In 1877, an Italian astronomer, Joe Schiaparelli, observed the great opposition of Mars. He used an excellent telescope at the time to measure Mars very patiently and draw a map of Mars. picture. In his map of Mars, there are large areas of dark areas on the surface of Mars, which are connected by some thin and long black lines. Schipare named these black lines in Italian Canali, which means "water channel". . He saw about forty such "waterways" in total. Later, the word "waterway" was mistranslated into English as Canals, that is, "canals". "There are canals on Mars", this news went viral and soon became "breaking news" among the public, causing a sensation around the world. Later, someone further pointed out that the bright areas on Mars are dry deserts, while the dark parts are large areas of vegetation. The "canals" were dug by intelligent "Martians". They divert water through "canals" to maintain the survival of their own species. Some people even saw small round spots at the intersection of "canals" and thought they were oases in the desert. For a time, "Martians" became a hot topic around the world. In August of the same year that Schiaparelli discovered the "canal" on Mars, American astronomer Hall discovered two satellites of Mars. They were both small in size and orbited very close to the surface of Mars. Therefore, some people announced that this was an "artificial satellite" launched by Martians. The spread of rumors makes the idea of ??the existence of "Martians" even more mysterious. At the beginning of the 20th century, "Martians" had become popular all over the world and deeply rooted in the hearts of the people. In fact, as early as when the Martian "canal" was first discovered, many calm scientists expressed doubts about it. Their reason is that because Mars is slightly less massive, it is difficult to contain an atmosphere sufficient to nurture and protect life. Moreover, Mars is 50% farther from the sun than the Earth, and the surface temperature must be very low, so the possibility of advanced life existing is very small. However, due to the lack of direct evidence, it is difficult for them to completely defeat the "canal" theory. By the 1960s, the development of space science helped people solve the mystery of the Martian "canal". According to the photos sent back by the probes that flew to Mars, people know that the so-called "canals" on Mars do not exist at all. They are just illusions and fantasies caused by human beings' good wishes. What Schiaparelli and others saw were just some large and small craters that happened to line up in a line. Interestingly, when scientists analyzed the high-resolution photos of Mars taken by the Viking 1 and 2 probes in 1976, they discovered that there are thousands of dry "river beds" on Mars. They do have obvious signs of being washed by liquid. However, these river beds are very thin and cannot be seen with even the best telescopes on the ground. The origin of these riverbeds is still being explored.