(Photo: The Perseus Cluster of Galaxies; credit: Jim Misti, Misti Mountain Observatory. "Each of the fuzzy blobs in the above picture is a galaxy, together making up the Perseus Cluster.... It takes light roughly 300 million years to get here from this region of the Universe, so we see this cluster as it existed before the age of the dinosaurs.")
The number of external galaxies beyond the Milky Way is at least in the thousands of millions, each of which contains a number of stars more or less comparable to that in our own galaxy. So if you multiply out how may stars that means…It’s something like one followed by twenty-three zeros, of which our Sun is but one. It is a useful calibration of our place in the universe. And this vast number of worlds, the enormous scale of the universe, in my view has been taken into account, even superficially, in virtually no religion, and especially no Western religions.
- Carl Sagan, The Varieties of Scientific Experience. The Penguin Press, 2006, p.27. (The author's 1985 Gifford lectures.)