In a twist to last year’s excitement over organic compounds found in samples from the asteroid Ryugu, researchers from Imperial College London have revealed that microbial life discovered in the samples likely originated from Earth.
Hayabusa2 retrieved samples from Ryugu in 2019, returning them to Earth in 2020. Scientists initially believed these samples could provide insights into life’s origins on Earth or confirm asteroids as possible seeders of life. However, microscopic “rods and filaments” discovered in the samples, identified as terrestrial microorganisms, grew over time, indicating active colonization.
The samples were transported and analyzed under highly controlled conditions, including a hermetically sealed chamber, nitrogen-purged clean rooms, and sterilized tools. Despite this, the resilience of Earth-based microorganisms underscores how easily contamination can occur, even with extreme precautions.
The study cautions against premature conclusions in future missions, as Earth-based biota may inadvertently infiltrate extraterrestrial samples, complicating efforts to identify evidence of extraterrestrial life.
The findings were published in Meteoritics & Planetary Science.
