Crater on North Polar Layered Deposits. Credit: NASA/JPL/University of Arizona

From the HiRISE Website

The north polar layered deposits, and the bright ice cap that covers them, are very young (by geologic standards) features. To try and figure out the age of an area, or how quickly it’s being resurfaced, planetary scientists count up the number of craters at different sizes. An older surface has more time to accumulate more craters whereas a younger surface, or one that has a lot of geologic activity that destroys craters, doesn’t have many impact craters.

These polar deposits have a very low crater count so it is possible that the ice cap (bright white in this image) might only by about 10,000 years old and the surface of the layered deposits (orange-brown in this image) may be only a few million years old. This sounds like a long time but is very short compared to other surfaces on Mars.

The ice has not melted because it is being sheltered from the sun by the high crater walls, keeping the contents of the crater well preserved.

So much for Mars being a dead planet, what with ice, avalanches, rain, moving sand dunes and weather systems, it seems quite alive!

NASA Reconnaissance Orbiter

Quote from Universe Today

Reconnaissance Orbiter has been circling Mars for over two years now, and has provided unprecedented views of the Red Planet with its HiRISE Camera. But did you also know that MRO is a weather-monitoring satellite, too? The Mars Climate Sounder instrument is examining the Martian atmosphere and has issued its first Mars weather report. “It has taken 20 years and three missions but we finally have an instrument in orbit that gives us a detailed view of the entire atmosphere of Mars and it is already giving us fresh insights into the Martian climate,” said Professor Fred Taylor of Oxford University. Within a paper issued by the Mars ‘weather team’ comes surprising news: during the freezing Martian winter the atmosphere above the planet’s South Pole is considerably warmer than predicted.

I wonder if a Mars forecast will be just as reliable as the forecasts we get on Earth?

Rain on Mars (Credit: NASA

Images of layered sedimentary deposits and deltas on Mars have provided evidence for lakes and flowing rivers that carried eroded material downstream. A team of researchers also believes there is evidence for precipitation in the Red Planet’s past. “For years scientists have been suspecting that the current appearance of the landscape has, in part, been shaped by rivers that cut into the surface,” said Ernst Hauber of the German Aerospace Center. “We can see layered sediments where these valleys open into impact craters. The shape of certain sediments is typical for deltas formed in standing water.” Hauber and his team also believe that surface runoff from rain or snowmelt completes the picture of past water on Mars.

There seems to be more and more evidense coming from NASA’s HiRISE that Mars was once very similar to Earth, in both it’s surface and it’s atmosphere. At some point however Mars has taken a very different tack and ended up as very cold, very dry and very barren. Other recent photographs from Mars show dried up lakes, river valleys, estuarys and other features associated with a once wet planet.

Whatever did happen was very brief in Mar’s overall history and any precipitation that did occur dried up around 3.5 to 3.8 billion years ago.

Read more on Universe Today

There seems to be a never-ending flow of stunning images coming from the High Resolution Imaging Science Experiment (HiRISE) on board NASA’s Mars Reconnaissance Orbiter (MRO). In today’s high-resolution look at the Martian surface, large flat-topped hills (a.k.a. mesas) can be seen to be eroded by the Mars winds, stripping them of their material, creating sand dunes downwind. An incredible sight, it shows just how dynamic and powerful the Martian winds really are…

Original Post from Universe Today

I am continually being blown away by the images coming from the HiRISE project and Mars. These sand dunes and errosion patterns are quite spooky in a way, but well worth a look!