Is it really impossible for humans to fly out of the earth?

In 1977, the United States launched an unmanned outer solar system space probe, named "Voyager 1". This probe has been operating for more than 40 years and is still flying in the universe. , as of last year, Voyager 1 was 21.1 billion kilometers away from the sun, making it the farthest man-made probe currently flying.

However, it is precisely because of this that mankind sadly discovered that mankind may be "imprisoned" in the earth.

The earth is not safe

We know that the earth’s environment does not mean absolute safety. Although the earth’s environment is still suitable for human survival, the earth’s environment has never been static; Various changes will occur, including: changes in oxygen content, changes in temperature, changes in air composition, etc., and each drastic change will lead to the extinction of a large number of organisms. In the history of the earth, such things have happened countless times, including five mass extinctions that almost led to the annihilation of the earth's biological mass.

According to scientists’ predictions, the earth’s environment may no longer be suitable for human survival in 100 million years. The reason is that the earth will usher in a major ice age every once in a while, which will cause the death of plants in large swaths. As the energy that organisms can use becomes less, organisms with larger bodies and greater energy requirements will become extinct first.

In fact, if the earth encounters another asteroid impact 65 million years ago, humans may not be able to survive on the earth for 100 million years.

It can be seen that finding another planet suitable for human habitation is crucial to the continuation of mankind.

However, we know that humans have very high requirements for a habitable planet, which must at least meet: the planet is located in the habitable zone of the galaxy, the planet has liquid water, an ozone layer, and a global magnetic field; There is the guardianship of a larger planet, etc.

Such harsh conditions mean that there are not many alien planets that can satisfy human immigration, and most of them are very far away from the earth.

What is even more despairing is that with human detectors, it is likely that we will not be able to immigrate to alien planets in our lifetimes because the universe is too big.

Earth’s “cage”

According to statistics from scientists, the average distance between star systems in the Milky Way is about 3 light years. If the star system travels at a speed of 120km/h Driving at such a speed, it would take 2.7 million years without eating, drinking or sleeping to reach the next star system.

Even if it flies at the speed of Voyager 1, it will take tens of thousands or even hundreds of thousands of years to fly to the next star system. In the science fiction novel "The Three-Body Problem", Liu Cixin describes the highly technologically advanced Trisolarans. Their galaxy is 4.2 light-years away from the earth, and their spacecraft reaches 10% of the speed of light. It took more than 400 years to Arrive at Earth.

Not to mention that our current technology cannot allow the spacecraft to fly at 10% speed. Just talking about the food and fresh water for the pilots in these 400 years has already determined that we cannot immigrate to other galaxies.

We know that human lifespan is less than 100 years, and the 400-year flight time means that it will take at least 5-8 generations of relays to reach us. The spaceship has limited space, and not only cannot it hold so much food, but the safety of pregnant women on the spacecraft cannot be guaranteed.

What is even more desperate is that this is only the distance between the earth and Proxima Centauri, and Proxima Centauri belongs to the three-star system, that is, it has three suns, so Proxima Centauri is not habitable. We want to find a suitable As for the planet where humans live, humans may have to look further afield, even beyond the Milky Way.

The diameter of the Milky Way exceeds 100,000 light-years. If we travel through the Milky Way at a speed of 120km/s, it will take at least 90 billion years. Even if we reach the speed of light, it will still take 100,000 years. Such a long time , humans cannot travel through it at all, so that humans are almost trapped on the earth forever.

Why explore the universe?

Since humans may not be able to immigrate to alien planets in their lifetime, why do humans still explore alien planets?

In fact, it is because the more humans know about the universe, the better they can find a way out for humans. In the past, we thought that the earth was the center of the universe and that life on earth was created by God. What it was like in the past is what it is like now.

But now we know that the earth is not special in the universe, and the creatures on earth are not created by God, but occur naturally and evolve with changes in the environment.

Since the earth is not special in the universe, and living things can arise spontaneously, we are curious whether there are other planets in the universe that have given birth to life or even civilization like the earth.

In addition, although humans cannot travel across the galaxy, they cannot find the next habitable planet. But humans can develop science and technology and transform their own planet, just like what is depicted in "The Wandering Earth". When one day the solar system becomes no longer suitable for human habitation, we can take the earth to wander and find the next one. Habitable galaxy.

Although everything is still in the guessing stage, as humans explore the universe, we can answer our doubts one by one, and this may contain the answer to how humans can continue to survive.