Any Era could end like this.

About 12,800 years ago, the Earth experienced a dramatic turn. As the glaciers melted and the last Ice Age faded into oblivion, a visitor from outer space burst into the atmosphere. It is believed that a large meteorite or a series of comet fragments struck the northern hemisphere. Shock waves, fires, and emissions of ash and soot into the atmosphere may have returned the planet to a frozen state for a millennium, a period called the Younger Dryas. The climate became sharply cold again, ecosystems collapsed, many large animals disappeared, and human cultures, if they existed at the time, were on the brink of extinction. (How did the end of the Pleistocene change the Earth, and what will happen in the future?) 2025