If you want to visit the deep earth, how deep can you go?

At the beginning of the story of "Journey to the Center of the Earth", Aksai said that if the temperature increases by one degree every 70 feet, the temperature at the center of the earth is 2 million degrees. His uncle retorted that if the temperature was really that high, the heat would overturn the earth.

But the real temperature cannot be calculated so simply. The temperature inside the earth does not rise gradually and steadily, but is divided into several layers, each with its own temperature law. So Aksay's argument is wrong.

But my uncle thought that the temperature at the center of the earth must be very low, which is also wrong. Today we know that the temperature at the center of the earth is about 6000 degrees Celsius, which is about the same as the temperature on the surface of the sun. This temperature is not as exaggerated as millions of degrees, but it is enough to melt all materials known to humans, and of course it is enough to bake people. Therefore, we cannot really explore the center of the earth.

So, can there be rivers, lakes, seas, and even life underground?

Of course, there can be rivers and lakes in the shallow underground. Occasionally, there will be a small amount of life, such as fish and bats. However, there will not be a single large cave underground. The rocks cannot support it, and it will be easily blocked by other things. Therefore, there will be no vast ocean underground.

Although there are vast mushroom forests underground in many stories, in fact, there are fewer mushrooms underground than on the ground. It is true that mushrooms do not need sunlight, but they need other nutrients, that is, the corpses of other creatures. Mushrooms can only be abundant where there are many other creatures. Without sunlight as an energy source underground, other creatures are rare, and mushrooms cannot grow in large numbers.

In addition, there would certainly be no extinct creatures surviving underground.

As for the deeper underground, the temperature is too high and the water has evaporated, so naturally there are no rivers, lakes or seas.

But if I just want to visit the deep earth like in the novel, how deep can I go?

Including the ocean, humans have only been to the bottom of the ocean at a depth of 10,000 meters. If we don't count them, humans have only been to natural caves at a depth of more than 2,000 meters. Because natural caves are too complicated, very dangerous, and very easy to get lost, so although there are definitely deeper caves, no one has gone that deep yet.

Of course, forget about the volcanoes in novels, as all volcanoes are blocked and there is no passage at all.

Natural caves are difficult to drill, so can they be dug artificially? The deepest drilled holes made by humans are more than 10,000 meters deep, but those holes are very small and people cannot drill into them.

As for the holes that humans can enter, they are mines. The deepest mine on earth is a gold mine in South Africa, which is about 4,000 meters deep.

If we ignore the existing hole and dig down with a super-powerful shovel, how deep can we dig? If you are unlucky, you will be burned to death in a place with geothermal activity. If you are lucky, you can dig four or five kilometers, and although it is very hot, it is still bearable. If you dig deeper, the temperature will definitely exceed 100 degrees, and people will not be able to bear it.

What if you wear a strong heat-insulating suit? Jules Verne's novel mentioned that the deeper you go, the greater the air pressure. When you reach a depth of five or six kilometers, the air pressure will be so high that even oxygen will become toxic to humans. If you stay here for a long time, you will die from oxygen intoxication.

What if you add pressure resistance to the heat-insulating suit and bring an oxygen tank? If you choose the best place to dig a hole and are lucky enough to avoid the magma halfway, then you can dig to a depth of about 50 kilometers at most. But that's it: at this depth, there are no regular rocks, and there is magma everywhere. The temperature of this magma is around 1000 degrees Celsius, which may not be enough to melt your protective suit, but if you soak in the magma, the heat will quickly penetrate the protective suit and roast you inside. So, 50 kilometers is basically the limit of human digging downwards.