Final answer:
The mean free path of hydrogen atoms in interstellar space is long, on the order of light-years, due to the extremely low density of atoms in such regions. This allows hydrogen atoms to travel vast distances without experiencing collisions.
Step-by-step explanation:
The mean free path of hydrogen atoms in interstellar space is extremely long, on the order of light-years. This is because interstellar space is extremely sparse, with densities of hydrogen atoms ranging from about 0.1 to about 100 atoms per cm³. Therefore, hydrogen atoms can travel vast distances without colliding with another atom, which makes the mean free path significantly larger than what we encounter here on Earth for gas molecules at standard temperature and pressure.
To answer your question, the mean free path of hydrogen atoms in interstellar space is long, in the order of light-years.
In contrast to the mean free path of hydrogen atoms in interstellar space, the mean free path for methane at a temperature of 269 K and a pressure of 1.11 × 10⁵ Pa is 4.81 × 10⁻⁸ m, illustrating the vast difference in conditions between interstellar space and conditions on Earth or in a controlled environment.