Earth Spinning Slower

December 09, 2008

If you missed the big news maybe you felt it in your bones: The Earth's spin has slowed enough to add a "leap second" to the end of 2008. The Associated Press story linked to above, however, fails to mention why the Earth is spinning down. Turns out it's all the fault of Al Gore. No wait, it's Exxon's fault. Just kidding. It's really not anyone's fault. Maybe God's fault, if you absolutely have to assign blame.

One thing not to blame, for a change, is global warming. Despite the fact that climate changes can cause winds and ocean currents to slow or speed up the spin of the Earth, those are tiny, itty-bitty changes that don't warrant a leap second. What's really happening is the same thing that's been going on for billions of years: The Earth's spin is very gradually slowing down. It's just one great big spinning top, after all, in a very low-friction environment that allows it to keep spinning for an extraordinarily long time. But not forever.

Some of my colleagues think this is a pretty depressing bit of news. But I say longer days are a good thing. Let's have more quality, not quantity of days. Enjoy that extra last second of December 31st by smiling and saying "One Mississippi" then "HAPPY NEW YEAR!"

Comments

[Dan]

This article is severely lacking !
It says nothing about how the Moon is "Tidally Locked" to the Earth (which is why that from Earth we always see just one face); or that our Earth / Moon Size : Mass ratios are the largest
of any other pair of Planet to Moon in our Solar System. The accepted theory is an Impact / Accretion process. It proposes that the Earth was
hit by a Mars-sized object very early in its own formation. This Impact not only added to the rotational velocity, it also blew-off a lot of the Earths crust which then orbited as an accretion disc originally at only about 5,000 miles above the Earths surface. In a surprisingly short period of time,some estimate that the accretion process may have only taken 100 years, the Moon was formed and has been moving away at the rate of about 2.2 cm. a year
presently. The primary mechanism underlying the Earths slowing rotation is friction in the ocean basins as the tides are pulled around the Earth.

[Grammar Klink]

"More Slowly"

I thought the Discovery Channel was into edumacation....

[Larry O'Hanlon]

It sure are. Fact is, this is a abbreviated sentence. The word "is" is missing. That's why it looks and sounds wrong. Btw, grammar is okay in small doses, but in my many years of writing for the public, I've found the only people who really obsess about it are people with very little experience actually writing for the public. We must remain flexible, within reason, in the face of deadlines and breaking news.

[So Lame]

Ah, yes. Dumbing down science to the point of inaccuracy for the uneducated masses of America. The leap second has nothing to do with the Earth's decelerating rotation. It is because our clocks can only approximate the length of a day and errors accumulate in our calendar. Hence it is necessary to make periodic adjustments.

[Miguel]

Duh... This has been known for quite some time. DUH

[Evan]

I'm confused! This is Larry O'Hanlon's column, he writes that the Earth is slowing down in a low friction environment and then posts a note saying that it's an aberration of our clocks and calendars???

[Evan]

Ooops. Sorry Larry. I just realized that the posts list the author below the comment. So, a separate question - we rotate around the Sun at 69,000mph. Is our rotation slowing down there as well?

[Larry O'Hanlon]

Happens all the time Evan. My apologies for the way the names are posted (which is beyond my control). I'm no expert on this, but I believe I've heard that the Earth's orbit is supposed to widen over time. I think that would slow the speed of our orbit, lengthening our years. But I might be totally wrong about this. It's a good question for Ray Villard, who blogs on related matters for Discovery Space. Here's his link: http://blogs.discovery.com/cosmic_ray/

[Guy]

If the earth stops spinning, I'm moving to the dark side.

[HatlessHessian]

Actually, dams like China's Three Gorges do have an effect on slowing earth's rotation:

http://www.newsday.com/news/nationworld/bal-hs.earth07jan07,0,5860508.story

[Tim]

Has anyone seen the movie Southland Tales? It was all about Global Deceleration, and the Anti Christ taking over the world.