Want to lose weight? Move to the equator. What's this? Well, there's a couple things. As a child you probably learned that the earth is round; hopefully, sometime after that someone pointed out that "round" describes a disk, and that the earth really is a sphere. It's unlikely, though, that anyone got around to telling you that Earth isn't really spherical either; it's spheroidal.
As the earth rotates around its axis, the surface at the equator is
moving over 1000 miles per hour, but the poles are merely rotating in place, and the
equator bulges because of centrifugal force—the same force that throws you against the
side of a car when it makes a sharp turn at high speed. The weight reduction is due in
part to the direct action of the centrifugal force on your body. But there's
another angle. Because of the equator's bulge, you're farther from the center
of the earth, and thus gravity's pull is less. Here in the Chihuahuan Desert,
we're kind of in-between; heavier than at the equator, lighter than at the
poles.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.