Tree rings challenge history

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."

Jonathan Amos
BBC News
September 8, 2000