8th-century cosmic blast captured in cedar trees

Sydney: In the late eighth century, Earth was hit by a mystery blast of cosmic rays, say Japanese scientists who 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 led by Fusa Miyake of Nagoya University report in the journal Nature on Sunday.

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“With our present knowledge, we cannot specify the cause of this event,” Miyake said.

“However, we can say that an extremely energetic event occurred around our space environment in AD 775 ... (but) neither a solar flare nor a local supernova is likely to have been responsible,” he added.
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http://zeenews.india.com/news/space/8th-century-cosmic-blast-captured-in-cedar-trees_779701.html