Very interesting everything that has been stated so far. I think my curiosity asks now what and HOW were the exact experiment that preformed to determine the speed of light. Technically Fizeau wasn't the first to calculate it "accurately" because his calculation was an inaccurate one, as well we have the Ole Romer team determining it as well. I would say that goes to the team that most precisely determined it in 1975, at least so far. If i have things in order chronically the idea/theory to the transformation goes as so:I. Ole Romer - In 1676 Made the first quantitative measurements of the speed of light. He did this by being influenced by the works of Phillip III of Spain with his method of determining the longitude of ships out to see (no detail on how this was performed). As well as being influenced by Galileo on his method of establishing the time of day and thus longitude based on the eclipses of the moon, also no real idea of the process used. Romer had a team of people working with him to calculate this with observatories. Over several months Romer and Jean Picard observed 140 eclipses of Jupiter' moon, lo. while in Paris Giovanni Domenico Cassini observed the same eclipses. By comparing the times of the eclipses, the difference in longitude of Paris to Uranienborg was calculated. Cassini had observed the moons of Jupiter between 1666 and 1668, and discovered discrepancies in his measurements that, at first, he attributed to light having a "finite speed". In 1672 Rømer went to Paris and continued observing the satellites of Jupiter as Cassini's assistant. Rømer added his own observations to Cassini's and observed that times between eclipses (particularly those of Io) got shorter as Earth approached Jupiter, and longer as Earth moved farther away. Cassini made an announcement to the Academy of Sciences on 22 August 1676:
This second inequality appears to be due to light taking some time to reach us from the satellite; light seems to take about ten to eleven minutes [to cross] a distance equal to the half-diameter of the terrestrial orbit.
Romer actual experiment goes as follows. Assume the Earth is in L, at the second quadrature with Jupiter (i.e. ALB is 90°), and Io emerges from D. After several orbits of Io, at 42.5 hours per orbit, the Earth is in K. Rømer reasoned that if light is not propagated instantaneously, the additional time it takes to reach K, that he reckoned about 3½ minutes, would explain the observed delay. Rømer observed immersions in C from the symmetric positions F and G, to avoid confusing eclipses (Io shadowed by Jupiter from C to D) and occultations (Io hidden behind Jupiter at various angles). In the table below, his observations in 1676, including the one on August 7, believed to be in opposition H,[5] and the one observed at Paris Observatory to be 10 minutes late, on November 9. By trial and error, during eight years of observations Rømer worked out how to account for the retardation of light when reckoning the ephemeris of Io. He calculated the delay as a proportion of the angle corresponding to a given Earth's position with respect to Jupiter, Δt = 22·(α⁄180°)[minutes]. When the angle α is 180° the delay becomes 22 minutes, which may be interpreted as the time necessary for the light to cross a distance equal to the diameter of the Earth's orbit, H to E.[6] (Actually, Jupiter is not visible from the conjunction point E.) That interpretation makes it possible to calculate the strict result of Rømer's observations: The ratio of the speed of light to the speed with which Earth orbits the sun, which is the ratio of the duration of a year divided by pi as compared to the 22 minutes 365·24·60⁄π·22 ≈ 7,600.
II. James Bradley - in 1795 he discovers the Aberration of light which is attributed with the finite speed of light. At the instant of any observation of an object, the apparent position of the object is displaced from its true position by an amount which depends solely upon the transverse component of the velocity of the observer, with respect to the vector of the incoming beam of light (i.e., the line actually taken by the light[where?] on its path to the observer). The result is a tilting of the direction of the incoming light which is independent of the distance between object and observer. Which was based on Romers points that light is finite, it was only until Bradley proved it seems that it was fully accepted as fact.
III. Jean Baptiste Joseph Delambre - In 1809, again making use of observations of Io, but this time with the benefit of more than a century of increasingly precise observations, the astronomer reported the time for light to travel from the Sun to the Earth as 8 minutes and 12 seconds. Depending on the value assumed for the astronomical unit, this yields the speed of light as just a little more than 300,000 kilometres per second. The modern value is 8 minutes and 19 seconds, and a speed of 299,792.46 km/s.
IV. Armand Hippolyte Louis Fizeau - In 1849 he was the first person to measure the speed of light on Earth. He used a beam of light reflected from a mirror 8 km away. The beam passed through the gaps between teeth of a rapidly rotating wheel. The speed of the wheel was increased until the returning light passed through the next gap and could be seen. He calculated the speed of light to be 315,000 km/s.
V. In 1865, James Clerk Maxwell proposed that light was an electromagnetic wave, and therefore traveled at the speed c appearing in his theory of electromagnetism.
VI. Albert Einstein postulated that the speed of light with respect to any inertial frame is independent of the motion of the light source,[4] and explored the consequences of that postulate by deriving the special theory of relativity and showing that the parameter c had relevance outside of the context of light and electromagnetism.
VII. After centuries of increasingly precise measurements, in 1975 the speed of light was known to be 299,792,458 m/s with a measurement uncertainty of 4 parts per billion. On wikipedia it does not tell who this was proven by nor how.
Just so there is no confusion most of what i posted above is wikipedia. So during the time Einstein was creating his theory of relativity he only knew that light was finite and that nothing could exceed it, not the precise measurements of which were discovered in 1975. My curiosity strikes me more as i read through, does anyone know the process of Romer and his team, were they using synchronized watches to figure out the time delays of lo? if anyone can illuminate on anything stated that would be fantastic.
