Take a brief look at the history of pulsar navigation and the opportunities that still lie ahead.

The first pulsar was observed in 1967 by Jocelyn Bell and was nicknamed "little green men," a playful name for intelligent aliens. So far, more than 2,500 pulsars have been discovered. Most of the discoveries were made using the 64-meter Parkes radio telescope in Australia.

Research shows the 500-meter FAST radio telescope completed in China's Guizhou province this September has the capacity to discover 65-hundred pulsars, more than twice of what the world has already found.

Photo taken on Sept. 24, 2016 shows the 500-meter Aperture Spherical Telescope (FAST) in Pingtang County, southwest China's Guizhou Province. The FAST, world's largest radio telescope, measuring 500 meters in diameter, was completed and put into use on Sunday. (Xinhua/Ou Dongqu)