Scientists have long debated how much of Earth’s material came from the outer solar system. Many earlier studies suggested a substantial share might come from beyond Jupiter. To test this, Paolo Sossi and Dan Bower at ETH Zurich re‑examined existing data on isotopic ratios in a wide range of meteorites, including samples from Mars and Vesta.
Isotopes are atoms of the same element that differ in mass. The team used data from ten isotopic systems and a specialised statistical method; previous work had mostly used only two systems. With this broader data set, the researchers reached a clearer conclusion.
They find that the material that makes up Earth originates entirely from the inner solar system. Material from the outer solar system is likely to be very small or absent. The study appears in Nature Astronomy and finds no strong evidence for large-scale exchange of material across Jupiter.
The authors note that Jupiter probably acted as an early barrier, and they plan to study why the hot inner system had enough water and whether similar processes apply to other planetary systems.
Difficult words
- isotope — atoms of the same element with different massIsotopes
- meteorite — rock from space that reaches a planetmeteorites
- isotopic ratio — comparison of amounts of different isotopesisotopic ratios
- statistical method — way of using data to find patterns
- originate — come from a particular place or sourceoriginates
- barrier — something that blocks movement or progress
- exchange — movement of something between two places or groups
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Why is it important to know whether Earth material came from the inner or outer solar system?
- How might an early barrier like Jupiter affect the amount of water on Earth?
- Do you think similar processes could happen in other planetary systems? Why or why not?
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