Most likely non-self-inflicted natural extinction events for Earth-derived life1. Asteroid or Comet ImpactTime Range: Any time, but significant impacts are statistically expected every few million years.
Details: Large impacts (like the one that caused the dinosaur extinction 66 million years ago) can cause mass extinctions by triggering climate change, fires, tsunamis, and blocking sunlight.
2. Supervolcanic EruptionTime Range: Hundreds to thousands of years.
Details: A supervolcanic eruption, such as the one that formed the Yellowstone caldera, could lead to a "volcanic winter," drastically affecting global climates and ecosystems.
3. Gamma-Ray Burst (GRB)Time Range: Thousands to millions of years.
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