Nasa’s Mars rover has spent six months exploring a strange, web-like landscape that could change what we know about how long life may have existed on the Red Planet.
The space agency’s Curiosity rover has been crawling across one of the most visually striking regions on Mars: a vast stretch of low, criss-crossing ridges that look like giant spiderwebs when seen from space.
Up close, these formations are turning out to be far more scientifically significant than they appear.
WHAT ARE THE SPIDER WEBS ON MARS?
For about six months, Curiosity has been exploring a region packed with geological formations called boxwork, low ridges roughly 3 to 6 feet tall with sandy hollows in between.
These formations criss-cross the surface for several kilometres.
Scientists believe this formation was formed when ancient groundwater flowed through cracks in the bedrock, leaving behind minerals that strengthened certain areas. Wind then gradually eroded the weaker sections, carving out the hollow spaces we see today.
DID ANCIENT LIFE EXIST ON MARS?
The existence of life for a prolonged period is the possibility that is driving this deep exploration mission on Mars.
“Seeing boxwork this far up the mountain suggests the groundwater table had to be pretty high,” said Tina Seeger of Rice University, one of the scientists leading the investigation. “And that means the water needed for sustaining life could have lasted much longer than we thought.”
The boxwork formations sit high up on Mount Sharp, a 3-mile-tall mountain Curiosity has been climbing.
Each layer of the mountain represents a different chapter in Mars’ ancient climate history, and finding evidence of water this high up pushes back the timeline for when habitable conditions could have existed.
WHAT HAS CURIOSITY FOUND?
Getting where Curiosity has reached wasn’t easy.
Rover drivers had to carefully navigate the rover, which weighs nearly a ton. They navigated across ridges barely wider than the vehicle itself and rough, unchartered terrain. But the effort paid off.
Curiosity discovered bumpy, pea-sized nodules scattered along the walls of ridges and in the sandy hollows between them. These features, scientists believe, were formed by minerals left behind as groundwater dried up billions of years ago.
Interestingly, these nodules were not found near the dark central fractures running through the ridges, which surprised the science team.
Scientists collected rock samples from the boxwork region that revealed clay minerals in the ridges and carbonate minerals in the hollows. Both the discoveries are considered important chemical signatures of past water activity.
Curiosity also recently analysed a fourth rock sample using a special wet chemistry technique designed to detect organic compounds. Organic compounds are carbon-based molecules important to the formation of life.
The rover is expected to leave the boxwork region sometime in March, continuing its climb up Mount Sharp to study how Mars’ climate dried out over billions of years.
