Clues to the Past

Human beings have short memories. But Earth's memory is very long.

Geologists can find clues to Earth's past in sedimentary rocks. The layers of material and their chemical components tell us something about the environment at certain times, similar to the way the rings of a tree can indicate periods of drought or heavy rainfall during the tree's lifetime.

Relative to the lifetime of planet Earth, our human existence has been like the blink of an eye. We have barely lived long enough to create a thin sedimentary layer for future scientists to study. What would that layer consist of anyway? Plastic, cell phone components, coffee pods? When we're gone, what will be left and what will those leftovers say about this timeframe?