Spurious periods in the terrestrial impact crater record

We present a simple solution to the controversy over periodicity in the age s of terrestrial impact craters and the epochs of mass extinctions of speci es. The first evidence for a 28.4 million year cycle in catastrophic impact s on Earth was presented in 1984. Our re-examination of this earlier Fourie r power spectrum analysis reveals that the rounding of the impact crater da ta distorted the Monte Carlo significance estimates obtained for this cycle . This conclusion is confirmed by theoretical significance estimates with t he Fourier analysis, as well as by both theoretical and Monte Carlo signifi cance estimates with the Rayleigh method. We also apply other time series a nalysis methods to six subsamples of the currently available more extensive impact crater record and one sample of mass extinction epochs. This analys is reveals the spurious "human-signal" induced by rounding. We demonstrate how the data rounding interferes with periodicity analysis and enhances art ificial periodicities between 10 and 100 million years. Only integer period icities connected to irregular multimodal phase distributions reach a signi ficance of 0.001 or 0.01. We detect no real periodicity in the ages of terr estrial impact craters, nor in the epochs of mass extinctions of species.