It’s the oldest meteorite ever found, dating back to nearly 4.6 billion years ago, at a time when Earth didn’t even exist.
Now space rock Erg Chech 002 is shedding new light on what our early system looked like — and the revelations aren’t what scientists expected.
A team of Australian researchers say their research casts doubt on the accuracy of how experts calculate the age of meteorites, suggesting some may not be as old as originally thought.
That’s because they found EC 002 contained more of the radioactive isotope Aluminum-26 (26Al) than other ancient achondrites, or stony meteorites, of a similar age.
This is important because it calls into question the theory that 26AI — thought to be a source of heat for the building blocks of planets — was evenly distributed throughout the early solar system.
Oldest meteorite ever found: Space rock Erg Chech 002 (pictured) sheds new light on what our early system looked like — and the revelations aren’t what scientists expected
The meteorite was discovered in 2020 in the Erg Chech region of the Sahara Desert in Algeria
Experts estimate the age of meteorites based on the amount of 26AI present in them when they formed.
But if the isotope was unevenly distributed across the early solar system, as the new study suggests, it can’t be relied upon to give an accurate indication of how old a space rock is or what role it might have played in the formation of planets.
That contradicts previous research that suggested 26AI was evenly distributed leading up to the formation of planets like Earth.
We know that our solar system was formed about 4.5 billion years ago from a collapsing cloud of interstellar gas and dust, which was likely part of a much larger nebula.
Scientists think its collapse may have been triggered by the shock wave from a nearby supernova, or exploding star, which in turn led to the creation of a solar nebula — a spinning, swirling disk of material from which the solar system formed.
26AI was then vital in the process that led to what we walk on Earth today, as it provides enough heat through radioactive decay to produce planetary bodies with layered interiors like ours.
It also helps dry out early planetesimals, creating water-poor, rocky planets.
Because of its very short half-life of about 770,000 years, scientists believe that 26AI must have formed shortly before the condensation of the first solid matter in our solar system or mixed with the surrounding planet-forming disc of the young sun.
Its existence in EC 002 therefore offers an opportunity to further investigate the initial distribution of the isotope before the formation of the Earth.
Whether the isotope was evenly distributed throughout the early solar system is important in determining the age of meteorites.
Researchers at the Australian National University, led by Evgenii Krestianinov, analyzed EC 002 and determined that the lead isotopic age was about 4.566 billion years old.
The rock is mostly volcanic rock, leading experts to believe it comes from the crust of a very early planet
They combined this finding with existing data on this meteorite and compared it to other very old meteorites that crystallized from melts.
The researchers showed that 26Al had an uneven distribution within the early solar nebula.
For this reason, they said, studies on meteorite chronology should be careful and take a general approach when dating short-lived isotopes responsible for their uneven distribution.
This, the researchers added, would improve the accuracy and reliability of determining the age of meteorites and planetary materials.
Developing a general approach to isotope dating with Al-Mg and other extinct isotope chronometers that takes into account the heterogeneous distribution of the original radionuclide would allow more accurate and reliable age data to be produced for meteorites and asteroid and planetary materials to determine a promote a better understanding of the formation of our solar system,’ the authors wrote.
The meteorite was discovered in 2020 in the Erg Chech region of the Sahara Desert in Algeria.
It’s mostly volcanic rock, leading experts to believe it came from the crust of a very early planet.
A previous study found that the rock was once liquid lava, but cooled and solidified over 100,000 years to form the 70-pound piece that eventually made its way to our planet.
No asteroids with similar properties have been found, suggesting that the protoplanet it came from has since disappeared, either becoming part of larger bodies, or “simply destroyed,” the researchers said.
Other oldest achondrites previously found include NWA 1111942, estimated to be about 4.565 billion years old, and the 4.564 billion-year-old Asuka 88139427.
The new study is published in the journal Nature communication.