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Scientific guide to the mountains | Training, wildlife and higher peaks

How are mountains formed?

Most mountains owe their existence to the movement of tectonic plates, large sections of the earth’s crust. Where two tectonic plates converge, they warp and bend, resulting in the most common type: folded mountains.

The Himalayas, for example, are the result of the slow collision of the Asian and Indian plates. Mountains of boulders are created when the pressures between the plates allow cracks (faults) to appear, with huge slabs of rock pushing upward.

Volcanic activity can also produce mountains. When a volcano erupts, the accumulation of molten rock can form peaks. Sometimes the rising magma can get trapped underground, causing the dome-shaped surface to swell.

With tectonic plates typically moving only three to five centimeters per year, mountains slowly take shape over tens or hundreds of millions of years. The oldest mountain range in the world is the Barberton Greenstone Belt in South Africa, with some mountains estimated to be 3.5 billion years old.

What is the largest mountain in the solar system?

Olympus Mons on Mars is often described as the highest mountain in the solar system. One of the many volcanoes on the Red Planet, it towers over its neighbors 21.2 km above the Martian equivalent of “sea level”, making it about two and a half times the height of Mount Everest. (8.8 km). However, an unnamed mountain peak comes in second. Located in the center of a huge crater on the asteroid Vesta, it has a height of at least 20 km. Its size is even more impressive considering that Vesta’s diameter is only 530 km.

Determining a clear winner is difficult, in part because of the difficulties in establishing a reference height equivalent to sea level on Earth. For example, “zero altitude,” the equivalent of sea level on Mars, is often measured as the height at which temperature and atmospheric pressure would allow water to exist simultaneously in all three states: solid , liquid and gas.

Are the mountains getting higher?

Many mountain ranges continue to grow under the continuous displacement of tectonic plates. These include the Himalayas, whose height increases on average by 5 mm per year. However, after an earthquake that hit Nepal in 2015, some of its peaks retreated by as much as one meter.

In other areas, tectonic movement has slowed down or ceased, such as the tectonic plates that produced the Appalachian Mountains in the United States, which no longer converge. Instead, over the past 200 million years, climate erosion has been the primary force shaping these mountains.

Other processes can also change the height of a mountain. Well, at least seem to be changing. The elevation is measured relative to the mean sea level in the local area – so the exact height depends on the local area chosen as a reference point.

While the first measurements were based entirely on trigonometric calculations, these are now assisted by GPS or gravitometers to assess altitude more precisely.

Is it dangerous to climb Everest?  © Getty Images

Is it dangerous to climb Everest?

More than 300 people have died on Everest since 1922. Injury and bad weather can be fatal in this remote environment, and our bodies have not evolved to cope with low oxygen levels at high altitudes. Mountain sickness can lead to fatal pulmonary or brain edema, which occurs when a lack of oxygen causes fluid to leak into the lungs or brain.

To avoid this, climbers acclimatize in stages, allowing their bodies to gradually adapt. Above 8,000 meters, climbers enter the “death zone” where atmospheric pressure is so low that humans cannot survive for long periods without supplemental oxygen.

In 2019, the strong winds left only a few favorable days for climbers to attempt the summit of Everest. Many have been forced to wait their turns at extremely high altitudes, amplifying the effects of exhaustion and altitude sickness. This led to one of the deadliest years on the mountain, with 11 reported deaths.

What animals live in the mountains?  © Getty Images

What animals live in the mountains?

With a lack of oxygen, high winds, freezing temperatures and strong sunshine, the mountains are a harsh environment. Yet many animal species have adapted to settle on mountain peaks, developing red blood cells capable of absorbing more oxygen.

One of the most famous mountain dwellers is the snow leopard, which lives at altitudes of 3000 to 5000 meters in Central Asia. Its prey includes various species of mountain goats and pikas (tiny members of the rabbit family that are considered the tallest mammals on Earth, sometimes found at elevations in excess of 6,000 meters).

Spotted up to 7000 meters, the bar-headed geese fly over the Himalayas during their annual migration. Flying in such a thin atmosphere is difficult, but these birds with large lungs fly at night when the air is colder and denser.

About 12% of humans live in such habitats, and some people have also evolved to live at altitude – most Tibetans have a genetic mutation that prevents their bodies from overreacting to low levels of oxygen.

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