Murchison Meteorite Reveals 7-Billion-Year-Old Stardust Grain, Earth's Oldest Known Solid
Updated
Updated · spacedaily.com · Aug 10
Murchison Meteorite Reveals 7-Billion-Year-Old Stardust Grain, Earth's Oldest Known Solid
2 articles · Updated · spacedaily.com · Aug 10
Summary
A silicon carbide grain extracted from the Murchison meteorite was dated to about 7 billion years old, making it the oldest solid material yet identified on Earth.
Researchers led by Philipp Heck isolated the microscopic grain by dissolving meteorite material in acid and dated it from neon-21 isotopes created by cosmic-ray exposure in interstellar space.
The grain formed in the outflow of a dying star more than 2 billion years before the Sun ignited, while the meteorite that carried it is much younger at about 4.6 billion years old.
Analysis of 40 presolar grains from Murchison, published in 2020, suggested some material is 5 billion to 7 billion years old and hinted at a burst of star formation around 7 billion years ago.
The 1969 Murchison fall in Australia remains a cornerstone of cosmochemistry because its rare carbonaceous material also preserved abundant extraterrestrial organic compounds and other presolar grains.