Late in the 8th century, Earth was hit by a mystery blast of cosmic rays, according to a Japanese study that found a relic of the powerful event in cedar trees. Analysis of two ancient trees found a surge in carbon-14 – a carbon isotope that derives from cosmic radiation – which occurred just in AD 774 and AD 775, the team report in the journal Nature.
Earth is constantly battered by protons and other sub-atomic particles which are blasted across space by high-energy sources. The particles collide with the stratosphere and react with nitrogen to create carbon-14, which is then absorbed into the biosphere.
A team led by Fusa Miyake of Nagoya University found that levels of carbon-14 in the two cedars were about 1.2 per cent higher in 774 and 775 compared to other years :: Read the full article »»»»