To create a portrait of the earth in its present state, the Los Angeles artist Clarissa Tossin delved into the depths below its surface. Her Future Fossil (2018), the central sculptural piece that lent its name to her current solo show at Harvard’s Radcliffe Institute for Advanced Study (through March 16), is a six-meter-long, cylindrical cross section of the Earth, as if an enormous pipe had extracted thousands of years’ worth of compacted sediment from its crust. In the gallery, Future Fossil lies on its side like a fallen tree trunk, striped with colors and materials symbolizing different eras: The base is the terracotta color of iron-rich Amazonian soil, followed by a black stripe of the more fertile soil that indigenous peoples cultivated for growing their crops. The opposite tip ends in futuristic materials imprinted with alien patterns with a skin-like, silicon feel. And in between, the bulk of this core sample comprises the bright, synthetic colors of layers and layers of compacted trash.