Velocity of Light From far Away

Most recent answer: 08/24/2013

Q:
is there any experiment done to find out the velocity of light from extra terrestrial source ? for example ...velocity of light from receding stars ?
- B Rajkumar Daniel (age 49)
tamil nadu, india
A:

The very first measurements of the velocity of light measured light from an extraterrestrial source, the moons of Jupiter. () The velocity of light from high-orbit satellites must be very exactly the standard value in order for GPS systems to work. Various other measurements are done, e.g. bouncing light off the moon and back. 

Mike W.


(published on 08/24/2013)