To test this new theory, Stewart’s lab gets to play with cannons. By shooting rocks and minerals at one another, researchers can learn more about how celestial bodies might behave in collisions and reconstruct how our solar system was formed.

The new Moon-formation theory would explain why its composition is so similar to the Earth’s. The high temperatures—some 4,000 to 6,000 degrees Fahrenheit—at which the Moon formed vaporized certain elements while leaving others intact.

Stewart tells The Sacramento Bee that she was in shock after getting the “genius grant” call from the MacArthur Foundation. “It took a couple hours for my hands to stop shaking,” she said.

📬 Sign up for the Daily Brief

Our free, fast, and fun briefing on the global economy, delivered every weekday morning.