Frost in Argyre Basin on Mars

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Just like on Earth, a frost can develop on Mars. What you see below is a swath of land within the 1800km wide, 5km deep Argyre Basin, which was created from an enormous impact in the early part of Mars' history. The prominent crater partially captured in this image from Mars Express' High Resolution Stereo Camera is the 138km wide Hooke Crater.

Click to see original high resolution image from Mars Express. [See their article]

The frost you see in this image is actually carbon dioxide ice, which scientists believe only forms at ground level when it freezes out of the atmosphere. The reason why only the frost is only abundant in the southern (left) lowlands of this image is because of the angle of the sun at the time this image was taken. This image was taken at 1630 local time on Mars, when the Sun was at a 20 degrees above the horizon. It only had enough time to melt the frost off the north facing crater walls, but wasn't yet able to melt any in the low lying area to the south.

Understanding when and for how long frost can cover the surface of Mars will save future explorers from facing potential surprises! Imagine waking up in your space capsule only to look out the window and see the ground covered in ice!

Mars Photo of the Day - May 9 2012

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Today's Image of Mars shows frosted ground in the Southern Hemisphere of Mars during late fall, as imaged by HiRISE. The frost in this image is primarily carbon dioxide frost that began to accumulate as average temperatures dropped. Most of the frost is carbon dioxide frost because the Martian atmosphere is primarily carbon dioxide, which condenses onto the surface, not like the nitrogen that makes up most of the Earth's atmosphere and remains vapor at all Earthly temperatures. 

In this image the frost is blueish and primarily on south-facing slopes. The slopes facing north receive more sunlight so they contain less frost and appear red. During the winter months the frost will accumulate more heavily as the Sun becomes dimmer and less heat reaches Mars. Come spring the frost will sublimate until the next fall, and thus is the cycle on much of Mars. 

Clicking on this image will take you to the original high resolution image from HiRISE. [See the HiRISE caption for this image]

See All Mars Photo of the Day Posts!

Mars Photo of the Day - Mar 20 2012

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Today's Image of Mars shows frost in Utopia Planitia, as taken by the southwest facing Viking 2 lander on May 18 1979, approximately one Martian year (687 days) after the lander first imaged frost at the same spot. This thin layer of water-ice frost on Mars is thought to be only a couple thousandth's of a centimeter thick.

But how did the water-ice frost form? Scientists believe that dust particles throughout the Martian atmosphere pick up water particles , then when it gets cold enough for carbon dioxide to solidify some of it attaches to the dust and falls onto the surface.

Mars Photo of the Day - Dec 12 2011

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Today's Image of Mars shows frosted gullies in a North Polar region crater. This image was taken in the summer months on Mars. The frost has survived because it lies within the North facing alcoves of the gully and is constantly shrouded in shadow. There are similar gullies on the opposite side of the crater, but because they are facing south the frost inside them has melted.

The gullies depicted in this image have the large alcove at the top of the crater wall and channels that flow down into the crater. Some of these gullies show current activity, but it seems that the most activity is at the height of the winter season when the temperatures are the lowest, which leads scientists to believe that the activity is caused by falling loose material and not liquid water.

This image was taken by HiRISE. Clicking on the image will take you to the original captioned image from them.

See All Mars Photo of the Day Posts!

If you like the HiRISE images showcased in the Mars Photo of the Day posts I encourage you to enter for a free 2012 HiRISE Calendar