杏吧原创

SPACECRAFT Cassini will spend the next 40 days hunting for gravitational
waves as it cruises past Earth on its seven-year trip to Saturn. Gravity waves
are slight ripples in the space-time fabric of the Universe, created by massive
bodies such as black holes. Einstein predicted them, but they鈥檝e never been
detected directly. Three Earth-based stations will try to spot tiny fluctuations
in Cassini鈥檚 speed as gravity waves stretch and compress space. It鈥檚 a long
shot, says John Armstrong of NASA鈥檚 Jet Propulsion Laboratory. 鈥淏ut if you don鈥檛
look, you won鈥檛 see anything.鈥�