The 2017 Nobel Prize in Physics was just awarded to Rainer Weiss, Barry C Barish, and Kip S Thorne for their decades-long work that resulted in the detection of the long-sought echoes from distant collisions between two black holes.
Weiss, Barish, and Thorne’s work — along with the effort of hundreds of other scientists — has effectively ushered in a new era of physics in the space sciences.
The three researchers all contributed key findings that led to discoveries made by the Laser Interferometer Gravitational-Wave Observatory (LIGO), two twin observatories in Louisiana and Washington.
Both LIGO detectors are designed to pick up faint ripples in the fabric of space and time as they move through Earth’s part of space after being emitted by the collision of two black holes light-years from our planet.
Think of space-time as a sheet stretched out across the universe. Massive objects like black holes, planets or moons depress that 3D fabric, and when two particularly massive objects — like two black holes or two neutron stars — collide, they can ripple space-time sending those gravitational waves out into space like ripples on a pond.
When two black holes merge, the space-time ripples — known as gravitational waves — pass through all of us, stretching every atom in our bodies for a moment before moving on through the universe.
We don’t feel it, however. The ripples are occurring at such a low frequency that we can’t sense them, but LIGO’s sensitive instrumentation can.
The first detection of gravitational waves came on September 14, 2015, about 100 years after Albert Einstein first predicted the existence of gravitational waves in his theory of general relativity. Since that time, LIGO has detected signals from three other gravitational waves created by merging black holes.
By successfully confirming the existence of gravitational waves, scientists now have a new way of understanding the universe by using gravity to investigate some of the most massive, extreme objects in the universe.
The discovery of these ripples now allows scientists to “discover a way to listen to the death cry of stars, neutron stars, black holes, what we could not hear before,” LIGO scientist Szabolcs Marka told Mashable just before the first detection was announced in February 2016.
Each LIGO detector is shaped like an “L” with both arms of equal length. A mirror sits at each end of the detectors with a laser that emanates from the bend in the detector, split so that it runs down the length of both arms.
The powerful instruments are so well-calibrated that scientists know exactly when the two halves of the laser should make it back to the center after bouncing off the mirrors at the end. If they don’t match up, researchers know there was some kind of disturbance that prevented them from meeting in the middle at the expected time.
If a gravitational wave passes through Earth’s part of space, the two branches of the laser won’t line up perfectly. As the wave passes it stretches on of the arms of the laser, meaning the won’t meet back in the middle at exactly the same time.