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Science (non-SETI) :
LIGO detected gravitational waves at last!
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janneseti Send message Joined: 14 Oct 09 Posts: 14106 Credit: 655,366 RAC: 0 |
I think Marco listened to the waves instead of looking at the graphs. https://www.youtube.com/watch?v=599IgzzhhAs |
Kathy Send message Joined: 5 Jan 03 Posts: 338 Credit: 27,877,436 RAC: 0 |
Tonight a behind the scenes look: Join us on 2/23/16, 8pm PT, for "Ripples in Spacetime: A New Window On the Universe". Caltech lecture tonight at 11pm ET, 8pm PT. http://www.ustream.tv/caltech |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 30608 Credit: 53,134,872 RAC: 32 |
Tonight a behind the scenes look: Join us on 2/23/16, 8pm PT, for "Ripples in Spacetime: A New Window On the Universe". Caltech lecture tonight at 11pm ET, 8pm PT. Very good presentation. |
JakeTheDog Send message Joined: 3 Nov 13 Posts: 153 Credit: 2,585,912 RAC: 0 |
Some interesting vids. Probably not as informative as others. Some from "celebrity scientists" not involved with LIGO, but maybe more entertaining. More educational and informative material can be found from interviews of the lead scientists of LIGO, or on the LIGO website. 4 scientists involved with the experiment testify in the House Committee for Science Space and Tech (2 hours long, a bit boring, low rate of info): https://www.youtube.com/watch?v=mrvnnMQsUck Brian Greene with Stephen Colbert talking about it (8 minutes and demonstration, some funny jokes): https://www.youtube.com/watch?v=ajZojAwfEbs Lawrence Krauss on his monthly Arizona PBS appearance (25 minutes long, more detailed discussion and animated demonstration): http://www.azpbs.org/arizonahorizon/play.php?vidId=8384 Neil deGrasse Tyson on the Anthony Cumia Show (6 minutes, radio talk show): https://www.youtube.com/watch?v=DoOPEPVYAnU |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 30608 Credit: 53,134,872 RAC: 32 |
Tonight a behind the scenes look: Join us on 2/23/16, 8pm PT, for "Ripples in Spacetime: A New Window On the Universe". Caltech lecture tonight at 11pm ET, 8pm PT. If you missed it live, it is now on youtube https://www.youtube.com/watch?v=5s5NgZchlHs It runs almost two hours. |
Julie Send message Joined: 28 Oct 09 Posts: 34041 Credit: 18,883,157 RAC: 18 |
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Lynn Send message Joined: 20 Nov 00 Posts: 14162 Credit: 79,603,650 RAC: 123 |
Hoping this news goes here. Hunt for Big Bang Gravitational Waves Gets $40 Million Boost How did it all begin? The origin of the cosmos is probably the biggest mystery in science—but amazingly, researchers do have some hard evidence to consult in their attempts to solve it. The cosmic microwave background (CMB), a microwave fog that pervades space, is the oldest light in existence—it was released about 13.7 billion years ago when the extremely hot and dense baby universe cooled enough to allow photons to travel freely for the first time. That was about 380,000 years after the big bang, and the light has been flying through space ever since. Although the light itself is already unimaginably ancient, it may preserve a record of things that happened even earlier—specifically, it might contain imprints from gravitational waves that may have ripped through the cosmos in the very first moments of space and time. http://www.scientificamerican.com/article/hunt-for-big-bang-gravitational-waves-gets-40-million-boost/ |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
The graphs are very nice--how do we know the giggles in the interferometers didn't come from an Earth-bound event such as an earthquake. if they depict a cosmic event then I am very surprised that Earth-bound equipment would have sufficient isolation and sensitivity to detect such an event. |
Darth Beaver Send message Joined: 20 Aug 99 Posts: 6728 Credit: 21,443,075 RAC: 3 |
The graphs are very nice--how do we know the giggles in the interferometers didn't come from an Earth-bound event such as an earthquake. if they depict a cosmic event then I am very surprised that Earth-bound equipment would have sufficient isolation and sensitivity to detect such an event. 2 trains of thought 1. This is typical of America to ask silly questions to discredit a tech , witch is a reoccurring thing with America when they learn that Australia has designed and made it. We made and designed the optics for it 2. It is a real question but shows not much thought . Earth quakes move the ground side to side or up and down , it would put the optics out of alignment and they are not measuring any sideways or up down movements . They are measuring how long a photon takes to moves across the length of the machine . Earth quakes would move the laser off what ever they use to detect the light from the laser and would make it useless during the earth quake |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
Thank you for your response, your exception has been noted. I am not doubting this claim--just expressing my amazement and seeking further explanation. I believe that a claim was made regarding this announcement. The claim was something like: this was an event involving black holes at some precisely stated distance in light years==possibly even stating the location in the Cosmos. Though I also have designed interferometers for the Army (Army Research Lab, Durham North Carolina), albeit in the X-band microwave spectrum; I am ignorant as to how such an inference can be culled from the squiggles presented. Even at microwave frequencies I mounted my semi-confocal mirrors on an extremely heavy lathe bed in the deep sub basement of the engineering building at Duke University. I also had my Klystron bathed in a vat of transformer oil to obtain the stability and isolation from spurious vibrations. Can you enlighten me ? Sheppard and Rothamel suggested guidelines for Fabry-Perot cavity design re- sulting from examination of the confocal resonator [62]. |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
The basic idea, which goes back to Joseph Weber and his pioneering efforts with resonant mass detectors, is to put detectors in different locations. The two LIGO interferometers are one on Louisiana and one in Washington state. Only if an event happens in both at the same time it can be considered a candidate , and this is what happened. A third interferometer, GEO600, exists in Hannover, and a fourth in Italy at Cascina, near Pisa, Virgo. A fifth is being built underground at Cagra, in Japan. The two European interferometers were not working, being upgraded at the time of the event detected. Especially the Germans have done a very sophisticated attempt to eliminate spurious events, using also quantum mechanics. Tullio |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
A second event was registered on December 26 2015 and it was announced at a meeting of the American Astronomical Society in San Diego. I am waiting for further information after a press release of the Italian Istituto Nazionale di Fisica Nucleare which manages the Italian/French VIRGO interferometer in Cascina, near Pisa. Tullio The two black holes which merged at a distance of 1.4 billion light years had masses of 14 and 8 solar masses, while the merged black hole has a mass of 21 Sun masses. The rest has gone in gravitational waves. Being smaller than the two first observed black holes, the signal lasted for about one second instead of the 2/10th of a second of the first observation. |
Bob DeWoody Send message Joined: 9 May 10 Posts: 3387 Credit: 4,182,900 RAC: 10 |
I saw on the science channel that one object's gravity can influence another object over a distance of several light years. Does anyone know whether this influence propagates at the speed of light or is it instantaneous? Bob DeWoody My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events. |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
According to Einstein gravitational waves travel at the speed of light in a vacuum. Tullio |
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