A group of Spanish scientists found that some exoplanets have a gravity remarkably similar to that of Earth.
In science fiction films, you can often see that the main characters walk on the surface of distant planets just as if they were walking on the Earth: no big jumps, slow motion, not too fast, not too slow … But, for example, they could Star Wars characters walk on exoplanets also?
This is a very good question, especially for science fiction screenwriters, given that exoplanets have different masses and diameters, these two main factors that are responsible for gravity, the answer that most scientists or ordinary mortals would give is "no" …
However, surprisingly, this is not the case. Or at least that's what researchers at the Polytechnic University of Madrid and the University of Valencia think. The results of the study were published in the journal Astrobiology: despite the obvious differences in masses and sizes, many exoplanets known today have gravity similar to Earth.
The article, titled Walking Exoplanets: Is Star Wars Right ?, reveals a curious fact: The modeling of planet formation used cannot explain the dependence of gravity on their type and size.
For their research, scientists analyzed the gravity of exoplanets, which have known masses and diameters of the circle; in total, about 1,200 of the 3,500 exoplanets discovered to date.
Thus, they found that, on the one hand, for small planets of the solar system and planets whose rocky surface is smaller than that of Venus, gravity increases in proportion to the square root of the change in mass, on the other hand, for gas giants it is directly proportional to mass.
But surprisingly, among planets with masses of 1 to 100 Earth masses, gravity is quasi constant.
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The results, which were published by the researchers, are confirmed in our planetary system. Despite the fact that Uranus, Neptune and Saturn are respectively 14, 17 and 95 times the mass of the Earth, their gravity barely fluctuates between 0.9g and 1.1g. That is, just like the gravity of the analyzed planets, they are within the "universal gravitational constant".
According to scientists, "the current models of planetary formation predict not the law of this constant, but a power-law function, whose indicators smoothly increase from solid planets to gas giants."