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Conducting Miller-Urey Experiments
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大规模冲击对地球原始大气的化学效应
B Fegley1, R G Prinn, H Hartman
1Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge 02139, USA.
Nature
|January 23, 1986
概括
早期地球上的巨大冲击可能创造了生命的关键分子. 这项研究模拟了小行星撞击如何产生化 (HCN) 和甲 (H2CO),这是有机合成的重要前体.
科学领域:
- 天体生物学 天体生物学
- 行星科学 行星科学
- 大气化学 大气化学
背景情况:
- 早期的地球经历了小行星和彗星的激烈轰炸.
- 这次轰炸可能大大改变了原始的大气.
- 这种冲击可能产生了对有机化合物的非生物合成至关重要的前体分子.
研究的目的:
- 在撞击条件下的地球原始大气中模拟化 (HCN) 和甲 (H2CO) 的产生.
- 评估冲击产生的HCN和H2CO对前生物化学的潜在贡献.
主要方法:
- 使用了热化学平衡和化学动力学计算.
- 模拟各种温度,压力和初始大气成分的空气冲击包裹.
- 专注于大气中的碳与氧 (C/O) 比率大于或等于1.
主要成果:
- 玻化物冲击可以产生显著的HCN体积混合比率 (在冲击地区为10^-3至10^-5,全球为10^-5至10^-12) 对于C/O>=1大气层.
- 在冲击区域的H2CO混合比率在10^-7到10^-9之间,由于大气快速去除,全球分布有限.
- 在海洋中下雨的HCN每年可以提供 (3-14) x 10^11 mol HCN.
结论:
- 早期地球上的冲击是前生物HCN的可信来源,可能超过其他估计的来源.
- 产生的HCN可能在复杂有机分子的非生物合成中发挥了关键作用.
- 虽然产生了H2CO,但其短暂的大气寿命限制了其对全球益生菌化学的贡献.
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