NASA Rovers Capture Stunning Solar Eclipses on Mars

Guardian mag October 25, 2024

On September 30, NASA's Perseverance rover directed its Left Mastcam-Z camera skyward to capture a solar eclipse from Mars, photographing the planet's moon, Phobos, as it partially obscured the sun.

In the image sequence, the potato-like shape of Phobos is clear. Unlike Earth's moon or most moons in the solar system, Phobos, the larger of Mars' two small moons, is not round but irregularly shaped, more like an asteroid.

Phobos measures roughly 17 by 14 by 11 miles (27 by 22 by 18 kilometers) and orbits Mars at an extremely close distance of just 3,700 miles (6,000 km).

In comparison, Earth's moon is much farther away, orbiting at an average distance of 238,855 miles (384,400 km). Phobos also completes three full orbits around Mars in a single day.

While Phobos resembles an asteroid in shape, its origins likely differ. One of the most significant mysteries about Phobos is that it does not appear to be a captured asteroid. Its orbit around Mars is unusually stable and nearly circular, which would be unlikely for a passing asteroid simply snared by Mars' gravity.

Phobos begins crossing the solar disk during the eclipse of Sept. 30, 2024.

Current theories about the origins of Phobos and its smaller companion, Deimos, suggest that they may have formed from debris left over from Mars' formation or from material resulting from a massive collision involving Mars and another large body.

This isn’t Perseverance’s first eclipse photo session; the rover also captured Phobos passing in front of the sun in April 2022 and February 2024. And it’s not the only rover to document such a sight.

NASA's Spirit and Opportunity rovers recorded Phobos' solar transits back in 2004, and Curiosity filmed the first video of a Phobos eclipse in 2019. So yes, it seems Mars rovers really do have a thing for chasing solar eclipses!

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