Here is your weekly reminder of Psalm 19 — Mars.

This image shows Mars from 2500 km above its surface. The great slash covering more than half of Mars’ apparent diameter is Valles Marineris (Mariner Valley), named after its discoverer, the Mariner 9 orbiter that visited the Red Planet in the early 1970s. Valles Marineris dwarfs the Grand Canyon — it is 4,000 km long, 200 km wide, and in some parts it is 7 km deep. To put this into perspective, consider that the distance from Seattle to New York is 4,600 km.

Why do we love Mars so much? I think it’s because for two centuries Mars offered the most tantalizing possibility of extraterrestrial life in the universe. It started in the 18th century when William Herschel was moved by similarities between the Red Planet and Earth to speculate that it may be inhabited, and was further fueled a century later by Giovanni Schiaparelli’s observations of what he thought were canals on its surface.

We’ve observed Mars in much greater detail through several NASA missions, including landers, and have found no compelling evidence that is now or has ever been inhabited. Yet that hardly seems to matter. Perhaps it is because Mars offers a challenge that’s tantalizingly within reach — to visit the planet and perhaps even colonize it — that we remain so fascinated with our nearest planetary neighbor.

Image credit:NASA/JPL-Caltech.