As the Soviet academician Vsyesviatski (literally 'all-holy') noted somewhere around 1950 and as Velikovsky mentioned in "Earth in Upheaval" in 1955, there are three categories of phenomena, i.e. volcanos, earthquakes, and short-period comets, which have been damping exponentially since Roman times. In the case of short-period comets, the rate of attrition strongly suggests a common origin for all of them in some sort of a catastrophic event in our solar system within the last 6000 years, as Vsyesviatski noted. I'd just like to point out it is mathematically impossible to extract a time origin from an exponentially decaying process. Exponential decay is self-similar.
I'll suspend the hilarity that usually accompanies any mention of the name 'Velikovsky', and ask for evidence that earthquakes, volcanoes and short period comets are actually decaying.