Posts Tagged ‘gravity’
[LINK] “Gravitational waves detected for 1st time, ‘opens a brand new window on the universe'”
CBC continues to react to yesterday’s announcement of the detection of gravitational waves. What will the gravitational observatories of the near future discover, I wonder?
Gravitational waves, ripples in space-time predicted by Einstein’s general theory of relativity 100 years ago, have finally been detected.
“Ladies and gentlemen, we have detected gravitational waves. We did it,” announced Dave Reitze, executive director of the U.S.-based Laser Interferometer Gravitational-Wave Observatory (LIGO) at a news conference Thursday morning.
Scientists said gravitational waves open a door for a new way to observe the universe and gain knowledge about enigmatic objects like black holes and neutron stars. By studying gravitational waves they also hope to gain insight into the nature of the very early universe, which has remained mysterious.
“I think we’re opening a window on the universe,” Reitze said.
“Until this moment we had our eyes on the sky and we couldn’t hear the music,” said Columbia University astrophysicist Szabolcs Marka, a member of the discovery team. “The skies will never be the same.”
[. . .]
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.
[LINK] On the possible detection of gravitational waves from colliding black holes by LIGO
Adrian Cho’s ScienceMag article notes in detail about something potentially astounding, something scheduled for official release on Friday the 11th but literally causing waves right now.
It’s just a rumor, but if specificity is any measure of credibility, it might just be right. For weeks, gossip has spread around the Internet that researchers with the Laser Interferometer Gravitational-Wave Observatory (LIGO) have spotted gravitational waves—ripples in space itself set off by violent astrophysical events. In particular, rumor has it that LIGO physicists have seen two black holes spiraling into each other and merging. But now, an email message that ended up on Twitter adds some specific numbers to those rumors. The author says he got the details from people who have seen the manuscript of the LIGO paper that will describe the discovery.
“This is just from talking to people who said they’ve seen the paper, but I’ve not seen the paper itself,” says Clifford Burgess, a theoretical physicist at McMaster University in Hamilton, Canada, and the Perimeter Institute for Theoretical Physics in nearby Waterloo. “I’ve been around a long time, so I’ve seen rumors come and go. This one seems more credible.”
According to Burgess’s email, which found its way onto Twitter as an image attached to a tweet from one of his colleagues, LIGO researchers have seen two black holes, of 29 and 36 solar masses, swirling together and merging. The statistical significance of the signal is supposedly very high, exceeding the “five-sigma” standard that physicists use to distinguish evidence strong enough to claim discovery. LIGO consists of two gargantuan optical instruments called interferometers, with which physicists look for the nearly infinitesimal stretching of space caused by a passing gravitational wave. According to Burgess’s email, both detectors spotted the black hole merger with the right time delay between them.
LIGO’s prime target has been the death spiral and merger not of two black holes, but of two neutron stars. However, Marc Kamionkowski, a theoretical physicist at Johns Hopkins University in Baltimore, Maryland, says the signal from the merger of more-massive black holes should be stronger and detectable from a greater distance. Other, less specific rumors suggest that LIGO has seen more than one source.
A commenter at another blog notes that the detection of gravitational waves is hugely important, perhaps the biggest development since the development of eyes hundreds of millions of years ago. I agree. If this is true, I think I know who’ll be getting a Nobel Prize in Physics, if not this year than next.
More to the point, it is decidedly cool that we now can apparently detect gravitational waves. Most speculatively, I wonder what such a collision of black holes would look like. Apparently three solar masses were dispersed into gravity waves. Would there have been electromagnetic radiation expelled, too?