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Gravity waves from Big Bang detected
- sosuke 13y agoIs gravity a wave then, like light? I thought the jury was still out on that.
- maaku 13y agoGravity is the structure of space-time, and that structure supports waves. The proper analogy would be that gravity is like electromagnetic fields, and the equations of electro magnetism support wave-like events, and we call this light.
- omegant 13y agoSo mastering the energy Of gravity could be the ultimate advanced civilization objective. A warp drive is just the first practical (or at least the most obvious) aplication of such technology. <_end Startrek like voice>
- maxerickson 13y agoA reactionless drive (that just pushes on spacetime instead of trying to alter it) is probably even more practical.
- jp555 13y agovacuum propeller. Imagine if a submarine had to carry all the water it's propeller pushes on? That's rockets today. If we could make a vacuum propeller, that acts directly upon space-time, it would radically transform the prospect of space travel.
- deletes 13y agoThey are doing research in this direction. http://en.wikipedia.org/wiki/Quantum_vacuum_plasma_thruster http://en.wikipedia.org/wiki/Quantum_vacuum_plasma_thruster
- mladenkovacevic 13y agoYour comment just put a big goofy grin on my face.
- hackinthebochs 13y agoWarp drive would at the very least require an equivalent finding for momentum.
- jerf 13y agoMastering THE ENERGY OF GRAVITY! is trivial. Pick something up right now. Now, lift it over your head. You've given it GRAVITATIONAL ENERGY! Now, drop it. It has now expressed its GRAVITATIONAL ENERGY! Do not confuse science fiction with science fact. Exactly, exactly how gravity works is a mystery, yes, but interacting with the gravitational field is very, very settled science. If you want to harness the mighty power of gravity, build more tidal harnesses.
- saalweachter 13y agoNot to mention that gravity is kind of puny even at that scale. The rate of energy loss from the Earth's rotation due to the tides is about 3.3 TW. In 2007, the US consumed about 3.1 TW.
- wcoenen 13y agoAnother way to look at this is that human civilization consumes a scary amount of power. Our global energy consumption in 2008 was estimated to be 474 exajoules. The total energy received by the earth from the sun during a year is about 5 million exajoules, a fraction of which reaches the surface. So we are only a factor 10,000 away from that. At a seemingly modest 2% yearly growth rate, we could increase our energy consumption a hundredfold in two centuries, and waste heat will start to become an issue.
- saalweachter 13y agoYep, even today waste heat is equal to something like 5%[1] of the global heat gain. Still the lesser problem today, but once we bring a petawatt of clean fusion online... [1] it's been awhile since I looked up this number. Could easily be an order of magnitude lower, which is still fairly impressive.
- maxerickson 13y agoWhat is 'the global heat gain'?
- hackinthebochs 13y agoIf the propagation of gravitational effects is analogous to electromagnetic waves, then maybe this is an avenue for a "gravity cloaking device" which would have interesting implications (hoverboard anyone?)
- wcoenen 13y agoCloaking yourself from waves would not negate the effects of a constant field.
- deleted 13y ago[deleted]
- allochthon 13y agoKeeping in mind that gravity is only one of four interactions, and not even the only one working at long distances, I would have figured that it is an important component of the structure of spacetime. Have I overemphasized the other interactions in thinking this?
- AnimalMuppet 13y agoWell, the other interactions (electromagnetic) propagate through spacetime. Gravity waves are ripples in spacetime itself. So they aren't quite the same.
- miralabs 13y agoLight is both a particle and a wave
- privong 13y agoThe carrier for gravity may also have wave-particle duality, via the graviton[0]. 0 - https://en.wikipedia.org/wiki/Graviton https://en.wikipedia.org/wiki/Graviton
- mcguire 13y agoWhile light's behavior as both particle and wave can easily be observed, the particle carrier for gravity, the graviton, hasn't been observed in the wild. As a result, gravity is currently only a wave, in relativistic spacetime.
- gnaritas 13y agoOr, light is neither a particle nor a wave, but a distinct thing that seems to behave like both under various circumstances.
- lnanek2 13y agoThere are some cases in quantum mechanics where you just have to accept that a value can be two different things at once, not that is was really one thing. Like it or not, superposition is a real thing, so it is inarguable that assuming something has to have one value at any one time is wrong. Wave-particle duality is a lot like that as well, where it is tough to come up with some distinct thing that could possibly act like a particle, but still diffract like a wave.
- Double_Cast 13y ago> where it is tough to come up with some distinct thing that could possibly act like a particle, but still diffract like a wave. Armchairing here. But as I understood, objects in quantum-land are known as "amplitudes in the complex plane". They behave like this all the time and under all circumstances, and should be understood on their own terms. E.g. squaring the height of pond ripples doesn't return a probability distribution. The "sometimes it's a wave, but other times it's a particle" idea is a historical artifact, like how humanity uses a base ten number system.
- sethrin 13y agoThat gravity propagates as a wave is a consequence of Relativity. To date we have no direct detections of gravitational waves, but we have detected energy loss in a binary system which is consistent with theory. http://en.wikipedia.org/wiki/PSR_B1913%2B16 http://en.wikipedia.org/wiki/PSR_B1913%2B16
- Wintamute 13y agoAs far as I understand it gravitational waves are "ripples" in the fabric of spacetime caused by the motion of high velocity, high mass bodies. That's why they're called "gravitational waves" not "gravity waves", i.e. they're not waves of gravity, rather waves caused by gravitational bodies.
- deleted 13y ago[deleted]
- wozniacki 13y agoHere's an excellent explanation on cosmic inflation from Sean Carroll: http://www.preposterousuniverse.com/blog/2014/03/16/gravitational-waves-in-the-cosmic-microwave-background/ http://www.preposterousuniverse.com/blog/2014/03/16/gravitat...
- mcguire 13y ago...which seems to be unreachable for me at the moment. I'll have to check it out later. In the mean time.... Cosmic inflation has always bothered me. I just don't get it. I'm not a physicist at all, though. I get why it's postulated. (The uniformity of the universe requires it to all be in close proximity and the time scales don't have enough time for that part, IIUC.) But the expansion of inflation is significantly faster than the speed of light. What's up with that? I know, spacetime is expanding rather than things moving within spacetime, but still, during inflation, this particle here is watching that particle there recede at >> C. I doan geddit. (Grump.)
- GeneralMayhem 13y agoThe way I understand it is that the problem is with the definition of velocity. If you want to measure speed, you have to measure distance, which eventually comes down to the magnitude of the vector between two points - subtract the X's, subtract the Y's, subtract the Z's. Problem is, at cosmic scales, expansion means that those two points aren't in the same reference frame, because more space has appeared between them. You can try to measure it, but by the time you do the axes themselves have stretched again. The two X's can't be subtracted directly anymore, because they're on different reference frames. You get a result of >>C only by assuming that the relevant bits of space are relatively well-behaved Euclidean R^3, but that's not the case.
- marcosdumay 13y agoCurrent models state that the Universe is still expanding "faster than the speed of light" (that is, fitting your explanation) if you look far enough. (What, of course you can't do, because light from there is redshifted into zero.)
- 13y ago
- yeukhon 13y agoIs this the same as graviton in string theory? Or could this be used to further justify the existence of graviton?
- acjohnson55 13y agoI'm not a physicist, but I would think the answer has to be yes, since everything we know of with wave nature also has particle nature on some scale. But I can't even imagine what kind of experiment would detect one. Wikipedia has some interesting things to say about this: http://en.wikipedia.org/wiki/Graviton#Experimental_observation http://en.wikipedia.org/wiki/Graviton#Experimental_observati...
- swatkat 13y agoGuardian has a nice and simple article explaining gravity, gravitational wave, and about this detection: http://www.theguardian.com/science/2014/mar/17/gravitational-waves-bicep-inflation-big-bang http://www.theguardian.com/science/2014/mar/17/gravitational...
- Tarrosion 13y agoAs an outsider (PhD student in a quantitative field, no relation to physics), the experimental physics community really strikes me as a class act. High standards for statistical significance, vigorously working to rule out mundane explanations before publishing data, outlining which statistical tests will be performed before data is collected...I'm a fan. "In fact, the researchers were so startled to see such a blaring signal in the data that they held off on publishing it for more than a year, looking for all possible alternative explanations for the pattern they found." That's pretty amazing; as far as I can tell, such caution is less typical in e.g. the brain sciences.
- balsam 13y ago>outlining which statistical tests will be performed before data is collected Not knowing how things are usually run in this field, but I am surprised that these details were actually published. Do you have a link to them?
- tibbon 13y agoThe popular media really like to grab any neuroscience paper and twist the hell out of it. Talk to most neuroscientists and they are much more conservative in their leaps and jumps... in reality its moving slowly, but the media wants to portray a Ray Kurzweil reading of every finding.
- estebanrules 13y agoOf course. Would you expect anything less from popular media?
- return0 13y agoI think it's a two way relationship, scientists love a chance to reach out to the media too, even if a bit more reserved, you even get that from their press releases. Publicity helps in getting funding in the life sciences, for better or worse, it's part of the system.
- SoftwareMaven 13y ago
- sanxiyn 13y agoFrom the horse's mouth: http://bicepkeck.org/ http://bicepkeck.org/
- deleted 13y ago[deleted]
- DangerousPie 13y agoThey made a nice video of the researcher surprising Prof Linde with the news: http://www.youtube.com/watch?v=ZlfIVEy_YOA http://www.youtube.com/watch?v=ZlfIVEy_YOA The reaction of the couple is great!
- sanxiyn 13y agoLinde: "Can can can can can you repeat it?" It was very touching.
- cromwellian 13y agoI love the humility, skepticism of belief Linde professes at the end. Despite a deep desire to believe in the beautiful, he is well aware of how you can be seduced into believing things because you want to, not because the universe is that way.
- LeoNatan25 13y agoThis is what separates the scientists from ... others.
- Balgair 13y agoWe can only wish that is true, we are all just humans in the end: http://www.economist.com/news/briefing/21588057-scientists-think-science-self-correcting-alarming-degree-it-not-trouble http://www.economist.com/news/briefing/21588057-scientists-t... Also, I vaguely remember a study in 'some journal' that looked at all it's P values[0] and found an alarming number of them parked right at the limit of acceptance (.05), more so than chance could assume. If anyone remembers this study and can provide actual proof (not my terrible memory), I would be very thankful. [0]https://en.wikipedia.org/wiki/P-value https://en.wikipedia.org/wiki/P-value
- betenoire 13y agoI don't think he's commenting on statistical analysis, but rather saying that a scientist should follow the clues where ever it may take them, instead of looking for the clues that will get them where they want to be. And of course they fuck up, too.
- AnimalMuppet 13y ago> This pattern, basically a curling in the polarization, or orientation, of the light, can be created only by gravitational waves produced by inflation. I call BS. "Within our current theories, this pattern can be created only by..." would be a more accurate statement. The arrogance that "with this theory, we understand it all" has been shot down over and over in the history of science. [Edit: tarrosion noted the caution of experimenters in making sure that the data could not be caused by something else. This is appropriate, and it's good that they have it. You now have one, and only one, theoretical explanation for the data. But the statement in the article that I quoted is still a step too far. It presumes that our existing theories are the only possible ones.]
- carbocation 13y agoUsually publications are understood within the context of their field. It would be exhausting to list each limitation of your field in every paper, and the limitations are understood by the intended audience.
- mcguire 13y agoA friend-of-a-friend has the "science religion"---he seems to try to claim that what we "know" now is the closest to absolute truth that we could possibly get, and would therefore make the claim from the article with a straight face. (He seems unfazed by comments that some new discovery tomorrow might invalidate what we "know" now and seems to think that what we would learn would simply be more absolutely true.) Me, I'm of the opposite philosophy and understand that everything I think I know now is probably wrong. It's just slightly not-as-wrong as last week.
- BugBrother 13y agoYes, but note that there are differences in how you can work in experimental/historical sciences. Your friend^2 would probably gain by reading more about the scientific method, see wikipedia etc. (But then, so could probably you and me both, too.)
- 13y ago
- sixothree 13y agoNothing bugs me more than when a supposedly scientific magazine uses thumbnails of important images without actually linking to the full size. I just wanted to see the black lines in the image the article refers to.
- d0mine 13y agoGoogle search by image http://www.google.com/insidesearch/features/images/searchbyimage.html http://www.google.com/insidesearch/features/images/searchbyi... returns http://bicep.rc.fas.harvard.edu/bicep1_3yr/ http://bicep.rc.fas.harvard.edu/bicep1_3yr/
- astrosi 13y agoThe Paper and all the figures are located here http://bicepkeck.org/ http://bicepkeck.org/
- estebanrules 13y agoHow would you folks rate the significance of this, let's say as far as scientific discoveries / realizations go in the last 100 years? Yes, of course this is completely subjective. I would say in the top three.
- sanxiyn 13y agoAssuming it's real, I think it's up there with T ~ 3 K (cosmic microwave background itself, Nobel 1978) and Λ > 0 (accelerating universe, Nobel 2011).
- 3327 13y agoJust 5 sigma confidence...
- piratebroadcast 13y agoI'm very curious of how, if we now presume this to be true, if and how that may effect the "Are we living in a simulation?" question.
- yukichan 13y ago> and how that may effect the "Are we living in a simulation?" question. Not at all.
- benched 13y agoI think there exist potential implementations of virtualization that are not detectable from inside the virtualization.
- deleted 13y ago[deleted]
- eru 13y agoEspecially if you are willing to sacrifice speed.
- philip1209 13y agoThey have evidence of gravity waves, but cannot prove causation (i.e. big bang), right?
- marcosdumay 13y agoWe already have overhealming evidence of the Big Bang, this is yet more evidence. But we have only a relatively small amount of evidence of Inflation and gravitational waves, and this is evidence of both (even better, it's evidence against several theories of Inflation - including the current prefered ones). Correlations are evidence of causation, and quite strong evidence if you foud them because of a causal theory.
- npizzolato 13y agoAs someone who doesn't have a very good grasp of these things, can you explain the difference between the Big Bang and inflation to me? It seems like the Big Bang is the explosion of all matter that would be in our universe, and inflation is the rapid expansion of the universe itself. And inflation is believed to have taken place almost immediately after the Big Bang. Is that sort of accurate?
- wbhart 13y agoThe Big Bang theory is not about the "explosion" of our universe from a point. Firstly, the universe may have always been infinite in size. It's just that every small piece of that infinite universe has been expanding since about 14 billion years ago. Secondly, "explosion" is a misnomer. The universe is expanding, not exploding. As a theory, the Big Bang theory makes various predictions, such as the cosmic microwave background radiation, the relative abundance of elements in the universe and of course the expansion of the universe. But it doesn't predict that the universe will be the same in all directions. There just isn't time for energy fluctuations to have evened themselves out due to the transfer of energy from hot spots to cold spots. That process can only happen at the speed of light (energy is transferred at the speed of light). Because of the way space is expanding, the speed two points move away from each other depends on how far apart they are. Thus, very distant points on opposite sides of the sky are actually moving apart faster than the speed of light. What this implies is that there's no way they can have had time to reach thermal equilibrium (i.e. have reached the same temperature)! But satellite observations tell us the observable universe is very nearly the same temperature in every direction! The problem is resolved by the Theory of Inflation. This is a time of exceedingly(!!) rapid expansion which occurred before the time described by the Big Bang theory (remember the Big Bang theory is not about the "explosion" of the universe from a point, but about the subsequent expansion of the universe after inflation). The reason inflation solves the problem is that a very, very tiny region of space (subatomic scale) expanded exceedingly rapidly in a tiny fraction of a second, smoothing out any temperature fluctuations. What we see as our observable universe is just the temperature fluctuations in a subatomic sized piece of universe from before inflation happened. After that tiny fraction of a second, inflation stopped, and normal Big Bang physics took over. Moreover, inflation explains the formation of galaxies. Tiny quantum fluctuations became the seeds of galaxies, clusters, superclusters and giant strings of clusters that make up our universe today. Note that almost everything written in the current Slashdot summary of the breakthrough is completely wrong!
- platz 13y agoInteresting that they succeeded in detecting gravity waves where LIGO failed?
- sanxiyn 13y agoThey are using a different method. In their own words: "The presence of a water wave can be detected by feeling its up-and-down motion or by taking a picture of it. We are doing the latter." LIGO is doing the former. http://bicepkeck.org/faq.html http://bicepkeck.org/faq.html
- ErsatzVerkehr 13y agoLIGO has not failed. The second generation of LIGO detectors, called "advanced LIGO", is currently under construction. It will be around ten times more sensitive than the earlier configuration of LIGO, and is very much expected to yield astrophysical discoveries. More info at: http://ligo.org/ http://ligo.org/ Furthermore, what LIGO seeks to do, and what the BICEP project has done, are quite different. LIGO is something like a "radio" that receives gravitational waves. We'll be able to listen to gravitational waves as they arrive at Earth. The discovery announced today is of the "fossilized" imprint of primordial gravitational waves on the cosmic microwave background radiation. Very important, but complementary to LIGO.
- yukichan 13y ago> The finding is direct proof of the theory of inflation, the idea that the universe expanded extremely quickly in the first fraction of a second after it was born. Small nitpick, but wouldn't the use of the words "evidence for" instead of "proof of" have been better? Not that I am in any way trying to take anything away from the discovery. Just from a science perspective, the word "proof" has always bugged me.
- harshreality 13y agoIf you're not talking math (which includes logic), proof can never mean what you want it to mean. So why get upset about it being used differently outside of mathematical context?
- kremlin 13y agoIt's kinda a pet peeve of mine as well, having to switch between 'proof' meaning a conclusion that logically necessarily follow from premises, to proof meaning "really strong evidence". But, as harshreality was getting at, if we used 'proof' that strictly, nothing outside of pure math and logic would be a 'proof'.
- wfn 13y ago> But, as harshreality was getting at, if we used 'proof' that strictly, nothing outside of pure math and logic would be a 'proof'. True that. But isn't that an important part of the scientific method (at least in the karl-popper-scientific-method sense), and part of the point of science, really? Strictly speaking, you can't prove anything using the scientific method; only 'falsify' it (hence Popper's 'falsificationism', 'science as falsification', etc.) To 'kinda-sorta-prove' something in science, you formulate a null hypothesis, and then attempt to falsify it. But strictly speaking, one is not able to 'prove' anything (only provide weak/strong evidence for/against something.)
- andrewflnr 13y agoWell, then, don't use the word "proof" outside pure math and logic. Everyone agrees that "proof" means to render something beyond (reasonable) doubt, so it's not a problem of ambiguous definition, just incorrect usage.
- deleted 13y ago[deleted]
- slacka 13y agoSo just to clarify, this is only the measurement of an artifact most likely caused by gravity waves during the period of inflation. We still have not directly measured gravity waves in our current universe, right? I think the fact that gravity can't be measured is a subtle clue about one piece of the puzzle for a unifying theory of everything.
- gibybo 13y agoGravity can pretty clearly be measured. I'll assume you meant gravity waves in particular, but even then we have no reason to believe they can't be measured (only that we haven't done it yet).
- pointernil 13y agoI agree. For the sake of a future outlook ;) I'd just add: "can't be measured" with the current combination of theoretical and hardware apparatus...
- Steuard 13y agoThat's correct: it's an indirect observation, and really the "observing gravity waves" aspect of this is the least interesting part. There have been other indirect but compelling observations corresponding to gravity waves before (like the precise rate that pulsars' rotation slows down, which I'm told is a perfect match to the energy expected to be carried away by gravitational waves). The big deal here is the insight that it gives into the early universe (VERY early!) and into very high energy physics. As for the lack of direct detection of gravity waves, I wouldn't read too much into it. Gravity is very weak, and we've known that for most of the century. Figuring out what sources might produce strong enough waves to be observable is really tricky, not because we don't understand gravity but because we don't understand the complicated astrophysical processes involved at the level of precision that we'd need (e.g. merging binary stars: how does that play out in detail?).
- andrelaszlo 13y agoI find this concept of "directly measuring" things confusing. My theoretical knowledge is very weak though, maybe someone can explain. It seems to me like we never measure things _directly_. For example: To measure the temperature of something in everyday life, we use a tiny glass cylinder filled with some kind of liquid. The liquid expands or contracts, roughly linearly, because of the temperature exchange with its surroundings. We then compare the current level of the liquid to a little ruler inscribed in the cylinder, maybe the markings form a shape similar to "100°C". The photons that bounce off this little ruler into our eyes causes impulses in some neurons and so on and our brains compare the shape "100°C" to yet another reference point, boiling water. It's hardly direct¤, in any sense of the word. If we measure gravitational waves by observing "ripples in background radiation"¤¤, isn't that kind of the same thing? I've seen several people here mention that it's not "measured directly" - does it mean something else in this case? ¤ If you stick your hand into the boiling water to measure its temperature, it's a bit more direct but not as accurate. ¤¤ I'm just a programmer, this is kind of how I understood it. :D
- encoderer 13y agoReminds me of the way Einstein, not being an experimental physicist himself, would conclude his famous papers with suggestions for experiments to confirm them. Awesome for this research team to have the opportunity to confirm this discovery in Linde's lifetime.
- OOvsuOO 13y agoWow.. that's sweet but really come on only supporting mavericks OS. And already.. if you have a iPad the notes app automatically synchronizes with the mail server (I use web based email service mostly.) I didn't even set it up or should I say allow the iPad to do so.
- splawn 13y agoGravity waves work fine for me under ubuntu.
- analreceiver 13y agoWrong thread
- watson 13y agoAnother HN post from earlier today about the same discovery: https://news.ycombinator.com/item?id=7411341 https://news.ycombinator.com/item?id=7411341
- cellover 13y agoThis page allowed me to have an idea of the concepts underlying this discovery (CMB light, B-mode polarization): http://cosmology.berkeley.edu/~yuki/CMBpol/CMBpol.htm http://cosmology.berkeley.edu/~yuki/CMBpol/CMBpol.htm
- namelezz 13y agoCongratulation!
- deleted 13y ago[deleted]
- notastartup 13y agocan someone explain the significance of this, for those that are not familiar with this area?
- kimonos 13y agoInteresting info! Thanks for sharing!
- Hypx 13y agoA little bit of caution from here: http://profmattstrassler.com/2014/03/17/bicep2-new-evidence-of-cosmic-inflation/ http://profmattstrassler.com/2014/03/17/bicep2-new-evidence-... Very interesting result, potentially game-changing, but it also could be nothing too. Wait for more experiments before we can say for sure.
- trhway 13y agointeresting that BICEP2 polarization from gravitation waves as they describe it http://bicepkeck.org/faq.html http://bicepkeck.org/faq.html: "strong B-mode polarization at the much larger angular scales--2 to 4 degrees on the sky--where lensing is a tiny effect but where inflationary gravitational waves are expected to peak. " is of about the same scale as 500 million light years period of Baryon acoustic oscillations period (ie. baryonic (gravitating) matter density period): http://en.wikipedia.org/wiki/Baryon_acoustic_oscillations#BAO_Signal_in_the_Sloan_Digital_Sky_Survey http://en.wikipedia.org/wiki/Baryon_acoustic_oscillations#BA...
- snickell 13y agoIs there a way from this data to calculate the frequency of the wave(s)? Bandwidth? Or otherwise characterize the signal that is causing the polarization? Is that even a meaningful question in this case?
- lutusp 13y agoNot really. What's being observed are remnant polarizations from gravitational waves that had their effect long ago, under very different circumstances and mass-energy densities. What's interesting is that the present measurements can be interpreted as evidence for gravitational waves to the exclusion of other explanations to a high degree of certainty. Until now, evidence for gravitational waves was rather indirect and circumstantial, for example orbiting pulsars (very dense collapsed stars that emit periodic radio pulses) were observed to slow their pulse repetition rate over time in a way that suggested they were losing potential energy by radiating gravitational waves. Unfortunately those waves could not be detected directly. In principle, a gravity wave could have nearly any frequency/wavelength consistent with its source. The pulsars discussed above were thought to produce gravitational waves of relatively high frequency / short wavelength, proportional to their pulse repetition rates. A so-called "millisecond pulsar" would have a possible gravitational wave frequency of one kilohertz and a wavelength of 3 x 10^8 / f meters or 3,000,000 meters (3,000 kilometers). That's hardly short compared to a radio broadcasting station's wavelength, but for gravitational waves, it's remarkable.