Mike Baillie has a theory. We all know that millions of years ago asteroids and comets caused havoc on Earth. But Mike Baillie thinks that even in the past 5,000 years or so, we have experienced several catastrophic encounters with comets, and that accounts of these cosmic devastations are accurately preserved in Old Testament writings, ancient Chinese texts and in many of the myths and legends handed down in various cultures.
At least I think that's what his theory is.
And I hear you mumble: "Say! What kinda nut is this?"
But Prof M.G.L. Baillie of Queen's University, Belfast, is not a nut. He is a very eminent palaeoecologist, or more specifically a dendrochronologist, and one of the world's most respected authorities on tree-ring dating.
The science of dendrochronology is based on the fact that if you slice through the trunk of a tree the resulting disc is embossed with concentric circles, or tree rings, one for each year since the tree began to grow.
The width of each tree-ring varies with the weather of its formative year - low temperature and low rainfall both producing narrower rings than usual.
Each tree, therefore, displays a pattern which tells the story of the climate during its lifetime. By analysing trees with overlapping lives, dendrochronologists can build a "master chronology" for any region - a tree-ring pattern running backwards through time for many thousand of years.
Prof Baillie and his colleagues have assembled a precisely-dated record of oak growth for every year back to 5400 BC. The record allows us to see, as Prof Baillie puts it, "what the trees thought of conditions in the past - history according to the trees".
The record highlights, for example, periods of severe or benign weather, times of possible plague, and intervals when major volcanic eruptions, or even comet impacts, may have had a severe effect upon our weather.
It is these now precisely-dated climatic events which Prof Baillie tries to link to more traditional accounts of human trauma.
If these things interest you, you will enjoy Prof Baillie's book, Exodus to Arthur: Catastrophic Encounters with Comets, published by Batsworth earlier this year.
But I can offer you a great deal more. The sixth annual John Jackson lecture, jointly organised by the Royal Dublin Society and the Royal Irish Academy, takes place at 6.30 p.m. this evening, Tuesday, October 19th, in the RDS. The topic is "Surprising Things You Can Learn from Tree-Ring Dating", and the speaker is - Mike Baillie.
Enter, if you will, with diffidence and due decorum, through the Members' Door of the RDS, Ballsbridge.