"Most of the planets, no doubt, inhabited and uninhabited will eventually be inhabited," wrote Immanuel Kant in his "universal natural history". It was not only his personal opinion " that the planets of the Solar system are inhabited, in the XVII-XVIII centuries believed significant part of the scientific community. Christian Huygens, one of the founders of modern astronomy, who lived in the second half of the XVII century, even painted an idyllic picture of life on mercury, Mars, Jupiter, and Saturn, where, in his opinion, colocada fat field, "examples of good warmth of the Sun and irrigated fruitful dew and rain". Among these fat fields roam intelligent beings "may not be exactly people like ourselves, but living beings, or any other creatures, endowed with reason". In that way it is, Huygens had no doubts: "If I'm wrong in this, you don't even know, when you can trust your mind, I am left with the role of miserable judges when true estimate of things."

Special attention Huygens attracted Mars is the closest planet to Earth that looks much like ours. In 1659, watching Mars through a telescope, Huygens found that Mars, like Earth, makes a full rotation around its axis in 24 hours. He first noticed on the surface of Mars is constantly existing "spots". Further observations showed that the Martian surface has a number of light and dark areas that became known as "deserts" and "seas". Bright areas are reddish-orange color, and dark grey, blue or green. It was assumed that these are real Martian sea, filled with water. And at the poles of Mars can clearly see the ice caps, like ours, Arctic and Antarctic.

As the development of the optics Mars more and more intrigued by astronomers. It turned out that the polar ice caps of Mars annually come and recede, and the "sea" seasonal change color. In spring and summer, "the sea" looked bluish-green, autumn and winter - brown. In 1860, was made a bold assumption that it is in no way the sea and the woods! But the real "Martian boom" began when, in 1877, Italian astronomer Giovanni Schiaparelli discovered that Mars desert covered by the right of fine lines stretching for hundreds of kilometers. Channels! That is, artificial structures, created by reasonable creatures...

Observations Schiaparelli finally convinced many that Mars is inhabited by intelligent beings. One of the most rabid advocates of this version was an American astronomer Percival Lovell. Founded in 1894, the Observatory for the study of Mars, it is for the rest of his life devoted to the observation of this planet. Having collected the studies huge material, Lovell formulated the theory of life on Mars. He drew attention to the fact that the climate of Mars is very dry (except polar regions), and practically the only source of water on the planet are the polar caps, which, as believed Lovell, consist of water ice. Martian "sea" most likely anhydrous, as if in the Martian seas there was water, that they reflect sunlight, which is not observed. Thus, the "effect of meteorological conditions of the first transfers of water in the region of one pole, and then, after the ice melted, the concentration of the other pole, and this pendulum-like movement is the only source of hydration of the planet". But in spite of such harsh conditions, vegetation, according to the Lovell, on Mars there is argued annual seasonal increase the contrast of the dark areas, which, like waves, spreading across the surface of the planet from pole to pole within six Martian months. "Plant life manifests itself so obvious how this can be expected," wrote Lovell. But life without water is impossible - hence arose the need to create the Martians huge irrigation system. And this system ("channels") can be easily seen through a telescope...

"Based on the results of the observations I come to the conclusion that 1) the overall habitability of the planet and 2) real existence there currently any form of intelligent life", - made a conclusion Lovell.

Actively promoting their views, in his books - "Mars", "Mars and its canals", "Mars as the abode of life" and others Lovell wrote about the drama of the Martian people struggling for survival on dried and dying planet. Thanks to the Lovell image "Martians" stepped from the pages of scientific journals in the mass consciousness, creating "Aelita" by Alexey Tolstoy "War of the worlds by H. G. wells, and hundreds of other novels, movies and plays on the Martian topic.

Lovell died in 1916, but his theory throughout the first half of XX century tormented imagination of mankind. And then...

And then rovellasca theory under the facts of new data began to fade as the polar caps of Mars. Studies of Mars taken by the spacecraft series "Mars", "Mariner" and "Viking", showed that:

- polar glaciers are not from water and from the frozen carbon dioxide;

- light areas of Mars is relatively flat areas of soil, covered by a solid layer of dust and dark areas - areas covered with lots of craters;

- "channels" actually are chaotically located chain of small craters;

- seasonal change the color of the surface are associated with dust storms raging on the surface of the planet;

- in General, Mars more like the moon than on Earth.

And of course, no trace of the Martians... farewell, Aelita!

But...

Spacecraft found and photographed on the surface of the planet many beds of dried rivers. These channels are not visible from the Earth and have no relation to the notorious "channels". It means that the water was... Yes, it was! In 1976, the existence in the atmosphere of Mars water vapor was finally confirmed. At the same time was set, the existence of water ice in the Northern polar region of Mars. It is obvious that large amounts of water remain around the polar regions under the planet's surface in the form of permafrost.

But where is water there is life. Whether it? Or it was, but...

The search continued. And still remains absolutely true historical phrase, uttered in 1957 famous character: "is There life on Mars, there is life on Mars is the science is not known!"