Physicist: Meteorite in its original state

Meteorites can provide scientists with valuable information about the young solar system. The problem: After the collision, the terrestrial impacts changed the speed of the stones that fell from space, thus obliterating the traces from space. On February 28, 2021, thanks to several camera recordings, it was possible to track down a meteorite that fell in England a few hours after the impact. This meteorite is virtually uncontaminated and contains water and many of the building blocks of life, a research team reports in the journal Science Advances.

Collisions between rocks in the asteroid belt between Mars and Jupiter can send chunks of debris into the inner solar system — and sometimes into Earth’s atmosphere. On February 28, 2021 at 21:54 local time, a piece of debris crossed the skies over southwest England as a bright star. The tracking of the stone was recorded from space by special cameras as well as several surveillance and dashboard cameras. In addition, observatories and other research institutions have received more than a thousand eyewitness reports.

From all these recordings and observations, the meteorite fall can be reconstructed with great accuracy. Within a few hours, the meteorite was actually found: on a lane in the town of Winkcombe, it broke into a heap of dark fragments one to two millimeters in size with a total mass of 319.5 grams. In the days that followed, the researchers found several other fragments. The tracked parts of the meteorite were immediately packed into hermetically sealed containers and transferred to special laboratories for examination.

Ashley King of the Natural History Museum in London explains that the fragments that were discovered first are of particular value because they were less exposed to the terrestrial environment. Furthermore, studies show that the piece of debris may have remained virtually unchanged during its previous journey through the solar system. The scientists concluded that because cosmic rays have changed their surface over time, the orb could not have remained in space for very long, but it must have “fallen to Earth shortly after separating from its original body”.

During additional laboratory analysis, King’s team discovered a large amount of silicates that had water attached to it in the meteorite debris. This is an important indication that the rock was in contact with liquid water when it was formed. The research team closely examined the water impurities. Particularly exciting was the hydrogen in water molecules, which occurred in three different types — called isotopes —: light, heavy, and superheavy hydrogen. The frequency of different isotopes in the water allowed the researchers to draw conclusions about the origin of the water. King and colleagues show that the isotopic compositions of hydrogen in the Winkcomb meteorite and in Earth’s hydrosphere are very similar. This once again confirms the hypothesis that the majority of water on Earth comes from asteroids.

In addition, the meteorite contains many chemical compounds based on the carbon element. Even amino acids are among them – components of proteins. The researchers emphasized that “molecules like these amino acids are essential ingredients for the emergence of life.” These organics could also have reached the young Earth through meteorites.