More interesting data from our web statistics: rankings of the most popular images on our website. Some you’d expect to get lots of hits: special campaigns like Phoenix lander hardware and Phobos, and of course old favorites like a certain feature in Cydonia. Others have made a splash in the news, like the avalanche caught in action and a deep pit that might be the entrance to a cave – whether their popularity on our website is a cause or effect of the media coverage.

I find it interesting to see which “regular” images, out of the thousands we’ve taken, caught people’s attention – in May, for example, gullies in a crater wall and ridges in Huo Hsing Vallis (left) were popular. June saw lots of hits on this beautiful image of the north polar layered deposits (above) and this image of delicate-looking, multi-tendriled slope streaks.

In July, the “Mystery Mounds” (PSP_008778_1685 and PSP_008548_2205) were popular, presumably because they are so “mysterious” – ? (By the way, these two areas, despite their similar titles, are nowhere near each other on Mars.) Lesson learned: We should give more of our images “sexy” titles.

Hi. I’m a grad student who is co-author on a paper that just came out in Geology last week. It was very exciting to be a part of such an important project! The Mars Orbiter Camera found two locations on Mars where gullies had formed new bright deposits between images! Since gullies are thought to form with liquid water (either from the subsurface or surface), these new deposits were thought to be evidence of very recent (within the past 10 Earth years), liquid water on the martian surface.

A team of scientists at the United States Geological Survey used two HiRISE stereo images to create a very high-resolution topography model of the crater that contains one of the bright deposits. Our team at UA used this model to examine whether the bright deposit in the Centauri region is more likely formed by a water-rich or a completely dry flow. Our results show that a completely dry flow could explain the deposit’s location and shape. Since it is very difficult to produce liquid water on the surface of Mars today, our work suggests that this bright deposit was formed without water. This does not mean that the gully that the deposit is in formed without water or that water never existed on the martian surface. Our work is just relevant to the recent bright deposit we studied.

HiRISE images show similar bright deposits around Mars. I am studying these deposits to look for one that cannot be explained by a dry flow alone. Finding one would mean that liquid water might be reaching the surface today, which could help NASA figure out where to look for past and present life on Mars!

Three HiRISE papers are coming out in a special issue of the journal Science today. Our science team has been working hard on analyzing the images we take, and they’ve discovered some interesting things.

One paper talks about a few aspects of the history of water on Mars: HiRISE images of “rock glaciers” and bright deposits in gullies that might be extremely recent. HiRISE observations of an area called Athabasca Valles were used to show that it is actually covered with a thin veneer of lava. A third paper discusses thin layers in the North Polar cap. HiRISE is able to discern very fine layering (seen in an excerpt of image PSP_001636_2760 at left), as well as the color and thickness of each layer. Since these layers were laid down over hundreds of thousands of years of Martian history, they provide a record of climate change on the planet.

You can find a lot of things on the HiRISE website that are impossible to include in a print journal – like full-resolution color versions of the images from the papers, and (my favorite) cool 3-D flyover movies of the stereo observations. Our webmaster designed this lovely page for accessing these special products. Have fun flying over Mars!

PSP Image 1440-1255 shows a network of gully-like channels on the sides of dunes inside Russell Crater. On the sunward side, the channels are long and continuous, terminating at the base of the dunes. On the more shadowed side, strange stipples interrupt the otherwise silky smooth dune faces, as if the channel forming process never quite gets going.

Aside from the scientific significance of this image—which hopefully can tell us how these features formed and how recently—it is one sexybeautiful image, and my personal favorite so far!

This image and twelve others were released today; the first set of Primary Science Phase images from HiRISE.