Meteorites barely helped fill Earth's oceans, NASA finds
Turns out, meteorites didn't bring much water to our planet.
A new NASA study, using Apollo moon samples, shows that only a tiny bit of Earth's ocean water came from space rocks—even over billions of years.
How the study worked
Scientists analyzed moon dust collected by six Apollo missions, looking for signs of meteorite material.
Even after scaling up for Earth's higher impact rate, they found meteorites added almost no water compared to what was already here.
So where did all the water come from?
The Moon-based record makes it hard to reconcile late meteorite delivery as the dominant source of Earth's oceans.
As co-author Justin Simon put it, "They say the Moon's long-term record makes it very hard for late meteorite delivery to be the dominant source of Earth's oceans."
Future Artemis missions might reveal even more about how our oceans really formed.