With enough water on Mars to form frost and clouds, direct visual evidence of water ice, and water apparently responsible for the clumpy Martian soil, one would think that there would be the tiniest bit of free water molecules not bound up in ice in the soil of Mars.
With even an extremely small amount of frozen water, it could be detected by measuring how well electricity flows within the soil. That is exactly what the Mars Phoenix Lander did by sticking electrical probes into the soil. Puzzlingly, the measurements seem to indicate that the Martian soil is extremely dry with no unfrozen water.
Where is the missing water? Is it because it's so cold and the atmosphere so thin that water molecules would immediately be bound in ice or evaporated? Or is there actually unfrozen water in the soil, but some special chemical property of the soil affects the electrical conductivity? I guess we'll hear what's likely from the Phoenix scientists soon enough.
Being the dry planet it is, I usually think of Mars as a planet with hardly any ice or clouds. Of course, the Mars Phoenix Lander gave us close-up looks of the water ice at the Martian north pole. And Mars does have clouds. And they're clouds actually made up of water, not something like carbon dioxide! Phoenix also spent some time taking pictures of the Martian sky with its clouds. Before you think that this is a big discovery by Phoenix, you should know that we've known about them for decades. But the animated sequence of images is still very cool.
Frost has formed not just on the ground around the Mars Phoenix Lander, it has also formed on the telltale mirror it uses to measure how the wind is blowing. What's more, they also had the lander send a sequence of images so we can actually see how the mirror sparkles in the sun as water frost accumulates throughout the morning.
The Mars Phoenix Lander has observed water frost on a Martian morning. Water vapor in the atmosphere had frozen during the night, and as the sun rose through the morning the frost evaporated. I'm surprised that there is enough water in the Martian atmosphere for a visible amount of water frost to form.
Seeing a photograph of water frost got me wondering what it would look like when the Phoenix lander starts being encased in carbon dioxide ice when the winter starts. And will we see even more water frost as time goes by? Is the Phoenix mission going to last enough for us to even see carbon dioxide frost, or even the entire surface around the landing site being covered by a white layer of carbon dioxide ice?
The Mars Phoenix Lander has managed to take its first images of Martian dust from its atomic force microscope. This is about 100 times more detailed than images taken from its optical microscope. And unlike an optical microscope which gathers light bounced off a sample to get an image, an atomic force microscope actually moves a sharp tip up and down along the surface of the sample. An 3-dimensional image of the sample is constructed by measuring how much the tip went up and down at each position.
Using the atomic force microscope, Phoenix managed to image a single particle of Martian dust held in a pitted silicon substrate. It's incredible that we can see such microscopic samples on another planet. Below is also embedded a video graciously provided by NASA and its partners in the Phoenix mission which roughly illustrates how the microscope works