"Victor Clube, also of the University of Oxford, argued that we are living in the aftermath of the breakup of a giant comet in the inner Solar System. He suggests that this event may have been associated with the most recent Ice Age, which began about 100 000 years ago. According to Clube, it produced a stream of Sun-orbiting material linked with the Taurid meteor stream, which peaks around 30 June in daylight hours but is visible as "shooting stars" in the night skies of November.
Clube calculates that the Earth passes through the thickest part of this belt of debris every 3000 years, and that this happened most recently in 500 AD and before that in 2500 BC. On both occasions, Tunguska-like events would have been common, with one impact in each region the size of England over a period of a hundred years or so. Could this explain the collapse of past civilizations, the "Dark Ages" of Europe, and recurring legends about fire from the skies? Clube and his colleagues have been promoting this idea for ten years, but now they have a solid weight of scientific evidence to support their case. The Tunguska event itself came at just the right time of year to fit the pattern, as an isolated straggler in the stream, but the next main date to watch out for is the year 3000, give or take 200 years. For once, the scientists involved are happy that they will not be here to test their prediction.