Today, scientific history was made. At 3:30pm today, the National Science Foundation had a press conference to "update the scientific community on efforts to detect” gravitational waves. They reported that, for the first time, scientists have observed these gravatational ripples in the fabric of spacetime, arriving at the earth from a cataclysmic event in the distant universe. This discovery confirms a major prediction of Albert Einstein’s 1915 general theory of relativity. It also opens up an unprecedented new view on the cosmos.
We have been able to see the universe ever since the first human looked upwards to the skies. With the advent of the telescope in 1610 the process of using telescope to extend our sense of sight ever further into the Universe. Gravitational waves are different however. They are not at all like light or any of the other "electromagnetic radiations" such as radio waves, X-rays, infrared, ultraviolet rays. Instead, they are ‘ripples’ in the fabric of the universe (space and time itself!). These ripples could be interpreted as sounds, which are essentially oscillating waves (ripples) in the air. Researchers can even turn the simulated gravitational wave signals into audible sounds. Those sounds could then be translated into a piece of music, like a "gravitational wave symphony". The simulated gravitational wave signals are the oscillating sounds that increase in frequency until they abruptly stop with a ‘chirp’. These are the tell-tale signals for which gravitational wave astronomers search.
The LIGO project ( Laser Interferometer Gravitational-Wave Observatory), which is searching for, and has found, gravitational waves, was co-established in Livingston, Louisiana in 1992 by MIT, Caltech, and numerous other universities. The National Science Foundation funds the project and gets contributions from other international scientific groups. It didn't detect anything from 2002 to 2010, and after a 5-year shutdown to upgrade to detectors, it came online in the fall of 2015 with four times the sensitivity than before the upgrade.
As I said before, gravitational waves were predicted by Albert Einstein back in 1915 on the basis of his general theory of relativity. As they are also not possible in the Newtonian theory of gravitation (because that theory states that physical interactions propagate at infinite speed), this discovery disproves part of that theorem.
Gravitational waves carry information about their dramatic origins and about the nature of gravity that cannot otherwise be obtained. Physicists have concluded that the detected gravitational waves were produced during the final fraction of a second of the merger of two black holes to produce a single, more massive spinning black hole. This collision of two black holes had been predicted but never observed. However, scientists at LIGO estimate that black holes involved in the event were 29 and 36 times the mass of the sun, and that the event took place 1.3 billion years ago. During the combination, forces equal to about 3 times the mass of the sun were converted in a fraction of a second into gravitational waves—with a peak power output about 50 times that of the whole visible universe. This all happens because (according to general relativity), as a pair of black holes orbit around each other, they lose energy through the emission of gravitational waves. That causes them to gradually approach each other over billions of years, and then much more quickly in the final minutes. During the final fraction of a second, the two black holes collide into each other at nearly one-half the speed of light and form a single more massive black hole, converting a portion of the combined black holes’ mass to energy, according to Einstein’s formula E=mc2. This energy is emitted as a final strong burst of gravitational waves. It is these gravitational waves that LIGO has observed. By looking at the time of arrival of the signals—the detector in Livingston recorded the event 7 milliseconds before the detector in Hanford—scientists can say that the source was located in the Southern Hemisphere.
The ability to detect gravitational waves will not just be bring us new views of objects that we can already see, but will allow us to detect and study objects and events that are currently completely hidden from view. It also means that after years of research, hard work, and technological innovations, Einstein's theory is finally finally proven.
For more information see these links:
https://en.wikipedia.org/wiki/Gravitational_wave
https://en.wikipedia.org/wiki/LIGO
http://www.ligo.org/
https://www.ligo.caltech.edu/
http://www.nytimes.com/2016/02/12/science/ligo-gravitational-waves-black-holes-einstein.html?_r=0
http://www.nytimes.com/2015/11/24/science/a-century-ago-einsteins-theory-of-relativity-changed-everything.html
http://www.nasa.gov/feature/goddard/2016/nsf-s-ligo-has-detected-gravitational-waves
https://www.theguardian.com/science/2016/feb/11/gravitational-waves-discovery-hailed-as-breakthrough-of-the-century
https://www.theguardian.com/science/across-the-universe/live/2016/feb/11/gravitational-wave-announcement-latest-physics-einstein-ligo-black-holes-live
https://www.theguardian.com/science/2016/feb/09/gravitational-waves-everything-you-need-to-know
https://www.theguardian.com/science/across-the-universe/2016/feb/11/todays-gravitational-wave-announcement-could-be-two-great-discoveries-in-one
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