Why would it take a million years to fly at the speed of light and return to Earth for a year, I don

Look at the formula below.

This formula is the one in the theory of relativity regarding time dilation (or time delay). where v is the speed of flight, c is the speed of light, t is the normal time, and t is the time after the change.

When the velocity of motion is low, v c is basically equal to zero, and the denominator in the formula is almost equal to 1, and time is basically constant. So when we take a train, take a plane, or even fly in space at a speed of tens of kilometers per second, we don't feel that time has changed.

And when the speed of motion is close to the speed of light, v c has an obvious value, and the denominator in the formula is not equal to 1, but may be equal to, or even less. At this point, there is an extension of time (or time dilation). When the velocity is equal to the speed of light, the denominator is zero, and time becomes infinity, that is, time stands still.

After traveling at the speed of light for a year and returning to Earth, the time on Earth will pass a million years, indicating that time is expanded by a million times. The denominator should be that the speed of motion is the speed of light.

When moving at this speed, time is still passing normally for the people on the spaceship, only 1 year in motion. This time is called apparent time. But for people on Earth (or from beyond spaceships), a million years have passed.

This time is called actual time.

This is only theoretical, not practically achievable. Because while the time is delayed by a factor of 1 million, the mass of the spacecraft is also increased by a factor of 1 million due to the relativistic effect. A 10-ton ship becomes 10 million tons.

With such a heavy spaceship, it is impossible to accelerate or slow down. In other words, humans are not yet able to fly at such high speeds.

Why is it said that if you travel a few minutes at the speed of light and then return to Earth, then the Earth will pass for decades?

When an object reaches the speed of light, the concept of time does not exist, because the energy required to reach the speed of light is astronomical, and this energy is unimaginable. But if we answer this question from the dimension of distance, we may be able to calculate how many years have passed.

First of all, we know that the speed of light is 300 million meters per second, so according to three minutes, it is 180 seconds, and the distance traveled by the speed of light in three minutes is 50 billion meters.

The next thing we have to think about is, how is the earth time calculated, one rotation of the earth is one day, and the rotation of 365 revolutions is one year, so what is the converted distance? Then we need to know the circumference and rotation speed of the earth, different dimensions have different circumferences, and they are also different rotation speeds, so we choose the maximum value is that the circumference of the equator is 40 million meters, and the equator will travel so much distance in a day, so how much distance does it travel in a year? The distance of the equator in one year = the distance of the Earth's equator is 14.6 billion meters.

Knowing the above two data, the distance of three minutes at the speed of light is known, the distance traveled by the Earth's equator in a year is known, and the distance at the speed of light of three minutes divided by the distance traveled by the Earth's equator in a year is equal to the year, that is, it is equivalent to 4 years.

Everyone must be very strange, so different dimensions, there will be different times? That's true, because if we compare it to the equator, then it's equivalent to the speed of light in three minutes at the equator, i.e., four years after the Earth, and different dimensions will have different results, which is calculated relative to motion.

So when the speed of light is reached, the concept of time does not exist, and these three minutes may be years, or decades, or centuries, or even hundreds of millions of years. It's a very abstract concept that will make you feel incredible, but that's exactly what it turns out to be.

This is relative to the Earth, that is, after a few years and decades, if it is relative to the spacecraft that reaches the speed of light, different references have different results, and they are all relative results.

First of all, the speed of light cannot be reached, never will, just as 1+1 cannot be equal to 3. Second, assuming that people travel at close to the speed of light, time is close to static. He traveled to space for decades, and for him it was only a few hours, and humans on Earth were decades.

Because light can travel at high speed in the universe, the distance of the earth is very long, and even the speed of light takes a long time, so it will be decades after returning to the earth.

Mainly because there is now a theory that the flow of time at the speed of light is not the same as the flow of ordinary time.

According to Einstein's special theory of relativity.

Regarding the time dilation formula, when the speed reaches the speed of light, the person in the light-speed spaceship will not feel the passage of time, time will stop, whether it is a day or a year or a hundred years, it is an instantaneous thing, there is no sense of time passing. And the people on the earth saw the light-speed spacecraft leave, and it took a day to return to the original place, that is, one day, this spacecraft flew a light sky, if you ignore the process of speeding up and decelerating, completely calculated according to the speed of light, this light sky flew a total of 25.9 billion kilometers. But the people in the spaceship seemed to be only a matter of moments.

That's in a different frame of reference.

, people's perception of time. This is also the reason why there is a difference in age between the crew of a high-speed spaceship and the crew in the Earth's frame of reference. In the not-so-fast speed frame of reference, this difference is not obvious, the difference is almost impossible to see for a few seconds and minutes, and the faster the speed, the greater the difference, which is the slow clock effect.

However, according to Einstein's theory of the speed of light, as long as there is mass, objects cannot reach the speed of light, so the feeling of reaching the speed of light can only be described theoretically, and does not really exist in practice. To date, no incidents have been found in which the test data do not match the theory.

Although there is no way to really reach the speed of light at this speed, as the speed gets closer to the speed of light, the time dilation multiplier will increase. When the speed of flight reaches the speed of light, the time dilation multiplier will reach 707 times, that is, if the person flies at this speed for one day, the Earth will look like 707 days have passed.

That's about 180 years on Earth.

It's about 180 years on Earth.

If it is a day of flight, then there is no doubt that a day must have passed on Earth, but once this speed reaches the speed of light, the nature is completely different.

If you're at 50 percent of the speed of light, you're in outer space for one day, and you're more than 90 years old.

That's one day, it's a unit of distance, it's like a light year.

If you calculate it, you can calculate it.

It's not about time, it's about distance.

Flying at high speed must be very fast.

I really don't know, because I don't know what kind of speed it is.