Mystery over the giant cosmic explosion of 774AD, which has left absolutely no trace - except deep within the bark of two cedar trees

http://www.dailymail.co.uk/sciencetech/article-2154406/Mystery-giant-cosmic-explosion-774AD-left-absolutely-trace--deep-rings-cedar-trees.html

It is a mystery which is truly beyond even Sherlockian scale - a cosmic explosion which left no trace behind except deep within the bark of two cedar trees.

Fusa Miyake, of the Nagoya University in Japan, studied the growth rings of two trees dating back 1,200 years - and discovered that an explosion of epic proportions occurred between 774 and 775AD.

But there is no record of something happening in our skies in that period - except perhaps for one tiny, obscure account by a 13th-century historian.

The problem - and this is where we need to call in Mr Holmes of Baker Street - is that there should be a record.

If this was a supernova - a star exploding deep in space - we should either be able to spot the remains with modern telescopes, or find visual accounts in the written accounts of Chinese and European historians.

To get the technical details out of the way first: Trees capture particles from the atmosphere during photosynthesis, and one particle that gets buried within the annual growth rings is carbon-14.

Carbon-14 forms when cosmic rays - generally caused by massive solar flares, or by supernovae - interact with nitrogen and oxygen in our atmosphere.

In the two cedar trees - and doubtless many other tree records from the period - there was a giant increase of 1.2 per cent of carbon-14.

In comparison, the annual variation of the captured isotope is just 0.05 per cent, making this more than a 20-fold increase.

Read more: http://www.dailymail.co.uk/sciencetech/article-2154406/Mystery-giant-cosmic-explosion-774AD-left-absolutely-trace--deep-rings-cedar-trees.html#ixzz1wzdeP9HN