Mars Curiosity rover discovers massive field of polygons

The surface of Mars is home to some of the most breathtaking and awe-inspiring landscapes in the solar system. This is primarily because the Red Planet lacks several resurfacing processes that Earth possesses, including plate tectonics, volcanism and flowing water.

While Mars does have dust storms, these have done little to reshape the planet’s surface, which has remained largely undisturbed for billions of years. However, this near-pristine landscape has enabled scientists to look back in time while slowly piecing together what Mars was like long ago.

Now, NASA’s Mars Curiosity rover recently beamed back images of a landscape featuring polygon-like features. This unique landscape has been observed in other regions of Mars but was a first-time observation for the car-sized rover.

It is hypothesized that these polygonal features form as mud cracks, a process discussed in a 2023 study published in Nature, in which researchers hypothesized that intense wet-dry cycles formed the features from Curiosity rover observations within Gale Crater.

That study concluded that the mud cracks could have formed during what’s known as the Noachian-Hesperian transition, which occurred about 3.8–3.6 billion years ago and which researchers have hypothesized is when Mars could have exhibited an Earth-like climate. However, researchers studying these new polygonal features suggest more work is needed to understand their formation processes. The features measure about 4–8 centimeters (1.5–3 inches) across.

“We’ve seen a lot of fascinating landscapes through Curiosity’s eyes, but this sea of polygons took our breath away,” said Dr. Ashwin Vasavada, a Curiosity rover mission scientist at NASA’s Jet Propulsion Laboratory. “We measured their shapes and chemistry carefully and are hopeful there are clues in the data as to how these features formed.”

As noted, polygonal features have been observed across Mars. While these latest polygons are hypothesized to have formed as mud cracks, polygons in other regions of Mars are hypothesized to have formed from freeze-thaw cycles or tectonic or volcanic stress. While Gale Crater isn’t the only region on Mars where mud cracks have been observed, it is the only region observed at ground level by a rover.

Other polygonal surface features have been observed across Mars by orbiters, specifically NASA’s High Resolution Imaging Science Experiment (HiRISE) orbiter. HiRISE has orbited Mars since 2006, providing arguably some of the most breathtaking images of the Red Planet. The primary difference between ground-level and orbiter observations is the size of the polygons. Ground-level polygons have been observed to be about the size of those recently observed by Curiosity, whereas polygons observed by orbiters are much larger, ranging from 15 to more than 350 meters (50 to more than 1,000 feet) in diameter.

Examples of regions on Mars that display large polygons occur in features known as crater floor polygons (CFPs), which display large, cracked surfaces potentially indicative of past standing water. These regions featuring CFPs include Hellas Planitia, Noachis Terra and Margaritifer Terra. Hellas Planitia is the largest impact basin on Mars, measuring about 2,300 kilometers (1,400 miles) in diameter and just over 7,000 meters (23,000 feet) deep beneath the Mars datum, or the zero-point elevation for Mars.

Today, Mars is a cold, dry planet whose surface still displays processes that may have occurred billions of years ago during the planet’s Pre-Noachian, Noachian and possibly Hesperian periods, which are estimated to have collectively spanned 4.5–3.0 billion years ago. The current period is the Amazonian period.

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Swati Mestri

Swati Mestri holds a bachelor’s degree in Electronics Engineering and has worked as a content editor since 2019. She has experience editing research documents across technology, health care, and materials science, and has a particular interest in technology and space.

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Robert Egan

Bachelor’s in mathematical biology, Master’s in creative writing. Well-traveled with unique perspectives on science and language.

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