By Tim Carr
In 1676 a thirty-two year old astronomer from Denmark stood up in the Academy of Sciences in Paris and announced that he had made a discovery. Some people in the scientific community, such as Newton and Halley, paid attention to him; some, like the director of the Paris Observatory, Giovanni Cassini, didn’t. But what Romer had said was in fact of the most profound importance, not just to his field of work but to science in general.
Ole Romer had discovered the speed of light.
Born in Jutland in 1644, he studied under the Bartholin brothers who taught physics, mathematics and astronomy. During 1671, when Jean Picard travelled from Paris to do some work relating to Tycho Brahe‘s observations, Romer assisted him so ably that Picard took him back to Paris to work in the Academy. Rising quickly through the ranks, he became tutor to the Crown Prince and spent his time improving the accuracy of both observations and the instruments with which they were made.
His magnum opus, however, concerned eclipses of the innermost of Jupiter’s moons, lo. Romer noticed that when Earth and Jupiter were farther apart, the eclipses took place later than when the two bodies were closer. The length of time it took for the event to happen was the same, but when Jupiter was close to us we saw it sooner than conventional wisdom said we should.
Romer realised that we could see the eclipse sooner than expected when Jupiter was closer, simply because Jupiter was closer. The light got here more quickly, just as two bullets fired at the same target from different distances won’t arrive at the same time. The one fired from the gun closer to the target will obviously arrive first. The logical answer was that light must have a finite speed, just like everything else. The value he came up with was about 225,000 Km/sec. which is pretty close to the actual speed of 300,000 km/sec.
Well, obviously, says you. But it is only obvious because Ole Romer figured it out for us. Today, we take the fact that light has a finite speed for granted but in the Europe of the seventeenth century, many still assumed that light moved at infinite speed. People were still coming to grips with the fact that old assumptions, widely accepted without question, might not actually be true. It would be many years before Newton’s Principia completed the triumph of the scientific revolution.
Although his mentor, Picard, was among a number of influential names to support his findings, many in France were less impressed. The great Rene Descartes said that light travelled at infinite speed, as did Aristotle. Who was this Ole Romer anyway?
Eventually, Romer was appointed Astronomer Royal in his native Denmark, and even served a term as mayor of Copenhagen, but it would be another half a century before James Bradley‘s work on the aberration of light confirmed the truth of Romer’s idea. Ole Romer died in 1710 aged sixty-six.
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Speed and velocity are two different things. Speed refers to the motion of an object while velocity refers to the motion AND direction of an object. Velocity, in other words, contains a directional component or vector.
However, the constant "c" which is the speed of light in a vacum (300,000 km/h) is usually refered to as "the speed of light"
you do realize to get even to the speed of light would require so much energy that the spacecraft would be as large as the universe itself…lol the only way is to bend space around you sorta like how the the big bang expanded so fast and surpassing light speed..which wont happen anytime soon i say maybe 400-500 years we migght be close enough to actual try it but still doubtful..
A good question. The answer is yes. Light thinks the trip takes no time at all. If you could travel at the speed of light, time would stand still. This has important consequences in astronomy. When it was discovered that distant galaxies are red-shifted, somebody suggested the "tired light explanation"; the farther light travels, the less energy it's got and the longer its wavelength. Einstein's relativity theory had already been generally-accepted by then, so it was realised that this couldn't be true. Time stands still for a photon, so it can't change. It can't get tired or anything else.
Science has changed since 1996. The speed of light always presented a problem for the big bang theory because the hypothesis says, radiation scattered at different temps throughout the Universe. Problem was found when scientists discovered radiation's temp is the same in all directions. Maybe that is why the “inflation theory” was proposed…lol
I don't think we know enough about the physics concerning the speed of light, but I do also believe there are indication that the speed has indeed changed. It is quite possible for the speed of light to have been faster in the past than it is now.
Einstein's second postulate of his Theory of Relativity accounts for this and is stated as such: "The speed of light is constant in
all frames of reference." However counterintuitive, the proof is far beyond my scope.
Time may slow down for anyone onboard said vehicle moving at the speed of light – but not slow down overall. But it's also figured that if you are looking in the direction of the movement light would be doubled (Assuming you are moving at the speed of light) while it would be absolute black if you were looking backwards.