Speed ​​of light: the fastest possible speed

arrive to light’s speed! A phrase that has become commonplace. But you can find out What is this speed of light? exactly? If you have scientific training or are simply passionate about physics, you know the right formula. Let us try to shed some light on this phenomenon, which has always aroused great fascination and which is still a subject of study by physicists and mathematicians.

A Brief History of Light and Its Journey

The speed of light is the maximum that can be achieved in nature: no person can exceed it, even if it is possible to approach it. It is traditionally denoted by the letter C (the first letter of the Latin word Celeritas), The The speed of light in a vacuum It is a term written in the physics of our universe equal to 299.792.458 m/s (meters per second). According to the convention, it is closer to 300 million m / s, in order to facilitate calculations. If you are wondering about the value Approximate speed of light in km/secjust put a little effort and remember the valence table: 300,000 km/sec. This value is assumed to be a universal constant, based on Einstein’s theory of relativity.

Before Galileo Galilei, light was assumed to travel at an infinite speed. Then, thanks to the father of the scientific method, the speed of light radiation ceases to be considered a state and becomes a dynamic entity that reaches the eyes of the beholder. But the first to measure the speed of light was Romer, in 1676. Later, Einstein fixed its value at the aforementioned universal constant.

Because the speed of light cannot be exceeded

beat light’s speed It is the dream of many. The space is vast, the distances are vast and it would be nice to be able to travel quickly from one star to another. Almost all science fiction stories are based on the possibility that one day humanity will find the way Exceed there light’s speed, just as in the past, it was possible to overcome obstacles that seemed insurmountable. Unfortunately, the rules of the universe seem to forbid this. Without going into too many advantages, to understand why we need to start from the concept of energy and use the formula discovered by Einstein, according to which the energy needed to accelerate the body grows more and more, as we approach the speed. of light. In practice, no matter how much effort is put into it: the power will never be enough. To reach the speed of light, whatever mass to accelerate, it is necessary to expend unlimited energy. Therefore, not only is it not possible to exceed the speed of light, but this speed is not even achievable.

How was the speed of light measured?

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It was already expected: we owe it to the Danish astronomer Ole Romer measure for light’s speed. Before him, Galileo Galilei tried his hand at the project, but with little success. Armed with a protected lantern, the scientist goes to a hilltop and invites his assistant to do the same, one mile away. The idea is to calculate the time it takes for light to get from one point to another: Galileo was the first to discover his lantern. The assistant sees Noor El-Sayed, who in turn discovers the lantern that he is carrying with him. Nothing is done. Light takes about 0.000005 seconds. A value that cannot be measured by the hardware available to Galileo.

However, at larger distances, measurement is possible, even with less sophisticated instruments. This was shown by Romer, observing the movement of Io, one of Jupiter’s moons. It takes Io 1.76 days to make a complete orbit around Jupiter. However, the scientist realizes that this time period is variable and that the Moon seems to anticipate its revolution, when the Earth is closer to Jupiter, and slows it down as the two planets move away. Romer’s thesis is simple and original: the difference is due to The speed of light, which is not infinite It takes a certain amount of time to get from Jupiter to Earth. Now, the Danish astronomer has an inaccurate value for the diameter of the Earth’s orbit and, as a result, calculates the speed of light as 220,000 km per second. Subsequent physical studies measured this speed with absolute accuracy, and released the now known figure. However, Romer’s remains are the most reliable measure to date that allows us, today, to make unimaginable calculations. Like knowing that a beam of light can make seven and a half turns of the Earth in just one second, following the equator.

The speed of light in water

In the empty that light’s speed It reaches its maximum possible value: it spreads in a straight line with a uniform movement. But light can branch out in any transparent medium. For example, to select The speed of light in water It is necessary to know the value of the refractive index of water, which changes depending on the type of liquid (distilled, sweet, salt water). In seawater, light travels at a slightly slower speed than in fresh, distilled water.

man’s top speed

Fastest man of all time Usain Boltwhich ran 100 meters flat in 9.58 seconds, averaging 37.578 km/h. However, its primacy may be overtaken in the not-too-distant future. According to recent research in Texas, a person will be able to reach a speed of 65 kilometers per hour. What makes the difference will not be the athlete’s muscles, but the contact time between the foot and the ground, currently too short to release all the force possible. there man’s top speed It won’t even come close to light, but great progress will be made. The Jamaican runner’s primacy will be just a distant memory.

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