Murchison Meteorite
4.60 billion years ago
The rock and the grains have different ages
Murchison belongs to the early Solar System. Some microscopic minerals inside it are older: they formed around earlier generations of stars and survived incorporation into the meteorite. Calling the whole rock “seven billion years old” erases this distinction.
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Murchison belongs to the early Solar System. Some microscopic minerals inside it are older: they formed around earlier generations of stars and survived incorporation into the meteorite. Calling the whole rock “seven billion years old” erases this distinction.
Researchers separate these presolar grains from the surrounding material to examine their composition. Their unusual signatures preserve information about the stars in which they formed.
In the study reported by the Field Museum in 2020, exposure to cosmic rays helped researchers estimate how long grains had travelled before the Solar System formed. Most of the studied grains were about 4.6–4.9 billion years old; some were older. These are estimates for individual grains, not a single age for every fragment.