162173 Ryugu

Ryugu is important not because it is visually dramatic, but because it has become a source of unusually clean evidence from the early Solar System. JAXA's Hayabusa2 mission returned material from the asteroid to Earth, which means Ryugu can now be studied not just remotely but directly, grain by grain. That turns a small dark asteroid into a high-quality archive of primitive matter.

What makes Ryugu especially valuable is the cleanliness and chemical richness of its returned samples. They contain organic molecules, including amino acids, in material not blurred by long residence in the Earth's environment. That matters because it gives researchers a sharper look at the kinds of chemistry that existed in small bodies early in Solar System history, without confusing those signals too heavily with terrestrial contamination.

That is why Ryugu matters on this scale. It shows that even a modest rubble-pile asteroid can preserve subtle chemical information across billions of years. Ryugu is not interesting merely as a rock in space. It is interesting as a carefully recovered piece of early Solar System chemistry, delivered almost intact into the laboratory age.