First of all, why wasn't the sextant ever used for land navigation? The horizon is easier to see at sea, but land based sextants could be used in conjunction with artificial horizons (as at sea when ...
This is a funny question, but worth answering. The distance between the moon and the Earth is 384,400 km. The speed of light is 299792.458 km/s. It will take 1.3 seconds (Approx.) for my laser beam to ...