Water May Have Come To Earth From Meteorites, Say Scientists

Meteorites may have delivered water to Earth from the outer Solar System throughout its 4.5 billion years history—and may still be doing so.

That’s the suggestion from a new paper published in Science, the academic journal of the American Association for the Advancement of Science.

That meteorites may have brought water to Earth early in its history is not a particularly controversial claim, but this new research suggests that instead of halting billions of years ago the process may be ongoing.

The researchers studied carbonaceous chondrite meteorites, leftover building blocks of the Solar System, and found that they within the last million years they had liquid flowing across them.

Carbonaceous chondrite meteorites are from ancient parent bodies orbiting in the outer Solar System beyond the orbit of Jupiter, which have been largely undisturbed since its formation.

The scientists—led by Simon Turner at Macquarie University in Sydney, Australia—examined carbonaceous chondrite meteorites collected from around the world.

To find signs of recent liquid flow they searched for uranium and thorium isotopes. Why? Since uranium is water-soluble, it can be transported by liquids, but it radioactively decays into thorium, which is immobile. Their signature should disappear within a million years, due to radioactive decay, but that wasn’t the case on some of the meteorites.

Their conclusion is that the meteorites parent bodies out in the Solar System still contain water or methane liquids, probably because ice melted in the parent bodies during the very collisions that broke-off the meteorites.

That in turn suggests that the meteorites could have been delivering water to Earth throughout our planet’s history.

Wishing you clear skies and wide eyes.