2007-07-08 04:56:07 · 10 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
Its slowing down at 1/100000 sec per hour
2007-07-08 05:03:08 · answer #1 · answered by Saurabh 1 · 1⤊ 0⤋
Currently, the length of the mean solar day is increasing at a rate of 1.7 milliseconds per century. However, this rate is itself variable, and depends on a number of factors.
Note that the addition of leap seconds does NOT have very much to do with this rate of change. The primary reason for the addition of leap seconds is that the second is no longer defined in relation to the earth's rotation, but rather to an outside standard based on the vibration of cesium atoms. Therefore if these two standards ever get out of sync (as they have), leap seconds must be added forever, even if the rate of change in the earth's rotation were to drop to zero. (Why? because there are always 31536000 seconds in a rotation-based year. But if the "cesium" year has 31536000.1 seconds, you'll need a leap second every ten years regardless -- even if the deceleration in rotation were to stop entirely.)
2007-07-08 15:21:28 · answer #2 · answered by Keith P 7 · 0⤊ 0⤋
The Wikipedia has an excellent article on the leap second. It has a great graph that shows how the earth is slowing down. The rate does vary over time.
2007-07-08 19:30:06 · answer #3 · answered by Anonymous · 0⤊ 0⤋
The slowing down is not enough for you and I to notice. In the last 165 years, the Earth takes an additional 0.002 seconds to rotate.
So, every year the Earth rotation slows down by 0.0000121 seconds (.002 sec/165 years). Since these seconds to add up, every so often a leap second is added back to keep our clocks correct. Please read more at the below link....
2007-07-08 12:07:27 · answer #4 · answered by Ziggy 3 · 1⤊ 0⤋
Somewhere between 2 and 7 millionths of a second per year.
At one time, about 370 million years ago, the Earth's day could have been measured at about 20 hours and 35 minutes. (about 425 days in a year back then).
So don't get your underwear all in a "bunch" over the "tidal braking effect".
Petch, you're a trip, sweetie.
2007-07-08 12:01:58 · answer #5 · answered by Anonymous · 2⤊ 0⤋
Every 18 months ( about) a leap second is added to the time to keep the day consistent with atomic clocks and astronomical observations.
Every 18 months, the day gets a second longer.
2007-07-08 12:01:50 · answer #6 · answered by ck_pinna 3 · 0⤊ 3⤋
it isn't slowing down. Its at a constant speed off 2000mph and orbits the sun at 200,000mph
2007-07-08 11:59:57 · answer #7 · answered by hummmmm 3 · 1⤊ 3⤋
um, it never slows down. you should know this!
2007-07-08 11:58:22 · answer #8 · answered by theweirdstuff 2 · 0⤊ 3⤋
try this web site: http://www.nasa.gov/
2007-07-08 11:59:09 · answer #9 · answered by Ben G 1 · 0⤊ 3⤋
Dunno.
2007-07-08 11:57:57 · answer #10 · answered by ? 3 · 1⤊ 2⤋