Posted on 12/30/2003 5:44:51 PM PST by e_engineer
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.
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Take a Colorado Ski Vacation 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.
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 morganr@dailycamera.com or (303) 473-1333.
Aren't we all?
Yes, the article is perfectly clear. The earth revolves around the sun once a year, give or take a second. This has nothing to do with the earth's daily rotation about its axis.
Uh, I'm afraid that would be me. I had Mexican food for lunch this afternoon, and went outside to, er, "work off the effects." Must have been standing exactly 180 degrees from the direction of the Earth's rotation when I did.
My bad.
My Metemucil finally started working.
I like that one.
What is a leap second? A leap second is a second added to Coordinated Universal Time to make it agree with astronomical time to within 0.9 seconds. UTC is an atomic time scale, based on the performance of atomic clocks. Astronomical time is based on the rate of rotation of the Earth. Since atomic clocks are more stable than the rate at which the Earth rotates, leap seconds are needed to keep the two time scales in agreement. The first leap second occurred on June 30, 1972. There have been a total of 18 leap seconds to this date. This means that leap seconds occur at a rate of slightly less than one per year. Although it is possible to have a negative leap second (a second removed from UTC), so far, all leap seconds have been positive (a second has been added to UTC). Based on what we know about the Earth's rotation, it is unlikely that we will have a negative leap second in the foreseeable future.
Bold is my addition.
Very interestingly the Sun has many "modes" of "breathing". The primary mode is a very slight radial "breathing" of a few meters in diameter. The interesting thing is that it is precisely 960 minutes long. That is 2/3 of an Earth day, and I have never seen an explanation of why the SUN's internnal modes should give a rat's ass as to the length of an earth day.
There is still a debate about the "speed of gravity". Under classical mechanics (Newtonian) it is easy to show that gravity must have an infinite velocity. Otherwise the Earth and all the planets would be flung from orbit in a few thousand years due to a sort of inverse of the Poynting-Roberson effect. But general relativity resolves the issue, showing that gravity travels at the speed of light, not infinitely fast, and that planets will still stay in their proper orbits.
Interestingly, studies of the overall dynamics of the Solar System with the digital orrery at Caltech show that the solar system as a whole is chaotic and that the orbit of (e.g.) Pluto cannot be predicted with certainty into the far future. The implication is that if one planet's orbit cannot be predicted, then none of them can. However the persistence of the solar system as a stable (yet chaotic) system presents a powerful plausibility argument that things are likely to stay much the same, since they have for the last several billion years...
--Boris
My digestive system, thanks you.
There is a huge undiscovered mass in the vicinity of our sun. Superjovian planet, black hole, neutron star maybe.
It's on a highly elliptical orbit with a period of thousands of years. Right now it's out of our sight, but its massive gravity is affecting the earth's orbit.
Soon it will return, as it has many times in history, but this time it will come too close.
WE'RE ALL GONNA DIE.
No. The other planets, and this one,too, were effected one time back about when God said... That effect has affected Earth ever since.
# Solar flares are known to abruptly alter the Earth's rotation. For example, the great flares of 1959 and 1972 brought abrupt changes in the LOD. Both long-term and short-term changes in solar activity alter the Earth's rotation. The 11-year, 22-year and 56-year solar cycles are conspicuous in the LOD data. Long-term (secular) changes were noted at times of fluctuations in solar activity in the past, and the evidence indicates that these changes were very likely abrupt. Observations of the LOD, like so many other geophysical phenomena, reveal the solar-FEM linkage.
I wonder if the weakened solar magnetic field (due to the solar magnetic reversal) has temporarily halted the magnetic braking of the Earth's rotation.
An increasing number of fat people residing on the North American Continent which is affecting the earth's gravitational spin in a positive spin manner counteracting the negative spin effects of the fat people which dominated the European countries earlier in this century.......
This statement is true.
"Do I have to kill you? What if I was to kick the ever living sh*t out of you?" Joe Pesci-My Cousin Vinny.
You owe me a keyboard.
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