About 55 million years ago, the Eurasian plate collided with the Indian plate, forming the highest mountain range in the world: the Himalayas.
Like the hood of a car during a head-on collision, allegory of the National Geographic which illustrates the phenomenon well, mountains are formed by plate tectonics or, alternatively, by the process of eruption of a volcano, as we saw a few months ago with the volcano of La Palma. In this case, there was no new mountain range (fortunately for the inhabitants of the island), but the territory suddenly expanded by a few square meters.
The highest point on Earth, as we all know, is Mount Everest, which rises 8.8 kilometers above sea level. And the highest mountain, from base to summit, is the Mauna Keaa dormant volcano located on the island of Hawaii in the Pacific Ocean. From its base in the ocean, it rises to 10,204 meters, although it only rises to 4,205 meters above sea level. You've probably wondered more than once if there could be higher mountains, or how much higher these geological structures could rise on the planet to reach an even higher altitude.
“The effects of wind erosion and gravity mean that the taller the mountain, the greater the stresses on it.
What makes a mountain climb infinitely? The larger the mountain, the more it curves, “just as a ball of bread dough slowly flattens out if you put it on a table,” explains Gene Humphreys, a geophysicist at the University of Oregon, in a recent article in Live Science which addresses this issue. On the other hand, there are also many other natural forces that exert such pressure to keep the mountain from rising further. These include wind erosion or large glaciers, which are very good at carving and grinding the edges and tops of these rock formations.
Higher than the sky
“The effects of wind erosion and gravity mean that the larger the mountain, the greater the stresses it is subjected to and the more likely it is to collapse,” explains Gene Humphreys. In other words, the natural and gravitational conditions do not facilitate the task of these summits that aspire to reach the heavens. In the case of Everest, “although it could eventually rise a little higher, its steep slope seems unstable, which could lead to rock falls”.
But what makes a mountain have to be higher than Everest? First of all, as the geophysicist explains, it must be the result of a volcanic process, and not of the collision of two tectonic plates. Indeed, this is the fastest way to increase its size, otherwise it would take thousands of years for it to start forming. “The lava that comes out of the volcanoes cools in layers, building in its wake higher and higher volcanoes,” explains the scientist. “And finally, for the mountain to continue to grow, there would have to be a continuous source of magma pumped higher and higher each time, which would also allow it to erupt and flow down the mountain slopes and cool.”
In fact, it was through a volcanic process that the Olympus Mons of Mars was formed, the highest mountain in the entire solar system, with a total height of 25 kilometers, so high that it looms above the atmosphere of the red planet. To give you an idea, this is equivalent to six mountains the size of Everest. Why so high? It turns out that Mars does not have plate tectonics as active as ours. Its surface is essentially volcanic, so Mount Olympus rose from a very deep basin of incandescent magma that erupted continuously.
Another factor that differentiates Mount Olympus from large terrestrial volcanoes, such as Mauna Kea in Hawaii, already mentioned, is that the molten lava is not dispersed throughout the crust, because there is no plate tectonics; the Pacific plate is moving frequently, so there is no time for a large volcanic slope to form as a result of the release of all this magma. “On Mars, if the plate on which the volcanoes are located does not move, giant volcanic structures can form over hundreds of millions of years of activity,” concludes Briony Horgan, a professor at Pardue University in Indiana.