Difficulties
This lunar origin hypothesis has some difficulties that have yet to be fully resolved. For example, the giant impact hypothesis implies that a surface magma ocean would have formed following the impact. Yet there is no evidence that the Earth ever had such a magma ocean and it is likely there exists material that has never been processed by a magma ocean.
Read more about this topic: Giant Impact Hypothesis
Famous quotes containing the word difficulties:
“Let us consider that we are all partially insane. It will explain us to each other; it will unriddle many riddles; it will make clear and simple many things which are involved in haunting and harassing difficulties and obscurities now.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)
“I often think that all the difficulties we encounter only give us the more strength if we keep hold of our work, and we must not now give up while in the prime of life. It is best to keep trying, and by and by the opportunity will come. If we have given up, then we shall not be ready for it when it does come.”
—Ellen Henrietta Swallow Richards (1842–1911)
“If the underdog were always right, one might quite easily try to defend him. The trouble is that very often he is but obscurely right, sometimes only partially right, and often quite wrong; but perhaps he is never so altogether wrong and pig-headed and utterly reprehensible as he is represented to be by those who add the possession of prejudices to the other almost insuperable difficulties of understanding him.”
—Jane Addams (1860–1935)