The recent discovery of plutonium-244 in deep-sea sediments has scientists re-examining the nature of ancient cosmic explosions. This rare element, produced in violent events like supernovae or neutron star collisions, was found in samples dating back tens of millions of years. Dr. Dominik Koll, a physicist at the Helmholtz-Zentrum Dresden-Rossendorf in Germany, led the study. He notes that the detection of plutonium-244, with its half-life of 80 million years, indicates an explosion far more powerful than a standard supernova. These events are incredibly rare, with only one witnessed in our galaxy since the invention of the telescope, and the ones that create plutonium-244 are even less frequent.
The team's detective work involved dating techniques similar to carbon dating, using other radioactive elements like iron-60 and beryllium-10. They found peaks of iron-60 at specific depths in the Pacific Ocean floor, suggesting two nearby supernovae in the last ten million years. However, the plutonium-244 was evenly distributed, pointing to an older event that had spread its debris more widely across the interstellar medium.
The absence of curium-247, another radioactive element with a shorter half-life, further supports the idea that the event occurred over 100 million years ago. This discovery has challenged existing models, including the hypothesis of a collision with a dense interstellar cloud. Dr. Koll emphasizes the need for more detailed models and experiments to understand these rare cosmic events and their impact on our galaxy.
