The speed of light in a vacuum is measured at 186,282 miles per second, which is 670,616,629 miles per hour. The speed of light is denoted mathematically by the symbol "c." More »

Knots are the unit of measurement that describes the speed of boats and airplanes. One knot is equal to roughly 1.151 miles per hour. With this conversion factor, 18 knots is equal to roughly 20.718 miles per hour. More »

www.reference.com Science Measurements

Optimally, Mach 2 is 1,552.4141 mph. This measurement is twice the speed of a moving object relative to the speed of sound in a surrounding medium when placed under ambient conditions. More »

Light typically travels at 186,000 miles per second, but scientists have found a way to slow it down to 38 miles per hour. A team at the Rowland Institute for Science has found a new state of matter to help slow light do... More »

In a vacuum, the speed of light is 186,282 miles per second. This is equal to 299,792 kilometers per second or about 670,616,629 miles per hour. More »

The speed of light is 186,282 miles per second. An object travelling at the speed of light would make approximately 7.5 rounds around the Earth in one second. More »

The speed of light in mph (miles per hour) is 6.702 x 108 mph or more precisely 670,616,629 mph. In metric units, the speed of light in a vacuum is 2.998 x 108 m/sec. More »

www.reference.com Science Physics Optics & Waves