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The science fiction movie The Wandering Earth Ⅱ has been quite popular since its release on Jan 22. The space elevators in the movie are quite impressive—elevator cars travel quickly between the cables hat connect Earth’s surface and the space station. This device may not only be imagined in the future.

Early in 1895, Russian scientist Konstantin Tsiolkovsky was inspired by the Eiffel Tower. He pointed out that if humans could build a tower high enough to reach space, people would be able to travel by space elevators. However, such a tower is impossible because no matter how large its base is, it would not be able to support the whole system.

Scientists then considered the idea in a different way. Earth’s satellites, about 36, 000 kilometers high in the sky, appear to be fixed in space. They rotate around Earth once every day. According to Scientific American, if such a satellite could drop cables towards Earth, and the cables could be fixed to Earth’ surface, then the whole system would rotate along with Earth.

This seems possible, but one of the challenges that stop engineers from building the elevators is the cables’ material. According to an article by the Institute of Physics, Chinese Academy of Sciences, a carbon nanotube might be the most proper material. It weighs 1. 6 grams and it can hold more than 800 tons which is about the weight of 160 elephants. Since its discovery in 1991, scientists have been trying to create a carbon nanotube as long as possible. However, the longest carbon nanotube with a perfect structure was only about half a meter. It was developed by a team at Tsinghua University in 2013.

Space elevators require far less energy and money than rockets. With space elevators, space tasks would be carried out more easily and more frequently. Although scientists have not solved the key problem, they will continue doing research on carbon nanotubes. Maybe one day the space elevator will enter our life.