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For second time, scientists detect gravitational waves

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For the second time, scientists have directly detected gravitational waves — ripples through the fabric of space-time, created by extreme, cataclysmic events in the distant universe. The team has determined that the incredibly faint ripple that eventually reached Earth was produced by two black holes colliding at half the speed of light, 1.4 billion light years away.

The scientists detected the gravitational waves using the twin Laser Interferometer Gravitational-wave Observatory (LIGO) interferometers, located in Livingston, Louisiana, and Hanford, Washington. On Dec. 26, 2015, at 3:38 UTC, both detectors, situated more than 3,000 kilometers apart, picked up a very faint signal amid the surrounding noise.

While LIGO’s first detection, reported on Feb. 11, produced a clear peak, or “chirp,” in the data, this second signal was far subtler, generating a shallower waveform — essentially a faint squeak — that was almost buried in the data. Using advanced data analysis techniques, the team determined that indeed, the waveform signaled a gravitational wave.

The researchers calculated that the gravitational wave arose from the collision of two black holes, 14.2 and 7.5 times the mass of the sun. The signal picked up by LIGO’s detectors encompasses the final moments before the black holes merged: For roughly the final second, while the signal was detectable, the black holes spun around each other 55 times, approaching half the speed of light, before merging in a collision that released a huge amount of energy in the form of gravitational waves, equivalent to the mass of the sun. This cataclysm, occurring 1.4 billion years ago, produced a more massive spinning black hole that is 20.8 times the mass of the sun.

This second detection of gravitational waves, which once again confirms Einstein’s theory of general relativity, successfully tested LIGO’s ability to detect incredibly subtle gravitational signals.

... MIT News

Comparing "Chirps" from Black Holes - YouTube

Ripples in Spacetime Pond - YouTube

@sheffielduni (video)

With #GravitationalWaves in the news again today, here's our @LIGO scientist Dr Ed Daw explaining what they are
 

WinFonda

Member
so uh... what do ripples in the fabric of space-time mean... cuz it sounds mega... is that causing some serious shit to go down across the multiverse or somethin?
 

Truant

Member
so uh... what do ripples in the fabric of space-time mean... cuz it sounds mega... is that causing some serious shit to go down across the multiverse or somethin?

Basically that time sped up/slowed down for a very brief moment. It's not noticeable to us because space-time is "constant" to the local observer, at least outside extreme sources of gravity such as a black hole.
 

Alexlf

Member
so uh... what do ripples in the fabric of space-time mean... cuz it sounds mega... is that causing some serious shit to go down across the multiverse or somethin?

It's just gravity waves. Essentially, any object with mass has gravity, and gravity, no matter how small an amount, actually affects the entirety of the universe. As in, the gravity your body alone is "producing" is affecting planets lightyears away. Thanks to the inverse square law though, the effect is so incredibly small it's virtually impossible to detect. EDIT: And it's limited to the speed of light, hence it traveling like a wave.

This system uses very precisely tuned instruments to actually detect the ridiculously small changes in gravity that are affecting the earth, and using multiple points of detection we can triangulate the position of these objects and estimate their makeup based upon the strength of the changes.
 

FloatOn

Member
All so know is that Interstellar was dope

earlier in the year I got to see Hans Zimmer perform music from Interstellar.

the event was prefaced by a lecture on gravity waves by world famous physist Kip Thorne.

it was life changing.
 

fanboi

Banned
OP, that collision was like when yo mama did throw herself at that Big Mac.

Sorry OP just needed to :) awesome news
 
earlier in the year I got to see Hans Zimmer perform music from Interstellar.

the event was prefaced by a lecture on gravity waves by world famous physist Kip Thorne.

it was life changing.

I keep reminding myself I need to get the Interstellar science book. I love this shit, and I love that Nolan made a movie based on those concepts.
 

TyrantII

Member
so uh... what do ripples in the fabric of space-time mean... cuz it sounds mega... is that causing some serious shit to go down across the multiverse or somethin?

gravity-wave-space.jpg


The effect is so small that two black holes 60 time the mass of the sun only squeeze/ripple space by a tiny fraction of the width of a proton. But if you were right next to them you're probably having a very bad day.

The cool thing is all telescopes currently use photon detection and photons are scatted by certain things, the biggest being the CMB left over from the big bang.

Gravity waves are not.

Like seismic waves, they travel though everything, so eventually we can use them to see places in the universe that we could not with radio-telescopes. Like inside stars, past the CMB/big bang, and through opaque matter.
 

commedieu

Banned
gravity-wave-space.jpg


The effect is so small that two black holes 60 time the mass of the sun only squeeze/ripple space by a tiny fraction of the width of a proton. But if you were right next to them you're probably having a very bad day.

The cool thing is all telescopes currently use photon detection and photons are scatted by certain things, the biggest being the CMB left over from the big bang.

Gravity waves are not.

Like seismic waves, they travel though everything, so eventually we can use them to see places in the universe that we could not with radio-telescopes. Like inside stars, past the CMB/big bang, and through opaque matter.


What happens to matter that is squashed and squished by gravitational waves? Does its atoms retain the distance from one another?
 

TyrantII

Member
What happens to matter that is squashed and squished by gravitational waves? Does its atoms retain the distance from one another?

It would change. Effects are so tiny they don't effect us in any way though.

Spacetime itself is squished and stretched. Matter is imbedded in spacetime.

gw_elliptic.gif


The closes analogy is drawing something on a balloon and then squishing the ballon horizontally and then vertically. Watch the face get distorted and then return to normal. That's matter when a gravitational wave goes through.

A other cool thing because Einstein was right (per this discovery) is wave your hand. Since your hand is matter in motion, congrats you just created a gravity wave and moved the walls in the room (however infinitesimally small). If your hands were trillion of times the mass of a black hole you'd make the wall ripple like a stone thrown into a pond.
 

FyreWulff

Member
Also by the way, the reason it's all about black holes merging is because they create the biggest/"loudest" waves that stick out amongst all the noise. Everything generates gravity waves (as the above poster points out), we need bigger detectors to detect waves from smaller mass objects and events. Also once more detectors come online, we can even detect the exact direction they come from by calculating the time it took for the wave to hit each detector and triangulating.
 

commedieu

Banned
It would change. Effects are so tiny they don't effect us in any way though.

Spacetime itself is squished and stretched. Matter is imbedded in spacetime.

gw_elliptic.gif


The closes analogy is drawing something on a balloon and then squishing the ballon horizontally and then vertically. Watch the face get distorted and then return to normal. That's matter when a gravitational wave goes through.

A other cool thing because Einstein was right (per this discovery) is wave your hand. Since your hand is matter in motion, congrats you just created a gravity wave and moved the walls in the room (however infinitesimally small). If your hands were trillion of times the mass of a black hole you'd make the wall ripple like a stone thrown into a pond.

Thanks for the response. So is Spacetime a medium then.. the inbetween..?

Second question. I thought black holes had insane mass because of all the matter/light/time? Compressed to a single point. What bodies or energy expulsion would have a larger mass than a black hole..?

edit: I don't know why I waved my hand.
 

TyrantII

Member
Also by the way, the reason it's all about black holes merging is because they create the biggest/"loudest" waves that stick out amongst all the noise. Everything generates gravity waves (as the above poster points out), we need bigger detectors to detect waves from smaller mass objects and events. Also once more detectors come online, we can even detect the exact direction they come from by calculating the time it took for the wave to hit each detector and triangulating.


Hopefully this pushes congress to fund LISA. A billion wide mile gravity wave telescope in space is exciting.
 

Mindlog

Member
The sensitivity needed to achieve results is really quite remarkable and this is just the first revision of a first generation instrument.
 

HTupolev

Member
Second question. I thought black holes had insane mass because of all the matter/light/time? Compressed to a single point.
Being compressed to a single point means the density is insanely high ("infinitely high", in classical physics), but in and of itself that doesn't mean it's got lots of mass. A black hole made out of 5kg of mass would be a 5kg black hole.

However, when we talk about black holes in astrophysics, we're often talking about objects that formed from the collapse of stars and such, which obviously tend to have a lot of mass.

Hopefully this pushes congress to fund LISA. A billion wide mile gravity wave telescope in space is exciting.
Million mile wide, not billion.

Regardless, between the size and the "being in space" thing, it could potentially be waaaaaaay more capable than LIGO.
 

sphinx

the piano man
the thing that always blows my mind is how they know things like the masses of the black holes or at what speed they were rotating.

we know that two black holes collided and merged 1.4 billions years ago.

I am sorry, dogs, cats and dolphins, but I am gonna brag: we as species are pretty damn intelligent.
 

Xe4

Banned
Thanks for the response. So is Spacetime a medium then.. the inbetween..?

Second question. I thought black holes had insane mass because of all the matter/light/time? Compressed to a single point. What bodies or energy expulsion would have a larger mass than a black hole..?

edit: I don't know why I waved my hand.

Spacetime is the geometry of our universe. We don't perceive it because we can only see euclidian (3-D) geometry. Spacetime is the 3 dimensions of space, plus the dimension of time as a whole. To understand this requires understanding Riemannian Geometry, which deals with curved surfaces. It is extremely complicated to say the least.

Black holes come in different masses from a few dozen solar masses, to rediculous amounts for the black holes found in the center of galaxies. The poster was saying that you could move the wall just by the energy of the gravitational waves if you had a mass heavier than the average black hole.

As for the single point, or singularly, it should not exist by the current laws of physics. How the singularity does exists, or what exists if it does not, is one of the great mysteries of modern physics.
 
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