Speed of light?

Answer 1

299,792,458 m / s
186,282.397 miles per second, or 670,616,629.384 miles per hour

Answer 2

The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning "swiftness". It is the speed of all electromagnetic radiation in a vacuum, not just visible light.

In metric units, c is exactly 299,792,458 metres per second (1,079,252,848.8 km/h). Note that this speed is a definition, not a measurement. Since the fundamental SI unit of length, the metre, has been defined since October 21, 1983 in terms of the speed of light; one metre is the distance light travels in a vacuum in 1/299,792,458 of a second. Converted to imperial units, the speed of light is approximately 186,282.397 miles per second, or 670,616,629.384 miles per hour, or almost one foot per nanosecond.

Through a transparent or translucent material medium, like glass or air, it may appear to have a different speed than in a vacuum; the ratio of c to the observed phase velocity (which may be both smaller or larger than c) is called the refractive index of the medium. Changes of gravity, however, warp the space the light has to travel through, making it appear to curve around massive objects. This gives rise to the phenomenon of gravitational lensing, in which large assemblies of matter can refract light from far away sources, so as to produce multiple images and similar optical distortions.

Answer 3

Speed of light is 382000 Km per second

Answer 4

For general calculations 3*10^8 meters/sec.

Answer 5

3 * 10^8 m/ sec.. It is calculated as distance between by the sun and the earth and the time taken by it to reach earth.

Answer 6

Hi, the speed of light today is: 299792.458 km/s.

declared by Einstein (1905): "The velocity c of light in vacuum is the same in all inertial frames of reference in all directions and depend neither on the velocity of the source nor on the velocity of the observer". Einstein's theory of special relativity says that the speed of light in vacuum is always the same (at 299,792.458 km/s) but this is true only for systems that are inertial, which means not accelerating. From Newton's second law: if forces exist implies acceleration exists; this means that special relativity is valid only when no forces are acting; thus it cannot be used when there is a gravitational force present. Albert Einstein himself emphasized this in his paper written in 1917: "The results of the special relativity hold only so long as we are able to disregard the influence of gravitational fields on the phenomena". Therefore for the results of special relativity to hold the systems should not be accelerating (no gravitational forces).In conclusion, the velocity of light in a gravitational field is not a constant, but rather a variable depending upon the reference frame of the observer; what one observer sees as true another observer sees as false. The only observers that can actually agree that the speed of light outside gravitational fields is 299792.458 km/s are those who are themselves outside gravitational fields.

By using classical orbital mechanics we discovered that all observers will see the speed of light outside gravitational fields equal to 12000 Lunar Orbits/Earth Day. An observer near a black hole for example sees the speed of light outside gravitational fields a zillion km/s, but still equal to 12000 Lunar Orbits/Earth Day! This means that if the speed of light outside gravitational fields (or the speed of any object) were defined in km/sec then it will appeare to vary for observers in different gravitational fields; however if this speed is defined in Lunar Orbits/Earth Day then it will never appear to vary to anyone because 12000 Lunar Orbits/Earth Day is common to all observers. It also turned out to be a constant forever.

1667 Galileo: at least 10 times faster than sound
1675 Ole Roemer: 200,000 Km/sec
1728 James Bradley: 301,000 Km/s
1849 Hippolyte Louis Fizeau: 313,300 Km/s
1926 Leon Foucault 299,796 Km/s
Today: 299792.458 km/s

299,792.458 km/s is the speed of light in vacuum. However, according to Einstein's theory of General Relativity, the speed of light appears to vary with the intensity of the gravitational field.
But 1400 years ago it was stated in the Quran (Koran, the book of Islam) that angels travel in one day the same distance that the moon travels in 1000 lunar years, that is, 12000 Lunar Orbits / Earth Day. Outside gravitational fields 12000 Lunar Orbits / Earth Day turned out to be the known speed of light!

Answer 7

I dunno, it seems like red lights are longer than green lights.

and yellow lights, well they are the shortest of all.

I think it was Sr. Issac Newton that said. "Give me a fig bar and a place to sit and I will prism a rainbow.

Answer 8

1/4sec to reach the moon

Answer 9

30 billion cm per second.

Answer 10

0.001 Milli second at 3658 Kilometer this is my answer. This answer's best example is sun.