Antarctic Ice Reveals Clue of Supernova Explosions

Researchers dealing with drills in the Antarctic ice sheets have recently managed to identify the chemical traces of a supernova explosion that took place more than 1,000 years ago, by analyzing minute amounts of the particles that remained trapped in the ice. The samples that have been analyzed for the new research were harvested from the Dome Fuji station in Antarctica, and reviewed at the RIKEN research institute in Wako, Japan, by a team of scientists led by investigator Yuko Motizuki.

He explains that nitrogen is regularly produced in the atmosphere by nitrogen oxides, which interact with various other chemicals. The oxides themselves can be traced back to gamma radiation, which is usually emitted by an exploding supernova. By analyzing the levels of the chemical in core ice samples, the Japanese team hopes to be able to pinpoint other explosions as well, and maybe to later identify them with perfected astronomical instruments.

The researchers have discovered that, at a depth of approximately 50 meters (roughly 165 feet), the concentration levels of nitrogen were off the charts, hinting at the fact that Earth's atmosphere was at the time bombarded by large amounts of the gas, which more than likely came from an exploding supernova. Three layers of snow rich in nitrogen were found, roughly corresponding to the years 1006, 1054 and 1060. While for the first two astronomical and historical records confirm sightings, the third one is not to be found in any old writing or book.

The Japanese say that the 2 to 3 kilometer-thick layer of Antarctic ice could supply data for as much as 1 million years in the past, as far as supernova explosions and their density in time go. Knowing these pieces of information is crucial for astronomers, because they are aware of the fact that the number of supernovas that explode in the galaxy is of extreme importance for its well-being. Exploding stars eat up a lot of matter and dust clouds and trigger accelerated processes of stellar formation, which can in turn disrupt the internal balance of the Milky Way.