Western Slope Skies - Astrogeology: An Interplanetary Road Trip

Jul 9, 2021

Mars' Valles Marineris
Credit NASA

Famed astronomer and prolific author Carl Sagan put it succinctly: “Exploration is in our nature. We began as wanderers and we are wanderers still.”


With the summer travel season hitting full stride, crowds of adventurers far & wide are seeking to capture that same wandering spirit in search of the nation’s many outstanding superlatives – such as the tallest, the deepest, the longest, and the oldest of geologic features. While at Black Canyon we enjoy sharing in the splendor of the Painted Wall, the tallest sheer cliff in Colorado , the greatest superlatives exist not on our planetary home but across our interplanetary neighborhood.

The Black Canyon may boast 2,000 ft vertical walls, but if you were to stand upon the rim of Valles Marineris – the Martian “Grand Canyon”  – you’d be peering into a gorge 21,000 ft in depth. Not an advised stop for those among us with vertigo! If erosion via the Gunnison and Colorado Rivers carved their respective canyons, Marineris is instead a 2,500 mile fissure across the Martian equator lacking a distinct watershed. Rather, it’s a stretch mark formed by strain on the planet’s crust by the solar system’s largest mountains – among them the imposing Olympus Mons.

Mount Everest first comes to mind when discussing the tallest of Earthly mountains; however, its peak is merely the “highest” on Earth at 29,000 ft above sea level! The big island of Hawaii – formed by both extinct and active shield volcanoes collectively protected as Hawaii Volcanoes National Park – takes the cake at 33,000 ft in height, measured from the sea floor to the summit of Mauna Kea. Olympus Mons, too a shield volcano with the potential to erupt, dwarfs Hawaii at an astounding 82,000ft! Reaching a diameter as wide as Arizona, Olympus achieved its massive size as the Martian crust has remained relatively static above this roiling hot spot of volcanic activity.

Back home on Earth, we’ve now charted the deepest canyons, conquered the tallest peaks, and navigated the wildest rivers. Yet as perpetual wanderers and children of the space race, we yearn now to further chart the heavenly bodies that glint and glitter as they loom in the deep dark above. On this sentiment Sagan continued: “We have lingered enough on the shores of the cosmic oceans. We are ready at last to set sail for the stars.”

Western Slope Skies is produced by the Black Canyon Astronomical Society. This episode was written and recorded by Ranger Damian Popovic of Black Canyon of the Gunnison National Park.