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It's Official: LIGO Scientists Make First-Ever Observation of Gravity Waves (economist.com)
A few days ago, we posted reports that a major finding -- the discovery of the long-predicted gravity waves -- was expected to be formally announced today, and reader universe520 is the first to note this coverage in the Economist : It is 1.3 billion years after two black holes merged and sent out gravitational waves. On Earth in September 2015, the faintest slice of those waves was caught. That slice, called GW150914 and announced to the world on February 11th, is the first gravitational wave to be detected directly by human scientists. It is a triumph that has been a century in the making, opening a new window onto the universe and giving researchers a means to peer at hitherto inaccessible happenings, perhaps as far back in time as the Big Bang. Reader
DudeTheMath adds: NPR has a nice write-up of the newly-published results: "[R]esearchers say they have detected rumblings from that cataclysmic collision as ripples in the very fabric of space-time itself. The discovery comes a century after Albert Einstein first predicted such ripples should exist. ... The signal in the detector matches well with what's predicted by Einstein's original theory, according to [Saul] Teukolsky [of Cornell], who was briefed on the results."
Update: 02/11 18:08 GMT by T : Worth reading: this letter, inspirational and informative, from MIT president L. Rafael Reif, about the discovery. (Hat tip to Brian Kulak.)
Nobody actually ever thought that gravity waves wouldn't exist-- it's pretty much impossible to come up with a version of gravity that doesn't include waves.
But it's amazing that we can actually detect it.
Oh, wait, that wasn't LEGO scientists.
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
Wow, this must be a world record for slashdot - the press release only just made it out. Having said that, this was possibly the worst kept announcement in the history of science journalism.
This matters for a bunch of reasons. First, it helps close confirm predictions of general relativity. We had a lot of evidence already but more is good. Second, if we get more data we might be able to rule out or narrow down our search space for any eventual quantum gravity theory since they have predictions about how gravity waves should behave (although this would require massively upgrading LIGO). Third, this gives us insight into stellar objects that we normally lack the ability to examine. For example, we don't know much about what the cores of neutron stars are like, but different ideas about them give different predictions about what sort of gravity waves two merging neutron stars will create. So this may give us more data about what exotic objects are actually doing. Fourth, this gives us for the first time a way of getting data from very far away sources that isn't in the electromagnetic spectrum. Right now, we can detect neutrino bursts if they come from a few million light years away but pretty much everything from outside our little galactic neighborhood has to come either from electromagnetic radiation or detecting cosmic rays. But LIGO can already detect gravity waves from events that are a billion light years away. So this gives us a whole new long type of data.
It's not something that moves along is it? It's a perceived distortion of time space? I'm thinking of the metaphor of the flat surface with the heavy object in it that shows in 3d how mass would be attracted to mass. So what is a wave? A flexing of space time? or is it time to update the usual way of thinking of it?
Have you fscked your local propeller head today?
Build some more and we can actually pinpoint the origin of the waves.
love is just extroverted narcissism
the first gravitational wave to be detected directly by human scientists
I had to go read the linked story to make sure it wasn't typical /. submitter reading failure.
Please, The Economist, do tell more, I think you buried the lead there.
sigh. At least it's not a Forbes link.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
When are white holes going to be discovered? :-)
#BlackHolesMatter...
Browsing at +1 - no ACs, I ignore their posts. So refreshing!
Building blocks of the universe.
> Nobody actually ever thought that gravity waves wouldn't exist
Which is precisely why this is such a non-important result. You don't learn much about the universe by demonstrating something everyone already knew is true. It would be much, MUCH more interesting if it didn't work.
To the contrary. Now that we have detected gravitational waves, we can start comparing the predictions to the measured data. Until we had detected them, we couldn't compare theory to data. Now we we have a possibility to do so.
That's why the MMX is cool, and this isn't.
>But it's amazing that we can actually detect it.
From a technology point of view, yes. From a theoretical perspective, not so much.
http://www.geoffreylandis.com
Are gravitational waves different from gravity? Because this article would have you believe that the speed at which they propagate is speed of light, where as gravity has instant effect AFAIK.
Gravity does not have instantaneous effect.
Nothing physical has instantaneous effect.
In any case, if you're talking about the gravity of something just sitting unmoving, it doesn't really mean anything to say that the gravitational effect is instant, or delayed. It only makes sense to ask the question when something is accelerated away from sitting stationary, and in that case, the effect isn't instantaneous; the change in effect at an observer is at the speed of light.
http://www.geoffreylandis.com
I'll wait for the peer review.
#DeleteChrome
To create significant gravitational waves you need to accelerate extremely compact objects which have nuclear densities up to large fractions of the speed of light. If you can do that you already have a far more powerful weapon than any gravitational waves you might be able to get them to emit.
Yes. Einstein theorized that spacetime is curved around objects...
More accurately, if you chose to define a geodesic as being the path taken by a light ray, then the space-time coordinate system defined by light rays in the presence of gravity obeys a non-Euclidean metric that is described by the metaphor "curved"-- by which we mean, it has the same geometry as a (Euclidean) curved surface in a higher-dimensional embedding space.
http://www.geoffreylandis.com
When are white holes going to be discovered? :-)
Watch the Oscars.
It must have been something you assimilated. . . .
For those who are interested, the scientific journal has a companion article here. It describes the design and sensitivity of the experiment, as well as some of the context. There is also a link to the actual journal article to the right, but you may need institutional access to download it.
I would rather be killed by a terrorist than enslaved by my government.
I'm guessing you can't build a fusion reactor out of LEGOs.
given enough of them you can.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
What's sort of amusing here is that the Michelson-Morley experiment, which is EXACTLY what this experiment is, failed to detect Ether. Yet this experiment is actually detecting ether! it's not the ether distortion MM were looking for which is differences in some vaccum substance that supports electromagnetic wave propagation. Instead it is detecting gravity wiggles in in real matter. Yet those gravity wiggles traveled through vacuum too. And according to general relativity my understanding is that should have distorted the vaccuum too. Thus if MM had had a sufficiently sensitive interferometer they would have detected these and attributed them to Ether fluctuations!
Some drink at the fountain of knowledge. Others just gargle.
We detected the electromagnetic ether a long time ago. Today we call it "the photon field." If we had a quantum field theory of gravity we'd call the gravity ether "the graviton field" but instead we settle for calling it spacetime.
I'll see you and your FTL at Steven Hawking's post-announced party last year.
Some drink at the fountain of knowledge. Others just gargle.
It's very difficult to reason about the universe without causality. Personally, I would rather not go there, the possible delights of science fiction notwithstanding.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
No, the MM experiment was measuring the speed of light in different orientations. Just because both used interferometers does not mean that they are measuring the same thing. If the MM experiment were arbitrarily more precise they would not have detected any change in the speed of light regardless of the orientation of their device, and spacetime fluctuations would have been dismissed as noise, and not particularly significant noise at that.
You are deeply confused about pre-Einsteinian theories of light and the purpose and significance of the MM experiment.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
Any science you can explain in a few sentences to a layman will be so full of holes as to be nothing more than hearsay and astrology.
A big event, that would have created ripples that would arrive here roughly at the time of the experiment, happened. As we listened, at that time, we saw inconsistencies representative of just such a gravitational wave hitting the experiment. It's tiny, but above background noise and experimental error (it's mentioned elsewhere that this basically means 6-sigma certainty), and coincides with a particular event that we were able to "observe" (not literally) in other ways.
The source of the wave barely matters. We detected gravitational fluxes that would otherwise be unexplained. That we are able to correlate them to one single event, that's just of the type of rare event that we predict might be able to cause such signals "loud" enough to be "heard" by us, and match up the timing means that it's the most likely explanation too.
But more importantly - 100-year-old mathematics predicts some absolutely insane, bonkers things that - when we are finally able to look for them - turn out to be true. That's all science cares about.
You can't just make up shit and then - in 100 years - several people invent an instrument that correlates perfectly to the shit you made up, several times, to the satisfaction of major scientific institutions unless - basically - you were absolutely spot-on correct all along.
That's pretty much what happened. The Einstein field equations are fucking bonkers to understand, let alone try and solve the implications of them. And I'm a mathematician. But they predict stuff like this that we then find. When it came from barely matters. A simplification of the definition of "size" in a mass-media article doesn't matter at all (tell people black holes have no size, and they look at you like you're an idiot).
So, no, it's not as bad as you make out.
Nope, sound waves don't either.
Think of a giant rubber sheet with a ball bearing in every square inch. Squish the sheet and the balls in that part get closer together. Stretch it and they get further apart. Do both to the same sheet and you have a wave and the distance between them is half a wavelength. Repeat it regularly and you have a full, repeating wave of a certain wavelength.
The ball bearings are sound-carrying particles in audio terms, and mass-bearing particles in gravity terms.
Neither of them has "positive" or "negative" anything. They just further apart or closer together to each other.
That we sometimes represent them as a line on a graph that goes below zero (closer than without the presence of sound / gravity) or above it (further apart than without the presence of sound / gravity) is a matter of interpretation, nothing to do with anything "negative" at all.
Dude, all both of them detect is phase as a proxy for time delay at arrival. time delay can occur because things got shorter or things went faster. but the experiments are identical in what they actually measure.
Some drink at the fountain of knowledge. Others just gargle.
There's no difference between "change in speed of light", "change in distance", and "change in travel time for light". They're all the same thing. Don't both instruments detect very small changes in round-trip travel time for light, comparing one direction to the other?
Sure then 1880s apparatus wasn't going to detect gravity waves, but that's just a matter of sensitivity of the instrument. We still call an electron microscope a microscope.
Socialism: a lie told by totalitarians and believed by fools.
They are different in what they were TRYING to measure. But they ACTUALLY measure the same thing.
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When these two black holes merged, three solar masses worth of matter got turned into pure energy, in the form of gravity waves. Compare that to a nuclear bomb, where a mass of about one pea gets turned into pure energy. It's hard to wrap my mind around the scale of this event. But adding to that problem is that this is not your ordinary explosion with a bright flash. So what would happen to objects in the vicinity of this gravity wave "explosion"? Would it tear apart our bodies? Would it destroy planets? Would everything heat up from the friction of relative motion? Or would these waves just pass through us without us noticing?