Humans might be trapped on Earth? Scientists: Astronauts' hearts may shrink if they stay in space for too long

I believe you have seen many reports about interstellar immigration in recent years. For example, SpaceX plans to launch a spacecraft to send 1 million people to Mars by 2050 and build a Martian city on the surface of Mars. . The United Arab Emirates also plans to build a Mars city by 2117. From a time perspective, it may be very difficult to immigrate to Mars in the next 30 years, but it may still be feasible to immigrate to Mars in the next 100 years. However, humans may face many problems before reaching Mars, some of which may cause humans to be trapped on Earth.

According to a scientific report published in the American magazine "Circulation" on March 29, 2021, researchers from the University of Texas in the United States conducted a study on American astronaut Scott Kelly and long-distance swimmer Benoit Lecon. Studies have been conducted on special heart conditions and found that if humans stay in space for a long time or swim endurancely for a long time on earth, the heart will shrink.

Scott Kelly, the American astronaut who has stayed in space the longest, has lived in the International Space Station for nearly a year. During his flight in space, Scott Kelly’s ventricular weight decreased by 19%. % to 27%. Swimmer Benoit Lecomte once tried to cross the Pacific. Although his attempt to cross the Pacific failed, he swam a distance of 2,821 kilometers in the past six months, with an average swimming time of nearly 6 hours a day. During the crossing, Benoit Noir-Lecomte's left ventricle lost 20 to 25 percent weight.

In this study, both subjects lost weight in their ventricles. How did this happen? If humans want to immigrate to Mars in the future, the space flight time may also be very long. It stands to reason that the hearts of these astronauts going to Mars will also experience ventricular weight loss. Will these problems pose a threat to the astronauts' health? Will this one problem lead to humans being trapped on Earth forever?

Benjamin Levine, a professor of internal medicine at the University of Texas who participated in this study, said that our human hearts have very strong adaptability. When we humans enter the weightless environment of space, our hearts will Shrink to adapt to changes in space gravity. Although swimmer Benoit Lecomte was not flying in space, his heart would also experience similar shrinkage because he would offset part of the gravity by swimming in the water for a long time. Although the study found that their hearts had shrunk, no side effects of heart atrophy were found, and all functions were still normal.

In addition to discovering that astronauts’ hearts shrink during long-duration space flights, scientists have also discovered that astronauts’ brain structure and function will also change. According to a research report published in Science Advances, scientists studied and analyzed the brain structure of 11 astronauts. The average continuous stay time of these astronauts living and working in the International Space Station was 171 days. Before these astronauts entered space, the researchers performed diffusion magnetic resonance imaging on these astronauts. After returning to Earth, the researchers also performed two diffusion magnetic resonance imaging on these astronauts. Study the changes in the brains of astronauts under different circumstances before entering space and after returning to Earth. The results showed that when these astronauts were in the microgravity and low-gravity space environment for a long time, the distribution of white matter and gray matter in their brains changed, and the brain ventricles expanded and cerebrospinal fluid increased.

The reason why astronauts’ brains undergo such changes is similar to the heart condition mentioned above. When astronauts enter the microgravity and zero-gravity space environment, the nervous system will undergo These changes are adapted to the space environment. Although the brain structure and function of these astronauts will undergo certain changes, they will return to normal levels a few months after they return to Earth.

Judging from these studies, when astronauts fly to Mars and other alien planets in the future, their bodies may undergo similar changes when they are in a zero-gravity environment for a long time. However, when they arrive on the alien planet, these changes will Changes may revert to adapting to alien environments. So even though there may be changes that we don't expect, they won't be enough to keep us humans stranded on Earth. Moreover, in the future we humans may develop spacecraft that can generate gravity similar to that of the earth's surface. In these spacecrafts, we can live and work just like we do on the earth's surface, and these physical problems mentioned above will be avoided.