Physicists at the University of Technology (TUM) in Munich have found evidence of an explosion of a supernova that exploded near Earth (cosmic scale) about 2.5 million years ago. Supernovae usually occur at the end of star life, which is ten times the mass of our sun. A huge explosion produces heavy elements such as manganese. A team of researchers led by TUM physicists has confirmed the presence of iron-60 and manganese-53 in the Earth’s manganese crust for about 2.5 million years. The researchers say the increase in manganese-53 concentrations is clear evidence that supernovae do happen.
If the supernova had occurred very close to Earth, it could have caused great damage to the Earth and any life on Earth at that time. However, this particular supernova is far enough away from Earth that the only side effect is the ascension of cosmic rays that last for thousands of years. Researcher Dr Thomas Faestermann said the increase in cosmic rays could lead to an increase in cloud formation, and speculated it could be related to the Ernest Age, the ice age that began 2.6 million years ago.
Usually on Earth, manganese appears only in the form of manganese-55. Manganese-53 comes from cosmic dust, as found in the solar system’s asteroid belt. That kind of dust keeps hitting the earth, but there are very few big dust spots on the earth. The researchers say sediments on the seabed preserve the distribution of elements in manganese shells and sediment samples.
The team used accelerator mass spectrometers to detect increased levels of iron-60 and manganese-53 in layers deposited about 2.5 million years ago. The researchers point out that this is an investigative hyper-trace analysis, and they’re talking about just a few atoms. However, the accelerator mass spectrometer is sensitive enough for scientists to calculate that the mass of the exploding star must be about 11 to 25 times the size of the sun.