22 days ago
- Cosmic dust and rare isotopes of iron and plutonium found deep in the Pacific Ocean and other locations on Earth and the Moon originated from supernovae, indicating Earth is coated with stellar debris.
- Two waves of supernova ash arrived around two million and seven million years ago, potentially from multiple giant star explosions within the Scorpius-Centaurus Association, though the exact events and distances remain uncertain.
- Theories suggest the ash could have come from nearby supernovae or from passing through dense debris clouds left by more distant explosions, with the latter explaining the prolonged deposition seen in sediments.
- Current evidence points to a series of supernovae over the past 15 million years shaping a local interstellar bubble and scattering dust, which the solar system periodically encounters, such as a dense cloud around two million years ago.