Gravitational Waves

Posted by: GraemeH on 11 February 2016

How significant is the proof that gravitational waves exist?

Posted on: 13 February 2016 by Dan.S

Sure they have to prove all the limiting physics we learnt in schools, just to keep us in the dark.

Posted on: 13 February 2016 by Dozey

Interesting points Don. I will do some reading on the subject and see if the man down the pub is correct!

Posted on: 13 February 2016 by Dozey

Your man down the pub appears to be correct! I take it back, gps clocks are about general relativity after all!

Posted on: 13 February 2016 by Peter Dinh

This is from the President of my school.

On Thu, Feb 11, 2016 at 7:36 AM, President L. Rafael Reif <aacomments@mit.edu> wrote:

February 11, 2016

Dear MIT graduate,

At about 10:30 this morning in Washington, D.C., MIT, Caltech and the National Science Foundation (NSF) will make a historic announcement in physics: the first direct detection of gravitational waves, a disturbance of space-time that Albert Einstein predicted a century ago.

You may want to watch the announcement live now. Following the NSF event, you can watch our on-campus announcement event.

You can read an overview of the discovery here as well as an interview with MIT Professor Emeritus Rainer Weiss PhD '62, instigator and a leader of the Laser Interferometer Gravitational-Wave Observatory (LIGO) effort.

The beauty and power of basic science
I do not typically write to you to celebrate individual research achievements, no matter how impressive; our community produces important work all the time. But I urge you to reflect on today’s announcement because it demonstrates, on a grand scale, why and how human beings pursue deep scientific questions – and why it matters.

Today's news encompasses at least two compelling stories.

First is the one the science tells: that with his theory of general relativity, Einstein correctly predicted the behavior of gravitational waves, space-time ripples that travel to us from places in the universe where gravity is immensely strong. Those rippling messages are imperceptibly faint; until now, they had defied direct observation. Because LIGO succeeded in detecting these faint messages – from two black holes that crashed together to form a still larger one – we have remarkable evidence that the system behaves exactly as Einstein foretold.

With even the most advanced telescopes that rely on light, we could not have seen this spectacular collision, because we expect black holes to emit no light at all. With LIGO's instrumentation, however, we now have the "ears" to hear it. Equipped with this new sense, the LIGO team encountered and recorded a fundamental truth about nature that no one ever has before. And their explorations with this new tool have only just begun. This is why human beings do science!

The second story is of human achievement. It begins with Einstein: an expansive human consciousness that could form a concept so far beyond the experimental capabilities of his day that inventing the tools to prove its validity took a hundred years.

That story extends to the scientific creativity and perseverance of Rai Weiss and his collaborators. Working for decades at the edge of what was technologically possible, against the odds Rai led a global collaboration to turn a brilliant thought experiment into a triumph of scientific discovery.

Important characters in that narrative include the dozens of outside scientists and NSF administrators who, also over decades, systematically assessed the merits of this ambitious project and determined the grand investment was worth it. The most recent chapter recounts the scrupulous care the LIGO team took in presenting these findings to the physics community. Through the sacred step-by-step process of careful analysis and peer-reviewed publication, they brought us the confidence to share this news – and they opened a frontier of exploration.

At a place like MIT, where so many are engaged in solving real-world problems, we sometimes justify our nation's investment in basic science by its practical byproducts. In this case, that appears nearly irrelevant. Yet immediately useful "results" are here, too: LIGO has been a strenuous training ground for thousands of undergraduates and hundreds of PhDs – two of them now members of our faculty.

What's more, the LIGO team's technological inventiveness and creative appropriation of tools from other fields produced instrumentation of unprecedented precision. As we know so well at MIT, human beings cannot resist the lure of a new tool. LIGO technology will surely be adapted and developed, "paying off" in ways no one can yet predict. It will be fun to see where this goes.

* * *

The discovery we celebrate today embodies the paradox of fundamental science: that it is painstaking, rigorous and slow – and electrifying, revolutionary and catalytic. Without basic science, our best guess never gets any better, and "innovation" is tinkering around the edges. With the advance of basic science, society advances, too.

I am proud and grateful to belong to a community so well equipped to appreciate the beauty and meaning of this achievement – and primed to unlock its opportunities.

In wonder and admiration,

L. Rafael Reif

Posted on: 13 February 2016 by GraemeH

It sounds, from the various posts, that we are to appreciate the discovery that gravitational waves exist in the same way we might appreciate a great work of art.

Interesting, and I don't have a problem with that.

Posted on: 13 February 2016 by George F

All human life up this year has existed without this knowledge, however pleasing to scientific community.

It will not solve the Syrian crisis, and indeed I often wonder whether spaceflight has done more than cost the major countries unfeasible amounts to prove that they have the bravest technologies.

Please can we get back on plot and actually work on real problems that - if solved - may provide solutions for today ...

Posted on: 13 February 2016 by GraemeH

What prompted my post was that Channel 4 news had an interesting debate between two economists each out-doing the other on how fundamentally screwed the global financial monetary system is.

They then flipped to the scientists saying 'we did it....'.

'It' seemed quite trivial in comparison to the news 'where we are'....that being planet earth.

Posted on: 13 February 2016 by Don Atkinson

Dozey posted:
Your man down the pub appears to be correct! I take it back, gps clocks are about general relativity after all!

Hi Dozey,

The effect of these gravitational waves is quite profound. Hope you found it interesting to delve into the matter.

Posted on: 13 February 2016 by Steve2

Few if any know what this knowledge will lead to in terms of its impact on mankind. The spin offs from the space race are all around us making are lives safer and more enjoyable. The fact that some brilliant minds have solved an intractable problem is a good reason to celebrate. I think Donald Rumsfold got there before them or should I say prepared us for this moment when he informed us all of the known unknowns and even the unknown unknowns along with the unknown knowns......

Posted on: 13 February 2016 by GraemeH

Steve2 posted:
Few if any know what this knowledge will lead to in terms of its impact on mankind. The spin offs from the space race are all around us making are lives safer and more enjoyable. The fact that some brilliant minds have solved an intractable problem is a good reason to celebrate. I think Donald Rumsfold got there before them or should I say prepared us for this moment when he informed us all of the known unknowns and even the unknown unknowns along with the unknown knowns......

It's the known knows that we seem incapable of sorting. Scientific endeavour and responsible society seem to be pulling further and further apart to me.

Posted on: 13 February 2016 by Don Atkinson

GraemeH posted:
It's the known knows that we seem incapable of sorting. Scientific endeavour and responsible society seem to be pulling further and further apart to me.
G

Whilst a rise in global temperature springs to my mind as a known, known, what other known knowns did you have in mind ?

Posted on: 13 February 2016 by GraemeH

Don Atkinson posted:
GraemeH posted:
It's the known knows that we seem incapable of sorting. Scientific endeavour and responsible society seem to be pulling further and further apart to me.
G
Whilst a rise in global temperature springs to my mind as a known, known, what other known knowns did you have in mind ?

Global financial dysfunction, increasing social inequality and the necessarily limited use of present antibiotics come to mind. (as well as global warming and deforestation, wildlife depletion...)

Posted on: 13 February 2016 by TOBYJUG

GraemeH posted:
Steve2 posted:
Few if any know what this knowledge will lead to in terms of its impact on mankind. The spin offs from the space race are all around us making are lives safer and more enjoyable. The fact that some brilliant minds have solved an intractable problem is a good reason to celebrate. I think Donald Rumsfold got there before them or should I say prepared us for this moment when he informed us all of the known unknowns and even the unknown unknowns along with the unknown knowns......
It's the known knows that we seem incapable of sorting. Scientific endeavour and responsible society seem to be pulling further and further apart to me.
G

Whenever have they ever been close bedfellows. Time scale is relevant here , global warming - how will that idea and effect pan out in 200 years time - will we be toast or could it have been from cause and effect far greater than our contributions ? Wheras GW discovery will be written in stone somewhere forever.

Posted on: 13 February 2016 by Don Atkinson

GraemeH posted:
Don Atkinson posted:
GraemeH posted:
It's the known knows that we seem incapable of sorting. Scientific endeavour and responsible society seem to be pulling further and further apart to me.
G
Whilst a rise in global temperature springs to my mind as a known, known, what other known knowns did you have in mind ?
Global financial dysfunction, increasing social inequality and the necessarily limited use of present antibiotics come to mind. (as well as global warming and deforestation, wildlife depletion...)
G

Thanks Graeme,

Good list.

Sticking with a rise in global temperature, Tobyjug has pointed out some of the problems.

We "know" that global temperatures have risen over a relatively short time-scale.

We don't know the principal causes of this rise, although there are many theories.

We don't know whether any proposed "solutions" will be effective, or whether events outside our control will swamp any efforts that we implement.

In other words, lots of unknowns within a "known" parameter.

Not surprising that there is discord between different groups of society.

I rather suspect similar situations exist in some of the other "known" "knowns"

Scientists need to be more convincing. Politicians need to look further ahead than the next election.

People like me need to be less scepticle...............

Posted on: 13 February 2016 by Don Atkinson

...............but it's good news that gravitational waves have been "seen". Who knows what will follow.

As others have said, if Einstein hadn't wasted his time on his theories of relativity, we probably wouldn't have gotten around to GPS (even though it's not totally necessary for a GPS solution)...........

..oh ! and we probably wouldn't have gotten around to GPS without first having nuclear-missile-carrying submarines and atomic weapons....................

Posted on: 13 February 2016 by TOBYJUG

Originally they really wanted New Horizon to go into orbit around Pluto and stay longer rather than just a fly by. GPS or rather Galactic PS was short sighted and missed it by quite some margin, perhaps GW tech will make this sort of thing more possible.

Posted on: 14 February 2016 by robgr

fatcat posted:
staffy posted:
He is obviously in it for the money he makes from gullible people.
The same could be said about the thousands of scientists making a bloody good living from all this Higgs Boson/Gravitation Pulse, etc. hocus pocus.
I'm with Graham, this kind of research is of no use to anybody. (except the scientists). Who cares when or how the universe was created.

If it wasn't for quantum theory for example you wouldn't be reading this, that theory led to the invention of silicon chips :-)

Posted on: 14 February 2016 by fatcat

robgr posted:

If it wasn't for quantum theory for example you wouldn't be reading this, that theory led to the invention of silicon chips :-)

That's probably true, but I just don't get all the palaver.

They didn't create anything, apparently a couple of colliding black holes did that.

They didn't theorise the existence of gravitational waves. Einstein did that.

All they've done is built a transducer that allows them to detect/listen to gravitational waves. Or so they claim.

Posted on: 14 February 2016 by u77033103172058601

A scientific theory remains purely a theory until an experiment (preferably 2 independent experiments) confirms the theory to be correct, or not in the case of a few slightly wilder theories.

That the experiment was able to measure length changes at the miniscule levels required was a huge achievement. And not something to be dismissed in such a snivelling manner.

Posted on: 14 February 2016 by robgr

Agreed, perhaps we're actually contemplating where such experiments may or may not lead

For expample this techonlogy might one day lead to 'warp drives', any Star Trek fans out there?

Posted on: 14 February 2016 by fatcat

Nick from Suffolk posted:
That the experiment was able to measure length changes at the miniscule levels required was a huge achievement. And not something to be dismissed in such a snivelling manner.

Well I think it is. So There.

Posted on: 14 February 2016 by fatcat

robgr posted:
For expample this techonlogy might one day lead to 'warp drives', any Star Trek fans out there?

I'm more into Babylon 5, but I get your point. If it means we're one miniscule step towards cosmos wide jumpgates, that'll be billions of dollars well spent.

Posted on: 14 February 2016 by Don Atkinson

And if it leads to something the equivalent of GPS, which cost an initial $12bn to set up and is now free of charge to all non-USA tax-payers, again - money well spent !

Let's hope so.

Posted on: 15 February 2016 by Bananahead

What are the gravitational waves made from? Gravitons?

Can I have a packet please. I have a hoverboard that doesn't work properly.

Posted on: 15 February 2016 by GraemeH

Apparently finding the waves points us toward understanding 'a theory of everything'...

Do we then have to build another machine to prove the existence of everything?....