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Gravitational theory says every thing that has mass attract each other. So why don't people attract each other and overlap

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closed as unclear what you're asking by Cosmas Zachos, SRS, Kyle Kanos, Jon Custer, GiorgioP Apr 5 at 22:19

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  • $\begingroup$ You should notice that in order to have overlapping, you don't even need to have an attractive force. People can just run into each other and overlap. This doesn't happen due to the fact that matter is made out of Fermions which have an anti-symmetric many-particles state. Or, in other words, they follow the Pauli exclusion principle. See: en.wikipedia.org/wiki/Pauli_exclusion_principle $\endgroup$ – Dvij Mankad Apr 3 at 14:25
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They do attract. Just with very little force.

The entire planet Earth pulls in you with only some $\sim 800 \;\mathrm N$ of gravitational force. So, you can imagine how small the pull is from the tiny mass of another person. You can calculate it with the formula:

$$F_g=G\frac{m_1m_2}{r^2}$$

where $G=6.67 × 10^{-11} \mathrm{\frac{m^3}{s^2kg}}$. $r$ is the distance and the $m$s are the masses of you and the person. Just stand one meter apart and plug in the masses in this formula. You might get a force in the order of one-billionth of a Newton. You can blow at people with a larger force than that, so it is simply not detectable in practical circumstances. It will have to be measured with very delicate methods and tools; for instance have a look at the Cavendish Experiment which might even be possible to perform in your own bedroom.

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    $\begingroup$ +1: The OP asked as to why they don't attract and overlap. I think you might want to say "They do (attract)" to avoid implausible but possible confusion. $\endgroup$ – Dvij Mankad Apr 3 at 14:28
  • $\begingroup$ Thanks @DvijMankad, good point, added. $\endgroup$ – Steeven Apr 3 at 14:32
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    $\begingroup$ Re, "very little force," Yeah, very little force between two people, but gravitational interactions are mutual. Your body attracts the whole Earth with exactly the same force as the Earth's attraction to you. $\endgroup$ – Solomon Slow Apr 3 at 16:36
  • $\begingroup$ @Steeven Since the force is insignificant, relative acceleration is also. And there is also friction which is stronger between our feel and the ground. $\endgroup$ – SRS Apr 4 at 9:00
  • $\begingroup$ @SolomonSlow Indeed $\endgroup$ – Steeven Apr 4 at 9:02
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First, gravity is too weak, we don't have significant gravitational fields enough to pull other people towards us... although there is a very small gravitational tug between two people. The reason why people do not overlap, or even other objects merging into each other, is due to electrostatic repulsion.

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