The Hubble Constant

The main way that astronomers measured these great distances and connected them with the expansion way of the universe was using thesesepi ables. At the time when we started he key project, we still didn't know the value of the hubble constant or the expansion rate to better than a factor of two. And so in the 19 seventys, 19 eighties, those were the kinds of arguments that astronomers were having within the field. So at the current time, i would say we we have aae Know it t better than five percent. I we know that if we want to say, without any quibbling about it at all, we know it fi present.