Ancient Asteroid Shower Rocked Earth, Mars, and Moon

A study led by the Southwest Research Institute and published in July 2026 links a specific asteroid collision in the main belt to an inner-solar-system-wide bombardment episode that impacted Earth, Mars, and the Moon approximately 800 million years ago. The research connects the catastrophic breakup of the Eulalia parent body near Jupiter's 3:1 mean motion resonance to a massive influx of primitive carbonaceous chondrite fragments that triggered a long-lasting cosmic barrage. The researchers used collisional and dynamical models, along with lunar impact glass data collected during NASA's Apollo missions, to demonstrate how half of the debris immediately entered resonant orbits while another 25 percent gradually migrated over 100 to 150 million years driven by the Yarkovsky effect. Because Earth's plate tectonics, volcanism, and erosion erase craters older than 650 million years, the geologically static surface of the Moon served as a crucial historical archive for inferring the bombardment rates across terrestrial worlds. The findings indicate that for every large impact crater formed on the Moon, Earth experienced roughly twenty impacts of a similar or greater scale due to its larger size and stronger gravity. This ancient bombardment peaked during a period characterized by widespread global cooling and significant shifts in Earth's biosphere, raising the possibility that extraterrestrial impacts drove major environmental and biological changes. On Mars, the intense wave of impacts generated massive seismic shaking and coincided with a surge in subsurface volcanic activity, highlighting how a single catastrophic collision in the asteroid belt can induce far-reaching geological and geophysical consequences across multiple planets in the inner solar system.