No substance on Earth better represents humanity’s incredible power over the Earth more than trinitite. Trinitite is not a mineral; it has no crystal structure and is not naturally occurring. However, it serves as an important reminder of one of the most terrifying projects in human history. Trinitite is only found in one location, at Trinity Site in New Mexico, where the first atomic bomb was detonated on July 16, 1945. The energy released was so intense that it fused the sand in the area, creating trinitite — a radioactive glassy substance popular with collectors because of its historical significance. Not wanting people to wander onto this location to collect the radioactive glass, the government bulldozed Trinity Site in 1953 and made trinitite illegal to collect. Trinity Site is only open to visitors twice a year, where tourists can come and appreciate the incredible achievement and tremendous consequences of the atomic bomb.

Some geologists suggest that we are living in a new geologic epoch triggered by human modification of the Earth, called the anthropocene. The current epoch, the Holocene, started around 12,000 years ago at the end of the last Pleistocene glaciation period. Jan Zalasiewicz from the University of Leicester supports designating the anthropocene as an official geologic unit, arguing that littered plastics, unnatural materials such as concrete and synthetic compounds, and human activities will change the composition of the rocks that are forming now. However, these are predictions of how rocks will look in the future, not what is currently present.

The idea that humans have altered the Earth so dramatically that rocks are noticeably changing gives reason for pause. While it is certainly interesting and exciting (at least to geologists) to think we are living at the boundary of a geologic epoch, the reality is that there is little chance of this becoming an officially accepted time period. Stanley Finney, the chair of the International Commission on Stratigraphy, and Lucy Edwards, the commissioner of the North American Commission on Stratigraphic Nomenclature, remind us in a recent GSA Today publication that units of geologic time are defined by their content, not their beginnings.  While we may not designate the Anthropocene as an official geologic unit in the near future, the idea that humans have the ability to affect something as seemingly permanent as rock strata is astonishing, and should give us reason to think about our collective global impact.