Wednesday, June 08, 2011

And now for a change of reference frame...

This video of a camera attached to a hula-hoop gives a nice perspective of how the world looks from a different reference frame. Think of this as the person in the middle representing the sun and the spot on the hula-hoop representing the earth. From the perspective of the person in the middle, the motion is fairly simple and easy to understand. From the perspective of the camera, life is quite different.

Of course, with multiple planets all moving at different speeds around the sun, the motion of the solar system appears to be much more complicated from the earth. We see planets that appear to move sometimes faster, sometimes slower, and sometimes even in reverse. Add to this the motion of the moons around the planets and the solar system is an apparently complicated place indeed.

However, if you put the camera in the right place it all gets easy to understand.