German physicists at the Technical University of Munich recorded evidence of a supernova explosion near Earth more than two million years ago. The study, published in Physical Review Letters, is briefly reported in a press release on Phys.org.
Scientists analyzed the isotopic composition of manganese crusts from the seabed using accelerator mass spectrometry. They found elevated levels of manganese-53 and iron-60 isotopes in sediment layers that were 2.5 million years old. Terrestrial rocks are characterized by an abundance of isotopes of manganese-55, and manganese-53 is usually formed in space and enters the Earth with dust particles.
In a supernova explosion, when a massive star explodes, various heavy elements are formed, including manganese and iron. The increased concentration of the manganese-53 isotope in the earth's rocks can be considered a sign that a star has exploded near the solar system. The supernova was far enough away to cause serious harm to life on Earth, but it could trigger a burst of cosmic rays that bombard the atmosphere and lead to increased cloud formation.
According to researchers, the deceased star should have been 11-25 times larger than the Sun.
