"I want to be an astronaut and travel freely in space", which may be a childhood dream of many people.
It is true that in the past, if you want to get rid of the gravitational constraints of the Earth and go into space, you must become a professional astronaut, but all this is quietly changing, and on July 11, 2021, Virgin Atlantic founder Branson completed the first commercial space trip in the history of human spaceflight. Of course, at this stage of commercial space travel is still in the trial stage, the cost is very high, but in the future, commercial space travel will gradually become popular, the cost will gradually decrease, one day, ordinary people can also have the opportunity to go to space, that is to say, although we did not realize the dream of becoming an astronaut as a child, but there is still a chance to travel to space. Since we all have the opportunity to travel to space, there is a question that has to be considered, and that is whether space travel is dangerous?
There is no doubt that space travel is of course dangerous, and since human beings began to try to leave the earth, 21 astronauts have sacrificed their precious lives for the cause of spaceflight, which alone can fully prove that space travel is dangerous.
But the sacrifices of astronauts can all be attributed to various accidents, so if accidents are excluded, is space travel still dangerous? Yes, the real danger of space travel is not in the accident, but in the travel itself, and the reason why we say so is because we are all earth species, not space species, that is, the environment of space is not suitable for us. There is an idiom in China, "Southern Orange And Northern Orange", which means that the orange in the south will become a citrus tree when transplanted north of the Huai River, which fully illustrates the great influence of the environment on a species.
So how is the environment in space different from the environment on earth's surface? One of the biggest differences is gravity, and the weightless environment will cause many changes in the human body, one of which is the loss of red blood cells.
Since humans began manned spaceflight, a phenomenon known as "space anemia" has been discovered, and the so-called space anemia is the loss of red blood cells in the blood of astronauts. When this phenomenon was first discovered, the problem was not taken seriously, because scientists naturally believed that the decrease in the number of red blood cells was caused by changes in body fluids. That is to say, in the weightless environment, the body's body fluids will change, so in order to maintain balance, the number of red blood cells has also decreased accordingly, but is this really the case?
With the development of manned spaceflight and the advancement of commercial space travel, scientists began to pay more attention to human health in weightless environments, so the problem of reducing the number of red blood cells in astronauts returned to the scientists' vision.
In this context, Canadian researchers launched a study to track and observe astronauts on missions on the International Space Station, and a total of 14 astronauts participated in the study. So how do researchers get data on astronauts' red blood cells? Regardless of whether it is under the microgravity environment, the red blood cells in the human body are constantly destroying and regenerating every moment, while on the surface of the earth, the average person's red blood cells are destroyed at a rate of about 2 million per second, and the destruction of red blood cells will produce carbon monoxide, so it is only necessary to pass the carbon monoxide respiration test to grasp a person's red blood cell destruction data.
The researchers conducted a 6-month follow-up study of the astronauts, and found that the speed of red blood cells destroyed by astronauts in the microgravity environment reached 3 million per second, which is more than 150% of the normal situation on Earth.
So will this situation improve when astronauts return to Earth? Yes, but the process is quite lengthy. According to research data, a year after astronauts return to Earth, the rate of destruction of red blood cells can reach 2.6 million per second, which is still 130% of normal. And the longer you stay in microgravity, the slower the recovery process becomes. More importantly, the researchers found that the acceleration of the destruction of red blood cells is not due to the reduction of body fluids.
Indeed, in a microgravity environment, the total amount of blood in the human body decreases, and the distribution within the body changes, so it sounds reasonable to reduce red blood cells to compensate for the loss of blood volume, but it is not.
Researchers found that the loss of red blood cells did not keep the composition of human blood in balance, and even if they stayed in space for a long time, all the red blood cells in the human body were replaced by those born in space, and the destruction rate of red blood cells themselves continued unabated, which showed that humans as natives of the earth are still difficult to adapt to the environment of space. So if humans want to become a space species, they must first change the environment of space, of course, it is impossible to change space, but we can create a home in space, such as a space station or spaceship with a gravity simulation system, which is the disc-shaped and constantly rotating guys in science fiction movies.