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[FlyinJ]

Something I'm still confused about-

Did they know to "point" the detectors at a certain point in space, or did they just happen to catch this gravity wave? Do they know where it came from?

To use this discovery to analyze the "gravity spectrum" of the universe, can something be pointed at a certain point in space, or is it just a passive listening method?

 

[Dryk]

Not doubting it works. I just don't really understand the intricacies.

I'd have to ask exactly how this observation done when my friend gets back from the US because this isn't my field. But I do know a bit about steering acoustic arrays and they're probably working on similar principles. If you record the time series data at a bunch of different points then during post-processing you can sum them (though mostly people use more complicated algorithms for beam-forming) such that your focusing on a given point (ideally). Once you process the signal at that point you move onto the next one and so on and you can get a good idea of what signals are generated where.

As you change the time delay the contribution to your final result from different locations changes. So when you get a strong signal from a beam pointing in a given direction it's likely that that's where it comes from and generate a source map from that.

Here's an example, using the noise generated by a wall-mounted airfoil

EDIT: And here's an example of the sort of resolution they expect to get out of the existing GWI network (top) and one including a proposed Australian GWI that fell through (bottom). I'm not certain but from the looks of it it's showing what a point signal at each of those locations would be resolved as. So basically there's a bunch of locations at the moment where the estimated location will be really blurry but there's a few places that we should be able to get a decent picture of.

 

[chaosblade]

I think I get the gist of it, if I was going to ask further it would be about the post-process algorithms for this sort of thing, but even if it was explained I probably wouldn't understand it anyway

This is the kind of shit I'd love to do, space is so fascinating.

 

[MGrant]

Something I'm still confused about-

Did they know to "point" the detectors at a certain point in space, or did they just happen to catch this gravity wave? Do they know where it came from?

To use this discovery to analyze the "gravity spectrum" of the universe, can something be pointed at a certain point in space, or is it just a passive listening method?

The detector isn't really directional; it is built to detect gravitational interference within a radius of 190 million light years around us.

 

[Smash88]

What are some practical applications where knowledge of this could be applied to in the close future or even distant future? Will this help understand how to make potentially futuristic space ships? Or what?

 

[LookAtMeGo]

I cant wait to ride some gravity waves, dudes. Fucking cowabunga on my way to the horse head nebula bro.

 

[spekkeh]

The detector isn't really directional; it is built to detect gravitational interference within a radius of 190 million light years around us.

What do you mean? Surely it would only be able to detect gravity waves passing through it? And the cosmic event they measured was 1 billion LY away.

 

[Death Metalist]

This is incredible and beautiful, exciting stuff.

 

[Dreams-Visions]

What are some practical applications where knowledge of this could be applied to in the close future or even distant future? Will this help understand how to make potentially futuristic space ships? Or what?

https://www.youtube.com/watch?v=4GbWfNHtHRg
http://stuver.blogspot.com/2012/01/q-how-can-gravitational-waves-help.html

 

[Smash88]

https://www.youtube.com/watch?v=4GbWfNHtHRg
http://stuver.blogspot.com/2012/01/q-how-can-gravitational-waves-help.html

In other words, it helps us know about the Universe we are in. We don't yet know how it will affect our daily lives or even the future until more has been learned about it since we are still in the very early stages of understanding it. Got it, thanks.

 

[Dreams-Visions]

In other words, it helps us know about the Universe we are in. We don't yet know how it will affect our daily lives or even the future until more has been learned about it since we are still in the very early stages of understanding it. Got it, thanks.

yep and yep

 

[sono]

Cool

is that an n

No its a w

Okay picture the universe as being the inside of a closed fridge. You are a microbe living on a crumb somewhere in the fridge. To you the fridge is vast, and you spend years building instruments to try to figure out what is out there in that vast darkness.

One day you develop an instrument that can detect that a magnetic field is keeping your universe sealed. Since you now know this, you can use this information to work out the exact outer limits of your fridge (ie where the door is). In turn you can develop technology that will allow you to open the fridge door, turn on the light, and reveal the great beyond.

So if you're with me so far, then taking all that into account, it becomes pretty clear that I haven't the faintest idea what I am talking about.

Thats brilliant

 

[Monocle]

Always cool to see major predictions confirmed way down the line.

How is this the first time I've seen this glorious gif? I would have used it so much in the Transformers: Devastation thread.

 

[Dryk]

In other words, it helps us know about the Universe we are in. We don't yet know how it will affect our daily lives or even the future until more has been learned about it since we are still in the very early stages of understanding it. Got it, thanks.

A lot of good research in vibration isolation, optics, and laser physics goes into GWI development as well. That stuff flows onto our daily lives a lot faster than anything in cosmology will.

Something to keep in mind is that this discovery represents the proof-of-concept of a completely new tool. All of our other astronomical instrumentation is based in electromagnetic waves. I can't think of a very good analogy right now but it's like inventing the scales and asking what good knowing the mass of objects is.

I think I get the gist of it, if I was going to ask further it would be about the post-process algorithms for this sort of thing

The most basic one for acoustics/light is a simple delay and sum algorithm. Beyond that the rabbit hole goes deep, and the latest techniques are mostly based in the frequency domain.

 

[GameAddict411]

General relativity have been proved long before this. In fact, it's a fundamental part of how GPS works.

 

[Log4Girlz]

I want a Ben and Jerry's flavor. Gravity Ripple

It can have two Dark chocolate spheres in the middle to represent black holes and caramel ripple swirls as gravity waves. Because gravitons probably taste of caramel.

 

[Smash88]

A lot of good research in vibration isolation, optics, and laser physics goes into GWI development as well. That stuff flows onto our daily lives a lot faster than anything in cosmology will.

Something to keep in mind is that this discovery represents the proof-of-concept of a completely new tool. All of our other astronomical instrumentation is based in electromagnetic waves. I can't think of a very good analogy right now but it's like inventing the scales and asking what good knowing the mass of objects is.

I wonder if we'll see any technological (or other) improvements, as a result of our ongoing education into this field, in our lifetime. Colour me excited.

 

[spekkeh]

Of course this instrument is based on electromagnetic waves too. The things it detects aren't that though. I still marvel at how relatively simple the idea is and that they only just did it and not say forty years ago. But I can imagine building two 4 km tunnels where a laser is split, rebounded between a ton of mirrors and then returns at the exact same wavelength is an incredible engineering feat. I wonder how sensitive it would be to seismic activity, but I guess that's why they are building multiple ligos across the world.

 

[Armaros]

Of course this instrument is based on electromagnetic waves too. The things it detects aren't that though. I still marvel at how relatively simple the idea is and that they only just did it and not say forty years ago. But I can imagine building two 4 km tunnels where a laser is split, rebounded between a ton of mirrors and then returns at the exact same wavelength is an incredible engineering feat. I wonder how sensitive it would be to seismic activity, but I guess that's why they are building multiple ligos across the world.

A majority of the technological complexity comes from dampening everything else that would give out a false signal. We have had the idea to use lasers to test for the waves for years.

They are sensitive enough that they had to ban large trucks from driving close.

 

[shortstop]

What do you mean? Surely it would only be able to detect gravity waves passing through it? And the cosmic event they measured was 1 billion LY away.

A single detector (or LIGO station) doesn't give directional information. However, by using the time delay between the detections from the two LIGO stations in Washington and Louisiana scientist are able to restrict the location to what is basically a large arc on the sky. By adding information from the VIRGO detector in Italy later this year (or next year?) the ability to pinpoint the location will improve, but it will still be very uncertain. When Japan and India come online it might become possible to steer ground- and space-based telescopes into the general direction of a GW event and see if there was an electro-magnetic (e.g. radio, optical, or X-ray) event at that location in the sky as well, for example a Gamma Ray Burst or the explosion of a very massive star.

 

[Owari]

WAVES?

If only.

 

[Frillen]

So what is outside of the expanding universe? Nothing, nowhere? Was light as we know it created at the exact moment of the big bang? Or did it exist before?

 

[kyser73]

Now the ground based PoC has been ticked off the next one is an orbital LIGO with satellite groups doing the same thing without having to worry about a telephone ringing mucking the results up

 

[kavanf1]

So what is outside of the expanding universe? Nothing, nowhere? Was light as we now it created at the exact moment of the big bang? Or did it exist before?

Time and space as we know it started at the big bang. So there is no such thing as "before" the big bang, as that would imply that time existed before it happened.

Thats brilliant

 

[uncelestial]

For those who want a better explanation:

https://www.youtube.com/watch?v=FXlg3cr-q44

Sorry if this is a dumb question, but wouldn't LIGO be incredibly susceptible to tiny vibrations here on Earth? Little earthquakes we don't perceive would probably shift things by 1/1000th the diameter of a proton. Hell, a beetle crawling on one of the sensors would. All that instrument seems capable of is confirming that the lasers were disturbed.

Fake edit. Wrote this then searched it, and the answer is - yes indeed "It's a battle." They have to set a noise floor and filter out all kinds of vibrations.
https://www.quora.com/Is-LIGO-not-vulnerable-to-earthquakes-plate-shiftings-etc

Will be looking into how they confirmed these findings later.

 

[Faith]

Sorry if this is a dumb question, but wouldn't LIGO be incredibly susceptible to tiny vibrations here on Earth? Little earthquakes we don't perceive would probably shift things by 1/1000th the diameter of a proton. Hell, a beetle crawling on one of the sensors would. All that instrument seems capable of is confirming that the lasers were disturbed.

Fake edit. Wrote this then searched it, and the answer is - yes indeed "It's a battle." They have to set a noise floor and filter out all kinds of vibrations.
https://www.quora.com/Is-LIGO-not-vulnerable-to-earthquakes-plate-shiftings-etc

Will be looking into how they confirmed these findings later.

Can't wait till they build a much bigger one in space.

 

[Unai]

Is it possible that in the future we can make sensors powerful enough to "see" the waves from less massive objects like planets?

 

[Yagharek]

Is it possible that in the future we can make sensors powerful enough to "see" the waves from less massive objects like planets?

I think these waves were from a combined mass of fifty or sixty suns. Which is however many thousands of times the mass of a planet.

Inverse square law tells me you would need at least a sensor array a million times more sensitive. Dunno how close that would bring them to the Planck scale limit.

 

[Faith]

Is it possible that in the future we can make sensors powerful enough to "see" the waves from less massive objects like planets?

I think these waves were from a combined mass of fifty or sixty suns. Which is however many thousands of times the mass of a planet.

Inverse square law tells me you would need at least a sensor array a million times more sensitive. Dunno how close that would bring them to the Planck scale limit.

It's not only about the mass. The merging of the two black holes caused gravitational waves that were 50 times stronger than all stars in the universe combined.

 

[KooopaKid]

Nice marketing to sell it as the soundtrack of the universe. Transferring the data into a soundwave.

"They should have sent a musician"

 

[30yearsofhurt]

 

[FyreWulff]

They could just be lying to continue getting payed, and nobody would know the difference. :-/

The experiments have actually been fed continual false positives so that nobody can jump to conclusions on a positive result, because they don't know if it's a real one or one of the intentional false positives

 

[talisayNon]

Okay picture the universe as being the inside of a closed fridge. You are a microbe living on a crumb somewhere in the fridge. To you the fridge is vast, and you spend years building instruments to try to figure out what is out there in that vast darkness.

One day you develop an instrument that can detect that a magnetic field is keeping your universe sealed. Since you now know this, you can use this information to work out the exact outer limits of your fridge (ie where the door is). In turn you can develop technology that will allow you to open the fridge door, turn on the light, and reveal the great beyond.

So if you're with me so far, then taking all that into account, it becomes pretty clear that I haven't the faintest idea what I am talking about.

lol you bitch

 

[Faith]

Okay picture the universe as being the inside of a closed fridge. You are a microbe living on a crumb somewhere in the fridge. To you the fridge is vast, and you spend years building instruments to try to figure out what is out there in that vast darkness.

One day you develop an instrument that can detect that a magnetic field is keeping your universe sealed. Since you now know this, you can use this information to work out the exact outer limits of your fridge (ie where the door is). In turn you can develop technology that will allow you to open the fridge door, turn on the light, and reveal the great beyond.

So if you're with me so far, then taking all that into account, it becomes pretty clear that I haven't the faintest idea what I am talking about.

Lol you made my day xD

 

[Graphics Horse]

What is the 'chirp'? Do they have an isolated event or is there a continuous signal that phases per station to match the Earth's rotation?

 

[FyreWulff]

What is the 'chirp'? Do they have an isolated event or is there a continuous signal that phases per station to match the Earth's rotation?

it's the gravitational waves Hz played back as sound. It was a one off event, the wave has passed by and won't ever be seen again.

 

[Graphics Horse]

Huh, thar's depressing, how long did it last?

 

[Nicktendo86]

I find it hard to understand all this stuff but it's fascinating all the same. Am I right in saying this is the first concrete proof that back holes exist?

 

[Yagharek]

I find it hard to understand all this stuff but it's fascinating all the same. Am I right in saying this is the first concrete proof that back holes exist?

I think it's the first ever direct measurement. You can infer their mass from the behaviour of other orbiting objects and active emissions eg galactic nuclei and also lensing effects but this gravitational wave is possibly the first direct bit of information that has come from one. Or two, in this case.

 

[Catdaddy]

So this also confirms Half-Life 3, right???

Spoiler

Great news, will be interesting to see what comes from this discovery

 

[Dreams-Visions]

Huh, thar's depressing, how long did it last?

Fractions of a second.

 

[TheWorthyEdge]

Wow. I don't exactly understand this but wow. This is crazy right? We can look into Black Holes, no? That's incredible. Would this have any effect at all with finding other life forms?

Also, what is the benefit of looking into Black Holes anywho?

 

[NekoFever]

So this also confirms Half-Life 3, right???

This story is a cover-up. The waves were really from a resonance cascade.

 

[Nameless]

Maybe we will see that unified theory in or lifetime, after all.

 

[alundra311]

Stupid question, how do they know that two black holes colliding is the cause of the gravitational waves they detected?

 

[DistortionOfReality]

Stupid question, how do they know that two black holes colliding is the cause of the gravitational waves they detected?

This is actually an excellent question. If they measured this 'chirp' at two seperate locations, at almost identical times, and the wave from the collision only passes by Earth once (rather than a repeated wave ripple effect) How can they be 100% sure it's not something else?

 

[joshbob1985]

Stupid question, how do they know that two black holes colliding is the cause of the gravitational waves they detected?

I think they used GR to calculate what the gravitational wave produced by two colliding black holes would look like and it matched their measurements.

 

[LegendofJoe]

Now the ground based PoC has been ticked off the next one is an orbital LIGO with satellite groups doing the same thing without having to worry about a telephone ringing mucking the results up

It will be a while before something like that is built and launched. That said I'm sure some people are already working on designing it. Hopefully the James Webb will be a huge success and help speed up the timeline to launch LIGO satellites.

 

[Netherscourge]

Do gravitational waves act like water waves?

Do they move faster and gain momentum as they travel?

Can they warp the gravitational orbits of other celestial bodies as they travel?

Can they CARRY stuff like light or radiation or even matter along with them, at variable speeds? (aka surfing)

Can they move at the speed of light? Or faster?

How long ago did these two black holes send out the waves we just recently detected? Are they still there? Have they merged already? Or did they fizzle out millions of years ago?

 

[FyreWulff]

Can they warp the gravitational orbits of other celestial bodies as they travel?

Nope. They warp spacetime itself.

Can they CARRY stuff like light or radiation or even matter along with them, at variable speeds? (aka surfing)

No, they pass through matter.

Can they move at the speed of light? Or faster?

speed of light, so far as we know

How long ago did these two black holes send out the waves we just recently detected? Are they still there? Have they merged already? Or did they fizzle out millions of years ago?

a billion years ago, and I think the science we have so far would state that the merged black hole should still be there. the rate of hawking radiation, if it exists, wouldn't be fast enough.

edit: yeah, doublechecked it. mass of these black holes would take longer than the age of the universe to evaporate