Mars canals
The Mars channels are the finest line structures that were first seen in 1877 by the Italian astronomer Giovanni Schiaparelli while observing Mars . Some of them represent canyons or gradations in the terrain, but most of them do not correspond to any structures of the Martian surface known today . They can be interpreted partly as albedo and contrast effects, partly as optical illusions .
Schiaparelli had particularly keen eyes , which is why his "Canali" ( Italian for Rinnen) could not be seen by other observers until two years later at the next Mars opposition .
These even more detailed observations were made primarily at the observatory in the mountains above Nice and at times produced several dozen such lines. According to these findings and those of other Mars explorers around 1900 (especially Percival Lowell , USA) they ran almost in a straight line and most of them started from dark places on the planet.
Changes on the surface of Mars
Together with seasonal discolorations (gray, red, greenish) this gave the astronomers Camille Flammarion and Percival Lowell the idea that they could be artificial structures by " Martians ". Estimates indicated that the " channels " were at least one hundred kilometers wide, which most astronomers explained with broad belts of vegetation along watercourses. Lowell even assumed that a dying civilization would artificially irrigate its slowly drying planet with meltwater from the two polar caps .
Wrong interpretation as traces of life or engineering structures
This idea - which was based on the assumption of a relatively dense atmosphere - gave rise to numerous specialist articles and science fiction novels, including a realistic radio play by Orson Welles that alarmed parts of the USA in 1938. Observed with larger telescopes , however, the "Canali" mostly changed their shape, but in some cases they also doubled. Around 1910, traces of water vapor were observed spectroscopically (by Vesto Slipher, among others) and later supposedly also vegetation spectra, but were doubted by other scientists. In the 1930s, the suspicion increasingly arose that it could be a matter of optical illusions , such as those brought about by the line reinforcement of the visual image processing in the brain with special contrast conditions . Antoniadi's map of Mars from around 1935 only showed successive spots instead of line structures .
The phenomenon of the Mars channels was the main reason for the establishment of the Flagstaff or Lowell observatory in Arizona (1894). It soon became the leading institute for planetology , where Pluto was discovered in 1930 , and developed modern spectroscopy . Up until the 1960s, however , the relevant investigations of the periodic discoloration on the side of some Martian channels could not be clearly interpreted for or against lower traces of life, so that in 1963, shortly before the launch of two Mariner Mars probes, the astrobiologists discovered the existence of mosses and lichens on the “Red Planet “Thought possible.
Today, experts tend to believe that the Martian channels are simulated by the peculiarities of the refractors of that time and by the brightness, spots and contrast of the Martian surface. However, part of the Canali can be explained with spacious, only slightly curved line structures ( terraces , rows of craters , color and shadow effects). What is certain is that Schiaparelli and his successors were able to regularly see the huge, 4000 km long canyon of the Valles Marineris .
Literature (selection) and sources
- The Danish Mars Project. Aarhus Univ., 2002.
- K. Beatty among others: The sun and its planets. 1st edition. Physik-Verlag, Weinheim 1983, ISBN 3-87664-056-3 .
- G. Gerstbach : Mars Channel Observations 1877-90, Compared with Modern Orbiter Data. 2003. (PDF)
- M. Golombek: The Pathfinder Mission to Mars. In: Spectrum d. Knowledge Heidelberg, Sept. 1998, pp. 62-73.
- Hain Walter: The face of Mars and other secrets of the red planet. Herbig-Verlag Munich 1995, ISBN 3-7766-1912-0 .
- J. Herrmann : Life on Other Stars? In: Education and Knowledge. Volume 12, Bertelsmann, Gütersloh 1963.
- MOC 2003: msss.com
- Paul Raeburn: Mars. The secrets of the red planet. Steiger, Augsburg 2000, ISBN 3-89652-168-3 .
