- #1
Rising Eagle
- 38
- 0
The laser ranging of the moon doesn't make sense. The moon has a special mirror on it that doesn't reflect incoming light along the same angle as the angle of incidence only on the opposite side of the perpendicular, but instead reflects light back exactly on the same path as the light's approach. A telescope is aimed from Earth directly to the moon's reflector. A laser is aimed through the telescope, the laser beam hits the reflector and bounces back exactly to the same telescope for detection and time of flight measurement.
Consider the fact that the moon and Earth are in parallel motion in space at 370 kilometers per second. The problem is that in the 2.5 seconds trip of the laser beam to the moon, the moon has moved and the light should miss the reflector completely. Even worse, in the 5 seconds of the round trip of the laser beam, the Earth has moved quite a bit through space and the light should miss the telescope which has moved along with it.
The only way for this to work is if light slides sideways to parallel the motion of the moon and Earth which keeps the light beam always at the same angle of approach to the reflector, no matter what the path of the laser beam through space actually is. This sliding simulates the conditions as if the Earth and moon were both hanging motionless in space when the measurement is done. Arguing that the telescope is aimed forward to intersect the moon in the same way a quarterback aims for his receiver where he thinks he will be when the football arrives doesn't work because the reflector still returns the light back to where the telescope was when the laser beam was first sent, and not to where the telescope has moved to.
Does light move sideways? By what mechanism? SR doesn't really explain it. Do its postulates even predict it? How else could laser ranging be made to work?
Consider the fact that the moon and Earth are in parallel motion in space at 370 kilometers per second. The problem is that in the 2.5 seconds trip of the laser beam to the moon, the moon has moved and the light should miss the reflector completely. Even worse, in the 5 seconds of the round trip of the laser beam, the Earth has moved quite a bit through space and the light should miss the telescope which has moved along with it.
The only way for this to work is if light slides sideways to parallel the motion of the moon and Earth which keeps the light beam always at the same angle of approach to the reflector, no matter what the path of the laser beam through space actually is. This sliding simulates the conditions as if the Earth and moon were both hanging motionless in space when the measurement is done. Arguing that the telescope is aimed forward to intersect the moon in the same way a quarterback aims for his receiver where he thinks he will be when the football arrives doesn't work because the reflector still returns the light back to where the telescope was when the laser beam was first sent, and not to where the telescope has moved to.
Does light move sideways? By what mechanism? SR doesn't really explain it. Do its postulates even predict it? How else could laser ranging be made to work?