Successful detection of gravity waves!

[tomBitonti]

This just in:

Science Magazine: Gravitational waves, Einstein’s ripples in spacetime, spotted for first time

http://www.sciencemag.org/news/2016...nstein-s-ripples-spacetime-spotted-first-time

Washington Post: Cosmic breakthrough: Physicists detect gravitational waves from violent black-hole merger

https://www.washingtonpost.com/news...ational-waves-from-violent-black-hole-merger/

Haven't had a chance to read either article yet.

Cheers!
TomB

(Cross posted in "AMA: Ask a Physicist": http://www.enworld.org/forum/showthread.php?466337-ask-a-physicist&p=6821172#post6821172

 

[tomBitonti]

From the Science Magazine article:

On 14 September 2015, at 9:50:45 universal time—4:50 a.m. in Louisiana and 2:50 a.m. in Washington—LIGO’s automated systems detected just such a signal. The oscillation emerged at a frequency of 35 cycles per second, or Hertz, and sped up to 250 Hz before disappearing 0.25 seconds later. The increasing frequency, or chirp, jibes with two massive bodies spiraling into each other. The 0.007-second delay between the signals in Louisiana and Washington is the right timing for a light-speed wave zipping across both detectors.

The signal exceeds the “five-sigma” standard of statistical significance that physicists use to claim a discovery, LIGO researchers report in a paper scheduled to be published in Physical Review Letters to coincide with the press conference. It’s so strong it can be seen in the raw data, says Gabriela González, a physicist at Louisiana State University, Baton Rouge, and spokesperson for the LIGO scientific collaboration. “If you filter the data, the signal is obvious to the eye,” she says.

And:

The collision produced an astounding, invisible explosion. Modeling shows that the final black hole totals 62 solar masses—3 solar masses less than the sum of the initial black holes. The missing mass vanished in gravitational radiation—a conversion of mass to energy that makes an atomic bomb look like a spark. “For a tenth of a second [the collision] shines brighter than all of the stars in all the galaxies,” Allen says. “But only in gravitational waves.”

Bold added by me.

Whoa.

TomB

 

[Umbran]

Yeah, it's neat. A bit academic, from the perspective of the everyday person's life, but for those of us who like the far out stuff, it is intensely interesting.

 

[Dannyalcatraz]

Sooo...SURF'S UP!

 

[tomBitonti]

Sooo...SURF'S UP!

Haha, for 0.25s. Better be quick!

TomB

 

[Tonguez]

so is this the next step in defining the theory of everything?

or are these gravitational waves different to the ones generated by the big bang?

 

[freyar]

so is this the next step in defining the theory of everything?

or are these gravitational waves different to the ones generated by the big bang?

This is the first step in gravitational wave astronomy. Basically, the gravitational waves created during inflation ("during the Big Bang" in a hand-wavy sense) are extremely large wavelength and low frequency. We can't detect those directly at the moment but (if they are strong enough) may soon be able to see their effects on the cosmic microwave background radiation. The announcement today is for the direct observation of gravitational waves from the merger of two black holes --- for the first time! The observatory that saw this, LIGO, should also be capable of seeing smaller objects collide and merge, like pairs of neutron stars, and also effects from other exotic hypothetical objects like cosmic strings. So a lot of the information, what we really expect, is to get an entirely new window on extreme situations in astrophysics. However, we are talking about events involving black holes, so there could be things we learn about quantum gravity, and a signal/discovery of a cosmic string would also tell us a lot about a theory of everything. So we could learn some new fundamental physics in this way.

It's also worth noting that the 1993 Nobel Prize in physics was already for the discovery of gravitational waves, but indirectly. Hulse and Taylor discovered a binary neutron star system and were able to measure its orbital period precisely. It turns out that the orbit loses energy exactly as general relativity predicts it should lose energy to gravitational waves.

 

[tomBitonti]

Hi,

Are there any frameworks that this breaks? Any theoreticians who are not happy about this result?

Is there any "new" result here? The result seems to be exactly what was predicted, meaning, it confirms an already presumed theory, and maybe doesn't add a lot which is new?

Thx!
TomB

 

[Umbran]

Sooo...SURF'S UP!

Note that it is a very tiny wave. The arms of LIGO are kilometers long, and the change in length observed was less than the diameter of a typical atom.

 

[darjr]

It adds a confirmed technique to investigate the dark reaches of the universe.