Relative Motion and Flight
Name: Steven G.
We are studying forces in science class. If you were in
plane traveling 806 mph in the opposite direction of the Earth's
rotation, would the sun never move?
If you were at 40 degrees latitude this would be true. At the equator,
you'd have to travel at around 1050 mph.
Actually, the sun doesn't move much anyway. It is the Earth's surface that
really moves, rotating around once per day. By flying as you suggest, you
are causing the plane to "STOP" moving. You are making the plane stay
aligned with the sun. You are correct: you would never see the sun rise
Dr. Ken Mellendorf
Illinois Central College
I am not sure that 806 mph is the correct speed, because it would depend upon
latitude, but the principle is correct. If you moved at the same speed as
the earth is moving about its axis with respect to the Sun, the Sun would
just "hang there".
I do not recall the exact figures for the earth's circumference at the
equator but this number seems a little low to me. Of course, the speed
required would depend on your latitude as well. At the equator you
would have to fly much faster than if you were close to one of the poles.
Without dealing with the exact numbers, if you matched the earth's
rotational speed and flew in the opposite direction for one year the
earth would rise and set one time (as the earth moved around the sun).
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Update: June 2012