"The Earth doesn't rotate consistently," said Matt Deutch, chief engineer at the NIST radio station.
"As the earth's rotation slows down in order to keep noon where it should be (at the sun's highest point), we have to make adjustments to keep astrological time in sync with the atomic clocks."Deutch
said the variance in the Earth's rotation is largely due to the moon's gravitational pull on the Earth's oceans.
"The moon's pull on the tide is actually acting as a break on the earth and slowing it down," Deutch
The current difference between the ultra-precise atomic clocks and the earth's actual rotational time is 2 to 3 milliseconds per day, according to the NIST
Another factor according to Deutch
is the land mass of the Northern Hemisphere, which accumulates large amounts of snow in the winter and acts as a break.Deutch
used the analogy of an ice skater spinning in circles.As the skater moves her
arms away from her
Although the station is now largely automated, it still requires an engineer and three technicians to keep it operating, Deutch
"In Fort Collins, the ground is very conductive, which allows for better radio broadcasts," Deutch
...Matt Deutch, chief engineer at the National Institute of Standards and Technology, explains Friday that a second will be added today to the Time Code Generator to make up for the variance in the Earth's rotation.