MAR 28, 2022 10:00 AM PDT

Earth-forming meteorites may have formed in the outer Solar System

"The cosmos is also within us, we're made of star stuff," Carl Sagan famously stated on his original award-winning TV series Cosmos in 1980. These words encompassed a literal meaning and have stuck with us to this very day.

Our fantastic Solar System is believed to have formed approximately 4.6 billion years ago in a cloud of gas and dust known as the solar nebula. As this massive cloud began to contract, it began to shape and spin, ultimately forming a disk now having our Sun at the center and its family of planets and moons obediently orbiting around it.

While debate ranges on the number of those hundreds of planetary objects that might have had life at some point in history, only one of those objects currently has life, and it’s where this article is being written right now—Earth.

The planet we now know as Earth is believed to have formed partly from carbonaceous meteorites, which are thought to come from asteroids of the outer asteroid belt. A new study in AGU Advances led by researchers at the Earth-Life Science Institute (ELSI) at Tokyo Institute of Technology suggests these asteroidal materials may have formed very far out in the early Solar System then been transported into the inner Solar System by chaotic mixing processes. This is based on findings from meteorites recovered on Earth that lack features currently observed on asteroids in the outer asteroid belt.

The research team first used computer models to produce simulated reflectance spectra—color and brightness—for comparison to telescopically obtained spectra of asteroids in the outer solar system. models indicated that in order to match the asteroid spectra, the starting material had to contain a significant amount of water and ammonia, a relatively low abundance of CO2, and react at temperatures below 70˚C, suggesting the asteroids formed much further out than their present locations in the early solar system.

If true, this study suggests that Earth's formation and unique properties result from peculiar aspects of the Solar System's formation.

As always, keep doing science & keep looking up!

Sources: CNET, American Geophysical Union

About the Author
Master's (MA/MS/Other)
Laurence Tognetti is a six-year USAF Veteran who earned both a BSc and MSc from the School of Earth and Space Exploration at Arizona State University. Laurence is extremely passionate about outer space and science communication, and is the author of “Outer Solar System Moons: Your Personal 3D Journey”.
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