Is there really a planet inhabited by human beings in outer space?

A long time ago, after the American twin Mars probes "Courage" and "Opportunity" successfully landed on Mars, the desire of human beings to explore advanced life beyond their own planet and pursue extraterrestrial habitats became stronger. Besides the earth, can human beings find an ideal habitat, and can Mars become another habitat for human beings?

There may not be an exact answer yet, but some research results may help us make some rational analysis.

According to Charles Lineweaver of the University of New South Wales, about 10% of the planets in the Milky Way are suitable for human survival. They established the evolution model of galaxies, and after analysis, they put forward four conditions for the existence of life: the existence of a main star; There are enough heavy metals to form earth-like planets; There is enough time for creatures to evolve; Located in a safe place, it is not exposed to gamma-ray radiation generated by supernova explosion.

From this perspective, the Milky Way has a "region where life may exist", which is located in a slowly expanding region 25,000 light years away from the center of the Milky Way. This area includes planets formed between 4 billion and 8 billion years, and three-quarters of them were formed 1 100 million years earlier than the sun.

This is only an inference and needs to be proved by facts. Even if this inference is correct, it does not mean that these planets are suitable for human habitation, because the existence of advanced life does not mean that it is suitable for human existence. Secondly, it is a whimsical dream for human beings to run to a planet with a distance of light years. The best candidate may only be the liveliest Mars.

The National Aeronautics and Space Administration (NASA) and the American Geographic Society have come to an ambiguous conclusion. Although humans can reach Mars by space shuttle, the conditions that are not conducive to human survival on Mars are still very obvious. Mars is much colder than the earth, with an average temperature of MINUS 40 to MINUS 60 degrees Celsius. There are cosmic high-energy ion radiation and cosmic magnetic field (electromagnetic radiation) on Mars, which is extremely unfavorable to human health. Although they won't kill the people who landed on Mars immediately, the people who landed on Mars received twice as much radiation as the astronauts on the International Space Station.

This kind of injury is chronic and fatal. As long as you stay on Mars for a short time, you may suffer from various cancers, cataracts and various diseases after the nervous system is damaged by radiation.

Because the gravity of Mars is only 38% of that of the Earth, and the atmospheric pressure is only 1% of that of the Earth, the microgravity environment on Mars is also a challenge to human life and health. In microgravity environment, people's muscles will shrink, bones will become soft due to calcium loss, genes will mutate, people's immune system will be affected, the release of immune B cell antibodies will decrease, and the ability of T cells to identify pathogens and activities will also decrease. In this way, the number of viruses in the human body will also increase, just as the number of viruses in the saliva of astronauts will increase.

The recent research conducted by Russian experts on the International Space Station also confirmed that under weightlessness, people's immunity will decline. On October 20, 2003/kloc-0, Russian investigator Caglieri brought immune cells and cancer cells to the space station, and on October 28, 2003/kloc-0, two others brought them back to the ground. This study shows that under microgravity conditions, although the function of individual immune cells is not affected, cancer cells and heterogeneous cells can still be found, recognized and attacked, but the overall immune system of human body will be weakened and degraded under weightlessness conditions.

Of course, even with these conclusions, it is not enough to prevent human beings from marching and immigrating to Mars or other planets, because human beings have always been confident and proud: if conditions are not available, they will go ahead when conditions are created. So what conditions can Mars create for human migration?

Some people's plan is to build a house in a hidden place like Mars, using building materials that can effectively reduce radiation, and using radiation-proof materials for all clothes. From about 20 15, the environment of Mars is similar to that of the Earth. Of course, it does not rule out that there are other planets whose environment is more similar to the Earth, such as Titan, Saturn's sixth satellite, but it is too far away from the Earth. Other planets are worse than the environment on Mars. Based on the above situation, people can draw the conclusion whether human beings have habitats other than the earth. In 2030, the population on Mars will not exceed 100. The main task is to explore and analyze the climate and radiation conditions on Mars, find the environment for life and its survival, and try to grow crops.

From 2030 to 2080, chemical plants and nuclear power plants will be built on Mars, which will have a greenhouse effect and raise the temperature on Mars to several degrees below zero. At this time, scientists, engineers and technicians, doctors and so on all went up.

A small number of people will migrate in the third phase. At that time, the temperature on Mars has reached several degrees below zero, plants have grown and formed, the atmosphere has gradually thickened, and carbon dioxide and water can seep out of the ground. Humans don't have to wear protective clothing, but they still have to wear a respirator to breathe. At this time, you can probably move tens of thousands of people.

By 2 150, the Martian atmosphere will be formed, with an average temperature of zero degrees Celsius, and crops can be planted and harvested normally. Green plants dissolve and block radiation, and the air is enough for people to breathe. Cities have begun to form on Mars. At this time, it is possible to immigrate to Mars on a large scale.

Is this plan a science fiction or a grand blueprint? It depends on whether human beings have such ability and whether nature conforms to human imagination.