The Rarity of Life in the Universe

I will begin with the unique perspective of astronomy in understanding who we are and our place in the universe. The history of science and especially astronomy may be viewed as an ever increasing awareness that we human beings, and indeed our entire planet, are nothing special in the universe. Then I'll reminisce on the extraordinary progress astronomy has made just in the last century in understanding the nature of the cosmos. At this point, I'll consider a much grander perspective on our specialness or nonspecialness. This grander perspective looks at all life in the universe and considers all forms of matter, both animate and inanimate. Recent astronomical discoveries suggest that the fraction of matter in living form is extremely rare, in both time and space. In space, something like a few grains of sand on the Gobi desert. In time, the "era of life," the duration of time in which life can exist, is only a few powers of ten in the infinite unfolding of an accelerating universe. Finally, I'll consider the philosophical meaning of such a conclusion and the important role played by us grains of sand.