Japanese physicists have identified a mysterious blast of high-energy radiation that struck Planet Earth more than 1,200 years ago – some 20 times larger than normal variations. The cosmic origins of this ancient and massive radiation event, however, are still unknown.
Cosmic-ray physicists from Japan’s Nagoya University, led by Fusa Miyake, discovered the radioactive event – said to have occurred between 774 and 773 AD – based on carbon dating performed on ancient trees.
Their investigation of tree rings from that era show a 20% increase in levels of the 14C isotope over the course of a year. Those isotopes, according Nature.com, are formed “when highly energetic radiation from outer space hits atoms in the upper atmosphere, producing neutrons. These collide with nitrogen-14, which then decays to 14C.”
What happened is clear, but why it happened seems anything but. The usual suspects for this radioactive spike are supernova explosions or solar flares. According to Miyake and his team, both are unlikely culprits considering no other recorded evidence exists of such massive events.
The search for the cause behind this massive cosmic event will likely send scientists to pore through historical data to find any correlative events that might clear things up. Either way – the trees don’t lie (they can’t). Something huge happened 1,200 years ago.
Photo: Solar Flare from Big Stock Photo