A team of researchers has discovered a rare and ancient meteorite in the Sahara Desert that could shed new light on the formation and evolution of our solar system.
The meteorite, named Erg Chech 002, is the oldest volcanic rock ever found, dating back to 4.56556 billion years ago when the solar system was only a few million years old.
The researchers, led by Evgenii Krestianinov from the University of Manchester, published their findings in Nature Communications1. They used a combination of uranium and lead isotopes to determine the precise age of the meteorite, which is one of the most accurate measurements ever made for an extraterrestrial object.
The meteorite is composed of fragments of an ancient protoplanet, a small body that was one of the building blocks of the planets we see today. The protoplanet was heated by the radioactive decay of aluminium-26, a short-lived isotope that was abundant in the early solar system. This heat caused the protoplanet to melt and form a magma ocean, where different minerals crystallized and separated into layers.
One of these minerals is called plagioclase, which forms distinctive greenish crystals that are visible in Erg Chech 002. The researchers found that these crystals have a high concentration of aluminium-26, which indicates that they formed very early in the history of the solar system before most of the aluminum-26 had decayed into magnesium-26.
The researchers also compared the aluminium-26 content of Erg Chech 002 with other meteorites from different groups and origins. They found that there was a significant variation in the amount of aluminium-26 among these meteorites, which suggests that this isotope was not distributed evenly throughout the solar system. This challenges the assumption that aluminium-26 was a uniform heat source that affected all protoplanets in the same way.
The discovery of Erg Chech 002 opens up new possibilities for understanding how our solar system came to be. By studying this ancient space rock and its crystal-studded secrets, we can learn more about the diversity and complexity of the processes that shaped our cosmic home.