Who is the first discovered the speed of light?

Answer 1

The speed of light was measured by Ole Christensen Romer. He watched the moons of Jupiter, and observed that their movement around Jupiter appeared slower when the earth was moving away from Jupiter than when earth was moving towards Jupiter. This was because the light from the moons took longer to reach earth. He concluded that the speed of light is 220,000 kilometers per second. It is in fact 300,000 km/s, so he wasn't too far off.

In 1849, Hippolyte Fizeau performed the first earth-bound measurement of the speed of light. A beam of light was reflected off a two-way mirror; it then went through the teeth of an opaque cogwheel rotating very fast, was reflected off a mirror, returned through the teeth of the cogwheel, and went through the two-way mirror to a detector. In the time it took for the light to get from the wheel to the mirror and back, the wheel rotated slightly, which meant that some of the light which had previously gone through was blocked by the cogs. So the finiteness of the speed of light made the light slightly dimmer. By measuring its brightness, he calculated that the speed of light in vacuum was 313,000 km/s.

Fizeau's experiment was important because it could be used to measure the speed of light in any medium, whereas Romer's observation only worked for the speed of light in vacuum. Fizeau discovered that the speed of light is faster in air than in other media. This helped to resolve the long-standing question of whether light consists of particles or waves - the particle theory supported by Isaac newton predicted that the speed of light would be slowest in a vacuum.

Someone observed that the speed of light was (up to experimental error) exactly equal to 1 / sqrt(epsilon * mu), where epsilon and mu are fundamental constants connected with electricity and magnetism, respectively. At the time, this observation just seemed weird. But when James Clerk Maxwell published his equations for electromagnetism, which predicted the possibility of waves travelling at this speed, it all made sense: light consists of electromagnetic waves. So if we want to measure its speed we only have to measure epsilon and mu. The values of epsilon and mu are different in different media, so this explains the differences in the speed of light.

Answer 2

Danish astronomer, Olaus Roemer, was the first person to successfully measure the speed of light in 1676. He based his observations on the eclipses of the moons of Jupiter. Many believe Galileo was the first to measure light, but this is false. Galileo tried, but his experiment failed to provide a correct calculation.

Answer 3

a mathematician and physicist named sir isaac newton thought there was a force

that kept everything down. like earths gravitational field. of course he used his

math and physics skill to find out what it was. he thought that another force

called velocity gave gravity support by having things fall down very fast. he tested

his hypothesis and found out that the heavier and more mass an object has, the

faster the object will fall down. this question is coming out of my science project

of how he discovered it. his hypothesis was rejected because he could not explain

why and how gravity is made.

-- Velocity is not a force.

-- The object's weight and mass have no effect on the speed with which it falls.

-- Newton's hypothesis regarding gravitation was not rejected, because it instantly

explained the motions of the moon and planets, that people had been observing with

their own eyes and measuring with their own instruments for centuries.

-- Nobody can yet explain why and how gravity is made.

-- None of this has anything to do with the speed of light.

Regarding the speed of light:

-- Thinkers and experimenters have been trying to measure it since at least

200 years before Newton lived. Since that speed is so unimaginably fast, early

attempts were unsuccessful. They kept getting better and better for 300 years

or so, until the middle-1800s.

Then the problem took an unexpected turn. The British Physicist/Mathematician

James Clerk-Maxwell worked with all the discoveries in electricity and magnetism

that had been made during the previous hundred years, and developed a set of

mathematical equations that predicted something called electromagnetic waves,

and he even suggested that light is one form of them.

His math predicted the speed of these waves, and from then on, everybody who

found better, more accurate ways to measure the speed of light, kept coming up

with numbers that kept getting closer and closer to Maxwell's prediction.

Finally, Maxwell's hypothesis of electromagnetic radiation was accepted, light was

accepted as one form of it, and his prediction of the speed was accepted as the

official speed of light.

Answer 4

James Clerk Maxwell, the English Physicist/Mathematician, collected the set of

equations that would describe the behavior of light and give its speed if light

turned out to be an electromagnetic wave, but in his time, it wasn't possible to

measure the speed yet. In later years, almost up to the present time, the speed

of light keeps being measured with more and more accuracy. Every time it's

measured, the number gets closer and closer to the speed that Maxwell

predicted, and we become more and more convinced that light must be an

electromagnetic wave.

Answer 5

Larry o'rourke