Asteroid Ryugu Yields DNA Building Blocks

Six years after Japan’s Hayabusa2 mission returned a capsule from asteroid Ryugu, researchers are reporting a striking discovery: the samples include the five nucleobases that make up DNA and RNA. The study, published in Nature Astronomy, identified adenine, guanine, cytosine, thymine and uracil among Ryugu’s materials — molecules also seen in samples from asteroid Bennu and in some meteorites.

Scientists say these findings strengthen the idea that carbon-rich asteroids could have shipped key organic ingredients to the early Earth. Ammonia was also detected in the Ryugu samples, which may have helped synthesize or preserve those nucleobases in space. Lead author Toshiki Koga cautions that finding these molecules on Ryugu doesn’t mean life existed there, but it does suggest primitive asteroids were chemical factories capable of producing life-related compounds.

Back on Earth, a team in Germany has uncovered a microbial “consortium” that digests several common plastic additives called phthalate esters (PAEs). Two Pseudomonas strains and one Microbacterium strain were isolated from biofilm on bioreactor tubing and were shown to cooperatively break down diethyl phthalate and related compounds. The bacteria appear to rely on cross-feeding, where different strains metabolize sequential breakdown products. In lab tests the consortium consumed all DEP within 24 hours at moderate temperatures, hinting at potential applications for treating contaminated waste streams or accelerating plastic degradation.

Meanwhile, the Hubble Space Telescope captured a rare, close-in look at Comet C/2025 K1 (ATLAS) as it fragmented in November. Astronomers caught the comet just days after it began to crumble, recording multiple small pieces and even watching a secondary fragment begin to break apart. Observations like this help researchers study cometary structure and the processes that disperse material through the solar system.

Together, these stories underscore how small bodies — asteroids, comets and even microbes — can inform big questions about life's origins and how we might better manage planetary pollution.