An isotopic fingerprint is reported of a nuclear explosion in Russia last month. Researchers ask people living in the area or nearby to send them samples of dust or soil before the radioactive clues therein decay beyond recognition. Also, a near miss between an ESA satellite and a SpaceX/Starlink module in crowded near space strengthens the case for some sort of international Space Traffic Management treaty, whilst in the arctic circle, melting permafrost is disinterring the graves of long-dead whalers.

(Photo:Tell-tale radioactive isotopes could still be in dust on cars near the site of the blast. Credit: Humonia/iStock / Getty Images Plus)

Presenter: Roland Pease
Producer: Alex Mansfield