Curiosity rover cracked open a rock and may have settled the 'life on Mars' debate

Imagine taking a leisurely Sunday drive, and you accidentally smash something on the road that turns out to be an unprecedented scientific revelation. Well, that’s exactly what happened to NASA’s Curiosity Mars rover on May 30, 2024 when it struck sulfur.

While working its usual Martian shift, the rover stumbled upon, rather drove over, a rock and cracked it wide open, revealing a sight never before seen on Mars – a dazzling display of yellow sulfur crystals.

This unexpected discovery was relayed to a team of astounded scientists, including Ashwin Vasavada, the Curiosity’s project scientist from NASA’s Jet Propulsion Laboratory in Southern California.

“Finding a field of stones made of pure sulfur is like finding an oasis in the desert. It shouldn’t be there, so now we have to explain it. Discovering strange and unexpected things is what makes planetary exploration so exciting,” Vasavada enthused.

Sweet sulfur surprise on Mars

The bright, odorless crystals found by Curiosity open a window into a new chapter of study.

Researchers want to know what factors created this elemental form and how it can exist alongside other deposits that speak to the planet’s watery past.

Since October 2023, Curiosity has been rambling about in a sulfate-rich region of Mars. Now, sulfates aren’t exactly Martian novelties.

These salts, formed as water evaporates, had been detected before, but only as constituents of sulfur-based minerals – mixtures of sulfur and other stuff. But this time, it was pure, elemental sulfur, a first of its kind.

What’s so peculiar about this elemental sulfur? Well, contrary to the stinkiness associated with hydrogen sulfide gas, elemental sulfur is odorless.

Its formation requires specific conditions not previously linked to this Martian location. Hence, the revelation of an entire field of bright, sulfur-laden rocks is indeed something to marvel at.

Sulfur as a signal for life on Mars

Sulfur is an important element for understanding the potential for life, both on Earth and beyond. Certain microorganisms on our planet depend on sulfur compounds as an energy source.

The presence of sulfur on Mars, even in forms discovered in earlier missions, has always raised questions about ancient habitats.

Water influences the formation of sulfates, and water stands out as a critical ingredient for biology.

Finding pure sulfur, though, points to specialized conditions that could expand possible scenarios for past microbial life on the Red Planet.

Sulfur compounds also reveal information about Mars’s potential hydrothermal systems, volcanic activities, or ancient lakes and seas – habitats that might have supported life.

They are involved in chemical reactions that produce energy, a survival mechanism for some Earth microbes in extreme environments like deep-sea hydrothermal vents.

The identification of sulfur on Mars raises questions about the planet’s historical habitability. It suggests a range of chemical environments that could have supported microbial life.

While sulfur alone doesn’t confirm the existence of life, its presence alongside other life-sustaining elements like carbon, hydrogen, nitrogen, oxygen, and phosphorus strengthens the case for past life on Mars.

Scaling Mount Sharp

Curiosity has climbed Mount Sharp for more than seven years, examining its layered formations.

Each layer represents a separate phase of the planet’s development, offering glimpses of ancient river networks, lake sediments, and shifting climates.

Data show that different types of minerals, including sulfates, appear in these layers, hinting at cycles of evaporation and chemical alteration that occurred when water was likely more plentiful.

Mars’ Gediz Vallis and sulfur crystals

A site drawing particular interest is the Gediz Vallis channel. Researchers suspect it was shaped by water-driven events and landslides that left a jumble of rocks at the bottom.

Findings suggest that both factors had a hand in the formation of these Martian landscapes.

Becky Williams, a scientist with the Planetary Science Institute in Tucson, Arizona, and deputy principal investigator of Curiosity’s Mast Camera, has studied these processes.

“This was not a quiet period on Mars. There was an exciting amount of activity here. We’re looking at multiple flows down the channel, including energetic floods and boulder-rich flows,” she explained.

Drilling for more sulfur clues on Mars

Curiosity’s drill has stayed busy near the newly found sulfur field. On June 18, the rover created its 41st borehole in a rock called “Mammoth Lakes.”

That powdered sample is now under scrutiny. Researchers hope to see if the elemental sulfur sits alongside compounds that might reveal the chemical history of Mars.

Identifying the mixture of ingredients in the soil can shed light on previous hydrothermal processes, environmental conditions, or even the faint possibility of microbial life.

The journey so far has been an adventurous one, with unexpected discoveries and valuable scientific data turning up at every corner. The team eagerly awaits what other surprises lay within the channel.

Each new finding brings us a step closer to understanding the Martian history and whether the planet once harbored conditions favorable for life.

What happens next?

No single discovery confirms ancient life on Mars. Yet each sample broadens the view of what might have occurred on this neighbor world.

The discovery of elemental sulfur on Mars enhances our understanding of our neighboring planet while stoking our curiosity about what else lies out there in the cosmos.

The rover’s path offers new perspectives each time it rolls across unfamiliar terrain, revealing minerals that shouldn’t be there and sites that demand fresh explanation.

With every turn of its wheels, Curiosity encourages scientists to rethink prior assumptions and look forward to whatever else might be waiting in this dusty frontier.

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