Construction has begun on KAGRA, the latest gravitational wave telescope, to detect gravitational waves for the first time; successful detection of such waves, considered the last of Einstein's predictions yet to be observed, would surely be worthy of a Nobel Prize. What exactly is a gravitational wave? How do you detect one? What can be learned through such observations? We visit Kamioka in Gifu Prefecture where KAGRA is under construction.
Takaaki Kajita(Director, Institute for Cosmic Ray Research, University of Tokyo)