Letters from the November 4, 2006, issue of Science News
By Science News
Twisted logic?
I have a question concerning “The Sun’s Halo in 3-D” (SN: 8/19/06, p. 120). It says, “As the sun rotates, its polar regions make a complete circle in about 34 days, compared with the 25 days required by its equator.” I was wondering how it’s possible to have two points on a rotating body take different amounts of time to make a complete revolution.
Mike Crawford
Snohomish, Wash.
The sun is a giant ball of gas, not a solid like a planet. Different points rotate at different rates, in a process called differential rotation.—R. Cowen