Chunks of bright material unearthed by NASA鈥檚 Phoenix Mars Lander have vanished again after around four days. 快猫短视频s say this is the 鈥渟moking gun鈥� that convinces them they鈥檝e found water ice, which vaporised when exposed to the Martian atmosphere. Watch an animated gif of the ice vaporising.
鈥淚t must be ice,鈥� says Phoenix lead scientist of the in Tucson, US. 鈥淭hese little clumps completely disappearing over the course of a few days 鈥� that is perfect evidence.鈥�
The Phoenix lander uncovered the bright material when its robotic arm was widening a trench, informally called 鈥淒odo-Goldilocks鈥�, on 15 June. A camera called the Surface Stereo Imager revealed bright chunks roughly a couple of centimetres wide at the trench鈥檚 base.
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Vanishing chunks
One possibility was that the chunks were some kind of salt. But four days later, new images revealed that some of the chunks had vanished. 鈥淪alt can鈥檛 do that,鈥� says Smith.
The Phoenix team concludes that the bright material must be water ice that vaporised when exposed to the Martian atmosphere, a process called sublimation.
The lander鈥檚 robotic arm has also hit a hard surface that might be dense ice while digging another trench, dubbed 鈥淪now White 2鈥�. The arm went into a holding position after three attempts to dig through the hard material 鈥� the expected action when the arm hits something that鈥檚 challengingly hard.
Hard layer
Like the bright chunks, the hard layer is about 5 or 6 centimetres under the surface. 鈥淲e have dug a trench and uncovered a hard layer at the same depth as the ice layer in our other trench,鈥� says team member of in St Louis, Missouri, US.
Phoenix mission scientists are delighted that the lander has touched water ice, because the spacecraft鈥檚 main goal is to find out the history of water on Mars and assess whether the planet has ever been hospitable to life. NASA plans to release more details of the new findings at a press conference later today.
Mars Rovers 鈥� Mars is full of surprises; learn more in our continually updated .
