We thought we knew it all: icy asteroids, catastrophic impacts, boiling primordial pools. But no. A small meteorite collected in the Antarctic ice has decided to rewrite the tale of the origin of water on Earth.
Scientists fromOxford University they discovered that we do not have to thank asteroids for our glass of water, but the very material that formed our planet. A low blow to the theories we liked so much. But, as often happens, the truth is stranger than fiction.
The discovery starts from a space rock, the meteorite LAR 12252, a seemingly insignificant pebble collected in Antarctica. Under the lens of the most advanced technology, this stone has revealed itself as a living archive of the very first Earth, a treasure chest of forgotten truths about the origin of water. The results were published in the journal Icarus.
Hydrogen, the secret ingredient of the origin of water
Not the one that came from who knows where, but the one trapped in the bowels of the primordial matter that built the Earth itself. Thanks to the XANES spectroscopy, a technique that allows us to peek into the most intimate chemical bonds of matter, scientists have identified enormous quantities of hydrogen sulfide in the fine matrix of the meteorite.
“The presence of hydrogen sulfide in the matrix material suggests that hydrogen was already an integral part of the building blocks of the Earth.”
No contamination from external agents, no cosmic “gift”. Only the confirmation that the origin of terrestrial water already had all the necessary ingredients from the beginning. A lesson in humility for those who, for years, have told of epic asteroid rains as bearers of life.
Goodbye to the “cosmic shower” theory?
Of course, the dominant theory until yesterday sounded almost poetic: Earth's water as a gift fallen from the sky, carried by wandering asteroids. A fascinating idea, certainly, but apparently it could turn out to be completely wrong.
“The formation of water on Earth was a natural process, not a chance event due to extraterrestrial impacts.”
Discovering that the origin of water was already written in the primordial dust changes everything: it tells us that water (and perhaps life itself) could be much more common in the universe than we imagined. It doesn't take a stroke of luck from space, just the right chemical mix, the right primordial soup.
And while we fantasized about celestial knights on a mission to bring us water, the truth was much simpler… and, ultimately, even more extraordinary.
