Earth's journey is right on time: For fifth year, planet hasn't lagged in its trip around sun
By Ryan Morgan, [Boulder Daily] Camera Staff
The Earth won't be having seconds this year, thank you.
And that has scientists across the world including those who run the atomic clock at the National Institute for Science and Technology in Boulder scratching their heads.
Apparently, the Earth isn't slowing down as it used to, and no one knows why.
Flip your calendar back to 1972. That's the year the world began its current system of atomic time-keeping. NIST operates one of the clocks used to set "Coordinated Universal Time."
Scientists soon discovered they had a small problem: The rate at which the Earth travels through space had slowed ever so slightly, and as a result was completing its 365-day journey around the sun one second behind schedule.
To make the world's official time agree with where the Earth actually sat in space, scientists started having the atomic clocks count an extra "leap second" on the last day of the year.
"They came close to matching it, but they had to add a second to keep it in sync," said John Lowe, a NIST researcher who works in the agency's Time and Frequency Division.
For 28 years, scientists repeated the procedure. Then, in 1999, they discovered that the Earth was no longer lagging behind. It didn't need a leap second. [See Barbara Hand Clow's The Mayan Code. --J.N.]
This is the fifth consecutive year that the Earth hasn't lagged behind schedule.
Fred McGehan, a spokesman for NIST, said most scientists agree that the Earth has been very gradually slowing down for millennia. But, he said, they don't have a good explanation for the five years it's been on schedule.
Possible explanations include the tides, weather and changes in the Earth's core.
Contact Ryan Morgan at firstname.lastname@example.org or (303) 473-1333.