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Co‑orbital rocks: Earth has several tiny co‑orbital bodies – objects orbiting the Sun but influenced by Earth’s gravity – some in horseshoe, tadpole, or quasi‑satellite orbits
Lunar Origin? One of these, the 40 m wide asteroid Kamo‘oalewa, has a spectral signature closely matching lunar rocks, suggesting it may be Moon ejecta
Simulated trajectories: Simulations of 54,000 particles launched from the lunar surface show that about 6.7 % become Earth co‑orbitals, with over a quarter evolving into quasi‑satellite paths
Impact site: Kamo‘oalewa likely originated from the Giordano Bruno crater on the Moon’s far side, a relatively young 22 km crater formed about 4 million years ago
Capture conditions: Material most likely becomes co‑orbital if ejected from the Moon’s trailing (western) equatorial region, matching simulation patterns
Mission opportunity: China’s Tianwen‑2 mission launched in May 2025 aims to return a sample of Kamo‘oalewa by 2028, potentially confirming its lunar origin
Broader implications: If confirmed, lunar‑derived asteroids offer a new category of near‑Earth objects, helping refine models of impacts and lunar ejecta dynamics
Scientific value: Studying these Moon‑sourced bodies may deepen understanding of both lunar geology and the origin of small near‑Earth objects
Get the full story in our report on the tiny objects following Earth on its orbit around the Sun
