A giant volcano hiding in plain sight in one of Mars’ most iconic regions.
Olympus Mons is well known for being the largest volcano in the Solar System. It’s joined on Mars by three other shield volcanoes; Ascraeus, Pavonis and Arsia but a recent discovery has revealed a fifth. Provisionally called Noctis volcano, this previously unknown Martian feature reaches 9,022 metres high and 450 kilometres across. Its presence has eluded planetary scientists because it has been heavily eroded and is on the boundary of the fractured maze-like terrain of Noctis Labyrinthus.
A digital terrain model of a portion of Mars’ Valles Marineris, the largest canyon in the Solar System. Credit: ESA/DLR/FU Berlin (G. Neukum)
Anyone who’s visited the Grand Canyon in Arizona can attest to its beauty, magnificence and sheer sense of awe that comes upon approaching its rim, whether for the first time or hundred-and-first. “Grand” almost seems too inferior a title for such an enormous geological feature — yet there’s a canyon much, much bigger stretching across the surface of Mars, one that could easily swallow all of our Grand Canyon within one of its side gullies.
The image above, released online for the first time today by ESA, is a digital terrain model of a portion of Mars’ Valles Marineris: our Solar System’s grandest canyon. It’s easy to fall into hyperbole when describing Valles Marineris. Named for NASA’s Mariner 9 spacecraft, which became the first spacecraft to orbit Mars on November 14, 1971, the canyon is over 4000 km long, 200 km wide, and 10 km deep (2,480 x 125 x 6 miles) — that’s five times deeper than the Grand Canyon and long enough to stretch across the entire contiguous United States! It’s a rift unparalleled on any other world in the Solar System.
Valles Marineris is thought to be the result of the formation of the nearby Tharsis volcanic region, home to Olympus Mons, the Solar System’s largest volcano. As the region swelled with magma billions of years ago the planet’s crust stretched and split, collapsing into a vast, deep canyon.
Much later, landslides and flowing water would help erode the canyon’s steep walls and carve out meandering side channels.
The 45-degree view above was was made from data acquired during 20 individual orbits of ESA’s Mars Express. It is presented in near-true color with four times vertical exaggeration (to increase relief contrast.) Download a high-res JPEG version here.
The largest portion of the canyon seen crossing left to right is known as Melas Chasma. Candor Chasma is the connecting trough to the north, and Hebes Chasma is in the far top left.
Below is a video released by JPL in 2006 showing a virtual fly-through of Valles Marineris, shown as if you were on a Grand Canyon-style helicopter sightseeing tour (that is, if helicopters could even work in the thin Martian air!)
Hopefully someday we’ll be seeing actual videos taken above Valles Marineris and photos captured from its rim… perhaps even by human explorers! (Please exit through the gift shop.)
Image source: ESA. Video by Eric M. De Jong and Phil Christiansen et. al, Arizona State University.
