Asteroid sample reveals life's origin

A 'briny broth' may unlock the secrets of life on Earth... and further afield

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Atiny piece of space rock has revealed that life on Earth may have come from an asteroid and hints that extraterrestrial life could be more likely than we thought.

Five years ago, a daring NASA mission named OSIRIS-REx saw a probe visit Bennu, an asteroid on a near-collision course with Earth, and collect a small sample of it. In late 2023, a capsule containing 120g (4oz) of the asteroid landed in the Utah desert, in the US.

Ever since, the world has been waiting to hear what the capsule held. Now, scientists have confirmed that the asteroid not only carries organic matter, but all of the ingredients that make up DNA.

Bennu – an object currently travelling around the Sun in an orbit close to Earth – is an ancient fragment of the Solar System. Its parent asteroid is thought to have formed around 4.5 billion years ago.

“We now know from Bennu that the raw ingredients of life were combining in really interesting and complex ways on Bennu's parent body,” said Dr Tim McCoy, curator of meteorites at the Smithsonian's → National Museum of Natural History, in the US, and the co-lead author on one of the new papers that announced the findings.

The breakthrough suggests that life formed on Earth after an asteroid collision, but it's also a sign that on Bennu's parent body or through other asteroid collisions, life has all it needs to begin elsewhere.

SOUP OF LIFE

The most crucial finding is that Bennu seems to have hosted a 'briny broth' that allowed minerals and salts to intermingle. It's this concoction that developed into the complex structures that form the fundamental ingredients of life.