Exactly how the gas of the universe slowly evolves from the clouds we see to worlds like the Earth we live on is not entirely understood. We have big picture ideas, but they are like a mural painted with a giant brush; the ideas are there, but the details are lost.

To understand what happened, we need to understand not just how gravity evolved structures but also how chemistry evolved content. We know the end result – our world has been magnificently changed by time, geochemistry, and geophysics and is the end product of a water cycle, carbon cycle, plate tectonics, and more. 

Understanding how it started requires samples, and lucky for us, the Hayabusa 2 mission has returned a 5.4-gram sample of material from the asteroid Ryugu. This 900-meter-across space rock is too small to have the kinds of processes we have on Earth, and its material is more like the unmixed ingredients of a cake dripped onto the counter than like the mixed and baked result that is our Earth. 

Early analysis shows this material is visually dark – looking more like grains of pepper than regular sand. The material is also porous, like ground pumice, with chemistry like the most common meteorites found on Earth – the carbonaceous chondrites. How did this asteroid get to be so dark? Researchers are still working on that. Who knew the solar system was filled with goth space rocks hiding against the blackness of space?

More Information

Bits of asteroid Ryugu are among ‘most primordial’ materials ever examined (Live Science)

“First compositional analysis of Ryugu samples by the MicrOmega hyperspectral microscope,” C. Pilorget et al., 2021 December 20, Nature Astronomy

“Preliminary analysis of the Hayabusa2 samples returned from C-type asteroid Ryugu,” Toru Yada et al., 2021 December 20, Nature Astronomy