Movie 27 (1:05)

Script : Another interesting property of the rotations produced by relativity is that it preserves circles - that is, a sphere will always present a spherical outline to any observer regardless of their relative motion. This is a special property of circles, and does not apply to any other shape.

We see this demonstrated by orbiting a camera around the Earth at a constant high speed. The camera's position can be seen from above in the lower right hand corner of the screen. Though the camera is very close to the surface, aberration wraps the Earth into our forward field of view. But because we are so close to the earth, we can see only a small portion of its surface so small regions seem to bulge out and fill the sphere.

These effects are present even in our real world, although to a much smaller extent because of the great speed of light. Satellites and space shuttles and Global Positioning Systems all must account for these effects.

 

Comments : Orbiting the Earth like a satellite, ie; using gravity to "fall" around the earth, at this distance would be impossible at 95 % of c. So the movie's camera must sit on some powerful rocket constantly and smoothly blasting to keep it on a circular orbit of this small radius.

But extremely accurate GPS satellites. although they move much slower than 95 % c, are essentially in the same predicament as the movie camera, and employ the same relativistic calculations to pinpoint positions on the earth's surface.