The Martian global dust storm that started in mid-June and has left the rover Opportunity with little power appears to be finally clearing.
Don’t expect any word from Opportunity however for at least a month. The storm might be dying off, but it will take time for the dust to settle out of the atmosphere, especially in Mars’s light gravity.
Cool image time! I honestly can’t think of any better term but “vegetable grater” to describe the strange surface in the image on the right, cropped from the full sized image that was released with the July 11, 2018 monthly release of new images from the high resolution camera on Mars Reconnaissance Orbiter (MRO).
If you click on the image you can see the whole image, which merely shows more of the same terrain over a wider area. When I cropped it, I literally picked a random 450×450 pixel-sized area, since other than slight variations the entire terrain in the full image is as equally rough. The resolution captures objects as big as five feet across.
Looking at the full image there does seem to be flow patterns moving across the middle of the image, but if so these flow patterns had no effect on the surface roughness, other than indicating a very slight difference in the size of the knobs and pits. Overall, very strange.
The location of this place on Mars is in the cratered southern highlands, to the southwest of Hellas Basin, as indicated by the black cross in the image below.
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Data from Europe’s Mars Express orbiter has detected a pond of liquid water buried beneath the Martian south pole.
The radar investigation shows that south polar region of Mars is made of many layers of ice and dust down to a depth of about 1.5 km in the 200 km-wide area analysed in this study. A particularly bright radar reflection underneath the layered deposits is identified within a 20 km-wide zone.
Analysing the properties of the reflected radar signals and considering the composition of the layered deposits and expected temperature profile below the surface, the scientists interpret the bright feature as an interface between the ice and a stable body of liquid water, which could be laden with salty, saturated sediments. For MARSIS to be able to detect such a patch of water, it would need to be at least several tens of centimetres thick.
The data here is somewhat uncertain, but is also not to be dismissed. It is very likely this is liquid water.
I must add that this is not really a big surprise. Many scientists expected this. Also, this water is not very accessible, and is also located at the pole, the Mars’s harshest environment. Just because it is liquid is not a reason to aim to mine it. There is plenty of evidence of ice in much more accessible and reasonable locations.
What this discovery suggests is that it is possible to have liquid water on Mars. The great geological mystery of the planet is while that much of its geology appears formed by flowing water, scientists have not been able to devise good climate histories that make that flowing water possible. This discovery helps those scientists in devising those histories.
Cool image time! In my routine monthly review of the hundreds of new images released from the high resolution camera on Mars Reconnaissance Orbiter (MRO), I came across another most intriguing geological feature, the image of which is posted to the right, after cropping.
As the scale shows, the pit is about 300 feet across. Calculating the pit’s depth would require someone with better math skills than I. The website provides information about the sun angle, which can be used to extrapolate the shadows and then roughly calculate the depth.
The most fascinating aspect of this pit is the impression of incredible thinness for the pit’s overhung edges. All of the pit’s edges appear significantly overhung, and the thickness of the overhang seems incredibly paper-thin. This thinness is likely only an illusion, though in Mars’s light gravity it is perfectly possible for the overhang to be far thinner and more extended than anything you would find on Earth.
The image itself is in color, though the only color visible is within the pit itself. In that blueness at the base it seems to me that there is a pile of dust/debris, but once again, that conclusion should not be taken very seriously.
If you take a look at the full image, what is impressive is the bland flatness of the surrounding terrain. There is no hint that there might be underground passages hidden here. While most of the scattered craters are probably impact craters, many (especially those with unsymmetrical shapes) could be collapse features indicating the presence of underground voids. None however is very deep. Nor is there any other pits visible.
Below is a global map of Mars with the location of this pit indicated by a black cross. It is just on the edge of the transition zone between the lower northern plains and the southern highlands, where the shoreline of an intermittent sea is thought by some scientists to have once existed. This is also an area where not a lot of high resolution images have been taken, mostly because of its apparent blandness as seen in previous imagery.
This image demonstrates however that Mars is going to have interesting geology everywhere, and that we won’t really know it well until we have explored it all.
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Scientists have concluded that a large bulk of the dust that covers much of the Martian surface actually comes from one specific region called Medusae Fossae, located to the southwest of the planet’s giant volcanoes.
The dust that coats much of the surface of Mars originates largely from a single thousand-kilometer-long geological formation near the Red Planet’s equator, scientists have found.
A study published in the journal Nature Communications found a chemical match between dust in the Martian atmosphere and the surface feature, called the Medusae Fossae Formation. “Mars wouldn’t be nearly this dusty if it wasn’t for this one enormous deposit that is gradually eroding over time and polluting the planet, essentially,” said co-author Kevin Lewis, an assistant professor of Earth and planetary science at the Johns Hopkins University.
It is thought that Medusae Fossae is volcanic in origin.
Cool image time! The two images to the right, both cropped to post here, were taken six years apart by Mars Reconnaissance Orbiter (MRO) of the western lava slopes of the giant volcano Olympus Mons. They show the appearance of a dark dust avalanche during the interim. As noted by members of the MRO science team.
Dust avalanches create slope streaks that expose darker materials usually hidden below a lighter-toned layer. Cascading fine-grained material easily diverts around boulders or alters direction when encountering a change in slope. The dark steak … is approximately 1 kilometer in length that we didn’t see in a previous image. Past avalanche sites are still visible and fading slowly as dust settles out of the atmosphere and is deposited on the dark streaks over time.
We also see boulders and their shadows that are a meter or greater in size. Movement of any of these boulders down the slope could trigger future avalanches.
The appearance of these Martian dark streaks on slopes is actually not uncommon. As more pictures are taken of Mars scientists are beginning to accumulate a large number all across the Martian surface.
What I find fascinating is the wet look of these dark streaks. Below is a close-up of the new avalanche, near its head.
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The European Space Agency has created a website where people can offer their suggestions to name the ExoMars 2020 rover.
Astronaut Tim Peake is leading the hunt for a great moniker. He wants everyone to go to a special website set up for the purpose and enter a suggestion. But don’t think “Spacey McSpaceFace” is a goer because this is not an online poll. All ideas will be put before an expert panel and it is they who will make the final choice.
If all goes right, 2020 should see two new rovers arrive on the Martian surface.
Link here. This press release basically reviews what each Martian spacecraft, in orbit or on the surface, is doing to study or survive the global dust storm that erupted on Mars in in early June.
The storm itself has not yet eased, and the general expectation is that it will last for a couple of months, through August.
Using ten years of accumulated data from Europe’s Mars Express orbiter scientists have found that the Martian atmosphere appears to behave as a single unit, with changes its upper and lower levels closely connected.
“We discovered a surprising and significant increase in the amount of charged particles in the upper atmosphere during springtime in the Northern hemisphere, which is when the mass in the lower atmosphere is growing as ice sublimates from the northern polar cap,” adds Beatriz.
Mars’ polar caps are made up of a mix of water ice and frozen carbon dioxide. Each winter, up to a third of the mass in Mars’ atmosphere condenses to form an icy layer at each of the planet’s poles. Every spring, some of the mass within these caps sublimates to rejoin the atmosphere, and the caps visibly shrink as a result. “This sublimation process was thought to mostly only affect the lower atmosphere – we didn’t expect to see its effects clearly propagating upwards to higher levels,” says co-author Olivier Witasse of the European Space Agency, and former ESA Project Scientist for Mars Express. “It’s very interesting to find a connection like this.”
The finding suggests that the atmosphere of Mars behaves as a single system.
This finding might also explain why periodically Mars experiences a planet-wide dust storm, as it is doing right now.
Summary: Curiosity climbs back up onto Vera Rubin Ridge to attempt its second drillhole since drill recovery, this time at a spot on the ridge with the highest orbital signature for hematite. Opportunity remains silent, shut down due to the global dust storm.
For a list of past updates beginning in July 2016, see my February 8, 2018 update.
For the overall context of Curiosity’s travels, see Pinpointing Curiosity’s location in Gale Crater.
In the almost two months since my May 23, 2018 update, a lot has happened, much of which I covered in daily updates. Curiosity found a good drill spot to once again test the new drilling techniques designed by engineers to bypass its stuck drill feed mechanism, and was successful in getting its first drill sample in about a year and a half. The rover then returned uphill, returning to a spot on Vera Rubin Ridge that, according to satellite data, has the highest signature for hematite on the entire ridge. The light green dotted line in the traverse map to the right shows the route Curiosity has taken back up onto Vera Rubin Ridge. The red dotted line shows the original planned route off the ridge and up Mount Sharp.
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Scientists have found Martian pits formed by the leftover remains of dunes that long ago blew away.
Scientists have discovered hundreds of crescent-shaped pits on Mars where sand dunes the size of the U.S. Capitol stood billions of years ago. The curves of these ancient dune impressions record the direction of prevailing winds on the Red Planet, providing potential clues to Mars’s past climate, and may hold evidence of ancient life, according to a new study detailing the findings in the Journal of Geophysical Research: Planets, a publication of the American Geophysical Union.
Ghost dunes are the negative space left behind by long-vanished sand dunes. Lava or water-borne sediments partially buried the dunes and hardened, preserving the dunes’ contours. Wind subsequently blew sand off the exposed tops and scoured it out from inside, leaving a solid mold in the shape of the lost dune.
The claim that these geological features “may hold evidence of ancient life” is pure hyperbole, and absurd. However, the features are important because they will help date the sediment or lava flows around them, while also providing markers to help understand the history of the Martian climate.
Cool image time! Today’s release of new captioned images from the high resolution camera on Mars Reconnaissance Orbiter (MRO) included a wonderful image of the melting carbon dioxide cap of Mars’s south pole. On the right is a cropped portion of the full image, showing what the MRO scientists nickname spiders, features that appear as the CO2 begins to turn into gas.
But these aren’t actual spiders. We call it “araneiform terrain,” to describe the spider-like radiating channels that form when carbon dioxide ice below the surface heats up and releases. This is an active seasonal process we don’t see on Earth. Like dry ice on Earth, the carbon dioxide ice on Mars sublimates as it warms (changes from solid to gas) and the gas becomes trapped below the surface.
Over time the trapped carbon dioxide gas builds in pressure and is eventually strong enough to break through the ice as a jet that erupts dust. The gas is released into the atmosphere and darker dust may be deposited around the vent or transported by winds to produce streaks. The loss of the sublimated carbon dioxide leaves behind these spider-like features etched into the surface.
The image above shows older spiders, formed during past seasonal events. If you click on the image you can see the full image, which shows darker spiders produced by this season’s cycle.
The science team for the next American Mars rover, Mars 2020, has decided to consider a fourth candidate landing site, located between two other candidate sites.
The site has been dubbed “Midway,” because it’s roughly halfway between two other candidate landing locations — Jezero delta and Northeast Syrtis. The third previously identified candidate is the Columbia Hills region of Gusev Crater, which NASA’s now-defunct Spirit rover explored after touching down in January 2004.
Jezero, Northeast Syrtis and Columbia Hills were selected as finalists at the third 2020 rover landing site workshop, which was held in February 2017.
Midway has the same morphologic units as Northeast Syrtis and is relatively close to Jezero, explained John Mustard, a professor in the Department of Earth Environmental and Planetary Sciences at Brown University in Providence, Rhode Island. “It has emerged from Mars 2020 science team members I believe brainstorming on possibly getting two birds with one rover,” Mustard told Inside Outer Space.
Based on this story, it sounds to me as this new site has emerged as the favorite. It would put the rover down in the transition zone between Mars’s northern low plains and its southern highlands, an area where evidence of the receding shoreline of any past intermittent ocean might exist. It would also allow it to study geology similar to two previous candidate sites.
One problem they may have is that this candidate site has not yet been photographed in detail by Mars Reconnaissance Orbiter’s (MRO) high resolution camera, as have the other sites. They will need to get time on MRO to do this in order to make sure this site is acceptable.
New data suggests that the many meandering canyons on Mars were partly formed by rain.
Although Mars is cold and dry today, channels on its surface look as if running water shaped them, leading researchers to think the planet was warm and wet in the past. But scientists have struggled to determine whether that water fell from the sky as rain or seeped upward from the ground.
To discern the water’s source, Hansjoerg Seybold at the Swiss Federal Institute of Technology (ETH) Zurich and his colleagues analysed the geometry of Martian valley channels. The channels branch off at relatively narrow angles, as do waterways in arid landscapes on Earth, such as the US Southwest. More-humid landscapes with a lot of groundwater — the Amazon rainforest, for example — host river channels that branch at wider angles.
The discovery bolsters the idea that the Martian channels were carved by surface runoff rather than by water percolating from below.
The paper itself is behind a paywall, so it is unclear whether they included in their analysis the consequences of Mars’s lighter gravity. Regardless, this result is intriguing, even if it has a lot of uncertainty.
Cool image time! Europe’s Trace Gas Orbiter, now in its science orbit around Mars, has released some new pictures (the top five images at the link). The image above shows the very long and meandering canyon Uzboi Vallis as it cuts through the rim of Holden Crater, on the right. If you click on the image you can see a higher resolution version.
With this release the European Space Agency does a very poor job of providing relevant information. It does not provide the latitude/longitude of this image, its scale, or a context image. Thus, I can only guess at its precise location.
Regardless, this area, where Uzboi Vallis enters Holden Crater, is one of the candidate landing sites for the American 2020 Mars rover. Uzboi Vallis is thought to have been formed by flowing water as it cut through a number of craters in the southern high plains.
In one of my weekly posts last month (dated May 14th) delving into the May image release from Mars Reconnaissance Orbiter’s (MRO) high resolution camera, I featured an image of what planetary geologists have labeled chaos terrain, a hummocky chaotic terrain that has no real parallel on Earth but is found in many places on Mars.
This month’s image MRO release included two more fascinating images of this type of terrain. In addition, the Mars Odyssey team today also released its own image of chaos terrain, showing a small part of a region dubbed Margaritifer Chaos. Below, the Mars Odyssey image is on the right, with one of the MRO images to the left. Both have been cropped, with the MRO image also reduced in resolution. The full MRO image shows what the MRO science team labels “possibly early stage chaos” on the rim of a canyon dubbed Shalbatana Vallis.
Data from orbit and from Curiosity at Gale Crater confirms that the dust storm that has shut down Opportunity is now a global storm, encircling Mars.
The Martian dust storm has grown in size and is now officially a “planet-encircling” (or “global”) dust event.
Though Curiosity is on the other side of Mars from Opportunity, dust has steadily increased over it, more than doubling over the weekend. The sunlight-blocking haze, called “tau,” is now above 8.0 at Gale Crater — the highest tau the mission has ever recorded. Tau was last measured near 11 over Opportunity, thick enough that accurate measurements are no longer possible for Mars’ oldest active rover.
This will be first global storm to occur on Mars since Curiosity landed in 2012, thus giving scientists the best opportunity to study such an event.
Meanwhile, Opportunity remains silent. This does not mean it is dead, but that it doesn’t have enough sunlight to charge its batteries. It might die during this storm if the storm lasts long enough, but we won’t know one way or the other until the storm finally eases.
The eruption of Kilauea volcano in Hawaii has garnered a lot of deserved press coverage, having added at least a 200 acres of new land and destroyed at least 700 homes. Similarly, the recent violent eruption of a volcano in Guatemala, killing 100 people in its wake, has also gotten much deserved news coverage.
The magnitude of both however would pale in comparison to the stupendous eruption that occurred several hundred million years ago at the solar system’s largest volcano, Olympus Mons on Mars. While Kilauea is about 100 miles across, Olympus Mons is about 370 miles wide, and is so large that because of the curvature of Mar’s surface it is literally impossible for a viewer on the ground to actually see the volcano, in its entirety.
Both volcanoes are shield volcanoes, however, which means the lava flows don’t necessarily come from the caldera, but often from vents on the volcano’s slopes. Eruptions might be violent, but they generally do not involve the powerful explosive force of the sudden eruption, as seen in Guatemala and at Mount St. Helens in 1980 in the U.S. Instead, the lava seeps out steadily and continuously, an unstoppable flow that steadily overwhelms the surrounding terrain.
The flows that created Olympus Mons however were an epic event probably lasting millions of years, which brings us to this post. In the June release of Mars Reconnaissance Orbiter high resolution images, I found the image above, cropped and reduced in resolution to post here. It shows lava flowing down off one of the many escarpments on the slopes of Olympus Mons. This is not at the edge of the volcano’s shield, but just inside it. The map at the right, created using the archive of MRO’s high resolution camera, indicates the location of this flow, shown by the left light blue rectangle on the southeast slope of the volcano’s shield. The red rectangles show all the other images MRO has taken of Olympus Mons.
The scale of the MRO image above gives an indication of how big that eruption at Olympus Mons was.
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It appears that, after a descent down off of Vera Rubin Ridge and then spending 30 sols sitting at one spot to do its first drilling in more than a year, Curiosity is about to resume travel up Mount Sharp.
With its newly resurrected drilling capabilities, Curiosity will do one last pass over the Vera Rubin Ridge units, now that the rest of the instrument suite onboard can have access to this and future drill samples.
It appears they will be returning to their planned route, across the ridge and down off it to head up towards one known recurring black streak that might be a seep of underground water.
They have not provided any details about the lab results from the drill sample, but that isn’t surprising. It will take some time to analyze it, and the scientists involved will want the glory of publishing their results once that analysis is complete. What is clear from the update is that the drilling worked, and that this particular drillhole is likely to produce some of the more significant findings from Curiosity.
The Opportunity science team has lost contact with Opportunity as it automatically shuts down operations to survive low battery power due to the dust storm.
This does not necessarily mean the rover is dead. Depending on how long this period of low power lasts, the rover could return to life once the dust storm passes. Or not. We can only wait and see.
A press conference today on the dust storm and Opportunity’s status begins at 1:30 Eastern time today.
