8 September 2000 BBC news Article
http://news.bbc.co.uk/hi/english/in_depth/sci_tech/2000/festival_of_science/newsid_916000/916421.stm
By BBC News Online's Jonathan Amos
Could a comet hitting the Earth 1,500 years
ago have triggered a global disaster in which
millions of people lost their lives?
It is an old claim that historians say has little
evidence in written records to support it, but
now a tree ring expert has said the idea must
be re-examined.
Mike Baillie, professor of palaeoecology at
Queen's University in Belfast, UK, said it was
very clear from the narrowness of growth rings
in bog oaks and archaeological timbers that a
great catastrophe struck the Earth in AD 540.
"The trees are unequivocal that something
quite terrible happened," he told the British
Association's Festival of Science. "Not only in
Northern Ireland and Britain, but right across
northern Siberia, North and South America - it
is a global event of some kind."
Dark Ages
Professor Baillie favours the idea that cometary
fragments smashed into the atmosphere
throwing up dust and gas that blocked out the
Sun. This, in turn, led to crop failures, famine
and even plague among the weakened peoples
of the world.
Professor Baillie said astronomers from Armagh
Observatory in Northern Ireland had published
research 10 years ago in which they said the
Earth would have been at risk from cometary
bombardment between the years AD 400 and
AD 600.
"This event is in AD 540, so it fits very nicely
into the window," he said.
"We know from the tree rings to the year
exactly when this event happened. And some
archaeologists and historians are beginning to
come round to the opinion that this was the
date when the Dark Ages began in Northern
Europe. It wasn't just when the Romans left."
Oral tradition
However, there are many more historians who
believe that if such a major event had
occurred there would be much clearer
references to the disaster in written texts. But
Professor Baillie urged them to go back and
look again - "to read between the lines".
He said mythical stories certainly seemed to
point to a comet striking the Earth at about
the right time. He said King Arthur died in this
period and some stories talk about long arms in
the sky delivering mighty blows.
"Mythology tells you and history doesn't and
that raises some very interesting questions
because the implication is that you could
suppress the written word but you couldn't
suppress the oral tradition."
Professor Baillie said chemical analysis would
be carried out on the tree rings to investigate
the comet idea further. He hopes also to get
access to ice cores to see if they record any
interesting data that might support the comet
theory.