Last year I posted an ode to the Anthropocene -- the period in Earth's long history when humans are the dominant geological force. That would be the last 20,000 years or so. One anthropocenic question brought up by Jan Zalasiewicz, a geologist from the University of Leicester, is, as he puts it, "What Legacy Will Humans Leave in the Rocks?." He speculates that we'll leave fossil cities as the debris of our civilization is pressed into rock.
Reader Brett Lovgren was reminded on this on a walk along Wassenaar Beach in the Netherlands a few weeks ago. He tells me: "We were on a field trip with my son's 2nd grade class from the American School of the Hague. His science teacher had them identifying the shells, jellyfish and seaweed that wash up on the beach. The kids found this bit of barnacle encrusted plastic cup. It made me feel like an archaeologist from the future discovering a layer of the Technium."