Gravitational waves detected

[Henry]

http://www.bbc.com/news/science-environment-35524440

:drool:



The collaboration operates a number of labs around the world that fire lasers through long tunnels, trying to sense ripples in the fabric of space-time.

Expected signals are extremely subtle, and disturb the machines, known as interferometers, by just fractions of the width of an atom.

But the black hole merger was picked up by two widely separated LIGO facilities in the US.


"It is the first ever direct detection of gravitational waves; it's the first ever direct detection of black holes and it is a confirmation of General Relativity because the property of these black holes agrees exactly with what Einstein predicted almost exactly 100 years ago."


Being able to detect gravitational waves enables astronomers finally to probe what they call "dark Universe" - the majority part of the cosmos that is invisible to the light telescopes in use today.



"Gravitational waves go through everything. They are hardly affected by what they pass through, and that means that they are perfect messengers," said Prof Bernard Schutz, from Cardiff University, UK.

"The information carried on the gravitational wave is exactly the same as when the system sent it out; and that is unusual in astronomy. We can't see light from whole regions of our own galaxy because of the dust that is in the way, and we can't see the early part of the Big Bang because the Universe was opaque to light earlier than a certain time.

"With gravitational waves, we do expect eventually to see the Big Bang itself," he told the BBC.

This rocks.

[Bernanke]

"Until this moment, we had our eyes on the sky and we couldn't hear the music," said Columbia University astrophysicist Szabolcs Marka, a member of the discovery team. "The skies will never be the same."

Beautiful.

[Lewis]

Do the current eggheads get the Nobel Prize, or would Albert Einstein get to scrounge a load of credit from his grave?

[Giggles]

I garner this is important from its position on news websites today, but what exactly does it mean? I know most big scientific things are largely irrelevant and get buried as such but this seems bigger.

[Bernanke]

I garner this is important from its position on news websites today, but what exactly does it mean? I know most big scientific things are largely irrelevant and get buried as such but this seems bigger.

Gravitational Wave Megathread (https://www.reddit.com/r/askscience/comments/458vhd/gravitational_wave_megathread/)

[Giggles]

Gravitational Wave Megathread (https://www.reddit.com/r/askscience/comments/458vhd/gravitational_wave_megathread/)

A paragraph would do. Well, anything bar that eyesore.

[Disco]

The very first post is an FAQ. :cab:

[Giggles]

The very first post is an FAQ. :cab:

Maybe it's because I'm on mobile, but look at it. It's hard to read any FAQ with a million flashing epilepsy-inducing ads down the right hand side.

[Disco]

Fair enough, I don't get any ads here and have a giant monitor. The wiki might be better:

https://en.wikipedia.org/wiki/Gravitational_wave

[Giggles]

Fair enough, I don't get any ads here and have a giant monitor. The wiki might be better:

https://en.wikipedia.org/wiki/Gravitational_wave

So it proves black holes are real?

[Disco]

I think so, the first positive detection of one.

Also it proves relativity, Einsteins put forward his Theory of Relativity and it's taken this long to gather hard evidence that it is correct.

[leedsrevolution]

This seems great but I must admit I'm completely out of depth.

[Raoul Duke]

This is the quote that really stuck out:


With gravitational waves, we do expect eventually to see the Big Bang itself," he told the BBC.

:|

[Lewis]

That will presumably be a load of Hebrew muttering about not being able to find anything in the dark.

[QE Harold Flair]

I was going to post about this earlier but then I realised it would just be Ital knowing what he's on about.

[ItalAussie]

I was going to post about this earlier but then I realised it would just be Ital knowing what he's on about.:D

Gravity waves are near and dear to my heart from way back when I used to do pulsar astronomy. You could indirectly infer the existence of these waves from pulsar orbital pairs, which until now is the closest anyone could get to actually seeing them.

[ItalAussie]

A paragraph would do. Well, anything bar that eyesore.

General relativity predicts that the shape of space and time themselves are influenced by objects with large gravity. It turns out that because of this, when large gravitational bodies interact with each other, they should leave extremely small waves (like how when you throw a rock in a pond and it leaves ripples) in space and time itself. However, even with the huge masses of stars and black holes, the waves are phenomenally tiny, and it takes an incredible amount of resolution to detect them. In this project, they basically had to look at waves caused by the biggest objects in the universe - black holes - to ensure that they'd actually be big enough to see.

You detect "waves" in space-time by shooting a signal at a receiver and bouncing it back. If the signal is aligned properly, they should cancel each other out exactly. However, these ripples in space-time cause the signal to be ever-so-slightly out of phase. The new device (LIGO) is sensitive enough to detect this phase error, which can be used to calculate the shape of the ripples in space-time, and hence study them.

This is important for two reasons:
- It confirms that general relativity is the right way to be thinking about the universe. This is important, because we use it as a basis for astrophysical calculations.
- It provides us a mechanism to study the interactions that caused the ripples. These likely happened in the very distant past, and can tell us about the shape and structure of the universe in its early stages.

[QE Harold Flair]

Isn't general relativity sort of at odds with quantum theory?

[ItalAussie]

Isn't general relativity sort of at odds with quantum theory?

It's complicated, because they work on very different scales, so it's hard to study their particular unique aspects in any one frame. But they are very different ways of thinking about the geometry of the universe.

Quantum Electrodynamics incorporates electromagnetism and special relativity into the ideas from quantum mechanics, and it's pretty much the state-of-the-art as far as testable theories about small stuff go. GR and QED aren't consistent with each other, but any theory that can conceivably unify the two is unlikely to be testable without some huge technological advances. One thing we can be sure of is that whatever the truth actually is, it looks like GR on large scales, and QED on small scales. We're not quite sure how that works yet, though.

The annoying thing is that the one situation where interactions between the two become incredibly important is in the immediate aftermath of the Big Bang (extremely high energy, extremely small distance). We're doing our best with the Big Bang, but really hammering it down probably eventually requires unification in some fashion, as the lengths get smaller and the energies get bigger.

[mugbull]

Isn't it crazy that before real computers, before nanotechnology and honestly not too far removed from us being able to harness electrical impulses, a man came up with the correct theory about the universe, about things he had never seen nor detected? People like Newton and Einstein are mind-boggling.

[Magic]

James Clerk Maxwell was the Don of being impossibly right about things that couldn't physically be proven at the time.

He's got 'I told you so' written on his headstone.

[leedsrevolution]

General relativity predicts that the shape of space and time themselves are influenced by objects with large gravity. It turns out that because of this, when large gravitational bodies interact with each other, they should leave extremely small waves (like how when you throw a rock in a pond and it leaves ripples) in space and time itself. However, even with the huge masses of stars and black holes, the waves are phenomenally tiny, and it takes an incredible amount of resolution to detect them. In this project, they basically had to look at waves caused by the biggest objects in the universe - black holes - to ensure that they'd actually be big enough to see.

You detect "waves" in space-time by shooting a signal at a receiver and bouncing it back. If the signal is aligned properly, they should cancel each other out exactly. However, these ripples in space-time cause the signal to be ever-so-slightly out of phase. The new device (LIGO) is sensitive enough to detect this phase error, which can be used to calculate the shape of the ripples in space-time, and hence study them.

This is important for two reasons:
- It confirms that general relativity is the right way to be thinking about the universe. This is important, because we use it as a basis for astrophysical calculations.
- It provides us a mechanism to study the interactions that caused the ripples. These likely happened in the very distant past, and can tell us about the shape and structure of the universe in its early stages.

But how do I wave back?

[Magic]

This seems great but I must admit I'm completely out of depth.

This must be a fairly common occurrence for you.

[leedsrevolution]

This must be a fairly common occurrence for you.

Relativity common yeah.

[QE Harold Flair]

It's complicated, because they work on very different scales, so it's hard to study their particular unique aspects in any one frame. But they are very different ways of thinking about the geometry of the universe.

Quantum Electrodynamics incorporates electromagnetism and special relativity into the ideas from quantum mechanics, and it's pretty much the state-of-the-art as far as testable theories about small stuff go. GR and QED aren't consistent with each other, but any theory that can conceivably unify the two is unlikely to be testable without some huge technological advances. One thing we can be sure of is that whatever the truth actually is, it looks like GR on large scales, and QED on small scales. We're not quite sure how that works yet, though.

The annoying thing is that the one situation where interactions between the two become incredibly important is in the immediate aftermath of the Big Bang (extremely high energy, extremely small distance). We're doing our best with the Big Bang, but really hammering it down probably eventually requires unification in some fashion, as the lengths get smaller and the energies get bigger.

That's exactly what I was going to say.

[Giggles]

None the wiser but, working off the assumption that there aren't exactly any real benefits, then I'll happily live with my dumbness.

[Magic]

Imagine being able to harness that sort of power. :drool:

[Henry]

None the wiser but, working off the assumption that there aren't exactly any real benefits, then I'll happily live with my dumbness.

There are real benefits. We could potentially "see" the big bang.

[Magic]

Science thread, right?

http://www.bbc.co.uk/news/science-environment-39642992
Physicists have created a fluid with "negative mass", which accelerates backwards when pushed.

What.

[Lewis]

Sounds a bit like you.