Overview
- The peer‑reviewed study, published Wednesday in Physical Review Letters, reports traces of iron‑60 in Antarctic ice that formed 40,000 to 80,000 years ago.
- By comparing the ice with recent Antarctic snow and deep‑sea sediments, the team found lower iron‑60 deposits in that older interval than today, pointing to a changing influx of interstellar material.
- The pattern matches estimates that the Solar System began crossing the Local Interstellar Cloud tens of thousands of years ago, which supports the idea that this cloud carries ancient supernova dust.
- The time‑varying signal rules out a slow fade from million‑year‑old explosions, indicating instead a local source or density changes within the cloud that altered how much dust reached Earth.
- Researchers processed about 300 kilograms of EPICA ice, verified sample integrity at HZDR’s DREAMS lab using beryllium‑10 and aluminium‑26, and counted a handful of iron‑60 atoms at ANU’s HIAF, with plans to test even older Beyond EPICA cores to map the cloud’s history.