It is the oldest meteorite ever found, dating back almost 4.6 billion years and from before the earth even existed.
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 study questions the accuracy of experts’ calculations of the age of meteorites, suggesting some may not be as old as first thought.
That’s because they found EC 002 contained more radioactive isotope aluminum-26 (26Al) than other ancient achondrites or stony meteorites of similar age.
This is significant because it challenges the theory that 26AI – thought to be a heat source for the planets’ building blocks – was evenly distributed throughout the early solar system.
Oldest meteorite ever found: The space rock Erg Chech 002 (pictured) sheds new light on what our early system looked like – and the revelations don’t live up to scientists’ expectations
The meteorite was discovered in 2020 in the Erg Chech region of the Sahara Desert in Algeria
WHAT ARE SOME OF THE OLDEST METEORITES EVER FOUND?
– Erg Chech 002: 4.566 billion years old
Found in 2020 in the Erg Chech region of the Sahara Desert in Algeria
– NWA 11119: 4.565 billion years old
Found in Mauritania in 2016
– Asuka 881394: 4.564 billion years old
Found in Antarctica in 1988
Experts estimate the age of meteorites based on the amount of 26AI present in them when they formed.
However, if the isotope was unevenly distributed throughout the early Solar System, as the new study suggests, it cannot be relied upon to give an accurate indication of how old a space rock is or what role it might have played in planet formation.
This contrasts with previous research, which suggested that 26AI was evenly distributed in the run-up to the formation of planets like Earth.
We know that our solar system formed about 4.5 billion years ago from a collapsing cloud of interstellar gas and dust that was likely part of a much larger nebula.
Scientists theorize that its collapse may have been triggered by the shockwave of a nearby supernova or an exploding star, which in turn led to the formation of a solar nebula – a rotating, swirling disc of material that gave rise to the solar system.
26KI was then critical to the process that led to our living on Earth today, as it provides enough heat through radioactive decay to create planetary bodies with stratified interiors like ours.
It also helps dry out early planetesimals to create arid, rocky planets.
Due to its very short half-life of about 770,000 years, scientists believe that 26AI was formed or mixed into the planet-forming disc surrounding the young Sun just before the first solid matter in our solar system condensed.
Its existence in EC 002 therefore offers the opportunity to further explore the original distribution of the isotope before the formation of the Earth.
Whether the isotope was evenly distributed in the early solar system is important for determining the age of meteorites.
Australian National University researchers led by Evgenii Krestianinov analyzed EC 002 and determined its lead isotope age to be approximately 4.566 billion years.
The rock is mostly volcanic rock, leading experts to believe it came 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.
Researchers showed that 26Al was unevenly distributed within the early solar nebula.
Because of this, they said studies of meteorite chronology should be cautious and take a general approach to dating with short-lived isotopes that explain their uneven distribution.
This, the researchers added, would improve the accuracy and reliability of determining the ages of meteorites and planetary materials.
“The development of a general approach for isotope dating with Al-Mg and other chronometers for extinct isotopes, which takes into account the heterogeneous distribution of the parent radionuclide, would allow for the generation of more accurate and reliable dates of ages for meteorites, asteroidal and planetary material in order to gain a better understanding.” to promote it.” 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 is composed mostly of volcanic rock, leading experts to believe that 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 the course of 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 the protoplanet it came from has since disappeared, either becoming parts of larger bodies or “simply being destroyed,” the researchers said.
Other oldest achondrites found so far include NWA 1111942, estimated to be around 4.565 billion years old, and Asuka 88139427, which is 4.564 billion years old.
The new study was published in the journal Nature Communications.
Explained: The difference between an asteroid, a meteorite and other space rocks
A asteroid is a large boulder left over from collisions or the early solar system. Most are located between Mars and Jupiter in the main belt.
A comet is a rock covered with ice, methane and other compounds. Their orbits take them much further out of the solar system.
A meteor is what astronomers call a flash of light in the atmosphere when debris burns up.
This debris itself is referred to as a meteoroid. Most are so small that they evaporate in the atmosphere.
When one of these meteorites reaches Earth, it is referred to as an a meteorite.
Meteors, meteoroids and meteorites usually descend from asteroids and comets.
For example, when Earth passes through a comet’s tail, much of the debris in the atmosphere burns up, forming a meteor shower.