Einstein's gravitational waves 'seen' from black holes

[icebags]

Einstein's gravitational waves 'seen' from black holes - BBC New

Scientists are claiming a stunning discovery in their quest to fully understand gravity.

They have observed the warping of space-time generated by the collision of two black holes more than a billion light-years from Earth.

The international team says the first detection of these gravitational waves will usher in a new era for astronomy.

It is the culmination of decades of searching and could ultimately offer a window on the Big Bang.

The research, by the Ligo Collaboration, has been published today in the journal Physical Review Letters.

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.

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Spoiler

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some possibilities & thoughts :
# it would probably mean space is not practically "nothing", it is "something" that goes dense where objects are forms, and are lite where its just space, goes denser and denser at very small distances near an object, with a very steep carve of space vs space density.
# the experiments suggest gravitational change is not instantaneous, like em waves /lights take time to reach earth from sun, gravity also takes time to travel to distances.
# if space is "something" may be it could have some mass after all, dark mass may be.
# may also mean something to the string theory concepts. they kinda sound similar.


for more fun stuff, read the articles and play the gravitational music ! :dizzy_NF:


@Desmond David

 

[TechnoBOY]

So now,what this changes?

 

[icebags]

^ what u mean, u can not read it without clicking like button ?

 

[Desmond]

Great to know that it is possible to observe this phenomenon.

This appears to be a phenomenon similar to gravitational lensing. Gravitation waves form similar to waves in water, when two different sources of waves collide, new patterns form.

 

[Desmond]

*cdn.eso.org/images/thumb700x/potw1726a.jpg
Highest resolution image of the red supergiant Betelgeuse
Betelgeuse captured by ALMA

 

[icebags]

^ bright - bright - bright - then boom .....

but what it has to do with gravitational waves ?

 

[Desmond]

Nothing. I saw this link on reddit and thought to share it here.

Sent from my A0001 using Tapatalk

 

[Desmond]

OMFG. I thought this is the astronomy thread. That is why I posted it here.

 

[icebags]

OMFG. I thought this is the astronomy thread. That is why I posted it here.

right. so, what you think travels faster ? light or gravity ?

 

[Desmond]

Light no doubt. Gravitational waves can bend light though.

 

[whitestar_999]

No,They are of same velocity in vacuum.
Speed of gravity - Wikipedia

The speed of gravitational waves in the general theory of relativity is equal to the speed of light in a vacuum, c.

Also it is not gravitational waves but gravity that bends light,both are different.

 

[chimera201]

I read the article in OP.

A laser is fed into the machine and its beam is split along two paths
The separate paths bounce back and forth between damped mirrors
Eventually, the two light parts are recombined and sent to a detector
Gravitational waves passing through the lab should disturb the set-up
Theory holds they should very subtly stretch and squeeze its space
This ought to show itself as a change in the lengths of the light arms (green)
The photodetector captures this signal in the recombined beam

Scientists be like 'I sense a disturbance in the force'.
Jokes aside, I thought they were firing the lasers into space. The experiment was performed inside a lab. How the hell did they deduce that the gravitational waves data they got was from the collision of two black holes that are light years away?

 

[whitestar_999]

That's why you are not the one performing these experiments.

Imagine clicking photos of a ripple caused by a huge rock falling into the river out of your eye's view field.In case of gravitational waves,entire universe is the lake feeling the effect & that is why one can measure gravitational waves any where in the universe(including inside labs on planet Earth).

 

[chimera201]

That's why you are not the one performing these experiments.

Imagine clicking photos of a ripple caused by a huge rock falling into the river out of your eye's view field.In case of gravitational waves,entire universe is the lake feeling the effect & that is why one can measure gravitational waves any where in the universe(including inside labs on planet Earth).

I mean it could be anything other than gravitational waves affecting it like things that were never theorized. And there is also high chance for noise error.

Edit:

Just like I said
Controversy over gravitational wave discovery | Daily Mail Online

For those interested some images of the detection device.

*i.dailymail.co.uk/i/pix/2016/02/11/17/3119170E00000578-3442022-An_aerial_photo_shows_Laser_Interferometer_Gravitational_wave_Ob-a-23_1455210047914.jpg
*i.dailymail.co.uk/i/pix/2016/02/11/17/3119166F00000578-3442022-A_bird_s_eye_view_of_Laser_Interferometer_Gravitational_wave_Obs-a-14_1455210047369.jpg

 

[whitestar_999]

Just for future reference,don't use dailymail links for discussion on scientific topics.Saying it can be anything is like saying give a verifiable proof that God does not exist(nobody can prove existence or non-existence of God). Gravitational waves are based on solid theories by Einstein & unless someone comes along to prove otherwise,it is to be considered as true.As for validity of experiments,again there is no credible scientific organisations/people doubting it which is the least to be expected when doubting a $1 billion experiment.In fact ESA is preparing to send dedicated gravitational space detectors to space.
LISA - Laser Interferometer Space Antenna -NASA Home Page
Laser Interferometer Space Antenna - Wikipedia

 

[chimera201]

Just for future reference,don't use dailymail links for discussion on scientific topics.Saying it can be anything is like saying give a verifiable proof that God does not exist(nobody can prove existence or non-existence of God). Gravitational waves are based on solid theories by Einstein & unless someone comes along to prove otherwise,it is to be considered as true.As for validity of experiments,again there is no credible scientific organisations/people doubting it which is the least to be expected when doubting a $1 billion experiment.In fact ESA is preparing to send dedicated gravitational space detectors to space.
LISA - Laser Interferometer Space Antenna -NASA Home Page
Laser Interferometer Space Antenna - Wikipedia

Dude it's a proper claim by scientists not some cooked up article.
Gravitational waves

 

[whitestar_999]

I never said anything about cooked up article,I said "credible sources" & there is a big difference.Also here is the reply from a LIGO scientist to the study challenging the LIGO observation link posted by you:
A Response to “On the time lags of the LIGO signals” (Guest Post)

Now don't take it otherwise but neither you nor I understand anything written in either of the articles(by understanding,I mean the conceptual depth that matters.e.g.I have studied Fourier transformation in engineering but that does not mean I should claim to understand any line that mentions Fourier transformation in either article). Neither you nor I have the requisite qualifications to understand any of it but what differs me from you is that I do not cast doubts over any scientific claim that is made after the standard procedure of verification & peer review(Phys. Rev. Lett. 116, 061102 (2016) - Observation of Gravitational Waves from a Binary Black Hole Merger ,you can see it was made 5 months after the detection because of following this standard procedure) & has no credible challenges(credible means a claim made in the same manner of standard verification procedure & peer review,not simply a study conducted by a group).

 

[chimera201]

^ I'm not saying that it's not gravitational waves, but there is a chance that it could be just 'noise' as said by that group. LIGO hasn't publicly explained how they deduced that it is indeed gravitational waves (and that too from a particular merger of black holes) and why so sure of it. They will have to explain it at some point and present the raw data publicly so other scientists can study and verify it. The peer review was only done by LIGO/VIRGO themselves. An external independent body needs to do the review and agree with it.

 

[whitestar_999]

"That group" as of now is not a credible challenge(as explained in LIGO scientist reply link). LIGO peer review is credible enough as of now & there are no credible challenges to it either(unless one assumes entire community of LIGO/VIRGO to be involved in some kind of coverup which is more of a conspiracy theory area rather than scientific debate). If you consider it as an honest mistake then again chances of that by such a group of people,reputable scientists no less,is quite low. Looking from a purely objective viewpoint without any biases I don't see any reason to doubt LIGO as of now.

 

[chimera201]

"That group" as of now is not a credible challenge(as explained in LIGO scientist reply link).

Oh I forgot to post the link where their point still stands:
How Uncertain Are LIGO's First Gravitational Wave Detections?

It's a reproduction of the analysis he believes the Denmark team performed, and that they performed incorrectly. His explanation was as follows:

bla bla

Case closed? Only if this is what the Denmark team actually did.

But according to the Danish team, they did not. In fact, they wrote a response to Ian Harry's comment, where they graciously thanked him for access to his computer code, and worked with it to re-perform their analysis. The whole point of this, by the way, is not to claim that LIGO may have falsely detected gravitational waves. Even in the most extreme scenario, where there is noise contaminating the results seen between both detectors, a strong gravitational wave signal — one that matches the template for black hole mergers — still appears. The worry, rather, is that the noise has been dealt with sub-optimally, and that perhaps some of the signal has been subtracted out while some of the noise has been left in. When the Danes performed their full analysis, building off the methodology of LIGO, that's what they are forced to conclude.

Quite clearly, there is a signal that goes way beyond noise, and it appears independently in both detectors. But also of note is the black curve in the bottom graph above, which shows the noise correlations between two detectors. In particular, the big "dip" at +7 milliseconds correlates with the time at which the gravitational wave signal emerges, and this is what the Danish team wants to focus on. As they say explicitly:

The purpose in having two independent detectors is precisely to ensure that, after sufficient cleaning, the only genuine correlations between them will be due to gravitational wave effects. The results presented here suggest this level of cleaning has not yet been obtained and that the identification of the GW events needs to be re-evaluated with a more careful consideration of noise properties.

And this is something that I think everyone is taking seriously: making sure that what we're subtracting off and calling "noise" is actually 100% noise (or as close as possible to it), while what we're keeping as "signal" is actually 100% signal with 0% noise. It's never possible, in practice, to do this exactly, but that's the goal.