A research team consisting of Austrian and German researchers from various institutions has found evidence of iron that possibly originates from a supernova and the sediment holding this iron was taken from the Pacific Ocean floor.
This team explained how the core samples were analyzed and what led them to the conclusion that the iron could have come from an ancient supernova.
The study came about when researchers found information on Internet searches about magnetotactic bacteria. This bacteria can be found in ocean sediments and it absorbs small iron amounts. When the sediment builds the bacteria naturally dies off and as they do they leave behind small iron pieces in the sediment layers. These layers of sediment could hold a kind of iron that originated from space. This iron, called iron-60, would be millions of years old and would have been thrown into space during an explosion of supergiant stars according to earlier research.
Iron-60 is not commonly found on Earth and is in fact extremely rare. It has a half-life of just a bit more than 2 1/2 million years. This means that when the Earth formed any of the iron-60 that was present would have since disappeared. This type of iron cannot be produced naturally so the logical conclusion is it came from space. Earlier research has concluded that the iron comes from 2 possible sources including from a supernova explosion or from micrometeorites.
The team examined core samples that were retrieved from the Pacific Ocean to further their research. These samples came from other researchers that were working on different projects. Accelerator mass spectrometry was used to search for this iron-60 amongst other materials such as iron-56, which is more common. This type of spectrometry can isolate single atoms.
According to the research team, iron-60 in concentration levels were found from small atom clusters in single atoms. The largest concentrations date back 2.2 million years, which was when a huge marine die-off occurred. Researchers also noted that the iron-60 most likely originated from a supernova instead of from micrometeorites because the iron that comes from micrometeorites tends to harbor in silicate or magnetite.
Paper was published in Proceedings of the National Academy of Sciences.