LIGO announcement on Friday

[gary]

Thread about "Observation of Gravitational Waves from a Binary
Black Hole Merger" paper in Physical Review Letters here -
http://www.iceinspace.com.au/forum/s...51#post1230151

Paper available here in PDF under Creative Commons License -
https://journals.aps.org/prl/pdf/10....ett.116.061102

[DJT (David)]

Light bulb moment after seeing this.

http://www.phdcomics.com/comics.php?f=1853#italian

I have just danced in a circle with my wife and we have created ripples in the fabric of space time. My wife at this point is quite perplexed.

Enjoy

[csb (Craig)]

I can understand the basics of how the advanced LIGO detected the gravitational waves BUT I can't understand:

How scientists know these parricular waves originate from those 2 specific black holes?

How will they can use gravitational waves to get more detailed data/images about the universe?

Any layman's reading soneone can show me?

[barx1963 (Malcolm)]

Craig
Essentially the observation agrees with the computer simulation of a black hole merger. They know the direction because they used 2 widely separated detectors. Each detector saw the exact same signal, so that elliminates any local influence. The direction is only approximate, so that's why they are building more detectors to pin down more accurately the direction of future observations. Once they are online, more detections are possible and they have a pretty strong idea what other events making gravitational waves should look like.

Malcolm

[csb (Craig)]

Thanks Malcolm. I finally found some articles and they have the same info you gave.

I had read about 2 LIGO detectors being in operation but I am really surprised that any 2 earth-based detectors could triangulate the direction of something sooooo far away. 2,000 km is not wide on the cosmic scale.

Amazing!

[gary]

Originally Posted by csb

Thanks Malcolm. I finally found some articles and they have the same info you gave.

I had read about 2 LIGO detectors being in operation but I am really surprised that any 2 earth-based detectors could triangulate the direction of something sooooo far away. 2,000 km is not wide on the cosmic scale.

Amazing!

Hi Craig,

You might find the thread in the science discussion section of interest.
http://www.iceinspace.com.au/forum/s...d.php?t=142698

In a nutshell, the two detectors could only provide a very rough direction
in the sky from where the signal originated.

It is a very large region of sky in the direction of the Large Magellanic Cloud.
See contour plot of uncertainty here -
https://www.ligo.caltech.edu/image/ligo20160211b

As mentioned in the press conference, a minimum of four detectors
on various parts of the Earth in various orientations would be the
minimum number required to pinpoint with some precision.

The amplitude, frequency and damping response of the signal when the
black holes merged however reveals a wealth of information about the
size of the black holes, their distance and so on.

[barx1963 (Malcolm)]

Originally Posted by csb

Thanks Malcolm. I finally found some articles and they have the same info you gave.

I had read about 2 LIGO detectors being in operation but I am really surprised that any 2 earth-based detectors could triangulate the direction of something sooooo far away. 2,000 km is not wide on the cosmic scale.

Amazing!

It is fairly approximate. One of the graphics at the press conference showed the area that they believed the event happened in and it was a broad swath of sky. That said, the important thing at this stage is that the detection is possible, refinement and characterisation of the events being observed come next.

Malcolm

[csb (Craig)]

Thanks fellas. So the origin of the waves are in that general direction.

I see that the detected G waves fit with previously made predictions & modelling which then verifies they are detecting actual G waves.

[csb (Craig)]

Deleted doubled post.

[gary]

Originally Posted by Satchmo

Thats potentially exciting news .

Australia had a big hand in the early days of LIGO . We worked on the Ligo Pathfinder optics and first iteration instrumental optics at CSIRO Division of Applied Physics winning the contract for the worlds smoothest and most accurate fused silica surfaces over competitors like Hughes- Danbury who were known for the Hubble Space Telescope.

The recent starvation of funds to the CSIRO by the Abbott government was the death nell to this fantastic technological capability .

Hi Mark,

There is an article in today's Sydney Morning Herald by Peter Hannam
entitled "CSIRO hailed contribution to gravitation waves find – for work done by axed unit".

Originally Posted by Peter Hannam, Sydney Morning Herald

CSIRO executives are being accused of claiming credit for achievements of a science unit it has recently axed, amid on-going job cuts at the agency.

...

The organisation last week trumpeted its contribution to the discovery of gravitational waves – predicted a century ago by Albert Einstein and now detected for the first time.

In a media release hailing "Aussie innovation" on Friday, CSIRO cited its key role – while omitting the fact it had made many of the researchers involved redundant just last year.

"The coatings [on the mirrors], which were developed and applied at CSIRO, are among the most uniform and precise ever made," Cathy Foley, science director of CSIRO Manufacturing, said. "We really are world leaders in this area."

Chris Walsh, a former manager of the research team and now with Sydney University, said the CSIRO's crowing was "pretty bold-faced" given the program "had been run into the ground" and disbanded.

Article here -
http://www.smh.com.au/technology/sci...14-gmtmhu.html

[Slawomir (Suavi)]

If anyone would like to contribute to analysis and reasearching of low frequency gravitational waves, then one way would be to allow some computer time to Einstein@home : https://einstein.phys.uwm.edu

Also, IIS has a small active team at Einstein@home if you would like to join one.

[Robert9 (Robert)]

Hi all,
Just happened upon this thread today. I was fortunate to be able to attend this seminar given at Monash University earlier this month. It was recorded and is here: https://www.youtube.com/watch?v=9Gcs...ature=youtu.be
Enjoy.
Robert

[Somnium (Aidan)]

Thanks for the post Robert, i am keen to check that out tonight

[gary]

Originally Posted by Robert9

Hi all,
Just happened upon this thread today. I was fortunate to be able to attend this seminar given at Monash University earlier this month. It was recorded and is here: https://www.youtube.com/watch?v=9Gcs...ature=youtu.be
Enjoy.
Robert

Thanks Robert!

Just browsed some of it and I look forward to watching it all.

[multiweb (Marc)]

Originally Posted by Robert9

Hi all,
Just happened upon this thread today. I was fortunate to be able to attend this seminar given at Monash University earlier this month. It was recorded and is here: https://www.youtube.com/watch?v=9Gcs...ature=youtu.be
Enjoy.
Robert

Terrific video. Thanks for posting.

[Robert9 (Robert)]

There is also a whole lot more. If you go to https://www.youtube.com/watch?v=aEPIwEJmZyE there is a National Science Foundation (USA) press release that runs for over an hour. On this page there are many more links to talks including those by Stephen Hawking and Brian Greene.
A lot to listen to, but I think the Monash seminar and the NSF adequately covers it all. Certainly a mind boggling event.
Robert

[torsion (Bram)]

Here is a list of Australian hardware and software contributions to the LIGO project as a whole, http://www.aciga.org.au/news/australian-contribution, which may be of interest.