Ripples in space-time

[TheLurch]

Tomorrow, the people behind the LIGO detector are holding multiple press conferences in which they're expected to announce the first detection of gravitational waves. These are ripples in the fabric of space-time, caused by extremely energetic gravitational systems, like two black holes orbiting closely. They are a prediction of Einstein's theory of general relativity, but have never been detected before.

We've had indirect evidence they existed. For example, we've watched two neutron stars in a close orbit, and saw that they were spiraling closer together, with the energy they were losing matching with predictions of relativity to many decimal places. Relativity indicates the energy takes the form of tiny distortions in space time that radiate out from the system, but we've been unable to detect them.

Until now. LIGO (Sponsored by the US' National Science Foundation) went through an upgrade over the past several years that increased its sensitivity. LIGO works by sending lasers back-and-forth down a 4km tube multiple times, and looks for minuscule differences in the timing of their travel. Many of these are local sources of vibration, which need to be tracked. There are two of them at significant distances apart (Washington and Louisiana) in order to eliminate chance events, as well. If both detectors "see" the same events, and other sources are eliminated, then the cause of the distortion is likely to be a gravity wave passing through the space occupied by the photons in the laser.


This is a big deal, as big as the discovery of the Higgs boson. Step back and appreciate the fact that you're alive to see it.

[rogue06]

Tomorrow, the people behind the LIGO detector are holding multiple press conferences in which they're expected to announce the first detection of gravitational waves.

And they did. From Reuters:

Source: Einstein's gravitational waves detected in scientific milestone

Scientists said on Thursday they have for the first time detected gravitational waves, ripples in space and time hypothesized by physicist Albert Einstein a century ago, in a landmark discovery that opens a new window for studying the cosmos.

The researchers said they detected gravitational waves coming from two black holes - extraordinarily dense objects whose existence also was foreseen by Einstein - that orbited one another, spiraled inward and smashed together. They said the waves were the product of a collision between two black holes 30 times as massive as the Sun, located 1.3 billion light years from Earth.

The scientific milestone, announced at a news conference in Washington, was achieved using a pair of giant laser detectors in the United States, located in Louisiana and Washington state, capping a long quest to confirm the existence of these waves.



Source

© Copyright Original Source

The story continues at the link above

[Sparko]

and to think, they used Lego detectors.












feet make great lego detectors.

[TheLurch]

Best factoids from the press conference:

When the black holes merged, three times the Sun's mass was converted directly into energy in the form of gravity waves. For a brief instant, the event produced more energy than all the stars in the visible universe combined.

[robrecht]

Wow.

[oxmixmudd]

Tomorrow, the people behind the LIGO detector are holding multiple press conferences in which they're expected to announce the first detection of gravitational waves. These are ripples in the fabric of space-time, caused by extremely energetic gravitational systems, like two black holes orbiting closely. They are a prediction of Einstein's theory of general relativity, but have never been detected before.

We've had indirect evidence they existed. For example, we've watched two neutron stars in a close orbit, and saw that they were spiraling closer together, with the energy they were losing matching with predictions of relativity to many decimal places. Relativity indicates the energy takes the form of tiny distortions in space time that radiate out from the system, but we've been unable to detect them.

Until now. LIGO (Sponsored by the US' National Science Foundation) went through an upgrade over the past several years that increased its sensitivity. LIGO works by sending lasers back-and-forth down a 4km tube multiple times, and looks for minuscule differences in the timing of their travel. Many of these are local sources of vibration, which need to be tracked. There are two of them at significant distances apart (Washington and Louisiana) in order to eliminate chance events, as well. If both detectors "see" the same events, and other sources are eliminated, then the cause of the distortion is likely to be a gravity wave passing through the space occupied by the photons in the laser.


This is a big deal, as big as the discovery of the Higgs boson. Step back and appreciate the fact that you're alive to see it.

This is MAJOR. Thanks for the update!

And another 'win' for Relativity. A theory that has yet to have a direct prediction falsified (and a theory that is known to be incomplete in that is doesn't account for Quantum)


Jim

[shunyadragon]

Great discovery! It is good to see more threads dealing with 'real' science.'

[little_monkey]

How g-waves sound:

http://gizmodo.com/this-is-what-grav...ike-1758501755

[mossrose]

So, what does this knowledge do for us?

Does it cure cancer? Or the common cold?

[robrecht]

So, what does this knowledge do for us?

Does it cure cancer? Or the common cold?

I think it amazes us with the awesomeness of our universe.

When I consider your heavens,
the work of your fingers,
the moon and the stars,
which you have set in place,
what is man that you are mindful of him,
the son of man that you care for him?
You made him a little lower than the heavenly beings
and crowned him with glory and honor.

[mossrose]

I think it amazes us with the awesomeness of our universe.

When I consider your heavens,
the work of your fingers,
the moon and the stars,
which you have set in place,
what is man that you are mindful of him,
the son of man that you care for him?
You made him a little lower than the heavenly beings
and crowned him with glory and honor.

Yes. But I had that awe of God's handiwork before this.

[robrecht]

Yes. But I had that awe of God's handiwork before this.

Me too, but it just keeps getting better and better.

[Raphael]

Me too, but it just keeps getting better and better.

I like how Louis Giglio put it in his Indescribable talk. I paraphrase from memory: "from what we can see, we are perfectly positioned to be able to observe"

[Carrikature]

So, what does this knowledge do for us?

It gives us additional confidence that our picture of the universe is accurate. That counts for quite a lot especially since, as Jim points out, we continue to struggle to connect relativity to the quantum world.

Does it cure cancer? Or the common cold?

Do you know that these are both groups of related diseases? To the extent that cures are possible, they're known and implemented. Prevention is difficult but improving. It's not as if there will ever be a vaccine for cancer or colds. That's not how it works.

[JonF]