Computer Simulations Point To the Source of Gravitational Waves (theverge.com) 126
An anonymous reader writes from a report via The Verge: On February 11th, scientists at the LIGO observatory made history when they announced the detection of the first gravitational waves. A new study says the gravitational waves likely came from two massive suns that formed about 12 billion years ago, or two billion years after the Big Bang. The researcher's calculations have been published today in the journal Nature, and were determined by running a complex simulation called the Synthetic Universe: a computer model that simulates how the Universe may have evolved since the start of the Big Bang. The simulation even includes a synthetic LIGO detector to determine the types of objects that the observatory would detect over time. The Synthetic Universe can also make predictions as it includes a mock-LIGO to chronologically sync when we detected the waves. If the model is correct, we should see LIGO pick up to 60 detections when it begins its next observation run this fall. It could hear up to 1,000 detections annually at its peak sensitivity. The lead study author Chris Belczynski speculates specifically the size of black hole mergers that the LIGO should be able to detect from gravitational waves, a combined mass between 20 and 80 times the mass of our sun, indicating that they're likely from soon after the Big Bang when stars had lower metal content and formed proportionately larger black holes. His model suggests that the ones that collided to make these gravitational waves were stars that formed 12 billion years ago, became black holes 5 million years later, and then merged 10.3 billion years after that.
Re:Practical value? (Score:5, Informative)
The practical value is that we finally have a way to probe one of the biggest parts of physics that we don't actually understand, gravity. And it has direct implications for all of the other aspects that we don't understand or have major questions about, such as inflation, dark energy, the unification of relativity and quantum physics, etc. The field has massive potential to further our understanding of physics and the universe that we live in.
And LIGO is only the start. When something like eLISA comes online it'd be like going from the blurry images of Galileo's telescope to an actual astronomical observatory.
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Except that it's established there to "open the envelope" to determine whether something was a blind injection before making announcements. More to the point, the blind injection system wasn't even online [sciencemag.org] during the first discovery.
Re:Practical value? (Score:5, Interesting)
It's HUGE actually,
The very first practical application of understanding how gravity works would be ... Artificial Gravity'.
Pretty important and a *really nice to have* for growing plants and keeping humans and possibly animals healthy in low-grav like the moon, space. Or defeating the forces of acceleration and deceleration etc. Anywhere a force must be exerted or defeated.
Sure it's in an infant state of understanding right now, but the more we learn about how it works, the closer we come to making the above happen.
Re: Practical value? (Score:4, Interesting)
To be more precise, first we have to collect a lot of data, and then we have to build a mathematical model that describes how it works, and then we *might* be able to manipulate it, depending on what comes of the model.
My first thought would be communication with extremely long range that can easily pass through objects much larger than our sun. Hell, for all we know, this is how aliens do interstellar communication, and we presently lack the ability to intercept it.
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Or use the gravitational forces of our sun to focus a beam or use as a reflector and with the Earth as a giant listening station.
Hopefully without insta-frying the Earth.
At this point the possibilities are as endless as our imagination. We won't know until we understand more. But I would suggest just skipping the fancy mathematical equations used to make the scientists look smarter and get the cable guy to start manipulating magnetic fields.
Get 'er Done!
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Artificial gravity or "antigrav" would be a great application but I'm not sure they will be ever doable at all, what if it can be theoretically made but your device would need to be 1000 km or 1 0000 000 km wide?
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Is this some sort of joke? We know exactly what they're measurements of: gravitational waves. It's right there in the name.
Are you trying to claim that we don't know how to interpret them? We know exactly how to interpret them - that's why we started looking for them in the first place, because we knew what they should look like. This isn't some sort of cryptic white noise, things like the inspiraling of binary pairs have ver
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To double down on what Rei said;
The rest of science *may* only have 10% of the data, but I promise you're not smart enough to know the data is worthless either.
So in the meantime the rest of the community that enjoys exploring new things, forming hypothesis, and experimenting will continue to bring us out of the stone age. As they have for centuries.
Sure they have to make a dollar, and a lot of times they may nudge a decimal point to keep the lights on, but the modern technology we enjoy sure has hell justi
Re: Practical value? (Score:5, Insightful)
Sometimes the practical use will be revealed a lot later and result in new discoveries.
If you stop being curious then it's time to close the shop.
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Never mind that. What will it do for our quarterly profit figures?
Re: Practical value? (Score:1)
No - what will it do for ME , TODAY.
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well if we tap the Space Nut and the Build My Legacy markets we can see a 15-23% increase in profits with only a 4.2% increase in expenditures for the next several quarters and by the time actual practical results are needed everybody in this room will have retired.
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It will be used to send advertising to the cosmos.....
Re:Practical value? (Score:5, Insightful)
What is the practical value of this?
What's the practical value of you?
Furthermore, there's already abundant evidence supporting relativity (which does have practical uses)
It does now. What practical uses did it have when (or before) it was discovered?
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Yeah, if only those morons who were working on quantum mechanics in the 1920's and 1930s had some understand of how little practical value their work had, we wouldn't be saddled with computers, lasers, GPS, etc. now.
Does the simulation ... (Score:5, Funny)
Does the simulation also include a synthetic simulation in order to determine what it would find out by simulating the universe ?
Re: Does the simulation ... (Score:1)
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Yes that's the Turtle Infinite Recursion subsystem that ensures it's Turtles All The Way Down
wasteful intro (Score:2)
What seems more interesting? When the stars that were the precursors to the blackholes were formed, or when the event actually happened? I would have much preferred seeing an emphasis on the fact that the event happened 1.7 billion years ago, rather than than the stars that originated the chain of events were formed 12 billion years ago...
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The idea is that right after the Big Bang very nearly equal amounts of anti-matter and matter were formed. These annihilated each other leaving just hydrogen clouds which formed massive stars which in turn rapidly went supernova and created black holes. Then these merge together ... and the gravitational waves create enough disturbance to allow more gas clouds to coalesce into stars.
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Well, I didn't read that anywhere... Where can one read about that, the formation of matter and antimatter? And how is hydrogen the byproduct of that? I thought hydrogen was matter, not the leftovers of matter/antimatter?
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Well, I didn't read that anywhere... Where can one read about that, the formation of matter and antimatter? And how is hydrogen the byproduct of that? I thought hydrogen was matter, not the leftovers of matter/antimatter?
Hydrogen is matter and what we see around us in the leftovers of the original matter/antimatter created at the beginning of the universe. In this case, matter and anti-matter were created roughly equally from energy in the beginning of the universe. It all pretty much annihilated with each other and turned back into energy which formed matter and antimatter again. For some reason, matter had a slight edge, so after the anti-matter turned back into energy there was still matter left over, which caused the ne
Implications (Score:2)
Agreed. Maybe even a little context - assuming gravity waves propagate at the speed of light (consistent with the rate of energy loss we see in stellar binaries spinning down) 1.7 billion years ago translates to (roughly) 1.7 billion light years away, about 680 times further away than the Andromeda galaxy. Still practically next door in cosmic terms, so inflation isn't going to fudge the numbers too much.
I'm not certain exactly how gravitational waves propagate, nor how energy levels correlate to geometri
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That being the case, I've got to wonder exactly how insane the gravitational waves from a black hole merger are compared to the relatively steady fast-orbiting binary stars we can see via more traditional means? Are such waves theoretically too weak for us to detect with LIGO, or is it just that the signal-analysis is only looking for the distinctive "spike" from a black hole merger as a sort of low-hanging fruit to prove that gravity waves do in fact exist?
LIGO is looking for both, the problem is that such binaries don't emit a high-amplitude pulse, which is easy to see over the noise, you need to integrate over a large set of data to get a statistically significant SNR. As a result, it takes a lot more work, so they haven't published any findings on that yet.
Perhaps the more interesting question for me is, just how much will the proposed eLISA mission, with it's 250,000x longer arms (and I presume 250,000x greater sensitivity, plus much lower ambient noise levels) be able to detect? Being able to directionally detect the gravity waves from fast-orbiting binary stars, that we can then correlate with more traditional telescopy, could give us incredible insight into the workings of gravity waves including, in the case of binaries unmistakably spinning down, confirming whether the waves actually propagate at lightspeed.
While eLISA is a really cool and important next step, the advantage isn't entirely greater sensitivity (it's strain sensitivity is actually less than LIGO [wikipedia.org]), it's that it can explore an entirely differe
Re:Arithmetic - I am an idiot (Score:1)
see above. Time to wake up and take my meds. Sorry all
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Yeah the tines don't add up/
Bear in mind that black holes can do funny things to timr.
But my bet is on an error in the summary. That seems to happen much more often than black holes colliding
HHGTG Says (Score:2)
Yeah, well, Forget that. I mean do you know how the universe began for a kick off?
ARTHUR:
Well probably not
FORD:
Alright imagine this: you get a large round bath made of ebony.
ARTHUR:
Where from? Harrod’s was destroyed by the Vogons.
FORD:
Well it doesn’t matter -
ARTHUR:
So you keep saying!
FORD:
No, No listen. Just imagine that you’ve got this ebony bath, right? And it’s conical.
ARTHUR:
Conical? What kind of bath is -
FORD:
No, no, shh, shhh, it’s, it’s, it’s conical okay? S
You missed the punchline (Score:2)
And that’s how the universe began?
No, but its a great way to unwind.
(Or something like that - I can't find my copy of the scripts, which is winding me up).
Re: (Score:2)
You were born 50 years ago and took 40 years to get laid, thus you're 90-year-old?
Re:Simulations - Program them to agree with you (Score:4, Informative)
Re:Simulations - Program them to agree with you (Score:5, Informative)
Re:Simulations - Program them to agree with you (Score:5, Informative)
No, what you do is see something, try to figure out how it might work and model it. At this point you probably have a model that "works" because it fits your observation - not very useful. But then you use it to predict what else you might see. If the prediction matches the next observation, it strengthens the possibility that the model might actually describe something fundamental, more and more so as it gives consistent results over many observations. If the prediction doesn't match, you figure there's something wrong with the model and start again, or you refine the model, and so on and so on.
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I'll second the upvote for AC. The OP is ignorant (perhaps willfully) of how science works.
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In science, you make observations. You make a theory to explain them. You figure out what your theory predicts, and this is where the simulation comes in. You test the predictions. If your observations don't match your predictions, you adjust your theory. If they do, you make more predictions and test them. You can't refine a theory unless it predicts something false. (Alternately, you can make several variations and examine their predictions.)
Obviously, simulations aren't tests. You use simulati
Re: Simulations - Program them to agree with you (Score:1)
I never saw how this differed from the Michelson-Morley experiment, and could equally show the existence of luminiferous ether.
Re: Simulations - Program them to agree with you (Score:5, Informative)
I never saw how this differed from the Michelson-Morley experiment, and could equally show the existence of luminiferous ether.
Well, they are different.
The Michelson-Morely experiment was a failure: it was designed to observe changes in the speed of light in different reference frames, but it showed none. And that result changed our understanding of the universe in fundamental ways.
These gravitational-wave observations, and their subsequent simulations, appear to be a success for the theory of general relativity. And that's important too.
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Which says a lot for the scientific process - even failures contribute greatly to our understanding of the universe. I wish people would apply that principal to life in general more often. The only mistakes you make are the ones you don't learn from!
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Yeah, they should just whack away at the physics until the mathematics springs forth unbidden, something like strawberries in a field...you just add water and sunshine and they'll miraculously appear.
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when you make up the math to prove your point on the fly (which is what all theoretical physics does) its not impressive for the simulation to agree with your prediction
It never ceases to amaze me how violently anti-science a community of self-professed geeks can turn out to be.
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DO YOU understand how they work, cause you clearly don't since you're trying to make a snarky comment. ITS THEORETICAL. THERES YOUR SIGN.
Not sure why I bother to reply but:
n => f(n)
1 => 2
2 => 4
3 => 8
4 => 16
5 => 32
6 => 64
7 => 128
8 => 256
Find the function. I'm sure you could argue that you could make many other silly functions that'd also work, but 2^n seems like a good guess. That's what theoretical physicists do in a nutshell, look at observations and try to come up with formulas that fit. If you get new observations that don't fit, you try again. The more complicated it is and the less you can decompose forces, t
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A theory is a collection of observations and a model of how things seem to work to produce the observations. From the theory, you make predictions. You test the predictions, and adjust the theory. Eventually, you've got a pretty robust theory, and you know that because you've tested a whole lot of varied predictions and they hold.
You can't do theoretical physics without a source of observations. You don't have to make them yourself. You can come up with your theory, show how it explains things, and
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Its AC, the anti-bitstream dickhead do you feel better now? Or are you still secretly wishing to get the courage to actually use your account on a random website that hides everything about you.
You're nothing than a whiney pussy. Man up and attach yourself to your pathetic comments.
... says the hypocrite hiding behind a nick that doesn't provide any real identity.
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Its AC
" It's "
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Assuming the big bang produced gravitational waves which is not a given as its the two massive black holes rotating around each other that creates the waves, then the simple answer is they have gone. They are no longer around to detect.
It's like being near where a large stone was thrown in the pond last year and saying why can't I detect the ripples from the splash when I can detect the ripples from that pebble you throw in over there a few seconds ago.
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This gravitational wave isn't 12 billion years old. The stars that it sourced from formed that long ago.
It says the stars formed 12 billion years ago, lasted for 5 million years before becoming black holes (big stars live fast), and then 10 million years LATER they collided to make this gravitational wave.
If you do the math you'll noticed that this means that the gravitational wave itself is only 2 billion years old - not 12.
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Amazing how nobody can get these figures right. Million, billions, hundreds of millions, whatever, just throw them all together and don't bother to verify that it all adds up. According to Engadget, 1.2 billion plus 10.3 billion plus 5 million make 12 billion. The Slashdot comments have a bunch of other versions, but i have yet to see one that adds up.
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ffs, Sun and Sol are the same thing. Or did you forget that ours is not the only "solar system"?
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No, a star is just that, a star.
A sun has planets orbiting
Sol is our sun.
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... the anti-bitstream [slashdot.org] ...
News at 11: Slashdot's resident autism-hating troll, bitztream, can't even spell its own name!
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Math... (Score:1)
His model suggests that the ones that collided to make these gravitational waves were stars that formed 12 billion years ago, became black holes 5 million years later, and then merged 10.3 billion years after that.
Did he do his experiment 3.3 billion years in the future?
Of course, it could just be a typo...
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LOL... the 5 was million, not billion. Misread on my part... }:-)
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You missed that the middle number was million not billion.
Stars formed 12 billion years ago.
Stars collapsed to black holes 5 million (0.005 billion) years later.
Black holes collided 10 billion years later.
The waves were generated ~1.7 Billion years ago.
dissapointment (Score:1)
bummer... Although if the force of gravity is in step with the speed of light, there might be a correlation to be made about the nature of those two forces, one being cosmic one being quantum...
Re:Wrong! They were made by Jesus (Score:5, Funny)
That's only because he doesn't show any fiscal responsibility. He's always giving his money away to the poor and lepers, getting in trouble with the law, etc. If we moneychangers were to extend him a line of credit, why should we expect to ever get paid back?
Not that I'd want to tell him that to his face - the last time he stopped by he trashed the place and started attacking us with a whip. That guy is mental.
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What's wrong with a little honest profit?
Are you some kind of commie socialist wacko or something?
Re:Wrong! They were made by Jesus (Score:4, Funny)
When I'm president, we'll have smart messiahs, not stupid, loser messiahs. Tremendous, tremendous messiahs, on the classiest crosses.
#CrookedJesus.
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Read a book sometime! The GOOD book!
Ya'll motherfuckers need Talos.
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Dirty? Apparently your autocorrect doesn't believe in God, either!
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Come now, the real question of reality is. . . Who will be eaten FIRST ??? [foo.ca]
This message brought to you, by the Campus Crusade for Cthulhlu: It found me !!
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Read a book sometime! The GOOD book!
This one ?
https://www.amazon.com/Good-Bo... [amazon.com]
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Re: Wrong! They were made by Jesus (Score:4, Insightful)
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Science is the same way.
Freaking historians REFUSED for decades that the Norse were here in the americas way before any europeans and they dismissed all found evidence as "hoaxes" even though the evidence pool was sound and well documented.
Go ahead and try and overturn a science cart with a new hypothesis and see how welcoming scientists are. It's as much of a cult following in the science circles as it is in religious cults.
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Re: Wrong! They were made by Jesus (Score:4, Informative)
[Citation needed]
The first actual Viking discovery in the Americas, L'Anse aux Meadows, was not particularly controversial. Yes, there were things dismissed as hoaxes before that, like the Kensington Runestone [wikipedia.org]. That's because they were hoaxes.
The problem wasn't that people "disbelieved" claims of Norse settlement - it's that most people were simply unaware of them. There wasn't a great deal of interest outside of places like Iceland in the history of viking exploration until the early 20th century. Around the start of the 20th century there started being an increasing debate as to whether they referred to real places and if so where they were located. Expeditions really began to find them in the 1950s - Jørgen Meldgaard came extremely close, only about 15km from the site at L'Anse Aux Meadows, while following up on earlier suggestions by Tanner and Munn. The only physical find that Meldgaard found significant wasn't found in Canada or the US at all - it was from Greenland, an arrowhead in a viking settlement that matched Canadian native materials (ramah chert) and styles rather than Greenlandic. The Canadian government had offered significant support for his explorations (the Danish National Museum however was more hesitant, preferring that Meldgaard focus his research more on Native American cultures).
The biggest controvery that arose after Ingestad's excavation at L'Anse Aux Meadows was not people insisting that it was fake, but rather a row between Denmark and Norway as to who gets the credit for discovering it first. Denmark went back and tried to push Meldgaard's role in helping find the location (although he never did find any artifacts), and there was a lot of hostility in the Danish and Norwegian press over the issue (for what its worth, Meldgaard and Ingestad had a friendly relationship)