Welcome to the “Anthropocene” — a new epoch in our planet’s 4.5 billion year history. Thanks to the colossal changes humans have made since the mid-20th century, Earth has now entered a distinct age from the Holocene epoch, which started 11,700 years ago as the ice age thawed. That’s according to an argument made by a team of scientists from the Anthropocene Working Group. Scientists say an epoch ends following an event – like the asteroid that demolished the dinosaurs and ended the late Cretaceous Epoch 66 million years ago – that altered the underlying rock and sedimentary layers so significantly that its remnants can be observed across the globe. In a paper published Thursday in Science, the researchers presented evidence for why they think mankind’s marks over the past 65 years ushered in a new geological time period. Here are a few examples: