A GIANT cloud in space is acting like a maser 鈥� the microwave equivalent of a laser 鈥� which is flashing in synch with a pulsar, whose intense beams of radiation sweep across space like light from a lighthouse.
Joel Weisberg of Carleton College in Northfield, Minnesota, and his team monitored the pulsar, which is about 15,000 light years away, and an intervening giant gas cloud. While the cloud was absorbing some of the pulsar鈥檚 radiation, the team found that the hydroxyl molecules in the cloud were amplifying the pulsar鈥檚 signals at a frequency of 1720 megahertz and emitting additional, identical radiation. 鈥淗umans invented masers in the 1950s, but nature invented them first,鈥� says Weisberg.
Astronomers have know about maser in interstellar gas since the 1960s. But this is the first maser spotted in space that has been keeping time with a pulsar (Science, vol 309, p 106). 鈥淲e see the maser flashing on and off exactly when the pulsar pulse does, hence there can be no question about it being a maser,鈥� says Weisberg.
Advertisement
