1. Most of the atoms in the universe are not in stars but in ionized gas in intergalactic space. The Milky Way has mass in its stars equivalent to 50 billion Suns (5 x 10^10 Msun). If the gas in the intergalactic medium only has a density of one proton per cubic meter, about how big a volume of intergalactic space would you need to have to equal the mass of the Milky Way? (There are about 10^57 protons in the sun.) 2. v = m/d 3. Where I'm going wrong...being too tired, too frustrated, or too annoyed to figure out conversions. I know I have to find the volume, and I know I have the mass and density. But I have no idea where to begin in terms of figuring out what exactly the density is based on knowing the gas in the intergalactic medium "only has a density of one proton per cubic meter." I determined the hypothetical mass (50 billion times the mass of the sun) to be 9.9455 x 10^40, by the way...but again, am just too braindead to come close to figuring out the volume conversion. We never went over this in class, it has very little to do with what we're studying at this moment, but my professor always includes random hypotheticals on our homework because he is satan. Once I am pointed in the right direction in terms of figuring out the volume, it will be clearly very easy to solve because it's basic division, so if someone can help me figure out how to convert the density into something that's actually useful, I will cyber high five you so hard.