Simulating Kilometer-Size Asteroid Impacts on Earth
NASA and partners are developing the means to protect Earth from dangerous asteroids. Part of that work is understanding the extent of damage an impact would cause. Previous work has studied smaller asteroids that mostly explode in the atmosphere, like the Chelyabinsk meteor in 2013, which—even if detected in time to deflect it—would probably be allowed to hit if not striking near a populated area. Engineers at NASA’s Ames Research Center are running supercomputer simulations to investigate hypothetical kilometer- or mile-wide-size asteroids that would have the potential to devastate an entire country. As seen in observations from the 2022 Hunga-Tonga volcano eruption, the blast wave from the impact of such a large asteroid can be channeled by the atmosphere and decay less slowly than smaller explosions. Simulations and observations from the 1994 Shoemaker-Levy-9 comet both show that hot gas plumes can rise above the atmosphere and collapse back down to form a layer of hot gas that can bake the land below over a much larger area than just the hot plume from a smaller impact. Previous models predicted that impacts this size would not cause global extinction, like the Chicxulub impact 65 million years ago that killed the dinosaurs. Dust and smoke injected into the atmosphere are at the onset of where the climate could be affected enough to reduce crop yields, but effects on crops are highly dependent on weather at the time of impact.
Quick Facts
Thankfully, there haven’t been any large meteor impacts with Earth in recent history, but this means we don’t have good observational data from a large impact. NASA’s supercomputers allow us to simulate the impacts and determine the effects to improve the accuracy of our predictions. This work would not be possible without them.
- Simulations are run on the Pleiades, Electra, and Aitken supercomputers at the NASA Advanced Supercomputing facility, and use anywhere from 40–4,000 processors, and hours to weeks of runtime. Researchers used the ALE3D hydrocode from Lawrence Livermore National Laboratory, and the Ash3D fallout model from the U.S. Geological Survey.
- Simulation results show the extent of damage from the hypothetical asteroid impact. A surprising finding was that the blast wave alone can cause tsunami waves around the globe even if the asteroid doesn’t hit an ocean. This was seen from shock waves in the 2022 Hunga-Tonga submarine volcanic eruption.
- The extent of damage results will be used to suggest areas for evacuation to U.S. and international agencies, and estimate the cost of damage.
- Next, the Ames team will compare how the damage changes with impact location, as future mitigation methods may allow the impact location to be changed. If the warning time is too short, in-space deflection techniques may not be able to move the asteroid to a trajectory that misses Earth, but might be able to move it to somewhere less populated and damaging.
Researchers
- Darrel Robertson, NASA Ames Research Center Please enable Javascript to see email address.
- Larry Mastin, U.S. Geological Survey Please enable Javascript to see email address.
