Gravitational Waves: The First Swell!

A Big Discovery

On 14 September 2015 at 4:50:45 AM Eastern standard time, the LIGO experiment detected for the first time the passage of gravitational waves. Scientists saw a very specific pattern of stretching and compression of space-time called a “chirp”. The detection was done independently at the two locations of the experiment, one in Hanford (Washington) and the other one in Livingstone (Louisiana). This amazing discovery has occurred almost exactly 100 years after Albert Einstein published his General Theory of Relativy (Einstein, 1916), and represents the last verification of this beautiful theory of gravity.

How did the waves look like? Glassy and double-overhead!

Left: Al ’Surfer’ Einstein excited about gravitational waves (adapted from a Mark Summers artwork). Right: The first gravitational waves signal detected by humankind. Data from the Washington (Top) and Hanford (middle) detectors are compared to the expected theoretical signal from two merging black holes. The two detected signals are compared after being shifted by about 7 ms in the bottom panel (the small delay between the two signals is due to the finite speed of the gravitational waves, which move at the speed of light).