PARIS
\nScientists proposed a novel idea on Wednesday that could solve two of the world\u2019s mysteries at once \u2014 one that passes over our heads every night, and one that sits far below our feet.
\nThe first mystery has puzzled everyone from scientists to inquisitive children for millennia: where did the Moon come from? The leading theory is that the Moon was created 4.5 billion years ago when a would-be planet the size of Mars smashed into the still-forming Earth. This epic collision between early Earth and the proto-planet called Theia shot an enormous amount of debris into orbit, which formed what would become the Moon.
\nOr so the theory goes. Despite decades of effort, scientists have not been able to find any evidence of Theia\u2019s existence. New US-led research, published in the journal Nature, suggests they might have been looking in the wrong direction.
\nAround 2,900 kilometres below Earth\u2019s surface, two massive \u201cblobs\u201d have baffled geologists since seismic waves revealed their existence in the 1980s. These continent-sized clumps of material straddle the bottom of Earth\u2019s rocky mantle near its molten core, one below Africa and the other underneath the Pacific Ocean.
\nScientists have determined that the blobs are much hotter and more dense that the surrounding rock, but much else about them remains a mystery.
\nThe new research indicates the blobs are \u201cburied relics\u201d of Theia that entered into Earth during their formative collision \u2014 and have been hiding near our planet\u2019s heart ever since. As well as creating the Moon, this collision and the remnants it left behind may have helped Earth become the unique life-hosting planet it is today, the researchers proposed.<\/p>\n
Qian Yuan, a geodynamics researcher at the California Institute of Technology and the study\u2019s lead author, said it is \u201cvery, very strange\u201d that no evidence of the Theia impact has been found.<\/p>\n
It was during a class held by a planetary scientist discussing this mystery that Yuan first connected the dots. \u201cWhere is the impactor? My answer is: it\u2019s in the Earth,\u201d he said. The planetary scientist holding the class had never heard of the blobs.<\/p>\n
The research has since required experts in the often separate fields of space and geology to join forces. Yuan said that when Theia smashed into proto-Earth, it was travelling at more than 10 kilometres (six miles) a second, a speed that allowed some of it to penetrate \u201cvery deep into the Earth\u2019s lower mantle\u201d.<\/p>\n","protected":false},"excerpt":{"rendered":"
PARIS Scientists proposed a novel idea on Wednesday that could solve two of the world\u2019s mysteries at once \u2014 one that passes over our heads every night, and one that sits far below our feet. The first mystery has puzzled everyone from scientists to inquisitive children for millennia: where did the Moon come from? The […]<\/p>\n","protected":false},"author":2,"featured_media":365679,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":{"0":"post-365655","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-world"},"yoast_head":"\n