Here is a concise answer based on the newly published (June 2026) study in Nature Astronomy:

The discovery: Researchers detected interstellar plutonium-244 atoms in a ferromanganese crust from the deep Pacific Ocean. They used accelerator mass spectrometry (AMS) at the VEGA facility at ANSTO in Australia to identify the atoms .

Method and key negative result: The team analyzed successive layers of the crust and also searched for curium-247 (a shorter-lived r-process isotope). They found no curium-247 from space — only trace amounts from nuclear weapons testing . Because curium-247 has a much shorter half-life (15.6 million years) than plutonium-244 (80.6 million years), its since the event that produced these atoms. This shifts the production event to , not just a few million years as previously thought .

Here is a concise answer based on the newly published (June 2026) study in Nature Astronomy:

The discovery: Researchers detected interstellar plutonium-244 atoms in a ferromanganese crust from the deep Pacific Ocean. They used accelerator mass spectrometry (AMS) at the VEGA facility at ANSTO in Australia to identify the atoms .

Method and key negative result: The team analyzed successive layers of the crust and also searched for curium-247 (a shorter-lived r-process isotope). They found no curium-247 from space — only trace amounts from nuclear weapons testing . Because curium-247 has a much shorter half-life (15.6 million years) than plutonium-244 (80.6 million years), its since the event that produced these atoms. This shifts the production event to , not just a few million years as previously thought .