Earth will be "hollow" in it?.

<P> We know the density of the crust 2.8 grams / cubic centimeter, and the entire Earth's average density of 5.5 grams / cubic centimeter, so we'll be able to guess part of the Earth must have a density greater than 5.5 grams / cubic centimeter. .</ P> <P> this question we have many ideas, but one thing we are very clear, that this is only our inference. .Tested in the laboratory size of an ordinary sphere, its gravitational suffered small to be negligible. .But for the planet, its huge gravitational pull on Earth can be sucked all the material firmly. .If we assume that all of a rocky planet, then deep geological formations will be crushed by the weight of the outer layer. .This powerful force can compress the Earth's interior and to focus all of the quality of all of them a very small volume, so the deeper strata than the natural density of the outer density is larger. .This problem seems to be so solved. .</ P> <P> If you have never thought about this, then the problem may be daylights scared, but a long time, people have been held this view, and based on its interpretation of the many stories .and myths and legends. .Why do people have such ideas? .The reason, however, because the tunnel found on Earth, even though they are only distributed at the surface. .At present we know nothing but the deepest tunnel is only 1.17 km deep, with 6350 km radius of the earth than simply pale into insignificance. .However, there are still some people imagined to find the tunnel leading to center of the earth. .</ P> <P> "Hollow Earth" put forward this view can be traced back to ancient times, in ancient Greek mythology, the giant king of gods because defy the will of Zeus was buried in the ground, they cause painful twist .the earthquake. .The volcano seemed to further confirm the existence of the Earth's interior is a "large chamber", with fire and sulfur-rich, extremely easy to burn. .</ P> <P> early in the history of science, some scientists had indeed confirmed commitment "Hollow Earth" The religious views. .In 1665, radical German scholar Asa Shell Sike has published a book in the most spectacular time, he will be in the writings of the Earth depicted as a "big screen", and "eye screen" is that .widely distributed on the surface of the tunnel, in which dragons are often spotted in the tunnel. .</ P> <P> 19 century, the United States went so far in the defense strategist 托恩克里伍塞 Moss, "Hollow Earth" theory study took pains to show people that existed in the Arctic region's leading center of the earth .tunnel. .After following the Se Mosi, until today, this bizarre idea led people to post a lot about science fiction adventure center of the earth and articles. .The most famous is the French writer Jules Verne, published in 1864, "geocentric Travels", in this well-known science fiction novels, Jules Verne to the people painted a wonderful picture of the underground world, where .subsurface ocean, dinosaurs run amok, and Australopithecus who come and go around, and the channel leading to the mysterious wonders under the ice in the cold. .Prior to this, Yitzhak edited by Alan Ball has a similar story, he will this channel "moved" to the North Pole. .</ P> <P> results to 1909, U.S. explorer 罗博特爱迪 text Pirelli did not find anything in the Arctic, "center of the earth channel." .However, these legends have been passed down. .One of the most popular when the number of Yitzhak R. .Bo Luozi of a series of books, which first published in 1913. .Until 1798, people finally know the earth is not and can not be hollow. .When Cavendish calculate Earth's mass, the people further to calculate the density of the Earth is 5.5 g / cc (exact value is 5.518 g / cc), while the average density of rocks in the crust 2.8 grams / cubic centimeter. .If the earth really hollow, and assuming that the air filled hollow part, then the total density of the earth should be less than 2.8 grams / cubic centimeter. .Earth's density is 5.518 grams / cubic centimeter of the fact that: in the center of the earth crust density must be greater than the density of rocks. .Therefore, the Earth is definitely not hollow. .Of course, there are other examples can be sure that the earth is solid. .</ P>.