Human endeavours like the building of dams are now being held responsible for the planet spinning a wee bit faster. Benjamin Chao, a geophysicistat NASA's Goddard Space Flight Center in Greenbelt, Maryland, US, says that the days are shortening by about O;2millionthsofa second per year. Chao's observations are based on a study of artificial reservoirs like dams, and how this redistribution of water is affecting the earth's spin. As most dams are situated in the NQrthern Hemisphere, there has been a net shift in the water closer to the earth's axis and away from the equator, resulting in faster spins (DiScover, Vol17 , No 4).