A common equation (attributable to Fred Hoyle) for the mass of the observable universe is: c3/(2GH0). Despite that the whole universe is vastly larger than the observable universe, we can create an equation to calculate the mass of the observable universe, using the standard constants of nature, namely c, G, and H. If you think about it, the ability to calculate the mass of the observable universe is interesting. How is it that these constants give us the mass of the observable universe, instead of the whole? You might expect that these constants would be related to the whole universe, not some tiny fraction of it. To get the mass of the whole universe, we would have to scale up one or more of these three constants, substantially, suggesting that one or more are actually scaled to the size of the observable universe. What are the thoughts you Physics Forums people on this?