Its characteristic shape was sculpted by water many millions of years ago.
The image, of course, is most surprising and gives wings to the imagination. It was captured just a few days ago by the cameras of Curiosity, the NASA rover that has been traveling through the Gale Crater on Mars since August 2012, while studying a series of mineral deposits. And one of them, barely a centimeter wide, was precisely a beautiful branched rock whose shapes remind us of coral. [Find here all the information about Curiosity].
There ends, however, any resemblance to a living being. It is a simple mineral deposit, capriciously sculpted by water when it still covered a good part of the red planet.
The rover imaged this tiny mineral flower on February 25 and very close to Mount Sharp, which stands in the center of Gale Crater.
The image is a composite of several shots obtained with Curiosity’s Mars Hand Lens Imager, capable of capturing close-ups with a magnifying glass. This type of composite photo allows the rover to produce highly detailed images.
The rock, which has received the name Blackthorn Salt, is composed of minerals that precipitated after being mixed in ancient water on Mars, according to Abigail Fraeman, a scientist on Curiosity. This type of rock can have various shapes, from branched, as is the case, to practically spherical, like the others that appear in the same photograph.
“We’ve seen diagenetic features with similar shapes before,” Fraeman says, “but this dendritic shape is particularly beautiful.”
So far, Curiosity has discovered several other diagenetic features, which is not surprising because Gale Crater is thought to have once been a large lake more than 150 km wide. Back in 2004, Curiosity’s ‘big brother’, the Opportunity rover, found a series of small blue mineral spheres in Meridiani Planum, a plain near the Martian equator. Because of their hue, which is due to their high hematite (iron oxide) content, the spheres are known as ‘the Martian blueberries ‘.
In any case, further documentation of these rock formations is important to help researchers determine when exactly the liquid water on Mars disappeared. “We can learn more about the complex and long history of water at Mount Sharp,” says Freeman. And that could reveal more information about how long the environment might have been potentially habitable for life.
