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No More Leap Second?
WerewulfX writes "CNN reports: "In a phenomenon that has scientists puzzled, the Earth is right on schedule for a fifth straight year." Update yeah, this is a repost. Whatever- it's a holiday. Nothing else to post :)
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Those poor souls who are born on that second aren't going to have a birthday. T_T
Slashdot dupes are, as always, right on time!
webpage
the dupe second?
I want to delete my account but Slashdot doesn't allow it.
Who says that the extra second wasn't just deja vu? I know that I could have sworn I saw this post before.
Will we see more el ninjo effects
I hope so! El Ninjo is the bad-assest Mexican Ninja ever!
this article is soooo last year
Spare me please. You all are the biggest bunch of need-something-to-whine-about babies I have seen in a good long time. So what if something was double posted? It takes half a second to scan the headline and realize that its a repeat. You take more time crawling all over each other to be the first to whine/complain/joke about the repeated story. For God sakes, ignore the post if your time is so precious! "HELLO? What is the problem? I doubt I'll donate to Slashdot again!" That is the saddest sentence I have ever had the misfortune of reading. Slashdot pours all kinds of blessings upon us geeks daily and you refuse to contribute BECAUSE A STORY WAS REPEATED? GOD FORBID! Burn them at the stake! They have wasted your precious half of a second! Seriously folks, cry me a river.
If the Earth is assumed to be a homogeneous sphere and the rotational axis is assumed to be the straight line passing through the north and south geographic poles, the moment of inertia of the Earth is I = MR^2 where M is the total mass of the Earth and R is its radius. The kinetic energy of a rotating Earth is given by K = 1/2 I w^2, where w is the angular velocity.
The energy associated with an angular velocity which is increased by 1 second over a year is equivalent to an extra 1.6e22 Joules of energy or 40 times the annual energy consumption of mankind (DoE 1999). A detailed analysis and matlab script are available here
Yeah, this is a rereply. Whatever. It's a holiday. Nothing else to reply to.
Michael.
Linux : Mac
Update yeah, this is a repost. Whatever- it's a holiday. Nothing else to post
Sure there is. You could post about how the Stardust probe is about to enter a comet's tail, or perhaps India's plans for a hypersonic plane, or even the chnaging face of offshore programming...
CNN Says:
For 28 years, scientists repeated the procedure [of adding a leap second]. But in 1999, they discovered the Earth was no longer lagging behind.
Um, not exactly true. Not every year over the last 28 years has had a leap second. For example, 1984, 1986 and 1987 didn't have a leap second. It's generally determined if a leap second is necessary about 6 months ahead of time by IERS. However, this is the first 5 year gap of no leap seconds.
It's interesting to note that the "leap second protocol" permits a "reverse" leap second - meaning a "short" minute. This is because the folks involved in defining the leap second realized that the rotation of the earth is not 100% predictable, and therefore they theorized that there could be a "fast spinning year" that would merit the loss of a second. This hasn't happened yet.
This whole rotation-of-earth-isn't-constant idea is pretty new (50 years). So just because we have a 5 year period of smaller rotaional speed deltas isn't totally unexpected.
Heal itself? That implies that there is something natural about the 24-hour day. The Earth's rotation rate has been decreasing for billions of years. An Earth day was approximately 18 hours in duration 900 million years ago.
Mea navis aericumbens anguillis abundat
Particularly, the monsoon season I believe has the largest effect, particularly because the generated winds impact the himalayan mountains.
The combination of a large (albeit distributed) force impacting a large object (himalayas) affects the angular velocity of the earth.
I learned this first because a friend was writing an ephermeris program and got in contact with the guy an NIST who tracks these things. I beleive they can make some predictions of change in rotational velocity based on the force of observed storms.
Also the Navy has built an array of (radio or laser, I forget) interferrometers located in (I believe) the rocky mountains which are used to measure the actual variances against star positions.
Linux is Linux, if One need clarify their dist: <Dist>/GNU Linux
bsds are of course just BSD
When (greater) Sweden was going to change from Julian to Gregorian calendar they stuffed it up, got one day out of sync with all Julian countries, so to get back in sync they added an extra leap day, creating the only 30th Feb in history.
They eventually made the change from Julian in 1753 by having (gregorian) 1st Mar 1753 after (julian) 17 Feb 1753 removing ten days.
Makes a leap second seem a bit insignificant....
If you have no idea about Julian (as in Ceasar) and Gregorian (as in pope) calendars, have a look here