Could it not be possible that dark matter could just be heavy gases that are not hot but interact with light like Sulfur Hexafluoride, which could in turn have its own gravity helping hold the universe together. I am just using Sulfur Hexafluoride as an example of a heavy gas but it could be possible for a type of gas we have not yet discovered to have these properties. After the initial Big Bang we started off with gasses that clumped together but if we have gas then surely it is probable to have some sort of anti gas?
