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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.
* Strong Intergalactic Force, or the
* Weak Intergalactic Force.
When are white holes going to be discovered? :-)
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.
They've come a long way since those simple block sets.
SJW's don't eliminate discrimination. They just expropriate it for themselves.
Forget hoverboards, we need to start surfing gravity waves.
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.
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.
The wave motion engine gets built to travel between galaxies to Iscandar and save humanity from the Gamilon radiation bombs.
https://en.wikipedia.org/wiki/Space_Battleship_Yamato_(spaceship)
The real announcement is that they studying gravity waves using a device intended to electromagnetically reduce the weight of a suspended object. IN the process they discovered a strange mold that normally takes 1 year to grow a layer had completely covered their apparatus overnight. They built a larger machine and crawled inside of it with a tank of oxygen and found themselves at next thursday. Thus they could not actually make the announcement until time catches up with them. They could not go back in time to announce it since this was the first time abe turned on the machine (aaron secretly could but then their current selves might got to the same meeting and this might change the time line destroying the future Thursday.) So they have to wait till time catches up to them. Fortunately Aaron started a failsafe before he left so no worries.
1. gravity waves
2. time travel
3. ?????
4. Primer
Some drink at the fountain of knowledge. Others just gargle.
I swear I read this as "LEGO scientists....: and I thought wow... that's impressive.
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
Are they sexist pricks? This is more important than the discovery.
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
Could they be used in a directed energy weapon (hey, it's a wave, so it could be focused), or emitted by some kind of bomb?
Building blocks of the universe.
...need to figure out a way to surf these waves.
"Who are you?" "No one of consequence." "I must know." "Get used to disappointment."
We didn't really create or manipulate anything new, just observed. The data /could/ be important in future application, incl. new power sources that lead to weapons.
Yes, I know, you were making a point.
> 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
to the triggering event and the general direction it came from?
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
it's pretty much impossible to come up with a version of gravity that doesn't include waves.
Oh I don't know - Newton managed it 400 years ago.
Not that he was in need of further feathers, but this is yet another nice confirmation for GR. The now-incipient field of gravitational waves astronomy is sure to make many glorious discoveries in this century.
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
Your post will be used as proof of the name confusion when LEGO goes after LIGO for trademark infringement.
Violence is the last refuge of the incompetent. Polar Scope Align for iOS
k, so, like, do u learn what you need to know to make a hoverboard? wherz my huverboard?
Thanks abed.
Non physicist question, subject to immediate "you're an idiot" scorn. But have to ask:
Do gravity waves have sign? For example, sound waves have both negative and positive pressure, so 2 sound waves can either amplify or cancel each other out. Are gravity waves at all like that?
I need to know the answer because my anti-gravity gun project is currently on hold.
I guess I'll be the pedant here :) It's gravitational waves, the name gravity wave is already taken.
So what's the frequency, Kenneth? Can they cancel like light, sound waves too? Surf's up.
Did they mention at all if they've confirmed the speed at which gravity waves travel? It's assumed to be the same as the speed of light, but it would be interesting to know if they've been able to confirm that with data (or if LIGO is able to determine that at all)
We already have gravity bombs.
"Transparent" is a shit show that trades on every stereotype going. A man in drag is NOT a transsexual.
From TFA:
Known collectively as the Laser Interferometer Gravity-Wave Observatory (LIGO), the detectors are located in Washington state
This might have been a false signal created by state residents' jaws dropping simultaneously when our state treasurer suggested an income tax.
I'll wait until someone verifies their findings.
Sorry, teleporters just kill you and then make a copy. A perfect, soul-less copy.
Australia Cuts 110 Astrophysics/Astronomy Scientist Jobs
Because the science is settled there is no need for more basic research, the government says.
Marshall wrote in the memo that gravity waves, and therefore, astronomy, is now settled science, and basic research is no longer needed.
“The question has been answered, and the new question is what do we do about it, and how can we find solutions for gravity waves we will be living with,” he wrote.
Just wondering out loud here: It would be interesting to see if there is any correlation of such a large gravitational wave passing with things like earthquake frequencies/magnitudes. Or short term solar emissions or surface anomalies.
Have gnu, will travel.
Abbot et al. is here: http://journals.aps.org/prl/ab...
There are way too many assumptions and way too many inconsistencies with existing theoretical models.
The link mentions few details: event took place 1.3 billion years ago. two holes .. the radius of 100km...
First and foremost modern physics theorize that black hole does not have a dimension, and the size of the black hole cannot be measured using the usual three dimensional references. The radius of 100km is merely a Schwarzchild radius, representing a point of no return for the light.
Secondly, it has been announced that gravitation is a wave which automatically means it is subject to the 300,000 km/s limit. Otherwise how would they know when exactly the event took place.
I am not saying there are no gravitational effects. I am saying a confirmed chirp in dual interferometers is not enough to confirm weight, location, time and the nature of the event. I wish somebody would take time and explain the discover better. Hope somebody will provide not only good explanation, but also go over review process as well as peer review commentaries.
Other than that, it only looks that LIGO scientific insitution had to invent something to justify their existence. Historically, there were many announcements, that were later recalled. Let's hope this one is for real.
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.
Now help me assemble this space gravitational wave observatory using plastic blocks ...
-- Tigger warning: This post may contain tiggers! --
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.
Will this lead to hoverboards???
Does anyone have a link to an actual plot of the signal, where one could (hopefully) see the wave pattern, or any pattern?
Table-ized A.I.
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.
Otherwise all the most distant stars and anything viewed through a gravity lens should shimmer, or shimmy, or shake...
“He’s not deformed, he’s just drunk!”
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.
Yeah, just throw two black holes together next to what you want to destroy.
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.
but I forgot to climb into the chamber so it never happened. Now I'm stuck in this timeline.
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.
He was quick off the mark with this one, probably had it prepared: https://xkcd.com/1642/
Einstein does not have a perfect track record. His first marriage was a dud.
the coffin of the holographic universe?
You. You are what's wrong with humanity. Couldn't you at least give us a week of peaceful contemplation before you started working on that.
BTW, weaponization should be quite easy. All you need are two supermassive blackholes. Spin them around at great speed close to your enemy's country. The earthquakes will destroy all their buildings. Just before the entire planet gets squashed and ripped apart. Not that that matters to people like you.
In 1887, Al Michaelson and Ed Morely build an interferometer to check to see if there is "something out there" that transmits special things (e.g. Light) through space. They determine that space is empty: there is nothing there.
In 2002-20015, scientists build an interferometer to check to see if there is "something out there" that transmits special things (e.g. gravity) through space. They determine that space is actually full of this stuff.
CAPTCHA: precise
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LIGO measures differential distortions in the length of two 4 km arms. It needs to be able to distinguish changes in length at the level of one part in 10^21 to be able to detect these gravity waves. For comparison, it is able to measure a difference of distance between say here and the nearest star system 4 light years away to within the width of a human hair!!!
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 weren't going to find gravity waves because they weren't looking for gravity waves. Gravity waves would have been considered noise in their experiment, even if they had an arbitrarily precise machine, because that was not the thing they were trying to measure. That was the whole point of having a rotating interferometer. They were trying to detect a "preferred frame", and they would not have detected one no matter how precise their machine was because there is no such animal.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
Yes MM were measuring the speed of light, they were using the motion of the Earth around the sun to see if it added/subtracted from to the speed of a light beam. They could show that their equipment was sensitive enough to detect a change with direction if there was one, that's why their results were so convincing . MM were testing what Maxwell had predicted, ie: the speed of light is a constant value regardless of relative motion, Maxwell's constant (and it's value) falls out of his equations, it's a physical constant in the same way as the strength of gravity, or the charge of an electron, is a physical constant. Since the speed of light is a physical constant, time and distance must vary in different reference frames, this was the insight that Einstein came up with. To be fair to Newton, he only had two stated assumption in his "Principia", one stated that "time is constant". Everyone just accepted that as fact until Albert took a very fast tram ride.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
So are they faster than light?
Oh, perhaps. These were smart guys though, they might have done more than just dismiss the data as noise (I agree they wouldn't have thought it was ether).
Socialism: a lie told by totalitarians and believed by fools.
No, they are identical in the type of instrument they used, not in what they were trying to measure. MM were trying to find a "preferred frame", to see if the speed of light varied with the orientation (and motion around the sun) of the detector. They would not have found that no matter what the qualities of their detector were because it does not exist, and if they had detected gravitational waves, they would have been considered noise for the purpose of that experiment. You're saying that two different uses of an interferometer constitute the same experiment. You are very much mistaken.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
The thing here is that to date Einstein has a perfect track record. Which is pretty remarkable.
To date, everything they've ever tested says that the theory of relativity, as far as we've been able to investigate, hasn't shown any cracks.
Well, except for the niggling one where it demands a completely different vacuum energy level than the similarly well-tested theories of Quantum Mechanics.
But all the parts predicted by Einstein that have been tested have checked out. Quantum field theories predict high (or even infinite) values for vacuum energy... but those values aren't testable.
Strangely, Einstein's theories has been proved right even when Einstein himself was wrong. His objection to modern quantum mechanics was, basically, if it were correct then these bizarre Einstein-Podalsky-Rosen ("EPR") effects would be real, and that was just too weird for him, it would be spukhafte Fernwirkung. Well, turns out he was wrong about it being wrong, but his calculation was right-- the EPR effects are real, exactly as he (along with Podalsky and Rosen) described. And they are foundational to quantum mechanics as we know it.
That's like comparing a grocery cart to a Ferrari -- they both have four wheels, right?
It still follows basic thermodynamics once you break it down.
No, it does not. Neither quantum mechanics nor the relativity theory have anything to do with thermo dynamics, basic or not.
Huh? No, you can derive thermodynamics from quantum mechanical ensembles. (ref)
(Doesn't have anything to do with vacuum energy, though. Thermodynamics really only deals with changes in energy. An energy level that is inherent in vacuum is just a constant that can just be subtracted out.)
I'm confused. The tide is caused by the moon and earth pulling at each other. As they circle around each other, the water is rised. The water rises on the side facing the moon, and the side away from the moon, because of the centripetal force of the earth being pulled by the moon. HOWEVER, the backside doesn't rise as high as the front side, showing that the energy used to rise the water on the back side isn't as much as the energy used to raise the water on the front side, the difference must be the gravity (since energy can't be lost). Why isn't this proof of gravity waves, since the difference in those two heights can easily be plotted.
YUP, I'm full of it.
Okay, there was some uncertainty over the what phenomena could cause gravity waves, but that still creates mostly the same in issue on the generation side.
It pretty much took numerical simulations using supercomputers to be able to predict the gravitational wave signal from colliding black holes.
Up until these results, the search for gravitational waves was more like "well, gravitational waves theoretically could exist, we're not sure what would cause them or how strong they'd be, but let's look, and if we see any, then we'll know."
But, turns out, the earliest detectors were just way too insensitive to see these results.
A long time friend of mine used to work as a garbage collector, we used to go fishing a lot on weekends. He summed up your observations with the words "everything we do more than once becomes an art". We decided that the art of fishing is having a good time regardless of what the fish are doing.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
Who questions Relativity, including Gravitational Waves? Measurements from a Pulsar in the 70Âs gave us empirical evidence that supported Gravitational waves. This is new empirical evidence that supports an unchallenged theory. So, no new discovery, just new data. $ 620 Million so far, (the NSFÂs biggest project ever), and we purchased the worldÂs most expensive supporting evidence for a 100 year old theory that wasnÂt in question.
How far apart are the centers of the black holes when this event occurred? The physics and energies involved with such an event are mind-boggling....
love is just extroverted narcissism
The Michelson-Morley experiment is a perfect example of why it is important to actually detect something we expect from theory to be true.
Watch this video at about 25 seconds. You are correct that a star sitting in space does not produce gravity waves, but two massive stars orbiting each other produce waves as they move rapidly around each other and their position in space changes. These are the waves that are detected as they propagate through space.
https://www.youtube.com/watch?v=RzZgFKoIfQI
They are different in what they were TRYING to measure. But they ACTUALLY measure the same thing.
45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
We didn't really create or manipulate anything new, just observed. The data /could/ be important in future application, incl. new power sources that lead to weapons.
Not likely any time soon. Gravity is the weakest of the four known forces of nature. Electromagnetism still rules because it is somewhere around a billion times stronger than gravity and it has the range that the strong and the weak nuclear forces do not have. Don't bother investing in any "gravity-wave-based" power sources or weapons systems. Trust me on this.
The definition of an interferometer is not in dispute. If you're not trying to measure those specific vibrations, they are noise just like a passing truck would be. They weren't trying to measure vibrations at all, they were trying to measure differences in the baseline. Your argument is [a] redundant, [b] obvious, and [c] completely misses the point.
Ether theory had huge issues even before the experiment. There are probably better examples of unexpected discoveries.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
I guess I misunderstood. I came here thinking they had observed gravitons instead.
You know, like how people sometimes call photons "light waves."
Manuela Campanelli, Cheers, Phone chat before award ceremony in Brownsville. Information is never lost.
Or simply the GP's point completely flew over your head. But you're so arrogant about that, and so confident in your infallibility that I'm not going to argue with you.
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Are you seriously arguing that Ether and/or a preferred frame exists, or are you just retarded?
They weren't going to find gravity waves because they weren't looking for gravity waves.
If they had seen gravity waves they would have had no idea what they were but would certainly have regarded them as important. The real reason they weren't going to find gravity waves is that their apparatus was insufficiently sensitive by orders of magnitude.
When all you have is a hammer, every problem starts to look like a thumb.
Yeah, the point completely flew over your head.
But let me bite: Rename 'space' to 'aether'. Apply special and general relativity rules normally; that kills the idea of preferred frame of reference - one important point where Michaelson and Morley were wrong. Anything else about aether still doesn't check out?
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...
Yeah, rename 'red' to 'blue' and then your color scheme will work out right as well.
The point of aether was that it was a medium for light to travel through, the preferred frame of reference was consequent to that idea. Light being a transverse wave, it does not need a medium to propagate through. So Michaelson and Morley and anyone else talking about aether theory were categorically wrong. I hope you don't include yourself in that group.
captcha: mutandis
They would have seen gravitational waves as transient noise, in the same respect that passing vehicles and persons represented noise sources, and of far lesser magnitude. Without a physical framework suggesting that this noise was meaningful, there would have been no reason to suspect it was. Yes, they were intelligent fellows, but as far as I know, neither understood their experiments to mean that the aether did not exist, and continued to conduct experiments on the matter. I don't want to say exactly that they wouldn't have believed in gravitational waves if their hair was on fire due to that, but certainly in their famed experiment [a] they weren't looking for that, [b] it would have disturbed the thing they were looking for, and [c] they were not disposed to believe it even if they had found it. They were eminent and respectable scientists, their experiment was correct and well-founded, and they were dead wrong and no degree of accuracy could have changed that.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
I think what Tenebrousedge is getting at, is that MM was measuring for a DC effect, while LIGO is looking for an AC effect (with a very specific waveform). You can argue a DC and AC voltmeter are both measuring the same thing, voltage, but that doesn't mean they would see everything even with infinite precision. LIGO posses a lot of filtering, both numerically and inherent in the actual design, that would remove the DC components, even if it could spin (short of spinning on a couple Hz time scale).
I wonder if there was a "eureka!" moment where a researcher looked at preliminary data and thought, "Holy shit, we've really got something!"
Table-ized A.I.
It takes too long if you have several galaxies that need to go because they are blocking your view.
So.
What is the timescale for putting a gravity wave sensor in my smartphone?
I want this.
I would happily pay $10 extra for my phone if it had a gravity wave sensor in it.
sigs are hazardous to your health
A very lousy comparison implying red doesn't exist.
Space has quite enough properties to be considered 'a medium'. Only our lack of ability to detect anything more 'voidy' keeps the insistence that it's to be treated as a void, lack of anything. In reality it can be warped, like a tensor field, it can carry quite a few other fields, even matter can spontaneously manifest out of it. In light of the increasing number of features that can be assigned to any (empty) point of space, insisting space can't be qualified as a kind of medium becomes pure stubbornness.
Or - can light propagate through anything else than space?
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Man, that Dylan was way ahead of his time!
They would have seen gravitational waves as transient noise...
I seriously doubt that. Those dudes were pretty smart.
When all you have is a hammer, every problem starts to look like a thumb.
Will gravitational waves reflect from the boundaries and is it possible to have a resonant condition?
Since gravitational waves move at the speed of light, and the universe is expanding at less than the speed of light (correct me if I'm wrong) the waves will eventually reach the boundaries. Will they be reflected?. With additional energy input from more black holes crashing into each other can a resonant condition occur where everything starts ringing?
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?
OK, let me give this a try with a very simplistic analogy...
We're standing in a very large pond. Way out in the middle of the pond, we can observe that a pebble was dropped into it. We believe it happened. We expect that that occurrence will create a small ripple. Using maths we calculate when that small ripple will travel from the point of occurrence to where it will eventually touch our leg and we can feel it. However we're not sure our legs are sensitive to notice the difference, so we attach a device to do so. Fast forward, at the expected time, our super sensitive leg device has indeed detected the small ripple to the exact parameters. Doing so means that:
A) a wave was generated,
B) the maths used to predict the travel of the wave from the point of pebble impact to leg have been confirmed, and
C) having confirmed we can use said maths to accurately measure other such occurrences, perhaps ones that say happened behind us that we can't see, and
D) advance the understanding of how the whole pond mechanics work in relation to other forces that we happen to be standing in...
Am I very far off?
Or - can light propagate through anything else than space?
Yes. This is a stupid question even if phrased correctly. If empty space had none of the properties you mention, light would still go through it just fine.
Space has many interesting properties, but none of the properties predicted by aether theory. The implication was not that "red doesn't exist", but that they are two different things and simply calling one by the name of the other does not suddenly make the same thing. This is a semantic argument that Humpty-Dumpty would be proud of.
So - electromagnetic field can exist without/outside space?
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And many smart experimentalists also acknowledge there are certain frequencies of interest in an experiment, and signal to noise ratio can often be greatly increased by smart filtering design. Some interferometer configurations, particularly in how the light source and detectors are set up, are inherently AC signal only and useless of slow changing signal, others get very high sensitivity by averaging over AC noise.
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.
More or less in broad details.
Don't both instruments detect very small changes in round-trip travel time for light, comparing one direction to the other?
Not exactly.
To over simplify:
- MM experiment was about measuring a clear and constant difference of speed of light that depends on the orientation of the two beams. (if there's any fluctuation, it should be noise and discarded. It's the average speed in each direction of space that is important).
- LIGO experiment is about measuring a fluctuation of distance. It fluctuates around a set mean (because the speed of light is constant no matter which direction or travel speed), but as wave of space distorsion go through it tiny oscilliation might happen. (In other words, it *the noise* which is important. The mean speed should be constant no matter the direction.)
In very broad details (actual physicists and historians are both going to laught at me) :
Back in the 19th century, the theory of ether was that light was a pure wave (like sound waves, etc.) Like any wave it needs to travel inside a medium (e.g.: speech is a sound wave that travels through air - under the form of a compression wave of said air) (e.g.: ripples are surface displacement of water, etc.)
As lights travels through space, it should mean that space isn't void. Instead there's a medium that can carry this wave (just like air carries sound, water carry ripples) except that medium should be much thinner and lighter than air, because everything behaves as if there was void between the planets.
(Note: under this hypothesis, ether is just a simple substance/medium like anything else, just extremely light/thin).
Now the question is: how would you test it?
Well if stars roam around an universe filled with a medium called ether, that mean they move relative to the ether fluid.
And depending on the relative motion of earth in ether, the speed at which the light wave are carried in this ether should look different between the direction of the ether flux (relative of us) and perpendicular to it.
Think "doppler effect in water". Or think the distorted ripples caused by something travelling on the surface of water: as seen from the traveller's point of view, waves in front seem to move away slower (as the traveller catches up to them) whereas side way, the move away the usual speed.
So ether could be proved by setting up an interferometer. Then as you rotate it around (thus aligning differently them beams. Which beam is along the traveling distance of earth through ether, and which beam is perpendicular), you'll notice a shift in the interferometer. You're detecting the speed of travel of planet Earth across the ether medium.
Result of the experiment: Nothing. Silch. Nada. No matter how precise you measure, no matter how you orient the setup, *the speed of light is the same in all direction*. It's not direction dependent, it's not dependent on some flux of some "ether medium".
Nothing of the variation that was expected, given the speed of travel of planet Earth through ether.
A more precise instrument wouldn't have helped. The planet Earth travel rather fast around the sun, so the different of speed, though subbtle should definitely be noticeable.
Now back to LIGO:
Since the 19th century, the duality particle/wave is known (and has been proven by slit experiments, etc.).
Special Relativity states (among other) that the law of physics are invariant. The speed of light in void is always 1*C. No matter the reference, no matter if you travel, etc. (Thus, although the result of MM where surprising given the ether model, its absolutely what's expected under special relativity. Zero surpise. Speed of light should be 1*C in vacuum, no matter how you orient your experiment regarding the orbit of our planet around the sum. Or the
"Sufficiently advanced satire is indistinguishable from reality." - [Tips: 1DrYakQDKCQ6y52z6QbnkxHXAocMZJE61o ]
Space doesn't have a preferred reference frame. The M-M experiment was to find the preferred reference frame. The LIGO experiment assumed that there was no such reference frame, and detected gravitational waves that had nothing to do with any reference frame. The apparatus was similar, but what was being measured, and what the results would have meant is far different.
If I may trot out an old joke, an amateur astronomer is looking at heavenly bodies when focusing on Saturn, and when focusing on the bathroom window of that cute redhead, and using the same apparatus, but is really doing different things.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
With equipment that was sufficiently precise, and that they knew to be sufficiently precise, and able to filter out transient noise, M-M would not have figured they detected gravitational waves. They would have uttered those well-known words that often herald great breakthroughs: "Hmmm, that's funny".
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
Still, there's been a lot of neat stuff discovered when somebody had the idea "Let's just check to see if that thing we all know to be true actually is" or "Let's formalize this and see what we can do with it." There's also been a whole lot of times when those ideas just went nowhere, but that's science for you.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
Not only is this still a semantic argument, you're not being particularly clear what you're referring to.
Or - can light propagate through anything else than space?
Yes, light propagates through many transparent media.
So - electromagnetic field can exist without/outside space?
If by space you mean spacetime, then there is no such thing as "outside spacetime", and no point in speculating about anything not in this universe. However, do note that light would still propagate just fine in the event of vacuum decay which otherwise would go a long way towards making vacuum considerably emptier.
You're really hammering away at this idea that empty space somehow constitutes a medium. It's not true, and even if it were, it wasn't the medium MM were looking for. What they were looking for had very specific properties, and what they were looking for does not exist. You're not going to fix any of those issues by arguing about the definition of "medium". You're also not making yourself look particularly intelligent by trying.
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#2 of 3 - Windows 7 ONLY bypasses hosts for Windows Update
#3 of 3 - GOOD LUCK BYPASSING WFP/SFP in Windows ESPECIALLY WHEN MY PROGRAM SUPPLEMENTS THAT PROTECTION (not an exclusive lock either "pats self on back") ONTOP OF THOSE, & NOTHING IN USERMODE CAN PENETRATE THE PROTECTIONS I APPLY (nothing & I've tried).
APK
P.S.=> #4 = YOU FAIL & either you're an ignorant scumbag (which you are clearly) OR you're trying to spread falsehoods to no avail, stupid - people around this site actually KNOW computer science unlike yourself, & YOUR bullshit just won't wash - Unbelievable... apk
See subject: He's running from BOTH of these posts that shut him up easily http://science.slashdot.org/co... & http://science.slashdot.org/co...
APK
P.S.=> The price of shutting these transparent imbeciles' mouths & their LIES (of advertisers or webmasters that profit by them, possibly inferior competitors shills too) everytime I do it to them under their "registered 'luser'" accounts is they TROLL ME by AC afterwards with bullshit - thank goodness they're STUPID & are easy to put away with facts AND SUPPORT OF FOLKS LIKE YOURSELF (which I thank you for)... apk
Did you just equate space to vacuum? Did you just imply transparent media are outside space?
BTW, spacetime can be bent, compressed, stretched, it can be squeezed into a singularity. Is there any solid rule that states it can't, given the right conditions, have discontinuities?
MM were looking for THE medium through which EM waves propagate. They made some completely wrong assumptions as to the expected nature of that medium. Yes, what they assumed it to be doesn't exist. Which doesn't mean the medium doesn't exist, merely that it's quite different than their expectations.
It may be boiling down to a semantic argument - which doesn't mean the argument is invalid or wrong. Meanwhile refusing to accept an argument may be correct merely on basis that it may be semantic is outright wrong.
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.. Or do you keep thinking LEGOs were involved every time you read a headline about this?
What people are trying to measure, and what they are actually detecting, can often be quite different.
Looking for something else with the same equipment does not change the results, only their analysis of the data.
For true science, you should not decide what you are looking for until after you have the data, otherwise you will cause errors and bias.
P.S., yes your professors were wrong... 8-)
MM were looking for THE medium through which EM waves propagate.
And this medium does not exist, unless you redefine the term "medium" to include absolutely nothing at all -- again, light will still do its thing even if we go through catastrophic vacuum decay.
Did you just equate space to vacuum?
I noted then and will note again, you're using the term "space" very vaguely. However, there is not a hell of a lot of difference between hard vacuum on Earth and hard vacuum elsewhere, certainly in terms of its optical properties.
Did you just imply transparent media are outside space?
You're using the term "space" when you mean "spacetime", producing nonsensical statements. Again, your question was, "can light propagate through anything else than space?" And for a third time I am going to point out how dumb your phrasing is.
BTW, spacetime can be bent, compressed, stretched, it can be squeezed into a singularity.
Well, sort of. Singularities are more a property of your metric than spacetime per se. There's even less evidence to suggest discontinuity.
MM were looking for THE medium through which EM waves propagate.
Michaelson and Morley were trying to detect variations in the speed of light due to moving with or against the aether wind. The reason why they did not detect that is because it doesn't exist. If light needed a real, physical medium to travel through, that is to say something with mass-energy, we would be able to detect that, and probably MM too. Yes, vacuum is not the lowest theoretical energy level, but light would still function in that circumstance. Light does not need a medium to propagate.
It may be boiling down to a semantic argument - which doesn't mean the argument is invalid or wrong. Meanwhile refusing to accept an argument may be correct merely on basis that it may be semantic is outright wrong.
It being a semantic argument means that you are arguing about the definition of a word. In this case, you are arguing that two words with well-established and contradictory meanings are equivalent. The physical argument is completely specious, and you're too invested in the concept and your own imagined intellect to understand that down does not become up if you change the name.
In order to filter out transient noise, you have to define what you are looking for. If they are looking for an effect correlated with the angle they point their apparatus, then any effect at a frequency other than the one related to the rate of spin of their apparatus would be transient noise, and filtered out. There are not "That's funny" for data that is not outputted from an experimental device.
http://www.nytimes.com/2016/02/12/science/ligo-gravitational-waves-black-holes-einstein.html?_r=0
Casteism
For the pedants..
"In physics, gravitational waves are ripples in the curvature of spacetime which propagate as waves, travelling outward from the source." https://en.wikipedia.org/wiki/...
"In fluid dynamics, gravity waves are waves generated in a fluid medium or at the interface between two media when the force of gravity or buoyancy tries to restore equilibrium. An example of such an interface is that between the atmosphere and the ocean, which gives rise to wind waves." https://en.wikipedia.org/wiki/...
I have felt a great disturbance in the Force.
Then how are scientists supposed to get anything done? There was a time when a lot of science could be done with stuff that a scientist could have built in his basement (they were also virtually all male in that period). You can't do that with physics nowadays. You need to construct big and expensive things to get results, and in order not to waste money all over the place you need to have some idea what to build. The CERN accelerator costs something like a billion years a year to operate. Should we build numerous random apparatuses that cost billions in the hope that one will find something?
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
That is the delemma that we have always had. When you start you don't actually know what you will find, no matter how much everyone thinks so. So we build what we can, as generally as we can, and see what happens. That's why they always start small, but in that field we are at least somewhat past that.
Unfortunatly, people used to only working in areas where they can be sure of things expect to be sure of everything, even when no-one knows... 8-)
(Spoken by someone who has worked in fields where an accuracy of one part in ten to the 17th is "approximate".)
They were looking for a longer-term average, not specific short-term disturbances/changes. Maybe if their instruments were sensitive enough, they may have inadvertently spotted such waves, but that's not what they set out to find any more than Voyager was designed to find active Io volcanoes. (Galileo probe may have missed Europa's now-known plumes because mission planners didn't know to look.) It's often the case that you set out looking for X, but find Y instead.
Whether the existence of waves implies "ether" or not is probably a tricky definition issue. If they didn't pre-define ether clearly enough, then arguments could perhaps be made both ways. It was a general notion at the time rather than a precisely defined phenomenon. It's hard to precisely define a phenomenon until AFTER you discover and study it.
Table-ized A.I.