Olympus Mons is the solar system’s largest volcano. Astronomers say it holds clues to unraveling the Crimson Planet’s historical past.
4 large volcanoes make up the Tharsis Bulge on Mars. The most important of the 4, Olympus Mons, is at backside proper. Credit score: ESA/DLR/FU Berlin/Justin Cowart.
Younger Mars would have been a staggering place to discover. The Crimson Planet was coated in flowing rivers of each water and lava. On the time, a collection of 4 volcanoes — Olympus Mons and the three peaks of Tharsis Montes — have been all rising taller than any mountain on Earth.
Every of those peaks is spectacular. However Olympus Mons stands above the remainder, reaching an astonishing peak of 16 miles (26 kilometers), or round 3 times as tall as Mount Everest. That makes Olympus Mons the biggest volcano within the solar system.
Nevertheless, appreciating it requires an understanding that the volcano isn’t simply tall. It’s additionally obtained girth. Olympus Mons is about 20 instances wider than it’s excessive. Its diameter spreads 370 miles (600 kilometers) from edge to edge.
Should you set Olympus Mons on high of the US, it will cowl the whole state of Arizona. And when you plopped it over Europe, it will cowl France. A 2011 research recommended that the volcano comprises roughly a million cubic miles (4 million cubic kilometers) of fabric, which really dwarfs something on our personal planet. That’s round 100 instances the quantity of Earth’s largest volcano, Mauna Loa.
Olympus Mons sits on the identical volcanic “bulge” because the three volcanoes of Tharsis Montes — Ascraeus Mons, Pavonis Mons, and Arsia Mons.
And when 4 mega volcanoes fashioned so shut collectively it proved to be extra weight than Mars’ floor might bear. The volcanoes made the planet tip over a bit. Some 3 billion years in the past, Mars’ outer layers slipped underneath their weight. The crust and mantle traveled about 20°, transferring from the polar areas towards the equator. It was sufficient to reroute rivers and alter the planet’s local weather.
Earth volcanoes vs. Mars volcanoes like Olympus Mons
How did Olympus Mons develop so huge? Time.
It’s a shield volcano, which suggests it oozes enormous quantities of lava, fairly than merely blowing its high in a catastrophic eruption. Earth’s greatest volcanoes are additionally protect volcanoes. This lets them develop slowly over time.
Nevertheless, Earth’s plate tectonics additionally unfold magma out, which retains terrestrial volcanoes from indefinitely rising taller. Mars, alternatively, is simply too small for plate tectonics.
Olympus Mons is a few 3.5 billion years outdated, which suggests the volcano formed early on in Mars’ history. Astronomers suspect Olympus Mons might have stayed volcanically energetic for a whole lot of thousands and thousands of years. That’s far longer than any volcano on Earth might stay energetic.
Clues to Mars’ local weather historical past
In a Nature Communications paper printed in 2017, astronomers studied a household of meteorites known as nakhlites, which have been all flung from Mars when an asteroid struck a volcano on the Crimson Planet some 11 million years in the past.
The research confirmed that Mars’ volcanoes have been seeping lava at a significantly sluggish tempo: The volcano that fashioned the nakhlites grew 1,000 instances slower than volcanoes do on Earth. The discovering implies that Mars’ volcanoes last more than scientists beforehand anticipated.
And in Olympus Mons’ case, the craters on its floor are additionally solely round 200 million years outdated, which suggests this volcano was energetic surprisingly lately, no less than to a restricted extent.
By learning Olympus Mons and different volcanoes on Mars, scientists will help unravel clues to the Crimson Planet’s local weather historical past, too. The meteorites born from the volcano really present indicators of minerals that type as water passes by way of rock, which suggests water was flowing on Mars as lately as 1.3 billion years in the past. So, it seems, the Crimson Planet’s period of working rivers and flowing lava may not have solely been confined to the extraordinarily distant previous.
