Stars die when they run out of fuel, and sometimes, they end up producing a powerful explosion known as a supernova. These supernovas expel material that spreads all across the universe.
Now, astronomers from the Australian National University have discovered traces of a supernova right here on Earth buried in the Indian Ocean. The remnants of the ancient supernova are believed to have traveled here some 33,000 years ago.
That's all well and good but you may be wondering how the researchers knew the discovery was indeed from an ancient supernova. It is because they found traces of radioactive iron isotopes in the sediment samples collected.
This type of iron isotope, known as 60Fe, is not produced here on Earth. In fact, it can only be found in cosmic rays which means it must have been generated and ejected during a supernova explosion.
The study further speculates that the iron was deposited on Earth at a rate of 3.5 atoms per square centimeter per year over the past 33,000 years and that it came from a million-year-old supernova. The scientists also revealed that this explosion must have spread dust particles that may still exist in interstellar space today.
The researchers traced the spread back to the Local Interstellar Cloud (LIC), an interstellar cloud in the Milky Way that stretches 30 light-years across. Oddly enough, our very own Solar System has been moving through this same cloud for thousands of years.
The findings remain uncertain for now and the researchers indicate that further work needs to be done to confirm the exact source of the supernova and the timeline of when its fragments made their way to Earth. Regardless, it is still cool to know that our planet contains parts of a star's ancient explosion.
The study was published Monday in the Proceedings of the National Academy of Sciences.