Impact rates on Earth and the Moon The rate at which impacts produce craters on the Moon is used to calibrate ages in planetary science. Earth should also have received similar numbers of impacts, but many craters have been hidden by erosion, ice sheets, and so on. Mazrouei et al. used infrared images of the Moon to estimate the ages of young lunar craters (see the Perspective by Koeberl). They found that the impact rate increased within the past ∼500 million years, a conclusion strengthened by an analysis of known impact craters on Earth. Crater size distributions are the same on Earth and the Moon over this period, implying that terrestrial erosion affects all craters equally, regardless of their size. Science, this issue p. 253; see also p. 224 The rate of impacts producing craters on Earth and the Moon increased within the past 500 million years. The terrestrial impact crater record is commonly assumed to be biased, with erosion thought to eliminate older craters, even on stable terrains. Given that the same projectile population strikes Earth and the Moon, terrestrial selection effects can be quantified by using a method to date lunar craters with diameters greater than 10 kilometers and younger than 1 billion years. We found that the impact rate increased by a factor of 2.6 about 290 million years ago. The terrestrial crater record shows similar results, suggesting that the deficit of large terrestrial craters between 300 million and 650 million years ago relative to more recent times stems from a lower impact flux, not preservation bias. The almost complete absence of terrestrial craters older than 650 million years may indicate a massive global-scale erosion event near that time.

中文翻译：

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地球和月球撞击通量在古生代末增加

对地球和月球的撞击率撞击在月球上产生陨石坑的速度被用来校准行星科学中的年龄。地球也应该受到类似数量的撞击，但许多陨石坑已被侵蚀、冰盖等隐藏。马兹鲁伊等人。使用月球的红外图像来估计年轻的月球陨石坑的年龄（参见 Koeberl 的观点）。他们发现撞击率在过去约 5 亿年内有所增加，这一结论通过对地球上已知撞击坑的分析得到加强。在此期间，地球和月球上的陨石坑大小分布相同，这意味着地球侵蚀对所有陨石坑的影响是平等的，无论其大小如何。科学，这个问题 p。253; 另见第。224 在过去的 5 亿年里，地球和月球上产生陨石坑的撞击速度增加了。陆地撞击坑的记录通常被认为是有偏差的，即使在稳定的地形上，侵蚀也会消除较旧的陨石坑。鉴于撞击地球和月球的弹丸数量相同，可以通过使用一种方法对直径大于 10 公里且年龄小于 10 亿年的月球陨石坑进行测年来量化地球选择效应。我们发现，大约在 2.9 亿年前，影响率增加了 2.6 倍。陆地陨石坑记录显示了类似的结果，这表明 3 亿至 6.5 亿年前的大型陆地陨石坑相对于最近时期的缺失源于较低的撞击通量，而不是保存偏差。