In 1916, Albert Einstein predicted that in space, gravitational waves are ripples in the curvature of spacetime. The waves are caused by an oscillating movement between two large bodies of mass in space that are in interaction with each other, such as the proximity of two black holes or even an exploding star. The waves propagate themselves through space and time and reach other intergalactic bodies like our planet, Earth!
As a gravitational wave passes a distant observer, that observer will find spacetime distorted by the effects of strain. Distances between free objects increase and decrease rhythmically as the wave passes, at a frequency corresponding to that of the wave. A team of scientists from the LIGO Scientific Collaboration announced that they had “heard” and recorded the sound of two black holes colliding a billion light-years away, quantitative data that reinstated the magnificence of Einstein’s general theory of relativity. The waves are so small that it takes a detector like the ones at LIGO, capable of measuring distortions one-thousandth the size of a proton, to observe them! They were observed on September 14, 2015.
As Brian Greene mentions in his video, “The LIGO team achieved this with two detectors, one in Louisiana and one in Washington State. These detectors fire laser beams along two 4 km long vacuated tunnels and when the light recombines it creates an interference pattern. The only thing that we need to grasp is that if a gravitational wave were to roll by, it would squish and stress the arms of the detectors and THIS would have a measurable impact on the interference pattern causing it to shift! And it’s just this kind of shift in the interference pattern that the LIGO team has now observed. This is the first direct detection of gravitational waves”.
To watch a summary on how Einstein’s theory works, click on this 3-minute video:
And let’s not forget the scientists responsible for this discovery!!
Gravitational waves detected, proving Einstein right again – CNN.com. (n.d.). Retrieved February 13, 2016, from http://www.cnn.com/2016/02/11/us/gravitational-waves-feat/index.html
Overbye, D. (2016). Gravitational Waves Detected, Confirming Einstein’s Theory. Retrieved February 13, 2016, from http://www.nytimes.com/2016/02/12/science/ligo-gravitational-waves-black-holes-einstein.html?_r=1
(n.d.). Retrieved February 13, 2016, from https://en.wikipedia.org/wiki/Gravitational_wave