2017 Nobel Physics Prize Awarded to the “Cosmic Chirp”
Scientists have been looking for ways to measure gravitational waves for decades. On September 14, 2015, the Laser Interferometer Gravitational Wave Observatory (better known as LIGO) was able to observe gravitational waves after 1.3 billion light years of searching for evidence, thereby tracking the “cosmic chirp” of the universe. Founders of LIGO, Rainer Weiss (MIT), Barry C. Barish (Caltech), and Kip S. Thorne (Caltech) were recently awarded the 2017 Nobel Physics Prize for their discovery of gravitational waves. This discovery is a turning point in our understanding of space, and it provides information necessary to deepening our knowledge about what is happening outside our world.
Early predictions of gravitational waves date back to 1915, when Albert Einstein posited the idea that if space can warp, then it should also be able to vibrate. This led to his discovery of gravitational waves. Gravitational waves occur when two objects, such as black holes, collide. They fall towards each other in space’s fabric, into each other’s holes, and create energy in tenths of seconds. They create a ripple in the shape of spacetime that travels outwards. It causes things to stretch and expand continuously, until the wave has passed. Gravitational waves are often compared to a ripple in a pond, because they send outwards.
LIGO is an observatory unlike any other, using parallel 4-kilometer-long tubes to detect these waves. A laser beam is sent and then split to go down each tube, exactly measured at the same length. At the end of these tubes is a mirror that the laser bounces off of, and sends the lasers back to the base. At the base, they should come back at the same time, cancelling each other out. But when a gravitational wave is present, they should come back at different times due to the stretching and squeezing, so that they don’t cancel each other out. It is very hard to measure them accurately, due to noise, as it can easily mess up the data. The tubes are inside huge vacuums and have magnets and shock absorbers at the end of the tube, so that they don’t pick up any sound other than the gravitational waves. That is why LIGO has two locations, one in Livingston, Louisiana and one in Hanford, Washington. They are completely identical, so as to prevent the collection of false data.
By determining the existence of gravitational waves, scientists are getting closer and closer to finding more in space, such as evidence of the so-called Big Bang. In 1973, Kip Thorne, one of the founders, said, “The technical difficulties to be surmounted in constructing such detectors are enormous, but physicists are ingenious and with support of a broad public lay, all obstacles will surely be overcome.” It is a true example of how hard work pays off. Kip Thorne said that what characterizes scientists is that “They are people who never lost their childlike wonder about the universe; and they’re still driven by that childlike wonder.” LIGO offers various programs from field trips, to undergraduate internships, to tours in order to foster new ideas and educate the youth about the universe.