In the 19th century, the late Italian astronomer Giovanni Schiaparelli conducted numerous observations of Mars, giving the names of the "seas" and "continents" of the Red Planet, to name a few. He was a staunch observer, studying Mars from 33.9 million miles away with only his telescope.
There was one observation though that dwarfed his other discoveries. In 1877, when Mars underwent a "Great Opposition," or the moment when it is in the sky opposite the Sun, a prominent network of dense linear structures on the surface of Mars near its equatorial region showed itself to Schiaparelli. Struck with what he had seen, he called it "canali," which meant "channels" in his native tongue.
The English men seemed to have misunderstood the term, and instead translated it to "canals," giving a notion that these were artificially made instead of the intended meaning channels, which aptly meant that these strange features on Mars' surface are made of natural causes, hence, sparking speculations on whether intelligent life existed on Mars.
Now known as Noctis Labyrinthus, a deep gorge system between a massive canyon called Valles Marineris and the Tharsis upland, further observations led scientists to conclude that they must be either carved by massive water surges on Mars then, as they look similar to terrestrial canyons formed by water or they resulted in tectonic activities on the planet.
That is until two centuries later, when a scientist from the Eidgenössische Technische Hochschule Zürich (ETH Zurich) University, who bear the first name as Schiaparelli, claimed that the assumptions are far from ironclad. To him, these gorges we formed from immense lava flows.
"Everything that I observed on those images were structures of lava flows as we know them on Earth," said Giovanni Leone, who is also a specialist in planetary volcanism, in a statement. "The typical indicators of erosion by water were not visible on any of them."
"One must therefore ask oneself seriously how Valles Marineris could have been created by water if one cannot find any massive and widespread evidence of it," Leone added, noting that there is not plausible area as to where water could have originated.
This may be the case, but Leone cleared that he could not yet rule out water as one of the contributors to the formation of the gorge system since evidence of water such as salt deposits or alluvial fans might be "scarce but still existing."
As for the origin of the lava flow that could have carved the Noctis Labyrinthus, Leone points to the volcanic region of Tharsis as the main source of these hot molten rocks. The lava could have created tubes from beneath Mars' surface and stretched out to the edge of the gorge system.
When the pressure from an eruption subsided, some of the tube ceilings collapsed that eventually led to the formation of a chain of almost circular holes called the "pit chains," Leone explained. Then lava came in the tubes again, and when it cooled down, the ceilings came crashing down completely, forming V-shaped troughs. More lava in the area created a much larger canyon.
To come up with this conclusion, Leone spent years in analyzing thousands of high-resolution photos taken by the probes sent to Mars, including the latest images from the Mars Reconnaissance Orbiter.
The study came out in the Journal of Volcanology and Geothermal Research.
