U.K. Stargazers: Save the Leap Second

Abstract

Astronomers in the United Kingdom are fighting a proposal before to the International Telecommunication Union (ITU) to abolish the venerable leap second. Leap seconds, added once every 500 days or so, keep high-precision atomic clocks from running ahead of solar time, which is gradually falling behind as tidal friction slows Earth's rotation. Clock resetting happens irregularly, says U.S. delegate Ronald Beard of the Naval Research Laboratory, and could potentially affect systems for air traffic control or economic transactions. But astronomers, led by the Royal Astronomical Society (RAS), say the leap seconds are integral to the programs that align telescopes and track satellites, so a change would require an expensive overhaul. “Otherwise, you could point your telescope in the wrong place,” says Mike Hapgood of RAS. In November, ITU will debate the proposition, but a final decision could take years.