True, But You Don't Have To Sound So Happy About It

USGS

The BBC has an article on the Chesapeake Bay Meteor Crater: “It carved a crater twice the size of Rhode Island and as deep as the Grand Canyon." This 35-million-year-old asteroid impact wrecked the United States

In the Late Eocene, roughly 35 million years ago, a 5km-wide asteroid smashed into the eastern United States, just off the coast of what is now Virginia. At the time, sea levels were unusually high and the shoreline was more than 100km inland from where it lies today. This meant that the asteroid landed in the ocean, colliding with the carbonate-covered continental shelf that lay beneath. The impact created a crater 85km in diameter and 1.3km in depth, which is twice the size of Rhode Island and as deep as some of the deepest parts of the Grand Canyon!

Another two devastating asteroid impacts are also believed to have occurred during the Late Eocene: the Popigai impact in Siberia, Russia, and the Toms Canyon impact in offshore New Jersey, US.

Several studies have suggested these asteroid impacts may be associated, pointing towards a disturbance in the asteroid belt approximately 35 million years ago that sent multiple giant space rocks hurtling towards Earth.

How devastating was the impact? During the Late Eocene, North America was covered in open woodlands and savannah-like habitats, creating an environment that would have looked a lot like today’s Great Plains.

This environment supported a rich diversity of mammals, including early horses like Mesohippus, strange, cat-like animals called nimravids, and deadly predators commonly known as bear-dogs. Any animals that were living in the immediate vicinity of Chesapeake Bay 35 million years ago would have faced a similar fate to the dinosaurs that were incinerated by an even more devastating asteroid impact 66 million years ago.

Those that weren’t vaporised by the initial impact blast were arguably subject to even worse fates, falling victim to a giant tsunami hundreds of metres high or the many wildfires that erupted along the East Coast. A 2025 study presented evidence of tsunami deposits in the Sandhills of North Carolina, nearly 400km from the impact site!

While it didn’t trigger a global mass extinction and its ecological devastation was largely localised, some research suggests that the impact, along with other impacts that occurred around the same time, may have initiated a long-term pulse of global warming. This warming episode eventually dissipated two million years later, coinciding with the Eocene-Oligocene extinction event.

35 million years? That doesn't sound too frequent, but just in case, how's that asteroid intercept program coming?