How we thought Mars has life

 

 Before we explored Mars, many scientists had believed, or better said, hoped that life existed on the Red Planet.

 But why Martians? Why so many fantesies about martians and not, let's say Venusians?
Maybe because at a first glace, Mars resembles the Earth. It has rougly the same size, same solar day (24 hours), two frozen poles, sandstorms, and many more.

 Giovanni Schiaparelli, an italian astronomer, observed in the late 19th century some linear features on Mars's surface. He described them as "canali" (italian, meaning "channels"). Later, it was mis-translated as canals, leading to speculations about intelligent life existing on the planet.

 Percival Lowell championed the idea of canals.He dedicated his life to studying Mars and made detalied observation of this phenomenom at his observatory near Flagstaff, Arizona. Lowell believed that the Martians were an ancient, advanced civilization that had built those canals to conduct water from melting polar caps to the inhabitants of equatorial cities.

A map of Lowell's canals

                                            

  Observations with better telescopes and ultimately spacecraft like Martiner 4 revealed that these markings weren't present.It became broadly accepted that the canals were instead some kind of optical illusion, even though we don't know exactly what caused them.

 Alright, Mars isn't populated by intelligent life, but maybe there is microscopic life. Viking 1, the first successful Mars lander in history, conducted three experiments to search for microscopic life on Mars.Each of the three microbiological experiments answered a different kind of question, but each time a question about Martian metabolism. If there are microorganisms in the Martian soil, they must ingest food and expel gases, or they must absorb gases from the atmosphere and convert them, maybe with the help of sunlight, into useful materials. Then we see if any new gases come out of the soil. Or we provide our own gases, which are considered radioactive, and see if they are converted into organic matter.

                                                                                                     

Viking 1

Two of the three microbiology experiments on the Viking mission appear to have yielded positive results. But scientist hadn't considered the existence of some types of clay that reproduce some of the key features of both photosynthesis-like and respiration-like features on Mars.

 

All in all, the martians remain just a beautiful science-fiction dream. But we shouldn't give up! There are billions of planets waiting to be analysed!