Fate of the Open Universe

Abstract

One of the major reasons for studying the dark matter mystery is that the fate of the universe depends on how much dark matter there is in it. Since we now have some understanding of the problems involved, we will direct our attention throughout the rest of the book to the fate of the universe. In an earlier chapter we saw that its fate depends on its average density. If it is under a certain critical density it will expand forever; if it is over this density it will eventually stop expanding and collapse back on itself. It is important, therefore, to determine the average density of the universe accurately. And this, in turn, depends on how much dark matter there is. Is there, in fact, enough dark matter to close it (stop its expansion)? As we have just seen, we’re still not certain, but we do know that it is close, and because of this I will discuss both the open and closed universes. This chapter will consider the open universe.