Dear Tom,
In its rotation around the sun, the Earth is hurtling through space at 66,559 m.p.h. Does that have anything to do with our weather?
Robert Legner
Dear Robert,
When we look into space, we see motions superimposed upon motions, and you have described one of them: the annual revolution of the Earth around the sun. That motion is of utmost importance because, coupled with Earth’s tilt relative to the plane of its orbit around the sun, it is responsible for the annual cycle of the seasons.
Another motion is also of great importance to the weather: the 24-hourly rotation of the Earth on its axis. That motion is responsible for the cycle of day and night and the daily cycle of maximum and minimum temperatures, and indirectly through the Coriolis force, the spin of winds around low and high pressure systems.
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Tom Skilling is chief meteorologist at WGN-TV. His forecasts can be seen Monday through Friday on WGN-TV News at noon and 9 p.m.
Write to: ASK TOM WHY, 2501 Bradley Pl., Chicago, IL 60618 or asktomwhy@wgntv.com (Mail volume precludes personal response.)
WGN-TV meteorologists Steve Kahn, Richard Koeneman and Paul Dailey plus weather producer Bill Snyder contribute to this page.
