NASA's Curiosity rover has found evidence of clay on Mars. The presence of clay on a planet suggests that there was once water, so this is a big deal for the Curiosity team. Orbitors scanning the red planet were the first to find evidence of clay at the rocky ridge known as Mt. Sharp, which has now been confirmed by the ground team.
When the Curiosity landed on Mars, looking for clay was one of its primary tasks. Curiosity sampled rocks at two locations to find the clay. One called "Aberlady" and one called "Kilmarie," both on the lower regions of Mt. Sharp.
Clay cache big win for scientists
The mountain peaks at 5.5 km (18,000 ft) above the crater floor. It's easily accessible for the rover. Mars' strong winds have exposed the planets layers making them good targets for Curiosity's drill.
Mt. Sharp is a big target for NASA because of how they suspect it formed. The ridge, also known Aeolis Mons is suspected to have formed when the ancient Gale Crater gradually filled with sediment; a process that took more than a billion years.
Another theory is that the crater was filled with sediment which eroded leaving Mt. Sharp behind. Researchers have lots of questions regarding the timeline of Mt. Sharp's formation and they hope the work done by Curiosity will help answer them.
As Curiosity slowly samples rocks at different layers, the team back on Earth hope to understand the formation of Mars with more clarity.
Clay means water
One thing for certain is that the clay confirms the evidence that Gale Crater once had an abundance of water. The research so far suggests that the clay-containing rocks formed as sediment at the bottom of the lake.
Over a huge expanse of time, water and sediment interacted to form clay. The sediment will inform scientists about when and how much water was present on the planet.
Layer by layer
This information will come gradually as scientists work with the rover to sample each Martian layer of soil at the investigation site.
So far it's been determined that the lower layers contain clay, but layers at higher levels contain sulfur, and even higher above, there is evidence of oxygen-bearing minerals.
The sulfur layers suggest areas that dried out, or the water became more acidic.
Another area for interest in the landscape is the river that runs through Gale Crater. Understanding this distinct river landform will also be a massive step towards wholly understanding the formation of Mars.
"Each layer of this mountain is a puzzle piece," said Curiosity Project Scientist Ashwin Vasavada of JPL. "They each hold clues to a different era in Martian history."