Suppose we have 2 rigid rods, immensely long, with absolutely no elasticity. If we hold the rods
so that they cross a few meters in front of us at some point A. Now slowly move them
towards a parallel direction, the intersection point, P of the 2 rods will move away from us at an
ever-increasing rate.
The intersection point P will surpass the speed of light apparently, but why?
2007-01-21 05:26:14 · 4 answers · asked by sh 1 in Science & Mathematics ➔ Physics
Because the intersection point is not a real object, it is just a virtual location; there is no matter there moving with that point, and no information contained; so it is not bound by the laws of physics that states nothing physical can go faster than the speed of light.
Suppose you look at a star in the night sky, and then look at another star: your gaze has jumped from one star to another one that is light years from the first one in just one second. Your gaze "focus" has moved much faster than the speed of light. But has any information or matter moved? No.
Same thing.
2007-01-21 05:45:26 · answer #1 · answered by Vincent G 7 · 1⤊ 0⤋
There are numerous thought experiments and concepts that will move an object as fast or faster than the speed of light. For instance, if a rigid rod the length of the radius of a circle with a diameter of 186,000 miles was rotated 1 revolution per second, the end of the rod would be traveling at the speed of light.
Unfortunately, in the real world, there are no perfectly rigid rods.
When an object's velocity equals light speed, the equation for kinetic energy becomes undefined (MC^2 / 0). Some assume this to mean infinite because up to the speed of light, this quantity of energy increases dramatically.
If we exceed the speed of light, the denominator in the energy equation becomes the square root of a negative number - and your guess is probably as good as any ones as to what that might mean in reality.
Proofs:
E=MC^2 / sqrt(1-[V^2/C^2)]
If V^2 = C^2 (i.e. the velocity equals the speed of light) the denominator becomes 1 minus the square root of 1, or zero. If V > C, then it becomes the square root of a negative number.
2007-01-21 06:34:41 · answer #2 · answered by LeAnne 7 · 0⤊ 0⤋
nonphysical eperiment. An even better one is to take a rod that is 10 miles in length and spin it on an axle. The tip traces a path of a little more than 300 Miles. Now spin the rod at 700 times per second. The tip would be going faster than the speed of light by a CLASSICAL calculation. The problem is, you can't use classical arguments when at near relativistic speeds. To get to the speed of light requires infinate energy.
Basially, the rod breaks well before the speed of light
2007-01-21 05:43:38 · answer #3 · answered by walter_b_marvin 5 · 0⤊ 0⤋
It is a virtual point. The Laws of Physics say that matter cannot move faster than the speed of light, but they say nothing about whether a point in space can move faster. Since a point in space is not comprised of matter, it is free to move as fast as it wants to.
2007-01-21 05:55:19 · answer #4 · answered by Anonymous · 0⤊ 0⤋