Everyone knows that the speed of light is the fastest, right? What about other celestial bodies?

I think the knowledge in physics textbooks is limited, and some of it should be wrong. Suppose there is a planet A 1 billion light years away from us, and human beings measure this data to say that planet A is the distance from us equivalent to light in 1 billion years, and human beings only use a few minutes or seconds to measure the distance of point A from point B of the earth, when humans measure the distance of star A, do you first have to observe at point B on the earth, since you want to observe star A, then do you have to send a beam of light from point B to A, after reaching point A, you can only say that you have arrived, But how do you know whether it has arrived, then do you want to see something, to see point A, point A is not to reflect the light that has reached point B must be reflected to point B through point A, point B can know its existence, size, position, that is to say, we see an object is not simply the object light enters the retina and we see it, we only see the light of the object at this time, when you know its size, position, distance, the light that the object enters the eyeball is reflected back to the object itself again in an instant, Almost at the same time, the brain has already calculated the complex program of this moment, that is, it has to go through the process of going back and forth. If the light only goes or only returns, how do you know where it is going, and how do you know where it has come and how long it has come?

That is to say, if you want to determine it and determine its distance, etc., you must have a process of determining and verifying it again, just like you see an object, but the reflected light of the object enters the eyeball and we see the object, but you have to further determine its size, distance, at this time, it can be said that at the same time, due to the speed of light, our eyeball reflects the light back to the object, so that our brain can roughly know that the object is far away from us. It takes 1 billion light-years for the light of star A to reach point B of the earth, if the light of star A is only coming, we can only see its light, and we can see the light of various planets in the universe and the light passing through every moment, but we only see its light, and cannot determine the distance of its object planet itself, here we are only talking about seeing. If we want to measure how far away star A is from us, we must also reflect the light that reaches point B back to star A, so that it should also take a billion light-years to determine its distance, but we humans don't know how many billions of light-years away from us such and such a star, so I think human scientists are lying, even stupid, unless something faster than the speed of light has been, but this contradicts the statements of scientists today.

So the theme I'm going to react to is the conclusion that humans measure the speed of light, and it's wrong to say that so-and-so planet is hundreds of millions of light-years away from us, unless he can live hundreds of millions of light-years. I hope you will speak, discuss! Don't look at the problem from the perspective of elementary school or junior high school!

Question adds:1Calculated according to simple planar trigonometry?

The premise is that you already know where its point is, and since you know its location, that is, you have known or found its detailed coordinates from the earth with a tool, if so.

The speed of light is so fast that on the scale of everyday life, people simply do not realize that it takes time for light to travel from A to B, and in ancient times, it was widely believed that light had no speed. At the same time as departure, a beam of light arrived at its destination. So far, although there have been occasional faster-than-light phenomena, most scientists still use this theory as a standard, often looking for evidence to explain the faster-than-light phenomenon.

Therefore, as the fastest speed in the universe, the speed of light remains unbreakable.

In the 17th century, the Italian scientist Galileo Galilei decided to do an experiment to measure the speed of light. Galileo designed the experiment in such a way that two men stood on two hills with a lantern each, each covering the lantern in their hand with a baffle.

Next, a person took off the baffle in his hand, and the person on the opposite hill immediately took off the baffle in his hand when he saw the light. The first person records the time from when the baffle is removed to the time when he sees the lantern in the other person's hand, that is, the time when the light travels back and forth between the two mountains. The speed of light can be obtained by dividing the distance between two mountains by time.

In fact, the measurement of the speed of light has gone through a long process. The wisdom of mankind has been continuously improved, and this great cause has finally been accomplished. Today, let's take a look at how scientists measure the speed of light.

Aristotle is a famous representative of ancient Greece (although he was not a Greek). Although some of his theories were overturned, they were very popular at the time and were even praised to the sky. Hundreds of years ago, many people believed that the speed of light was infinite and that light could reach instantaneously, no matter how far away.

However, this view was difficult for physicists to accept, so in 1638, the physicist Galileo Galilei devised an experiment.

The ancient Greeks, represented by Aristotle, also believed that the speed of light was the fastest. But unlike Einstein, they believed that the speed of light was infinite, which is known as the distance effect. That is, no matter how far away, the light can be lit at one end and the other end can receive light at the same time.

Therefore, it is completely ridiculous and unnecessary for them to measure the speed of light. According to his hypothesis, Subjects A and B each stood on the top of two mountains with a lamp with a sunhat (they could see each other). When everything is ready, A opens the visor and records the time at the same time, and B opens the visor as soon as he sees the light and records the time at the same time.

When A sees B's light, he records the time again.

The speed of light self-test method, remove a bag of marshmallows and a microwave oven, and the microwave oven rotating disk, and then measure the middle spacing of the marshmallows, and then we know that the frequency of the microwave oven is generally on the half back of the microwave oven or on the manual, and then use the microwave frequency, the central sentence of Liang Dexiang's two marshmallows, and the result is the speed of light.

The speed of light is calculated by scientists according to the previous high-speed measurement history, because scientists at that time measured the speed of light at 214,000 kilometers per second, and then slowly developed, modern scientists through many instruments and the previous development of the speed of light, calculated that the speed of light is 299792458 meters per second.

Using the method of light travel of perseverance, the astronomer discovered that the positions of stars are constantly changing, using astronomical phenomena and observations to determine the speed of light.

Geographers use the method of perseverance in light to discover that the status of stars is constantly changing, and measure the speed of light by controlling the meteorological and observed values of geography.

Gear velocimetry. The gear velocimetry method is a highly accurate and reliable measure of the speed of light. Soon after (1861-1862), the great Maxwell (1831-1879, a Scottish physicist) appeared, giving Maxwell's equations, which perfectly described the motion of electromagnetic waves, and he derived from the equations that the speed of electromagnetic waves was about c=3*10 8m s, which was very close to the value of the speed of light at that time, so he boldly guessed that light was a special frequency of electromagnetic waves.

Later experiments did prove his guess.

History of light-speed measurements.

The first time in human history the speed of light was measured was in 1676. At that time, the Danish astronomer Ole Romer discovered that the speed of light is finite, not infinite, by studying Jupiter's moon Io, and estimated the value of the speed of light. The process of his estimation is shown in the following diagram:

The Great Ring is the Earth's orbit around the Sun, and the Minor Ring is Europa's orbit around Jupiter. When the Earth moves away from Jupiter (from L to K) and approaches Jupiter (from F to G), the time for Io to emerge from Jupiter's shadow (C to D) will change, and the speed of light can be estimated by adding the orbital period of Io around Jupiter and the orbital period of the Earth and the orbital speed of the Earth. The speed of light estimated from this method is very small, about 26% smaller than the actual value.

The speed of light is measured by the same method that measures the frequency of the laser and the wavelength of light in a vacuum.

The speed of light refers to the speed at which light waves or electromagnetic waves propagate in a vacuum or medium, and the speed of light in a vacuum is the maximum speed of motion of objects in nature that has been discovered so far.

With the discovery and exploration of modern science, people have learned that the light that fills every corner of the world is only a small band in electromagnetic waves, and now this small band is called visible light.

Electromagnetic waves also include invisible light in the wavelengths of radio waves, infrared, ultraviolet, X-rays, and rays. Both visible and invisible light have the characteristics of electromagnetic waves, and the wavelength is related to frequency and speed.

The velocity of these electromagnetic waves in a vacuum is the same, and the speed of light is equal to the product of the wavelength frequency, i.e.: c=f. Therefore, as long as the wavelength and frequency are known, the speed of light can be calculated.

Does the speed of light change?

The speed of light is finite, according to Galileo's principle of relativity, the velocities are all relative, the velocities measured with different reference objects are different, and the velocities are superimposable.

So, is the speed of light shot by a flashlight on the ground still the same as that shot by a flashlight on a high-speed train?

This question bothered scientists for a long time, until the advent of Maxwell's equations and the conclusion that "the speed of light is constant", that is, the principle of the invariance of the speed of light, that is, the speed of light is constant relative to any observer.

The first correct value of the speed of light is measured by celestial bodies.

In 1675, the Danish astronomer Romai noticed that the time interval at which Europin disappeared into Jupiter's shadow varied, and that it became longer or shorter with the incomparable distance between Jupiter and Earth during each lunar eclipse. Recognize that this is due to the fact that light travels over different lengths and takes different amounts of time. Based on this idea, Romai calculated that c is equal to 2 times 108 meters per second.

In 1849, there was a good measurement of the speed of light in the ground blind interview experiment. At that time, the French physicist Fisso used high-speed gears for this work.

In 1862, Foucault succeeded in developing another method for determining the speed of light, using a high-speed rotating mirror to measure tiny intervals of time.

Einstein. Because Einstein proposed the great theory of relativity, the speed of light was calculated by Einstein.

At first, Galileo measured but failed, and then an American physicist named Michelson, who measured very close values at the time, but the more accurate values were measured by Ferum.

After using a laser that measures a specific frequency wavelength, the speed of light can be calculated by using the formula: velocity = wavelength x frequency.

The speed of light is so fast, I personally think that his speed is measured, so I know that the speed of light is very fast.