Early speculation proposed that the Moon broke off from the Earth's crust because of centrifugal離心的 forces, leaving a basin凹地、海灣– presumed to be the Pacific Ocean – behind as a scar.This idea, however, would require too great an initial spin of the Earth and also would have resulted in the Moon's orbit following Earth's equatorial赤道的 plane rather than its current path.
第二種 Co-formation hypothesis
The co-formation hypothesis proposes that the Earth and the Moon formed together at the same time and place from the primordial最原始的 accretion添加 disk. The Moon would have formed from material surrounding the proto最初的-Earth, similar to the formation of the planets around the Sun. Some suggest that this hypothesis fails to adequately explain the depletion of metallic金屬的 iron in the Moon.
A major deficiency in all these hypotheses is that they cannot readily account for the high angular momentum動力 of the Earth–Moon system.
第三種Capture hypothesis
Other speculation has centered on the Moon being formed elsewhere and subsequently being captured by Earth's gravity. However, the conditions believed necessary for such a mechanism to work, such as an extended atmosphere of the Earth in order to dissipate消散 the energy of the passing Moon, are improbable似不可信的.
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2009-9-8 09:32:00
