Show earths rotation slowing british astronomer says washington sir harold spen jones great britain astronomer reports the mean period of 0 the earths rotation Is changing in two ways way one change he says Is well known and nd well understood it amounts to bout a thousandth of a se second cond f P century sufficient to upset serious ly some ome astronomical calculations the th change is due to the drag ol of tides over the beaches of shallow shallo seas leaf this change also affects the day length of the moon the other change equally minute Is incalculable and unpredictable sometimes it hastens and sometimes blows low down the earths earth rotation |