# Distance between molecules in outer space

I read that space has a pressure of about $$1.322*10^{-11}$$. I am curious to know how far apart molecules are from each other because of this extremely low pressure.

• Feb 27 at 15:37

It depends what exactly you mean by 'space'. In our solar system (interplanetary medium) the particle density is about $$10-100/cm^3$$ so the atoms/molecules would be a few millimeters apart. In interstellar space it is similar but the density can be less or more depending on where you are (see https://en.wikipedia.org/wiki/Interstellar_medium#Interstellar_matter ). In intergalactic space the density is even much less, about 1 particle per $$m^3$$, so there the particles are about 1 m apart.