The frequency of impacts on Earth's surface increased about 290 million years ago Collisions and impact processes have been important throughout the history of the solar system, including that of Earth. Small bodies in the early solar system, the planetesimals, grew through collisions, ultimately forming the planets. Recognizing the remnants of impact events on Earth is difficult because terrestrial processes either cover or erase the surface expression of impact structures in geologically short timespans. Because Earth and the Moon are subjected to the same flux of impactors, the latter's crater record serves as a proxy for that of Earth. On page 253 of this issue, Mazrouei et al. (1) report that infrared images of the Moon taken by the Lunar Reconnaissance Orbiter Diviner instrument can be used to estimate the ages of young lunar craters. They find the impact rate increased within the last ∼500 million years.

中文翻译：

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当地球受到重创

大约 2.9 亿年前，对地球表面的撞击频率增加了 碰撞和撞击过程在整个太阳系的历史中一直很重要，包括地球的历史。早期太阳系中的小天体，小行星，通过碰撞成长，最终形成行星。识别地球上撞击事件的残余物是困难的，因为地球过程在地质学上很短的时间跨度内要么覆盖要么抹去撞击结构的表面表现。由于地球和月球受到相同的撞击流影响，后者的陨石坑记录可以作为地球记录的代表。在本期第 253 页，Mazrouei 等人。(1) 报告说，月球勘测轨道器占卜仪器拍摄的月球红外图像可用于估计年轻月球陨石坑的年龄。