SAN ANTONIO — June 8, 2026 — Southwest Research Institute scientists modeled the early impact history of Earth, seeking insight into potential origins of life. These models show that asteroid impacts on the early Earth plowed up surfaces and generated hydrothermal systems, environments where life could have evolved.
The team used a shock physics code that integrates how impacts fracture hard materials and generate porous environments, allowing the first comprehensive study to quantify impact-generated permeability. These conditions allowed water to flow through in the upper crust of the early Earth.
"This modeling is both novel and crucial for understanding the earliest environments life may have emerged from," said SwRI's Amanda Alexander, first author of an AGU Advances article about this research. "While often considered catastrophic in the context of dinosaur extinction, impact bombardment was also likely critical for creating environments for prebiotic chemistry."
The Earth formed around 4.5 billion years ago followed by a calamitous time characterized by intense bombardment. Hypervelocity impacts fragmented large volumes of underlying rock while also vaporizing and launching molten rock across the landscape. Intense heating from the impact, coupled with the background geothermal gradient of the Earth's interior, could allow hot fluids to circulate through the fractured crust. The resulting hydrothermal systems — comparable to the network of geysers around Yellowstone National Park — may have provided the environment for the origin and evolution of early life on Earth.
The modeling allowed the scientists to simulate asteroid impacts of different sizes and velocities hitting the Earth, while also varying the temperature conditions and crustal compositions. The team then calculated the volume of crust impacts made permeable by fractures to understand fluid flow for each case.
Each individual impact during this phase of bombardment may have generated up to 100 times the hydrothermal activity currently present in modern-day Yellowstone geography.
"Because life could have originated or evolved in hydrothermal environments, it is important to understand and quantify the generation of these systems by impacts on the early Earth," Alexander said, emphasizing that researchers will need to refine the data for a clearer understanding of the hydrothermal systems.
The simulations suggest that the volume of impact-induced permeable regions depends strongly on impact energy, determined by impactor size and velocity. The range of generated permeability within those regions, however, depends on the geothermal gradient and crustal composition. The models also considered the frequency of impacts.
"Using a bombardment history model to infer the cumulative effects of recurring impacts, we estimate that the upper 5-mile (8-kilometer) shell of the Earth's crust likely was highly permeable 4.3 billion years ago and that a significant portion of this volume may have remained permeable until 3.5 billion years ago," Alexander said. "These results show that impacts were instrumental in driving hydrothermal changes to the early Earth's crust, with important consequences for the geochemical evolution of near-surface environments."
To read the AGU Advances paper titled "Widespread Impact-Induced Crustal Permeability on the Early Earth," go to https://doi.org/10.1029/2025AV002097 .
