1. The problem statement, all variables and given/known data Interstellar space, far from any stars, is filled with a very low density of hydrogen atoms (H, not H2). The number density is about 1atom / cm3 and the temperature is about 3 K. Estimate the pressure in interstellar space. Give your answer in Pa and in atm. 2. Relevant equations Average translational kinetic energy per molecule: Eavg = 1.5KbT = .5mv2 p = F/A = (1/3)(N/V)mVrms2 Eth = 1.5nRT pV = nRT 3. The attempt at a solution V = 10-6 m3 T = 3K m = 1u = 1.66x10-27 n = 1.66x10-24 (not sure if this is right?) pV = nRT --> p = 4.14x10-17 Where am I going wrong, or is this correct? Thank you for any help/advice!