Gravitational waves may have been detected for the first time, more than a century after they were first proposed by the eminent physicist Albert Einstein. The announcement came following observation of the phenomenon by researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States.
The General Theory of Relativity predicted that massive events could warp space-time around them. These occurrences could then result in the production of waves that would emanate from their source, and propagate throughout space.
Even Einstein himself was not certain of the existence of gravitational waves, alternatively speaking for and against evidence for the phenomenon. In a 1936 paper, Einstein wrote that the waves he predicted 20 years before were not possible. However, an editor pointed out a mistake in the manuscript.
During 1962, a pair of Russian physicists proposed an optical method of detecting gravitational waves, but the paper was largely ignored.
Physicist James Weber announced in 1969 that he had detected gravitational waves utilizing aluminum cylinders. However, no other researchers were able to duplicate his results.
A second optical method of detecting gravitational waves was proposed in 1973, but the method was never successfully used to detect the elusive phenomenon.
The first observational evidence of the effect of gravitational waves came in 1974, when astronomers noted a pulsar was slowing in its orbit around a neutron star. This behavior was found to be consistent with the production of gravitational waves – a realization that lead to investigators winning the Nobel Prize.
Construction of the LIGO facility began in 1994, followed by groundbreaking for the GEO600 gravitational wave detector in Germany the following year. That facility came online in 2002. Italian physicists started to work on their own observatory, Virgo, in 1996, and that detector began its search for gravitational waves in 2007.
Upgrades to the American facility, totaling $205 million, took place between 2010 and 2015. Advanced LIGO made its first observations in September 2015.
The latest experiment appears to have detected gravitational waves from the collision of two black holes, sitting 1.3 billion light-years from Earth. One of these bodies was 26 times the mass of the sun, and the other was 36 solar masses. The gravitational waves produced in the mighty collision struck Earth, and were detected by the LIGO detectors on Sept. 14, 2015.
"The colliding black holes that produced these gravitational waves created a violent storm in the fabric of space and time, a storm in which time speeded up, and slowed down, and speeded up again, a storm in which the shape of space was bent in this way and that way," Kip Thorne, a physicist at Caltech, said.
If this discovery is confirmed by other scientists, and gravitational waves are seen in other bodies, it could herald a new age in astronomy. So far, all the information the human race has gathered about the universe around us has come in the form of electromagnetic radiation, including light, heat and radio waves. These emanations can all be hindered in their travels through space by dust, gas and other barriers. However, gravitational waves do not suffer from this drawback, providing the first "full story" on the celestial objects being observed.
