Scientists have recreated Martian conditions in a lab, offering fresh insights into Mars' strange spider-like formations. These features, sprawling across the Martian surface, have puzzled experts since they were first observed in 2003. With the series of breakthrough experiments, researchers can now better understand how these otherworldly formations are created, offering clues about the Red Planet’s past.
The Martian spiders, called araneiform terrain, are formations stretching up to a kilometre. Found in clusters across Mars' southern hemisphere, they resemble spindly legs stretching from a central point. Scientists believe these formations result from carbon dioxide ice sublimation — a process that occurs when solid ice turns directly into gas. Unlike anything found on Earth, this phenomenon is unique to Mars. Researchers had speculated for years, but recent lab experiments have successfully recreated this process under simulated Martian conditions.
Recreating Martian Conditions
Led by Lauren McKeown of NASA’s Jet Propulsion Laboratory (JPL), researchers used specialised equipment to mimic Mars’ extreme temperatures and pressure. The team used a liquid-nitrogen-cooled test chamber known as DUSTIE to recreate the icy environment. They submerged Martian soil simulant in a liquid nitrogen bath, gradually reducing the air pressure to Mars-like conditions. After many attempts, they managed to form thick, translucent carbon dioxide ice. This allowed them to mimic how sunlight heats the soil, causing gas to build up and escape in dark plumes of dust.
New Discoveries and Surprises
McKeown’s team was thrilled when they saw the results. After five years of attempts, they finally observed a carbon dioxide plume erupting from the simulant. The plume lasted up to 10 minutes, ejecting soil and creating holes in the surface. The lab experiment provided the first-ever visual evidence of this process, offering crucial insights into how Martian spiders form.
The experiments also revealed unexpected results. Unlike the leading model, ice was observed forming between the soil grains, which cracked open the surface. This new detail could explain why the spiders have a more cracked appearance. While nature often defies models, this finding could help refine future simulations of Martian terrain.
Next Steps in Martian Research
The team’s next goal is to conduct similar experiments using simulated sunlight, which could help fine-tune models further. However, many questions remain unanswered. Scientists still wonder why these formations only appear in some parts of Mars, and why they don't seem to grow over time. It’s possible that these formations are remnants from an ancient Martian climate, offering a glimpse into the planet’s geological history.
For now, laboratory experiments bring us closer to understanding these peculiar Martian features, though the ultimate answers may only come with future missions to Mars.