Final Mission from Einstein
This year's Nobel winner in physics, Takaaki Kajita, is embarking on a new challenge: to solve a mystery of the universe. Kajita will try to confirm the only phenomenon Einstein theorized that hasn't been observed. He'll carry out research in a state-of-the-art facility, and the results could change how we understand space.
Albert Einstein theorized the existence of gravitational waves 100 years ago in his general theory of relativity. It's like a ripple of space-time. And Kajita wants to be the first to detect them.
"Gravitational waves represent the expansion and contraction of space-time," explains Kajita, director of the Institute for Cosmic Ray Research at the University of Tokyo. "I want to establish the field of gravitational wave astronomy that would change our concept of space and study phenomena such as the moment a black hole is born."
When a heavy astral body moves in space, space is contorted in the form of waves spreading across the universe at the speed of light.
But the contortion is extraordinarily small. The vast space between the sun and the Earth may stretch or shrink at a size equivalent to the diameter of a hydrogen atom. That's why no one has ever successfully detected the waves.
Researchers will use a new facility called KAGRA to take on that challenge. It's located in a tunnel more than 200 meters under the ground in central Japan.
"A facility like this cannot be constructed without the understanding of many people. I'm very much grateful for the support on this project," Kajita says.
The facility consists of two 3-kilometer-long tunnels, connected to form an L-shape. Split laser beams emitted into the tunnels usually come back at the same time after being reflected by mirrors.
But when gravitational waves from space shower down on the Earth, they warp the space the laser beams travel through. Therefore, the beams will return at different times. Gravitational waves would be observed by the lag in the arrival time of the beams.
Scientists have so far observed astral bodies via three means: light, electromagnetic waves and elementary particles.
Gravitational waves may provide us with the fourth means to understand the mystery of the universe.