficient to create an ID test.

    So then do it. Create the test and give us the results, let us verify your test methodology and your data and your results. Until such a time, ID is merely conjecture and not a scientific hypothesis.

  • Re:Success! (Score:2, Insightful)

    by jimmydevice ( 699057 ) on Friday August 21, 2009 @02:01PM (#29148825)
    Fenyman was making physics fun before Jamie and Adam were daddy's little squirt.

Logic is the chastity belt of the mind!