If Shawn Bishop, a physicist at the Technical University of Munich, is correct about a certain iron-loving deep-sea bacteria, then their fossilized remains hold iron traces from a supernova that exploded 2.2 million years ago possibly in the Scorpius–Centaurus Association (above), the closest stellar association to our solar system, at a distance of about 130 parsecs (424 light years) from the Sun.
"This apparent signal of iron-60," Bishop said, :could be the remains of magnetite (Fe3O4) chains formed by bacteria on the sea floor as radioactive supernova debris showered on them from the atmosphere, after crossing inter-stellar space at nearly the speed of light."
Bishop and colleagues gathered samples of ocean core dating between 1.7 and 3.3 million years ago and took samples every 100,000 years in the rock, treating the samples with chemicals that would isolate only the iron-60. The only strata they could find traces of the iron-60 was in sediment samples dated around 2.2 million years old.The wide field X-ray image of the Scorpius-Centaurus association above was constructed from the data of the ROSAT All Sky Survey Background maps. The yellow dots mark the positions of bright X-ray sources detected in the survey (only about 10% of the brightest X-ray sources are shown). The blue circles mark the three subgroups Upper Scorpius, Upper Centaurus-Lupus, and Lower Centaurus-Crux (from left to right).
The Daily Galaxy via Nature.com