# Tag Info

They are very sparse. Typical densities are in the range of 100 to 10,000 particles per $\textrm{cm}^3$. This is much more dense than the general interstellar medium (1 particle per $\textrm{cm}^3$), but much, much less dense than anything you are used to - air is around $10^{19}$ particles per $\textrm{cm}^3$. You would very easily see your own hand in a ...