Dear Tom,
At water level looking across Lake Michigan, how far is the horizon? How about from the 95th floor of the Hancock building?
Jim Duffy, Wheaton
Dear Jim,
It’s been a while since we addressed this question. The horizon is defined as the boundary where the sky meets the ground or water. Due to the curvature of the Earth, the higher the view point of the observer, the greater the distance to the visible horizon. There is a simple formula for calculating this distance in miles. Take the square root of the height above the ground of your eyes (in feet) and multiply that result by 1.23. For a person about six feet tall standing at the Lake Michigan shore, the horizon would appear to be about three miles away.
Moving up to the 95th floor of the Hancock building (about 1,050 feet above the ground), the distance to the horizon would increase to about 40 miles.
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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.)
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