一个早期的月球核心动力发动机,由热化学地幔对流驱动
Dave R Stegman1, A Mark Jellinek, Stephen A Zatman
1Department of Earth and Planetary Science, University of California, Berkeley, California 94720, USA. dstegman@eps.berkeley.edu
Nature
|January 10, 2003
概括
一个早期的月球动力发电机,产生月球的磁场,可能是由核心热量流的暂时增加提供动力. 这种增加是由于一个富含放射性物质的层在月球地幔内翻转而导致的.
科学领域:
- 月球科学 月球科学
- 地质物理学 地质物理学
- 星球动力学 星球动力学
背景情况:
- 古磁数据和阿波罗卫星的样本表明,月球在39亿至36亿年前曾有磁场,这暗示着古代的月球动力发电机.
- 现有的热进化模型无法解释足够的核心热流来为42亿年前后的动力发电机提供动力.
研究的目的:
- 为了解释早期的月球动力发电机的存在和时间.
- 为了使古磁证据与热进化模型相协调.
主要方法:
- 使用了一个三维球形对流模型.
- 研究了一个分层的月球地幔与放射性丰富的基底层的作用.
主要成果:
- 在月球地幔底部的一个密集的放射性"热毯"最初抑制了核心冷却和动力发电机的作用.
- 随后的放射性加热增加了毯子的浮力,导致它升起并翻转成地幔.
- 翻转事件暂时增加了核心热量流,足以为短暂的月球动力发电机提供动力.
结论:
- 由于月球地幔翻转,核心热流的短暂增加可以解释早期的月球动力发电机.
- 这种翻转事件也可能解释富含和的月球海基岩的喷发.
- 拟议的机制使古磁观测与月球热史相协调.
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