In archaeology, context is the basis of many discoveries that are imputed to the deliberate workings of intelligence. If I find a rock chipped in such a way as to give it a sharp edge, and the discovery is made in a cave, I am seduced into ascribing this to tool use by distant, fetid and furry ancestors.

Clearly, enriching the cosmos with heavy elements takes a while. So there's inevitably an interval between the sterile aftermath of the Big Bang and a time when the cosmic chemistry set had enough ingredients to make rocky planets (and squishy biology).

We're not just any star stuff, most of which is humdrum hydrogen and listless helium. Our bodies include fancier ingredients like carbon, oxygen, nitrogen, phosphorous, and a few other herbs and spices.

Seth Shostak Quotes