This New Year's Eve, every second counts

The year 2009 is now a little further away than we thought it would be. The world's official timekeepers have slipped an extra second into New Year's Eve, a chronological fudging to make up for Earth's slightly slowing rotation.

Wednesday will be 24 hours and one second long, according to the International Earth Rotation and Reference Systems Service. Its decision will be honored by the US Naval Observatory and atomic clocks around the world. The rest of us probably won't notice.

This extra second will hit right after 11:59:59 p.m. GMT (6:59:59 p.m. EST) and will be 24th "leap second" since scientists started introducing them in 1972. The last was in 2005.

If one extra second "doesn’t sound like a big deal, consider that in one second a cheetah can dash 34 yards, a telephone signal can travel 100,000 miles, a hummingbird can beat its wings 70 times, and eight million of your blood cells can die,"  jokes The New York Times.

The real reason for these tiny corrections: Scientists count time in two different ways. There are the atomic clocks, which tick-tock at a near perfect rhythm, only losing about one-billionth of a second per day. Then there is rotational time, which follows the spinning of the Earth. The aim is to keep the two clocks within 0.9 seconds of one another.

But the globe moves at its own tempo. It spins around the sun every 365 days and six hours, so, we have leap years to make up for the extra quarter of a day. The Earth also does not twirl on its axis at a regular speed, so, we need leap seconds to close the gaps. Small disturbances such "the braking action of tides, snow or the lack of it at the polar ice caps, solar wind, space dust, and magnetic storms" can all affect Earth's rotation, reports Reuters.

While February 29 hits every four years, leap seconds come as they please. In the past, they've landed anywhere between six months to seven years of one another.