Without celebrating a birthday, the solar system just got hundreds of thousands of years older.
To deduce when its first solid grains formed, researchers analyse structures up to a centimetre across found in meteorites. Such 鈥渋nclusions鈥� were created when gases cooled to form the sun and planets and are among the oldest solids in the solar system.
Now at Arizona State University in Tempe, and colleagues, have analysed inclusions in a meteorite that fell to Earth in north-west Africa in 2004.
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Based on the extent to which uranium-238 and uranium-235 isotopes had decayed into their daughter isotopes lead-207 and lead-206, they say the solar system is 4.5682 billion years old. That鈥檚 between 0.3 and 1.9 million years older than previous estimates, which relied on the Efremovka and Allende meteorites found in Kazakhstan in 1962 and Mexico in 1969, respectively.
Life-friendly planets
It may seem like a trivial distinction for something billions of years old, but it could make a difference when pinning down the conditions that led to the solar system鈥檚 formation, says Bouvier 鈥� and those needed for other life-friendly planetary systems to form.
鈥淪tudies like these help tell us what triggered the formation of the solar system, and how that process occurred,鈥� agrees Ray Burgess, a geochemist at the University of Manchester, UK. 鈥淭hey can tell us how our planet formed, and why it has the structure it does.鈥�
The Allende meteorite is thought to have undergone great heating and deformation before landing on earth. Burgess says that the African meteorite almost certainly experienced fewer disturbances to its isotopic structure, making for more reliable data.
Journal reference: Nature Geoscience, DOI: 10.1038/ngeo941
