Scientists have determined that a person will not be able to move effectively with a gravity that is four times the earth's. They made this conclusion thanks to the model of increased gravity, in which a person can be, for example, on an exoplanet. The work is posted on the arXiv.org preprint server.
Astronomers consider a planet to be habitable based largely on the properties of its atmosphere and the distance it is from the nearest star. If we are talking about hypothetical human colonization, then other factors come to the fore. In particular, possible unfavorable parameters of the atmosphere can be overcome with the help of spacesuits, but humanity has not yet learned how to control gravity. In the new work, scientists from the University of Zagreb (Croatia) defend the point of view that, first of all, it is gravity that should be taken into account when considering the possibility of human survival.
The authors examine how well a trained athlete's body will be able to withstand the constant effects of increased gravity. Physicists first estimated the maximum tension that occurs in the bones while running. It turned out that the human skeleton begins to break under the weight of the body under gravity, which is ten times the earth's. Also, scientists have determined the boundary conditions, after which even a very developed musculature will not allow a person to stand up. They corresponded to the five earth gravity. Separately, scientists estimated how much energy a person would spend on movement, taking into account the capabilities of the strongest people. It turned out that gravity 4.6 times that of the earth will not allow even such people to walk.
A separate problem in such conditions is that the blood will rush to the legs, and an additional load will be imposed on the heart due to the fact that it will have to raise blood to the upper body. Having analyzed the capabilities of the body from this point of view, scientists have established the most stringent limitation: gravity must not exceed four Earth's. The authors write that these circumstances reduce the number of planets potentially suitable for colonization, since gravity is the only environmental factor that a person can not overcome.