In air or vacuum light travels at a constant speed of 3.0 X 10" m/s. To answer some of these questions you may need to look up astronomical data in Appendix F.
(a) One light year is defined as the distance light travels in 1 year. Use this information to determine bow many meters there are in 1 light-year.
(b) How far in meters does light travel in 1 nanosecond?
(c) When a solar flare occurs on our sun, how soon after its occurrence can we first observe it? (d) By bouncing laser beams off a reflector placed on our moon by the Apollo astronauts, astronomers can make very accurate measurements of the earth-moon distance. How long after it is sent does it take such a laser beam (which is just a light beam) to return to earth?
(e) The Voyager probe, which passed by Neptune in August 1989, was about 3.0 billion miles from earth at that time. Photographs and other information were sent to earth by radio waves, which travel at the speed of light. How long did it take these waves to reach earth from Voyager?