Prepare to be amazed! In 2019, Japan’s Aerospace Exploration Agency embarked on an incredible mission. They sent the Hayabusa2 spacecraft to explore 162173 Ryugu, an asteroid orbiting near Earth. This asteroid is made up of rocky fragments from a larger parent body. But here’s the really cool part: the spacecraft brought back samples from the asteroid’s surface for scientists to study!
These samples are like treasure troves of information. They contain chemically primitive meteorites, similar to Ivuna-type chondrites. And guess what? They also suggest the presence of water! The researchers discovered secondary minerals, such as phyllosilicates, carbonates, sulfides, and oxides, which were formed by water on the parent body. They wanted to understand how and when these changes occurred, so they studied the samples in great detail.
A group of 89 scientists from universities and research institutes around the world collaborated on this groundbreaking research. Their findings, published in Nature Geoscience, focus on two compounds: calcium carbonate (calcite) and calcium-magnesium carbonate (dolomite). These carbonates are believed to have originated from carbon monoxide, carbon dioxide, methane, or organic matter in the solar nebula, the cloud of gas from which our solar system formed.
To analyze the samples, the scientists used specialized microscopes for petrology, the study of rocks. They examined crystals of calcite and dolomite, which are highlighted in blue and purple, respectively, in the microscope images below:
