Earth’s water must have arrived here earlier than we thought

The arrival of water on our planet is shrouded in mystery. Our leading theory says icy meteorites brought it here after most of the planet and its core had formed, about 4.5 billion years ago. But now an analysis of isotopes from meteorites seems to imply that the wet stuff got here much sooner. Read more.

Tags: Geology Astronomy Ruthenium isotope Ruthenium