It assumes, however, that impactors arrive at a roughly steady rate and produce one crater per hit.After compensating for various complicating factors, like atmospheric density, gravity, and geological activity, scientists had been confident of their time charts -- until recently.
Dating methods are like human pyramids; they depend ultimately on the support of the bottom layer. If the bottom guy buckles under pressure, the circus act quickly turns into a dogpile.
One widely used technique for estimating ages of planetary surfaces is in similar jeopardy.
Note: There are craters of other origins, such as pit craters or caldera craters at the top of volcanoes.
Only impact craters are used to date surfaces, and for brevity I will only be referring to them from this point on as “craters” instead of “impact craters.” The basic idea behind using craters as an indicator of a surface’s age is that the longer the surface is around, the more craters will form.
This knowledge can be used to prove whether models predicting crater impact and frequency are accurate.