I can think of one set of interrelated effects that depends on the direction of the Earth's rotation, namely anything dependent on the Coriolis force, such as large-scale surface ocean currents (clockwise in the North Atlantic and North Pacific, counterclockwise in the South Atlantic, South Pacific, and Indian Oceans), large-scale wind currents (such as the generally east-to-west winds near the equator and the west-to-east jet streams at the top of the troposphere, including the one that crosses North America and has significant effects on its climate). If the Earth rotated the other way, these would simply reverse. Coastal climates would be affected. Generally speaking the east coast of any continent gets warm water from the equator, while the west coast tends to get cool water from nearer the pole. This situation would be reversed as well. Foucault pendulums would precess in the opposite sense (although that's not a huge factor in my everyday life), and winds spiraling around high and low pressure zones would switch directions (currently in the northern hemisphere winds spiral counterclockwise into a Low and spiral out clockwise from a High, due the combined effects of the Coriolis force, the pressure gradient force, and friction). Finally, anyone launching a rocket would need to recalculate launch windows, since launches are normally planned so that the Earth's rotational speed at the launch latitude effectively adds to the launch speed.
Oh, and in North and South America we would get our hurricanes from the Pacific rather from the Atlantic Ocean. Hurricanes forming in the Atlantic would hit Europe and Africa.
Ken Caviness
Physics Department
Southern Adventist University
-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu on behalf of David Bowman
Sent: Fri 04-Jan-08 2:04 PM
To: Forum for Physics Educators
Subject: Re: [Phys-l] earth's rotation
Regarding David Ward's question:
My physics colleague here was just asking me "What would happen if the Earth rotated from East to West rather than West to East? Would it alter our climate? Would it change where the deserts are? Has anyone ever simulated this?"
I told him it was a great Phys-L question. What's your opinion?
My first thought is that it would have no large effect- global air currents, the Sahara, etc would still be where they are today...the Sun rising in the West rather than the East would have no large-scale effect. Am I wrong?
Have a great day!
david
David Ward
Professor of Physics
UNU# 3160
Dept. of Physics
Union University
1050 Union University Drive
Jackson, TN 38305-3697
office (731)661-5241
FAX (731)661-5175
dward@uu.edu
Well, its impossible for the Earth to rotate from West to East, seeing that the definition of East is the direction the Earth rotates toward, and the definition of West is the direction the Earth rotates from. Asking this question is sort of like asking what would happen if green was magenta and yellow was blue.