[视频]月球在萎缩

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>>最近科学家在月球上惊奇地发现折皱纹,这为早期关于月球在萎缩提供了有力证据。

 

2010年科学家发现月球一直在缩小。收缩将使得月球像一个萎缩的葡萄,这就在其表面形成“纹脊”的特征。这种萎缩是有道理的,由于月球从40亿年前形成开始一直在丧失热量,因此月亮的内部是一直在缩小。同时在水星上也发现类似的纹脊。

华盛顿史密森学会Thomas Watters带领的一个团队说,虽然月亮总体上在缩小,但是目前看起来月球表面的版块最近才开始萎缩。
 
NASA月球勘测卫星显示这些称之为地堑带的波谷,通常是由于物体表面分离而形成的(见视频)。
 
之前科学家已经发现月球表面很久以前的折皱纹,但是最新发现的地堑带肯定是迟于5000万年前形成的,因为这些地带几乎没有发现火山口。也有科学家说,这些意外发现的伸展纹也可能是由于岩浆喷发后凝固在月球表面而使得地表隆起。
 
亚利桑那州立大学的Mark Robinson在一次NASA新闻发布会上说:“有些完全意外的发现总是让人激动。目前只有一半的月球表面已经进行高解析度扫描,所以月球上还有更多的东西去探索。”
 
via Nature Geoscience, DOI: 10.1038/ngeo1387
 
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Recent stretch marks have been found on the moon, a surprising find given previous evidence that the moon is shrinking. 
 
In 2010, researchers discovered that the moon has been contracting over time. The shrinkage is making the moon shrivel like a raisin, creating features called wrinkle ridges all over its surface. That shrivelling makes sense, because the moon's interior should be gradually contracting as it loses the heat from its violent formation more than 4 billion years ago. Similar wrinkles have been found on Mercury. 
 
Despite the overall contraction, it now appears that patches of the moon's surface have recently experienced stretching, says a team led by Thomas Watters of the Smithsonian Institution in Washington DC. 
 
NASA's Lunar Reconnaissance Orbiter revealed troughs called graben, which form when a body's surface is pulled apart (see this illustration). 
 
Very ancient stretch marks had been found on the moon before. But the newly discovered graben must be less than 50 million years old, given how few craters have formed on them. The unexpected stretch marks may be due to magma pooling in pockets beneath the moon's surface, causing the ground above it to swell, the researchers say. 
 
"It's exciting when you discover something totally unexpected," says team member Mark Robinson of Arizona State University in a NASA press release. "And only about half the lunar surface has been imaged in high resolution. There is much more of the moon to be explored."