Above the table on which the chattering telefax set was a mirror. In it she saw a woman neither young nor old, neither mother nor daughter. They had … - Carl Sagan

She had spent her career attempting to make contact with the most remote and alien of strangers, while in her own life she had made contact with hardly anyone at all.

Occasionally, I get a letter from someone who is in “contact” with extraterrestrials. I am invited to “ask them anything.” And so over the years I’ve prepared a little list of questions. The extraterrestrials are very advanced, remember. So I ask things like, “Please provide a short proof of Fermat’s Last Theorem.” Or the Goldbach Conjecture. And then I have to explain what these are, because extraterrestrials will not call it Fermat’s Last Theorem. So I write out the simple equation with the exponents. I never get an answer. On the other hand, if I ask something like “Should we be good?” I almost always get an answer.

There is an idea - strange, haunting, evocative - one of the most exquisite conjectures in science and religion. It is entirely undemonstrated; it may never be proved. But it stirs the blood. There is, we are told, an infinite hierarchy of universes, so that an elementary particle, such as an electron, in our universe would, if penetrated, reveal itself to be entire closed universe. Within it, organized into the local equivalent of galaxies and smaller structures, are an immense number of other, much tinier elementary particles, which are themselves universe at the next level, and so on forever - an infinite downward regression, universes within universes, endlessly. And upward as well. Our familiar universe of galaxies and stars, planets and people, would be a single elementary particle in the next universe up, the first step of another infinite regress.

Because it is clear from the fossil record that almost every species that has ever existed is extinct; extinction is the rule, survival is the exception.