Earth and Mars Formed in Fundamentally Different Ways, Study Finds

Researchers at the University of Copenhagen analyzed volatile elements in the mantles of Earth and Mars and concluded the two planets grew through very different processes. At least 75% of Earth's mass came from pebble-accreting protoplanets, while roughly three-quarters of Mars' mass came from planetesimals.

• At least 75% of Earth's mass came from pebble accretion, planetesimals up to 25%
• About 75% of Mars' mass came from planetesimals, the rest from pebble accretion
• Conclusion based on sodium, zinc and potassium abundances in planetary mantles
• Method is more precise than isotope analysis and could apply to exoplanets