Huge Asteroids Brought Gold to Infant Earth, Study Says

Pluto-size space rocks may have put precious metals in the mantle.

Scientists have long known that there's a mysterious amount of siderophile ("iron-loving") metals in Earth's mantle. Such metals, including gold, tend to affiliate with iron in their liquid forms.

The best explanation has been that some sort of space object brought the elements to the planet just after it formed its core, but the exact nature of the impactor has been a matter of debate.

Based on computer simulations, the new study says that a small number of enormous, random impacts roughly 4.5 billion years ago are the sources of Earth's iron-loving materials.

These impactors were rocky objects left over from our solar system's planet-formation phase. The largest one that hit Earth was roughly the size of Pluto—up to 2,000 miles (3,220 kilometers)

Unlock this story for free
Create an account to read the full story and get unlimited access to hundreds of Nat Geo articles.

Unlock this story for free

Want the full story? Sign up to keep reading and unlock hundreds of Nat Geo articles for free.
Already have an account?
SIGN IN

Read This Next

Why are these orcas killing sharks and removing their livers?
How to eat in 6 of the world’s most stunning places
Cliff art reveals the majesty of the Amazon’s aquatic realm

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet