Metallosphaera sedula is a thermoacidophilic archaeon—a microorganism that thrives in extreme environments of intense heat and extreme acidity. Found naturally in volcanic hot springs, this organism is a chemolithoautotroph, meaning it extracts energy purely from inorganic chemical compounds, using carbon dioxide to build its cellular structure. In 2019, astrobiologists made a fascinating discovery: M.
sedula can colonize, consume, and thrive on stony meteorites, such as the famous Northwest Africa 1172 meteorite. When placed on pulverized cosmic matter, M. sedula metabolizes the rich iron and sulfur compounds locked within extraterrestrial mineral structures far more efficiently than it processes terrestrial rocks.
As the archaea feed, they oxidize the iron within the meteorite, leaving behind distinct biochemical signatures and biological biomineralization patterns. This preference for space material stems from the unique, highly porous composition and ancient chemical makeup of meteorites, which provide a rich cocktail of accessible trace metals. Studying M.
sedula's appetite for extraterrestrial rock provides crucial insight into bioweathering processes on extra-terrestrial bodies and tests the boundaries of lithopanspermia—the theory that life could be transported between planets inside meteorites. It also demonstrates how ancient terrestrial organisms might survive using resources available on asteroids or Mars.