how fast dose light move. mph or light years brake down
Well, obviously light moves one light year a year. That's where we got the unit light years from. Light speed is 670,616,629 mph, but for some reason the more commonly known value is ~186,000 mps--miles per second. I guess the smaller number is easier to remember. The speed of light is also defined as exactly 299,792,458 meters per second. Actually, the meter is defined as the distance that light travels in 1/299,792,458 seconds, but it amounts to the same thing.
All those numbers in the above answer refer to the speed of light in a vacuum. In a transparent medium (like glass or water), the speed is slower and given by c/n, where n= index of refraction of the medium, and c = speed of light in a vacuum.
It is estimated at 186,000 miles per second. There are 3600 seconds in an hour, so 186,000*3600 = 669,600,000 mph. A light year is not a unit of time, but of distance. The speed of light is generally taken to be 3*(10 to the 8th power) meters/second.
speed of light is 186,000 miles per second or 669600000 miles per hour 1 light year is the distance light travels in 1 year. 669600000mph X 24 hr per day X 365 days per year = 5865696000000 miles per year = 1 light year.
