美国科学家们认为,他们已经探索出使研究人员迷惑了几十年的重大的地质奥秘之一,因为他们发现了地幔中的陷落层,他们称此层为曾组成地球的关键性的“失踪地壳”(mis-sing crust)。在丹佛召开的美国地质学会的年会上宣布的这一发现,终于解决了下面的问题,即地球的外壳为什么比月球和火星上的类似的外壳薄如此之多。月球和火星的外壳占该星体的10%,而地球的地壳只占本行星陆地质量的0.4%。 American scientists believe they have explored one of the major geological mysteries that have fascinated researchers for decades as they have uncovered subsidence layers in the mantle that they call the key “missing crust” (Mis-sing crust). The discovery, announced at the annual meeting of the American Geological Society in Denver, finally solved the question of why the Earth’s shell is so thin compared to similar shells on the Moon and Mars. The outer shell of the moon and Mars make up 10% of the planet, whereas Earth’s crust accounts for only 0.4% of the planet’s terrestrial mass.