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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.)
Essentially a flexing of space, but it isn't easy to visualize. Imagine a circle as a gravity wave goes through it then the horizontal direction will get flattened and the vertical (direction of the wave) will get stretched out, and then the reverse. The actual equations for what it does to an object though are non-trivial.
> We had a lot of evidence already but more is good
Oh come on. We have a lot of evidence that the sky is blue, how much money should be spend on gathering more evidence of that?
> 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
That would be true if the measurement *disagreed* with the predictions, but it *agrees* with them. That is, this result helps make QG *harder*.
> Third, this gives us insight into stellar objects
Oh god, it absolutely does not. You need to look at the magnitudes and the error bars.
> 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.
First time eh?
> Right now, we can detect neutrino bursts if they come from a few million light years
Oh, you mean "first time, except", like "fresh from the freezer".
Neutrino observation has the same range limits (the light cone) as gravity, but is far more useful and always will be. It's those magnitudes again.
Absolutely. My point was not so much about refuting relativity completely, but observing (at scales far beyond our normal ability to detect) data that suggests that relativity as we know it is an incomplete theory. Which has already happened, mind you, given that relativity did not at the time fully describe quantum physics and other phenomena.
But discovering that gravity waves didn't follow the pattern might have made LIGO a modern Michelson-Morley experiment, leading to completely new physics, just as relativity was a better description of gravitation and spacetime than Newtonian physics.
All my liberal friends think I'm a conservative, all my conservative friends think I'm a liberal.
Actually, no, this is a very important result. We've been looking for gravity waves for years, and until now had been unable to detect them despite looking at sources that we should have been able to detect. This detection essentially closes an "uncertainty gap" in the theory - think of it like replacing "Here there be Dragons" on an old map with, "Nothing but open ocean here". It doesn't really change much, unless you happen to want to travel across the previously unknown area.
In addition, the article doesn't mention it, but by comparing the measured spatial distortions with he predicted values we open the door on the study of why the waves aren't as strong as predicted. Is there a flaw in the machine, or some hither-to unpredicted attenuation factor? The latter could potentially be every bit as earth-shattering as when the study of black-boy radiation revealed Quantum Mechanics.
It is in looking for confirmation of the predictions in current theory that both confirm that theory, and occasionally expose its flaws, which lays the groundwork for new theories. It may not be as exciting or glamorous as discovering something unexpected and new, but it's the same exact search that does both, and it's largely the luck of the draw as to whether the previously unexplored nook you chose to investigate reveals anything new. Its primarily through the exhaustive search of such nooks that we discover the unexpected phenomena that allows further theoretical growth. And in that pursuit "nothing unexpected here" is vitally important, as it allows future researchers to concentrate their attention elsewhere. Not to mention, it develops the early stages of the technologies that eventually allow us to harness the phenomena for productive uses.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
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.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
I pay attention to how the inside of my head works. Extreme introspection. I'm kind of obsessed with knowledge, learning, and optimization, so it's become a sort of nervous tick.
The brain is an intuitive tool: you can pick it up and use it to reasonable effect without learning how. As with most intuitive tools, you can use it to *great* effect if you have better understanding of technique. This is why some people have shitty handwriting, and others are scribbling out professional-grade calligraphy just by using a slant pen: continuous cycles of practicing, of examining the results, and of recognizing and deliberately correcting your mistakes leads to picking up a slant pen and writing a thousand-dollar wedding invitation.
I'm the guy who learned to make wedding invitations while everyone else was learning to write barely-legible cursive.
The systems simulator is just my own constant tool: whenever I approach a problem, I simulate it. If I'm playing a video game, I'm looking at the sprites on the screen in terms of their direction and speed of travel, and accounting for any known behaviors: I see where things *will* be *simultaneously*, instead of just their current position, direction, speed, and maybe path. I instantly know if things will intersect. The same goes for real-world physics, although that domain is more complex *and* has variables I can't always measure, as well as many I don't often interact with and can't readily project. I do the same in economics, loosely correlating changes with the pressures they put on other changes and shifting the whole system at once. I manipulate data structures in my head when coding, essentially emulating an abstract representation of a computer processor.
Some of those are more or less abstract, and more or less accurate. I'm *very* good with video games--no surprise there. Real-world physics has the stated problems: don't know all variables, haven't observed every aspect in great detail; I can catch a ball for the same reason you can, but I can't fire a sniper rifle because I need a *lot* of time to (poorly) simulate wind resistance against a bullet. Economics is actually a pretty simple system, as long as you're dealing with billions of people and not dozens. Computer programs are like economics: analyzing the *whole* program is hard, and you have to do it in pieces with propagating effects--this is generally a good strategy.
Einstein was a scientist, yet he acted like a philosopher: he sat, thought, made a bunch of shit up, and somehow turned out right. He wasn't pulling experiments in a research lab; people are so amazed by Einstein partly because nearly everything he declared as truth--stuff he was *right* about--was impossible to test in his time. We're only now getting the equipment and the opportunity to vaguely identify that Einstein *might* have been correct, and that evidence exists which is fully explained by his theories, but not necessarily which would lead us to synthesize those same theories without a nudge in the right direction. Where do you think he got it from?
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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.