30 December 2004

[world_distasters] The Spin Of The World, The Tilt Of The Poles

I've left off any commenting on the Indian Ocean quake and tsunami distaster, since any comment I'd have to make would be trite anyway. Suffice it to say I've been boggled as everyone else, and in my own way I've said a prayer for the dead and for the survivors.

News on the quake's effect, in the physical science world, has been interesting, however. The quake, moment magntude 9.0, was the most violent since the 9.2 "Good Friday" Alaskan quake of 1964. The event caused detectable changes in the planet: The terrestrial rotation was sped up by about 3 microseconds, and the planet exhibited a wobble-a change in the tilt of the axis-of about 1 inch.

It kind of sounds scary. However, when put it context it becomes very insignifcant. While the rotation of the plant sped up by 3 micosec, tidal drag from the Moon actually slows terrestrial rotation by 15 microsec/year. Natural forces stand to cancel that change out in mere weeks. And, that's not all: while an axial variation of 1 inch (2.5 cm) was recorded, it is dwarfed by a natural ongoing polar oscillation called the Chandler wobble, which varies anywhere from about 10 to about 160 feet (9 to 30 metres).

Source:Wikipedia article at this link.

2 comments:

Mover Mike said...

Good find. Always enjoy your blog.
Mover Mike

Samuel John Klein Portlandiensis said...

Thanks, Mike. I learned something doing the research on this one. Those are always the best experience.

Thanks for continuing to read this.