A mystery surrounding the space around our cosmic region is unfolding thanks to evidence of supernovae found in deep-sea sediments. According to a scientific study which shows the Earth has been travelling for the 33,000 years through a cloud of faintly radioactive dust. The study suggests that these clouds could be remnants of previous supernova explosions, a powerful and super bright explosion of a start.
Researchers searched through several deep-sea sediments from two different locations that date back to 33,000 years using an extremely sensitive instrument called a spectrometer. They found clear traces of the isotope iron-60, which is formed when starts die in supernova explosions.
Iron-60 is radioactive and completely decays away within 15 million years, which means any iron-60 found on Earth must have been formed much later than the rest of the 4.6 billion year old earth and appeared here from nearby supernovae before settling on the bottom of the sea.
Scientists have discovered traces of iron-60 at about 2.6 million years ago, and maybe another at approximately 6 million years ago, suggesting earth had traversed fallout clouds from nearby supernovae. For the last few thousand years the solar system has been moving through a heavy cloud of gas and dust, known as the local interstellar cloud (LIC), whose origins are unclear.
If this cloud had originated during the previous few million years from a supernova, it probably would consist of iron-60, and so the team of researchers decided to search more recent sediments to find out. Turns out, there was iron-60 in the sediment at remarkably low levels – equating to radioactive levels in space far below Earth’s natural background levels – and the distribution of the iron-60 matched earth’s recent travel through the local interstellar cloud. But the iron-60 reached further back and was spread throughout all the 33,000-year measurement period.
The lack of correlation with the solar system’s time in the current local interstellar cloud seems to bring more questions than answers. Firstly, if the cloud was not formed by a supernova where did it come from? Some have theorised that it came from aggressive chemical reactions from distant galaxies that ended up travelling at the speed of light in all directions during the big bang. But there is no definitive evidence to support this kind of claim currently.
But secondly, why is there iron-60 so evenly spread out throughout space? A few scientists have suggested that iron-60 is a key element in the forming of a wide range of planets throughout the universe and it go there through a massive chain of gravitational pulls from different entities with high levels of mass throughout space to explain its even distribution. This is currently speculation at best, but it could provide inspiration for future research methodologies.
Other scientists say there are recent papers that suggest iron-60 trapped in dust particles might bounce around in the interstellar medium, so the iron-60 could originate from even older supernovae explosions, and what we measure is some kind of echo. One thing is for certain though, more data is required to resolve some of mysteries.
There could be potentially so many more secrets about our universe hidden in the depths of our deepest oceans. That might become more of a research focal point for astrophysicists as they attempt to uncover the origins of our universe. Even though it can sometimes feel like we are close to a unifying answer, when more research is done, more questions arise. This is only natural when attempting to quantify the extremely large and extremely small solar system mysteries.