At www.dailygalaxy.com August 12th … palaeontologist Bruce Leiberman suggests we should think about extraterrestrial events leading to higher rates of mutations in organisms and damage to DNA. However, the rate of change is on a uniformitarian scale and relates to the rotation of the solar system within the Milky Way galaxy and periodic encounters it may have with greater rates of radiation and cosmic ray bombardment. The solar system has a bowshock that is due to cosmic rays from outside, and in turn the galaxy may also have a bowshock when it is bombarded with cosmic rays from other galaxies (or wherever) as it moves through space. Also, the hypothetical black hole at the centre of the galaxy may also be a threat. In another study the marine fossil records appear to show an increase in biodiversity on a 62 million year cycle and here we have just the sort of thing that might be incorporated into the uniformitarian timescale – on the other hand it might just be a cycle churned out by a computer playing with numbers, but such cycles, we might note, can be used as a ploy in order to negate random catastrophic events.