Massive stars produce a large number of radioactive elements that can be released into space by stellar winds and supernova explosions. A new study has revealed that our solar system collects some of these elements as it moves through the interstellar space.
One of the unusual elements is iron-60. The radioactive isotope doesn’t appear naturally on Earth, and its presence infers that supernova explosions took place a few million years ago. Traces of it have been dated to 2.6 million and approximately 6 million years ago, as it seems that Earth may have traveled through fallout clouds released by supernova events.
The rare isotope was also present in samples of lunar soil that were collected and returned to Earth during a few of the Apollo missions, as well as in samples of snow collected from Antarctica.
In the last thousands of years, the solar system has been traversing a dense area filled with cosmic gas clouds and dust, which is known under the name of Local Interstellar Cloud. The potential origin of the cloud has attracted the interest of a team of researchers.
Several samples collected from two deep-sea locations were analyzed by the researchers with the help of an advanced spectrometer. The age of the sediments can be traced back to 33,000 years ago. In a surprising twist, the researchers observed the presence of iron-16 throughout the entire timeframe of the samples.
There is a lack of correlation between the position of the solar system within the Local Interstellar Cloud that leads to more questions instead of answers. Some argued that the cloud might have been released by a different source, but there is no conclusive proof. In addition, the isotope is spread evenly across the timeframe of the samples.
Further research will take place, and the current results were published in a scientific journal.