The very best mountains on Earth tower virtually 9,000 metres above sea degree, and are all on the Tibetan Plateau in Asia — within the Himalaya and Karakoram mountain ranges.
Probably the most well-known are Mount Everest (additionally referred to as Chomolungma), K2 and Lhotse.
“Mountains can’t get a lot increased than people who exist now,” Haakon Fossen mentioned to sciencenorway.no.
Fossen is a professor of geology on the College of Bergen, and sciencenorway.no has interviewed him about excessive mountains on Earth and in the remainder of the photo voltaic system.
As people have despatched out probes and mapped the floor of different planets, these spacecrafts have recognized enormous mountain peaks in our personal photo voltaic system — no less than in comparison with what we now have on Earth.
There are a number of forms of mountains. Some are volcanoes, whereas others are mountains that type as plates within the crust push and collide with one another.
And there are some pure guidelines that govern how excessive mountains on Earth and different planets may be, Fossen mentioned.
There’s a tiny little continent wedged between the Eurasian and North American tectonic plates
Mountains are pressed down and constructed up
There are two necessary elements particularly that have an effect on how excessive mountains may be on Earth, Fossen mentioned.
- The primary is the Earth’s gravity, which always pushes every part down.
- The second is the power of the Earth’s crust beneath the mountains.
The Earth’s floor consists of comparatively skinny plates that float on high of the mantle — the recent rock that lies beneath. The mantle is semi-solid — no less than once you have a look at it from a geological time scale, the place it behaves like a viscous fluid.
Though there are a number of forms of mountains, the very best mountains on Earth are shaped when the Earth’s continental plates collide with one another.
The Himalayas are a dramatic instance of how mountains on Earth are shaped. About 40-50 million years in the past, the Indian plate started to crash into the Eurasian plate, and the Himalayan mountains shot up.
However in some unspecified time in the future, mountains can’t develop any taller, even when the collision continues, in keeping with the Vox information web site.
“It’s simpler to create excessive mountains through the first 15-20 million years of the collision,” Fossen mentioned.
However in some unspecified time in the future they virtually cease rising. Deep beneath the mountains which are pushed up, the Earth’s crust is being pushed down and heated — each from the underside and from radioactive substances contained in the rock itself.
The heating makes the deep elements of the mountain softer, similtaneously gravity is pushing every part down.
“Ultimately it begins to break down — very similar to once you put yeasted pastry dough on a desk,” he mentioned.
The forces that type and form the mountains attain an equilibrium — the forces within the collision trigger the mountains to develop, similtaneously the Earth’s crust beneath the heavy mountains softens, melts and “flows” outwards — as a result of the mountains are pressed down by gravity. The mountains are additionally formed and eroded by climate, wind, rivers and ice.
Wind erosion has created a sculpture park in Antarctica
Geological surveys of the Tibetan Plateau present that this top restrict — the equilibrium top — is round 5,000 metres above sea degree on common, Fossen mentioned. There are particular person mountains which are a lot increased than this, however that is the typical.
“You will get native peaks like Mount Everest that rise above this equilibrium top, but it surely’s not consultant of the typical,” he mentioned.
Consequently, native, random variations assist decide how excessive a mountain may be, reminiscent of rock varieties, rainfall, assist from the encompassing plateau and different native variations. However it’s unlikely that there have ever been mountains which are increased than the very best peaks that exist now, Fossen mentioned.
However these are the situations on Earth. Different planets have fully totally different bodily parameters, which additionally leads to fully totally different mountain heights.
Volcano and mountain?
There isn’t a clear definition of what a mountain is, Fossen mentioned to sciencenorway.no.
What’s also known as the very best mountain within the photo voltaic system is Olympus Mons on Mars. It is a volcano that’s about 22 kilometres excessive. The height is known as after the house of the gods in Greek mythology — Olympus.
This hovering volcano was in a position to be created on Mars as a result of particular situations on Mars itself.
First, Mars has a lot decrease gravity than Earth, solely about 38 per cent of what’s discovered right here, in keeping with NASA. This implies the forces that restrict mountain development are weaker, and mountains can theoretically turn out to be a lot increased than on Earth.
However Olympus Mons is an extinct volcano and got here into existence fairly in another way from the tectonic processes that created the Tibetan Plateau, dwelling of the Himalayas. It shaped greater than three billion years in the past, in keeping with this research within the journal JGR Planets.
When Olympus Mons shaped, Mars was a geologically energetic planet. The volcano was shaped by magma from the planet’s inside, which can have pushed up via the crust and constructed up the volcano over a really very long time, Fossen mentioned.
Earth can also be dwelling to some very excessive volcanoes. Among the many largest is Mauna Kea in Hawaii, which is over 4,200 metres above sea degree. For those who measure the volcano’s top from the seabed, Mauna Kea is 10,000 metres from backside to high.
Relying upon the standards you employ to evaluate heights, Mauna Kea will also be thought-about the world’s highest mountain, in keeping with Enterprise Insider.
However Mauna Kea lies on a plate that “floats” on the mantle under. Beneath the plate is a plume of warmth the place magma is lifted to the floor. This plume of warmth is fastened in the identical place, whereas the plate floats on high and strikes.
For the reason that plate strikes over this plume of warmth, the magma involves the floor elsewhere over geological time. You may see this off Hawaii, the place there’s a line of islands and seamounts which were created over a protracted interval. The magma finds new methods out of the mantle over the course of many hundreds of thousands of years, which is clearly seen on the map under.
However no proof of tectonic plates has ever been discovered on Mars. It appears as if Olympus Mons has been in a position to develop larger and larger as a result of it has remained in a single place.
There are additionally examples of mountains within the photo voltaic system which are far bigger than these discovered right here on Earth — which can have been created by volcanic processes.
It’s unsure whether or not there’s something much like the Earth’s plate tectonics on different planets within the photo voltaic system, in keeping with the EarthSky web site.
However there are a number of locations within the photo voltaic system the place mountains type. One such world is the moon Io, which orbits the large planet Jupiter. The moon has been photographed by a number of probes, though no probe has ever landed there.
It does seem that the moon may be very volcanically energetic, and scientists have proposed theories about what is going on on Io, one in all which is described on this research within the journal Nature Geoscience from 2017.
Io has very excessive, attribute mountains that rise many kilometres straight up from the plains. The very best mountain known as Boösaule Montes and may be as excessive as 18 kilometres in elevation.
An necessary level is that Io has a lot much less gravity than each Earth and Mars, with gravity that’s simply 18 per cent of the Earth’s.
The mountains on Io have totally different shapes and have been in comparison with giant slabs of rock which were flipped on their facet and pushed up by the crust, in keeping with researchers behind this survey from the journal JGR planets. The researchers imagine that the mountains resemble what are referred to as flatiron formations present in some mountainous areas on Earth.
Precisely what processes are accountable for Io’s mountains are unknown, however one principle means that Io’s innards are spewed out by volcanoes in such giant portions that there’s much less and fewer matter beneath the crust.
This causes the crust to shrink and crack open, inflicting giant blocks to be thrust up from the crust, in keeping with Ars Technica.
Translated by Nancy Bazilchuk
This text was up to date on 28 October – the phrase magma was corrected to scorching mantle within the caption beneath the illustration of the boundary between two tectonic plates.
Learn the Norwegian model of this text at forskning.no