Each year, millions of visitors flock to Yellowstone National Park to marvel at its natural wonders. Inside the park, which spans parts of Wyoming, Idaho, and Montana, geysers spray boiling water high into the air next to multicolored hot springs. But Yellowstone’s most unique feature isn’t something people can see—it’s buried 8 kilometers (5 miles) underground.
Gigantic chambers of magma lie hidden beneath Yellowstone. This mixture of melted rock, crystals, and dissolved gases churns underground, providing the heat that fuels Yellowstone’s geysers and hot springs. But the magma chambers aren’t just furnaces for the park’s natural wonders. They’re also the heart of a supervolcano—an extremely large volcano that, if it were to erupt, could change the face of Earth.
Scientists once believed supervolcanoes slowly built up from dormancy—a period of relative inactivity—to an eruption over thousands of years. But a recent study suggests that the time between dormancy and a supervolcano blowing its top could instead be decades. Today, researchers are working to learn more about what’s going on inside the Yellowstone supervolcano to better understand when and how it could erupt.