When Betelgeuse’s brightness plummeted several months ago, some observers suspected an impending supernova – a stellar explosion that could even wreak havoc on Earth. However, Betelgeuse did not explode, but physicists at the Technical University of Munich (TUM) have found evidence of another supernova that exploded near Earth about 2.5 million years ago. The scientists reported the results of their research in an article for Physical Review Letters.
As you know, the life of stars with a mass more than ten times the mass of our Sun ends in a supernova, a colossal star explosion. This explosion leads to the formation of iron, manganese and other heavy elements.
In the layers of manganese crust found on the seabed, which are about 2.5 million years old, a research team led by physicists from the Technical University of Munich confirmed the existence of both iron-60 and manganese-53.
The increased concentration of manganese-53 can be viewed as a “smoking gun” – the ultimate proof that a supernova near-Earth did indeed explode.
Dr. Gunther Korshinek, first author of the article
While a very close supernova could wreak havoc on life on Earth, this one was still far enough away for devastating consequences. However, this caused a burst of cosmic rays. “There may be a connection between the supernova and the Pleistocene epoch, an Ice Age that began 2.6 million years ago,” explains study co-author Dr. Thomas Festermann.
Manganese is commonly found on Earth as manganese-55. On the other hand, manganese-53 is usually formed from cosmic dust, like the one found in the asteroid belt of our solar system. This dust continually falls to the Earth; but only occasionally can more specks of dust be found glowing like meteorites.
New layers of sediment that accumulate from year to year on the seabed retain the distribution of elements in manganese crusts and sediment samples. Using accelerator mass spectrometry, the team found both iron-60 and elevated levels of manganese-53 in layers that were deposited about two and a half million years ago.