Hi! This video was a stitch with a TikTok from science communicator Astro Alexandra. If you'd like to view her video in full, please click here!
This volcano is Olympus Mons, and as Astro Alexandra explains, it is by far the largest volcano in our solar system. In fact, it's so tall that its peak pokes out above Marsâ thin atmosphere. So if you were to climb to the summit, youâd essentially be hiking out into space!
But even though Olympus Mons is 2.5 times the height of Mount Everest, because its base is so huge, you could probably just walk up it! Its average slope is just under 3 degrees! If you compare that to typical Mount Everest slopes, they range between 20 and 60 degrees.
But why is Olympus Mons so huge? and why do we have nothing even close on our own planet? Well, lower surface gravity and higher eruption rates on Mars in the past might have contributed. But, crucially, while Earth has plate tectonics, Mars does not.
On Earth, the crust is broken up into plates. These slide around over liquid magma below. Where thereâs a hotspot (a plume of rising magma), magma might break through the crust, forming an active volcano. But in time the crust will move, the volcano will no longer be above the hotspot, and will become inactive. Now, a new part of the crust finds itself above the hotspot, forming another volcano. This is how the Hawaiian islands formed!
However, on Mars, it's believed that the crust remains stationary, meaning a part of the crust above a hotspot will always be above that hotspot. This is what allows volcanoes like Olympus Mons to grow much, much larger than on Earth!
Please note: I use present tense throughout this TikTok to talk about volcanoes forming both here on Earth and on Mars. However, scientists believe the type of volcanism capable of producing giants like Olympus Mons seems to be long in Mars' past. Therefore, past tense might have been more appropriate!
But, whilst most Martian volcanism occurred between three and four billion years ago, recent research seems to suggest that Mars might still be volcanically active! Since landing on Mars in November 2018, NASA's InSight lander has detected more than 1,313 marsquakes (as of May 2022). The most recent of these, detected by InSight on May 4th 2022, was the most powerful yet (estimated at magnitude 5 on the Richter scale).
Furthermore, in 2021, David Horvath and his team of researchers at the University of Arizona published a paper detailing their discovery of a volcanic deposit in Mars' Elysium Planitia region. This discovery is really exciting as the team estimate that the deposit was produced very recently on geological timescales (between 46 000 and 221 000 years ago). Therefore, this suggests that Mars has been volcanically active to some extent recently in its history, and may even be volcanically active today!
If Mars is still volcanically active today, this might have serious implications for astrobiology in our solar system. As David Horvath explained in an interview about the discovery:
"The interaction of ascending magma and the icy substrate of this region could have provided favorable conditions for microbial life fairly recently and raises the possibility of extant life in this region" ...
... "This does not necessarily confirm past life on Mars, but does imply an environment conducive to habitability"
It's worth noting, though, that it's not yet known what precisely caused this eruption. Whilst it seems likely that the deposit was caused by magma interacting with trapped gas or permafrost under the Martian surface, there is also a possibility that a large asteroid impact may have triggered the eruption.
But regardless of the cause, one thing is clear: Mars is not a dead planet after all.
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