Tag: Mars

A potential landing site for next Mars rover

3:32 pm

This week’s release of cool images from Mars Reconnaissance Orbiter included the color image below of a region on the floor of Holden Crater, one of the four possible landing sites for Curiosity, the Mars Science Laboratory planned for launch later this year. (If you want to see the entire image at higher resolution, you can download it here.)

Two things that immediately stand out about this image (other than this looks like an incredibly spectacular place to visit):

Holden Crater canyons

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Astronauts simulate Mars landing

9:14 pm

Astronauts on the Russian Mars500 simulated Mars mission simulated a Mars landing on Saturday. Key quote:

Three astronauts on the Mars500 simulated mission will make a simulated walk on the Mars “surface” Monday. After working 30 days on the simulated planet, the crew will then embark on a simulated 240-day return trip to Earth. Officials said the 520-day Mars500 mission is designed to test how humans cope with the physical and mental stresses of a long space flight.

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Sand dunes and dry ice on Mars

12:07 pm

Time for some more sightseeing on Mars. A recent news release from Mars Reconnaissance Orbiter noted the discovery of seasonal avalanches on Mars. This new image of the northern martian sand dunes illustrate again how the surface of Mars changes seasonally. The white patches on the ridges of the sand dunes is frozen carbon dioxide, dry ice that condenses on the crowns of the dunes every winter. When spring comes, the dry ice evaporates, and as it does so it disturbs the underlying sand, which then tumbles down the sides of the dunes, producing the dark streaks.

Ice-capped sand dunes

The process is less dramatic, however, than the avalanches seen in the previous news release, as suggested by this image below, showing the same dunes in summer without the dry ice. The dark streaks in the second image are not significantly different from the first, indicating that the process that forms them is slow and subtle.

Sand dunes with ice-cap

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Opportunity takes a rest stop at a crater

9:57 pm

In its 14 mile multi-year trek to Endeavour Crater — now about half completed — the Mars rover Opportunity has stopped to take a short rest stop at a small crater.

The crater, dubbed “Santa Maria Crater” by the scientists who operater Opportunity, is about the size of a football field. What makes it especially interesting are the sharp rocks piled up on its rim, as they are probably debris ejected from the crater at impact. Since this material probably came from deep below the Martian surface, it is also likely to hold information about the Martian geological past, thereby making it a prime research site.

Santa Maria crater

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A Martian eclipse

9:39 am

The hubbub about this week’s lunar solstice eclipse was, from my perspective, mostly manufactured press blather. For those who had never seen a lunar eclipse, it was a spectacular experience, but there really was nothing scientifically or technically unique about the fact that it happened to occur on the solstice.

However, below is an eclipse that is definitely unique both technically and scientifically. Scientists using the Mars rover Opportunity have filmed an eclipse on Mars, showing the Martian moon Phobos crossing in front of the Sun. Consider the engineering accomplishment: not only did they need to be able to calculate exactly when this would happen at a very particular spot on the Martian surface, they had to have a camera there able to take the movie. And they had to operate it from Earth!

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More caves on Mars

8:15 pm

And damn, do I want to rappel into them!

This week’s release of images from the HiRISE camera on Mars Reconnaissance Orbiter included these spectacular photos of two deep pits, approximately 180 and 310 meters in diameter and located aligned with a series of depressions that suggest additional passages at their base.

The first image shows the pits in the context of the surrounding terrain. From the caption:

These pits are aligned with what appears to be larger, degraded depressions. The wispy deposit may consist of dark material that has been either blown out of the pits or from some other source and scattered about by the local winds.

wide shot of pits

The next two images are heavily processed close-ups of each pit in order to bring out the detail within. From the caption:

The eastern most and smaller of the two pits contains boulders and sediment along its walls and brighter aeolian dune sediments on its floor. The larger, western most pit contains sediment and boulders with faint dune-like patterns visible on the deepest part of the floor. Both pits have steep eastern walls and more gently sloped western walls that transition gradually into the pit floor. Steep resistant ledges containing boulders that overhang and obscure the pit floors form the eastern walls.

The smaller pit, with dunes on floor

The larger pit

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Martian stream gullies

9:55 am

The image below from Mars Reconnaissance Orbiter shows gullies remarkably similar to gullies formed on Earth by flowing water, thus providing striking evidence that at some time in the past liquid water did flow on the Martian surface, something that is not possible now. Key quote from the caption:

The gullies shown in the subimage (approximately 710 x 1100 yards) have well developed alcoves, deeply incised channels, and large depositional fans, and are similar to terrestrial landscapes sculpted by surficial water.

The gullies shown in the subimage experienced several periods of activity, as evidenced by older channels cut by younger ones or by their deposits. The current and recent Martian temperatures and atmospheric conditions would not allow for water to be stable at the surface for extended periods of time: it is so cold that the water would freeze, and then it would sublime quickly, because the air is very thin and dry. These gullies could have formed under a different climate, or maybe by repeated bursts of transient fluids. Current leading hypotheses explaining the origin of gullies includes erosion from seepage or eruption of water from a subsurface aquifer, melting of ground ice, or dust-blanketed surface snow.

gullies in Sisyphi Planum

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Sightseeing on Mars

12:47 pm

Those who visit this website regularly know that I repeatedly post images from the various Mars orbiters and rovers. I do this not only because the images have scientific interest or that they are cool, but because it is simply fun to sightsee, even if it is done by proxy using a robot many millions of miles away. Here are two more images of the sights of Mars.

The first is a mosiac image of a small crater that the rover Opportunity strolled past on November 9 in its four year journey to Endeavour Crater.

small crater on Mars

What always amazes me about the images that Opportunity has taken as it travels across the Martian desert is how totally lifeless this desert is. You would be very hard-pressed to find any desert on Earth like this. On Earth, life is everywhere, even in deserts with their harsh environment. Moreover, life on Earth has reshaped the surface drastically. Environmentalists like to whine about the havoc humans wreck on nature, but the truth is that all life does this continually. Plants and trees help soften the terrain. Animals (not just humans) mold the surface to their needs.

On Mars, however, all one sees is wind-strewn sand across barren bedrock. What this suggests is that, if there is life on Mars, it is well buried, not very visible, and possibly quite rare. It will thus be difficult to spot.

The second image is another one of those Martian collapse features, where some form of fluid flow under the surface washed out the supporting material. causing the surface to eventually collapse. In this case, however, the collapse left at least one natural bridge. Based on the scale (25 cm = 1 pixel), this bridge is about 80 feet wide and 100 feet long. (To calculate its height requires more mathematical skills than I have.)

Boy, wouldn’t this be a magnificent thing to hike under and across!

Natural Bridge on Mars

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Sinkholes on Mars

2:06 pm

Caver alert! Releases this week from both the Mars Express orbiter and the Mars Reconnaissance Orbiter show a variety of sinkholes and collapse features on Mars, which in turn suggest the possibility of underground passages.

First, there is this picture from Mars Express, showing the area called Phoenicis Lacus (Latin for Phoenix Lake).

Phoenicis Lacus

The large and long canyon in box 1 is actually a collapse feature, almost two miles deep and formed as this region was stretched, warped, and cracked by the powerful volcanic activity of the nearby giant volcanoes of the Tharsis plateau, including Olympus Mons, the solar system’s largest volcano. You can also see how this activity causes several sinkholes and craters in all three boxes to become elongated and distorted.

In places where the surface is deformed in this way on Earth, you often find tectonic caves, underground cracks produced as the ground is pulled apart. The large collapse feature suggests the possibility that there are voids below it.

Then there is this subimage from this release of Mars Reconnaissance Orbiter, showing the central peak and southern slope of an old crater in the Terra Sirenum region of the Martian southern hemisphere.

central crater peak

Down that south slope can be seen what look like fluvial-like flows. In the center of these flows as well as near the top of the peak are what appear to be a string of collapse features. Below is the close-up as indicated by the box above:

inset closeup of sinkholes

From the caption: “It is possible that these pits are evidence of subsurface piping or hydrothermal activity. Piping occurs when subsurface water flows through soil, takes some soil with it, and causes the overlying ground to collapse. These fluvial-like features and the connected pits may have formed during a late stage of crater formation when temperatures were suitable for liquid water.”

On Earth, this is one of the geological processes that forms sinkholes on the surface as well as caves underground. When cavers go out to look or dig for new caves, we often head for just this kind of string of sinkholes, as they are excellent evidence that an unentered cave lies hidden below, ripe for exploration.

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