|Jake- You have two main categories of question. One is about motion
relative to the Earth and Sun, and the other deal with hypothetical
motion at the speed of light. The types of answers will be very
different for these. |
If you fly in the same direction that the Earth is rotating, you are rotating around the center of the Earth even faster than the Earth's surface is. So you will cross the terminator (the day/night boundary) more often than you would if you stayed home. Try to model this with a lightbilb (Sun) and a globe.
If a plane were travelling at bullet speed relative to the Earth, and you fired a bullet backward in the plane, the bullet would indeed be at rest relative to the Earth. (So far as we know, it is entirely meaningless to ask if something is stanidng still unless you say with respect to what you are measuring the motion.) Of course, that wouldn't make it at rest relative to the plane, and would not prevent it from puncturing the fuselage. So don't try it.
Wondering about what it would be like to travel at the speed of light (relative to the Earth or the bullet or the plane or whatever) can lead to some interesting thoughts, as it did for young Einstein. However, one conclusion of those interesting thoughts is that it's absolutely impossible for any object with rest mass to travel at the speed of light past any other object with rest mass. So there's nothing we can say about that situation except that it couldn't happen in a universe whose basic rules are like the ones of this universe.
(republished on 07/23/06)