Gravitational waves from black holes detected - sounds like big news

[CTID1988]

However simplified stuff like this is explained... i still don't get it

Reading Damocles' summary, what i gather is they chucked a mountain into a pond and rode the wave it made. Where was this pond what could fit a mountain in it?! Something doesn't add up

 

[west didsblue]

No, gravitational waves pass through matter which is how they were able to be detected underground and they're far far too weak to do things like this.

You have to remember that every piece of moving matter generates gravitational waves from black holes that we detected to a bird flying in the sky. Detecting them however has been like trying to detect a ripple from a dropped stone whilst sat on a cruise liner - there's a boatload of interference from natural and man made causes that make this extremely difficult and only by digging miles underground then completely reinventing suspension and movement calculation technology have they finally been able to detect something from the most gravitationally powerful event that humans can conceive of in terms of the collision of two black holes.

Gravity might keep the planets moving around the Sun but it is a spectacularly weak force for reasons that nobody is really sure of. When you pick up your mug of tea for example, your muscles defeat the entire gravitational pull of the Earth against that mug. Gravitational waves are just like ripples in the pond of spacetime, and we're like a big boat. We measured it by dumping two mountains into the pond and even then it was extremely difficult.

Does this discovery prove the existence of Gravitons as elementary particles?

 

[Damocles]

Might be a stupid question, but if gravitational waves pass through matter, why don't we all just float away into the sky? What pulls us down to the ground?

Gravity is often made more complicated than it should be explained.

You can see in the GIF above that the big stationary object in the middle is sat on spacetime and it curves that spacetime towards it. You can also see that a different moving object supposed to represent a planet or whatever is moving around it and also warps the spacetime, which then warps back after it has passed.

Gravity is just the name given to that bending of spacetime. It isn't anything else, it's just the name for that curve.

You might here things like "no light can escape because the gravity of a black hole is too overpowering" or something like "light bends around stars" and stuff of this nature. Once you understand that gravity is a bad name for curvature (or you can even say that gravity is another name for acceleration, because you're measuring the effects of that curvature), these things become pretty simple:

In Figure A the curving of spacetime due to an object (that isn't shown, pretend a Sun is there) distorts the red light beam and makes the circle think it's coming from somewhere else. Because spacetime is curved and light travels across spacetime then it can't just "jump", it has to follow the curve.

In Figure B is a black hole showing why a very large distortion of spacetime like a blackhole means that light can't escape. It goes so far down that it doesn't have the energy to get up the other side of the hill, so to speak.

Now remember that we live in a 2D world and not a 3D world, so when we see the above we're actually talking about a 3 dimensional grid/mesh that is being warped:

So we don't float away into space because all of the space around us in 3D is curved by the mass of the Earth. We have to insert energy into us to "get up the hill" of the curve so to speak which is why flying and space travel is so very difficult and requires big engines.

Now that you understand what gravity is, ask yourself this question. If gravity warps spacetime and things move through spacetime then shouldn't that movement create a ripple of some sort?

Einstein said yes. Some other people said no. Einstein was right.

The ripple however is so small and hard to detect because it doesn't really affect the matter within spacetime. Why doesn't the ripple created when you spit over the side of a cruise liner tip the whole ship over? Because it's incredibly small compared the distortions of the whole ship has on the water and the ship is sat on the water itself.

This is exciting to many scientists because everything in the Universe moves. What we think of as temperature is in another way of looking at it just how fast things move. Anything that is above absolute zero has some form of movement to it and will generate gravitational waves which can be detected and we can find information about it. That is science fiction at the moment because we've only just been able to detect the movement of black holes which are massive and make massive waves comparatively (but still not big enough to be noticed by the ship) so detecting gravitational waves from atoms seems like an impossible task but it opens up a whole new branch of science.

The first telescopes used visible light to look at things. Then we got smarter and used non visible light and radio waves aswell. Now we've got a bit smarter than that even and can now use gravitational waves to look at things. This is especially important for early age cosmology as unlike electromagnetic radiation which has a time limit on it, gravitational waves could theoretically look right back to the Big Bang itself. Just as on a perfectly calm ocean a stone's ripple from one side would reach 1000 miles away, the ripples in spacetime don't go anywhere and are still available to be measured.

 

[I'm no cynic but...]

So a Navas cross is always likely to enter a black hole in a time warp?

 

[willipp]

Gravity is often made more complicated than it should be explained.

You can see in the GIF above that the big stationary object in the middle is sat on spacetime and it curves that spacetime towards it. You can also see that a different moving object supposed to represent a planet or whatever is moving around it and also warps the spacetime, which then warps back after it has passed.

Gravity is just the name given to that bending of spacetime. It isn't anything else, it's just the name for that curve.

You might here things like "no light can escape because the gravity of a black hole is too overpowering" or something like "light bends around stars" and stuff of this nature. Once you understand that gravity is a bad name for curvature (or you can even say that gravity is another name for acceleration, because you're measuring the effects of that curvature), these things become pretty simple:

In Figure A the curving of spacetime due to an object (that isn't shown, pretend a Sun is there) distorts the red light beam and makes the circle think it's coming from somewhere else. Because spacetime is curved and light travels across spacetime then it can't just "jump", it has to follow the curve.

In Figure B is a black hole showing why a very large distortion of spacetime like a blackhole means that light can't escape. It goes so far down that it doesn't have the energy to get up the other side of the hill, so to speak.

Now remember that we live in a 2D world and not a 3D world, so when we see the above we're actually talking about a 3 dimensional grid/mesh that is being warped:

So we don't float away into space because all of the space around us in 3D is curved by the mass of the Earth. We have to insert energy into us to "get up the hill" of the curve so to speak which is why flying and space travel is so very difficult and requires big engines.

Now that you understand what gravity is, ask yourself this question. If gravity warps spacetime and things move through spacetime then shouldn't that movement create a ripple of some sort?

Einstein said yes. Some other people said no. Einstein was right.

The ripple however is so small and hard to detect because it doesn't really affect the matter within spacetime. Why doesn't the ripple created when you spit over the side of a cruise liner tip the whole ship over? Because it's incredibly small compared the distortions of the whole ship has on the water and the ship is sat on the water itself.

This is exciting to many scientists because everything in the Universe moves. What we think of as temperature is in another way of looking at it just how fast things move. Anything that is above absolute zero has some form of movement to it and will generate gravitational waves which can be detected and we can find information about it. That is science fiction at the moment because we've only just been able to detect the movement of black holes which are massive and make massive waves comparatively (but still not big enough to be noticed by the ship) so detecting gravitational waves from atoms seems like an impossible task but it opens up a whole new branch of science.

The first telescopes used visible light to look at things. Then we got smarter and used non visible light and radio waves aswell. Now we've got a bit smarter than that even and can now use gravitational waves to look at things. This is especially important for early age cosmology as unlike electromagnetic radiation which has a time limit on it, gravitational waves could theoretically look right back to the Big Bang itself. Just as on a perfectly calm ocean a stone's ripple from one side would reach 1000 miles away, the ripples in spacetime don't go anywhere and are still available to be measured.

Not sure i really understand it if i'm honest. So as the earth moves through spacetime and creates its own ripples, is it our force we use to work through those ripples that is effectively what we feel as gravity?

 

[whp.blue]

Does this help with any of the quantum Gravity theories? because even Einstein didn't have all the answers

Black holes defeat Newton as well as Einstein this is the only real step forward in Physics fully explaining Black holes.
Physics is no closer to doing this than in Newtons day or so I am told.

 

[Chippy_boy]

Einstein really was a clever bastard wasn't he, none of this technology and he still got it right. I would love to have a chat with him, id be sat there confused as fuck like my dog when i talk to it

You know, I think you wouldn't be (as confused as your dog, that is).

I did Physics at Imperial College and I found that whenever I got to sit down with one of the real genius's there (we had a couple of Nobel Prize Laureats) their understanding was so utterly immense that they were able to explain it all to you in a way that suddenly became crystal clear and it all made sense.

Unfortunately, you'd then have to go off an do all of the maths behind it, which was beyond super-difficult and the wheels would fall off. But the top professors were really great at explaining things. I am sure a meeting with Einsten would have been like that. Apart from anything else, the concepts here are very simply and straightforward, it's just the sodding maths which is incomprehensible.

 

[Chippy_boy]

Not sure i really understand it if i'm honest. So as the earth moves through spacetime and creates its own ripples, is it our force we use to work through those ripples that is effectively what we feel as gravity?

What you feel as gravity is actually the curving of space-time.

Does this discovery prove the existence of Gravitons as elementary particles?

Since all waves have their particle counterpart, then yes, I would say it does. Having said that "existence" is a word rich in meaning ;-)

 

[East Level 2]

So a Navas cross is always likely to enter a black hole in a time warp?

I think his crossing and shooting is more likely to be covered in Heisenberg's uncertainty principle.

 

[goalmole]

So in a couple of sentences, just what is this post trying to say?

1. Einstein was right again.
2. Ignore this and keep watching Jeremy Kyle.