Are we due for an extinction event on Earth?

We can then look for patterns in these extinction events. The easiest way to do it, quantitatively, is to take the Fourier transform of these cycles, and to see where (if anywhere) patterns emerge. If we saw mass extinction events every 100 million years, for example, where there was a big drop in the number of genera with that exact period every time, then the Fourier transform would show a huge spike at a frequency of 1/(100 million years). Let’s not beat around the bush: what does the extinction data show?

It shows relatively weak evidence for a spike with a frequency of 140 million years, and another spike at 62 million years. These spikes look huge, but that’s only relative to the other spikes, which are totally insignificant. In a timeframe of just ~500 million years, you can only fit three possible 140 million year mass extinctions in there, and only about 8 possible 62 million year events. (We don’t see that many; if there is periodicity like this, it doesn’t happen every time.) But as you can clearly see, there’s no evidence for a 26-30 million year periodicity in these extinctions; there’s not even a suggestive bump at those frequencies. What’s even worse is that, of all the impacts that occur on Earth, less than one quarter originate from the Oort cloud! There’s an old saying that “extraordinary claims require extraordinary evidence,” but Christopher Hitchens flipped the script on that, looking at it from the reverse point of view…