The most massive stars are the celebrities of the cosmos: they are very
rare, but live extravagantly and die in spectacular and violent
supernova explosions. While these events are awesome to observe, they
can take a sinister shade when they occur closer to home, because an
explosion inside a certain "minimum safe distance" would pose a grave
threat to Earthlings. We will discuss these cosmic insults to life and
present recent evidence that a star exploded near the Earth about 3
million years ago. Radioactive iron atoms have been found in ancient
samples of deep-ocean material found around the globe, and also on the
Moon. These unique atoms are tiny, telltale samples of debris from the
supernova explosion. Thus, for the first time we can use sea sediments
and lunar cores as telescopes, probing the nuclear fires that power
exploding stars. Furthermore, an explosion so close to Earth was
probably a "near miss," which emitted intense and possibly harmful
radiation.
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