An ancient cosmic collision that created the moon may have also made life on Earth possible, findings of a new study suggest.
Where Did The Volatile Elements On Earth Come From?
Many of the theories on how life on Earth originated try to explain how the planet got its life-giving elements like carbon and nitrogen.
A popular theory suggests that meteorites brought these elements to Earth, but many scientists do not find the idea of Earth's volatile elements arriving on primitive space rocks completely satisfying.
The isotopic signatures of elements on our planet match up with those of the meteorites known as carbonaceous chondrites, but the ratio of carbon to nitrogen is out of whack.
Chondrites have 20 parts carbon for each part nitrogen, but Earth's non-core materials have a ratio of about 40-1, which is about 20 times greater than those found in carbonaceous chondrites.
Scientists now propose that the crucial elements may have been delivered by something else. In a research published in Science Advances on Wednesday, researchers point at a violent collision between Earth and a Mars-sized object called Theia about 4.4 billion years ago.
The collision, which may have occurred while Earth was still forming, seeded the fledgling planet with the volatile elements needed for life.
Study researcher Rajdeep Dasgupta, from Rice University, and colleagues simulated the collision based on experiments that tested the behavior of nitrogen, carbon, and sulfur during the core formation on a rocky planet.
They ended up with a geochemical simulation that accurately modeled the observations of volatile elements on Earth.
"Our simulation results suggested that the most probable scenario of the origin of carbon, nitrogen, and sulfur on the silicate portion of Earth is where these elements are brought by a Mars-sized (8-10 percent by mass of the present-day Earth) planet merging with the proto-Earth," Dasgupta said.
Violent Collision Also Formed The Moon
Researchers also said the scale of this ancient planetary collision suggests the impact is also the same event responsible for the formation of the moon.
"We connected the dots," Dasgupta said. "Given we are suggesting that carbon, nitrogen, sulfur were established through one of the last giant impacts, it makes sense if the same impact also likely formed the moon."