1999 KUIPER PRIZE LECTURE: Cometary Origin of the Biosphere
1999 KUIPER PRIZE LECTURE: Cometary Origin of the Biosphere
复制标题
1999 年柯伊伯奖讲座：生物圈的彗星起源
DOI：
10.1006/icar.2000.6404
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
A. Delsemme
中科院分区：
文献类型：
--
作者：
A. Delsemme
Abstract Most of the biosphere was brought on the primitive Earth by an intense bombardment of comets. This included the atmosphere, the seawater and those volatile carbon compounds needed for the emergence of life. Comets were thrown into the inner Solar System by the strong perturbation induced by the growth of the giant planets' cores. The bulk of the Earth's bombardment came from those comets that accreted in Jupiter's zone, where the original deuterium enrichment had been diminished by steam coming from the hot, inner parts of the Solar System. This steam had condensed into icy chunks before their accretion into larger cometary nuclei. In contrast, comets that accreted in the zones of the outer giant planets kept their interstellar isotopic enrichments. Those comets contributed to the Earth's bombardment for a small amount only; they were mostly ejected into the Oort cloud and are the major source of the long-period comets observed today. The short-period comets, which come from the Kuiper Belt, should also have the same interstellar enrichment. The deuterium enrichment of seawater, accurately predicted by the previous scenario, has become one of the best telltales for the cometary origin of our biosphere. This cometary origin may have far-reaching cosmological consequences, in particular for the origin of life in other planetary systems.
