And the astronomer's model of surface cratering is more accurate than the astronomer's model of orbital dynamics & planet formation? Since I was alive during the period when plate techtonics was finally acknowledged, even after every schoolboy/schoolgirl for hundreds of years had pointed out the obvious jigsaw puzzle pieces, I've been amazed by the ability of scientists self delude. Prior to the 1960's, engineers & scientists studied "steady state" behavior because "transient" analysis was too hard. Similarly, they studied "smooth" functions, because chaotic/fractal functions were too scary. As a result, they were (are) constantly blindsided because nature wasn't smooth & steady. Financial engineers continue to marvel that "100 year" and "1000 year" events keep happening with decade-like regularity. Just because rare things are rare doesn't mean that they never happen. And rare things of great magnitude can quickly compensate for their rarity by their magnitude. At 08:00 AM 6/17/2011, Hans Havermann wrote:
Henry Baker:
Why does such an impact necessarily have to be "early" in Mercury's history?
Presumably so as not to disturb the existing chronology of the planet's surface cratering.