Discovery of iron-60 and manganese-53 substantiates supernova 2.5 million years ago — ScienceDaily
When the brightness of the star Betelgeuse dropped dramatically a few months ago, some observers suspected an impending supernova — a stellar explosion that could also cause damage on Earth. While Betelgeuse has returned to normal, physicists from the Technical University of Munich (TUM) have found evidence of a supernova that exploded near the Earth around 2.5 million years ago.
The life of stars with a mass more than ten times that of our sun ends in a supernova, a colossal stellar explosion. This explosion leads to the formation of iron, manganese and other heavy elements.
In layers of a manganese crust that are around two and a half million years old a research team led by physicists from the Technical University of Munich has now confirmed the existence of both iron-60 and manganese-53.
“The increased concentrations of manganese-53 can be taken as the “smoking gun” — the ultimate proof that this supernova really did take place,” says first author Dr. Gunther Korschinek.
While a very close supernova could inflict massive harm to life on Earth, this one was far enough away. It only caused a boost in cosmic rays over several thousand years. “However, this can lead to increased cloud formation,” says co-author Dr. Thomas Faestermann. “Perhaps there is a link to the Pleistocene epoch, the period of the Ice Ages, which began 2.6 million years ago.”
Typically, manganese occurs on earth as manganese-55. Manganese-53, on the other hand, usually stems from cosmic dust, like that found in the asteroid belt of our solar system. This dust rains down onto the earth continuously; but only rarely do we perceive larger specks of dust that glow as meteorites.
New sediment layers that accumulate year for year on the sea floor preserve the distribution of the elements in manganese