Analysis of sediments in the ocean confirmed that a supernova explosion about 2.7 million years ago suspiciously coincided with the era of global cooling.
Only a few million years ago, 300 light years from Earth, the supernova exploded. Our ancestors probably admired her a bright flash in the sky which might have been visible during the day. And soon the Solar system was covered with a cloud of particles, scattered by an explosion. These tracks can be found so far: in 2004, scientists discovered a supernova dust in the sediment, raised from the bottom of the Pacific ocean.
Sean Bishop (Shawn Bishop) from the Technical University of Munich, and his colleagues from Germany and Austria conducted a new analysis of sedimentary rocks. This allowed to precisely set the time of the supernova explosion, and therefore will help to better understand the role that this flow of substances has played in life on Earth. As the authors write in an article published in the journal PNAS, it has occurred since 2.7 million years ago and lasted for about 800 thousand years.
Interestingly, around this time (about 2.6 million years ago) on Earth ended the Neogene period of the Cenozoic era, and began the modern, Quaternary. Global temperature has dropped significantly, had become extinct and, by the way, the reduction in the area of African forests, which may have played a key role in the emergence of our species.
After receiving the samples of ancient sedimentary rocks, the authors assessed the content of the radioactive isotope iron-60, the half-life of approximately 2.6 million years. This isotope is formed only in a supernova fusion reactors, however, are not chemically different from the other.
Therefore, once on the Ground, it was composed of magnetite which is formed by some bacteria. “The idea that the dust of stars is on our planet and enters the magnetite crystals synthesized by bacteria in the ocean for me is simply astounding,” says Sean Bishop.
However, for a long period of time during which the Sun and its planets have passed through a cloud of the remains of a supernova, remains a mystery. According to modern concepts, the substance ejected such dying stars, flies at incredible speed about 5-10 thousand km/s And it took him almost a million years to fly past the Solar system? “There is some mystery – continues the Bishop. – It remains to explain and understand”
