London, June 17 : NASA's Phoenix Mars Lander has uncovered a patch of what may be ice on the border of a polygon-shaped section of soil in the northern plains of the Red Planet.
According to a report in New Scientist, Phoenix's robotic arm uncovered the white substance after further excavating sites called Dodo and Baby Bear to create one large trench.
The patch sits at the edge of a polygon, a geological formation created by the seasonal expansion and shrinkage of ice in the Martian soil.
Though it is too early to say whether the bright area is made of ice or salt, but over the coming days, the Lander's cameras will periodically snap pictures of the area to see if the exposed layer changes.
If the layer is an isolated chunk of ice, exposure to the Sun will likely cause the patch to shrink as it turns into water vapour, a process called sublimation. An isolated chunk of ice may hint that liquid water once pooled in the trough between polygons and then froze.
"But if the patch is part of a larger body of subterranean ice, the area may instead form frost as the underlying stores of ice cause water vapour in the air to recondense," according to Ray Arvidson of Washington University in St Louis, Missouri, US, head scientist for the robotic arm's activities.
The Lander's arm is next set to begin excavating an area called Wonderland, which sits on a flat area on top of the polygon.
There, Phoenix mission members hope to sample for both ice and soil and deliver samples to a number of Lander instruments.