If humans leave the Garden of Eden on earth and enter outer space, then we will die instantly because of the drastic changes in the environment. It stands to reason that the earth is inseparable from the human body.
But with our ingenuity, we have developed spaceships and spacesuits, which can provide astronauts with a land environment in a narrow space, so that we humans can stay in outer space and walk in space;
However, spaceships and spacesuits can only ensure a short stay in outer space, because there are still two problems that cannot be solved, namely, microgravity environment in outer space and high radiation.
These two problems are the biggest problems that restrict human beings to live in outer space for a long time, travel in space and colonize other planets. And it may not be solved for a long time.
In fact, as early as the 1960s, during the Apollo program, NASA launched manned spacecraft to orbit the earth and the moon several times to understand the influence of the outer space environment on the physical and psychological quality of astronauts.
After many experiments, the astronauts performed well in a short time, and there was no particularly serious injury before carrying out manned landing on the moon. However, NASA knows that living in outer space for a long time is unbearable for astronauts' bodies.
One of the most famous experiments is the study of twin astronauts, which gives us a better understanding of how outer space affects the human body.
The names of the twin astronauts are Kurt Kelly and mark kelly. In 20 15, Kurt Kelly went to the international space station and stayed there for a whole year, which was the longest record of American astronauts staying in outer space, and his physical changes became the research object of scientists.
And its twin brother, mark kelly, stayed on the ground. This is Kurt Kelly's experimental control group. So scientists can clearly know what has happened to Kurt Kelly's body.
We know that the International Space Station has always been inhabited by astronauts, but every astronaut will return to Earth for recovery training after staying in the space station for less than six months.
So it is beyond the normal time limit to let astronauts stay in outer space for one year. Before astronaut Kurt Kelly went to the space station, scientists collected urine, feces and blood samples from him and mark kelly.
Kurt Kelly also collected some samples of himself in space. After returning to Earth, scientists made medical analysis on them.
A paper published in Science magazine shows the effects of space environment on Kurt Kelly's body, some of which are expected and some are surprising.
Scientists say: after leaving the earth, microgravity will make all human metabolism disorder, there is no magnetic field protection outside the earth, and solar radiation and high-energy rays of the Milky Way will cause radiation damage to human beings. Therefore, the study of the twins is by far the most comprehensive study of the human body's response to space flight. "
On earth, the way our body fluids and blood flow has adapted to the gravity of the earth. If we go to the microgravity environment in outer space, our body fluids will flow around, which affects the way our heart pumps blood to the whole body.
Therefore, long-term space travel will make heart health a big risk. We found that all astronauts who returned to Earth in the past had cardiovascular problems.
Microgravity can also affect the eye muscles, causing irreversible damage to astronauts' vision. Therefore, every astronaut returning from the International Space Station needs to wear special glasses to restore the eye muscles.
Long-term microgravity will also reduce the muscle strength and bone density of astronauts. These problems are very serious for Kurt Kelly.
The paper also points out that scientists have found genetic changes in the Kelly brothers, which is the worst news for human beings. Because genes are, after all, the blueprint of living things, genes have been damaged and mutated, which is fatal to living things.
The reason is that the radiation from outer space, that is, when charged particles penetrate the human body, will ionize the molecules in the human body. Of course, this will lead to the breakage of DNA chains, which will lead to the mutual extrusion of chromosomes and even the exchange of positions.
These changes may cause some genes to be overexpressed and some genes to stop expressing. Such problems can lead to cancer or other diseases in human beings.
Surprisingly, scientists found that Kurt Kelly's chromosome telomere also changed. Telomeres are structures at the ends of chromosomes. With the aging of organisms, telomeres of chromosomes will become shorter and shorter.
It stands to reason that Kurt Kelly's telomeres will also be shortened, and the speed of shortening may be accelerated. Scientists believe that the unique stress (nutrition, physiology and psychology) and extreme environmental exposure (microgravity and space radiation) experienced by astronauts in long-term missions will definitely accelerate telomere shortening, thus increasing the risk of aging and age-related diseases such as cardiovascular disease and cancer.
But to everyone's surprise, his telomeres not only didn't get shorter, but became longer, which is completely contrary to the idea of scientists.
However, when scott kelly returned to Earth for a period of time, scientists found that his telomeres were shortened rapidly and much shorter than before.
In other words, after 1 year of space travel, Kurt Kelly's aging was actually accelerated. What scientists don't understand now is why telomere length changes so dramatically, and what does this have to do with space flight?
Because the sample size is too small, it is difficult for scientists to find out the reason. They will continue to study this problem in the future, which also requires more astronauts to stay in space for a longer time, so that scientists can really have a chance to find the answer.
Whether microgravity affects human body or radiation damages genes, it shows that human beings cannot expect to be in space for a long time. Even if we build a moon base and a Mars base in the future, these problems are inevitable.
This also means that it may be difficult for human beings to survive outside the earth. As long as you leave the earth where you were born, the result is a dead end.
So this limits the fantasy of human interstellar travel, the fantasy of colonizing the solar system and even the Milky Way. Unless we can always simulate the gravity of the earth, we can always surround the human body with magnetic fields and block the radiation from outer space.
This is difficult for human beings to do in a short time, so at present, the earth is the cage of human beings and the best and only destination for human beings.
In the future, if we want to get rid of the shackles of the earth completely, we need to experience several major scientific and technological revolutions.