Tag: science

Lacy patterns in the high north of Mars

12:27 pm

lacy patterns in the high north of Mars

Cool image time! The photo to the right, cropped, reduced, and rotated so that north is up, was taken on May 12, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the strange lacy patterns seen routinely in the very high northern latitudes surrounding the Martian north pole.

Located in a region of the vast northern lowland plains dubbed Scandia Tholi, such features are apparently common here. From a 2011 geology paper of the region’s geological history:

We find that Scandia Tholi display concentric ridges, rugged peaks, irregular depressions, and moats that suggest uplift and tilting of layered plains material by diapirs and extrusion, erosion, and deflation of viscous, sedimentary slurries as previously suggested. These appear to be long-lived features that both pre-date and post-date impact craters.

The small circular feature near the bottom of the picture appears to be a mesa, and might be a pedestal crater, so old that the surrounding terrain has worn away and left the hardened-by-impact crater as a butte. To its right is a larger circular mesa with its scarp well eroded into hollows. This might also be a pedestal crater, or not.

The white lacy patterns could be frost, either water ice or dry ice. That the white lace tends to favor the north-facing slopes lends support to this guess. The photo was taken in the early spring, so the thin mantle of carbon dioxide that falls to cover the polar region south to sixty degrees latitude is only beginning to sublimate away.

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Saturn’s core is a slushy mix of rocks and liquid

9:31 am

Saturn's rings
Click for more information.

Using archival data from the Cassini orbiter that mapped ripples in the rings of Saturn, scientists have produced a model of Saturn’s core that suggests it is a slushy soup that as it sloshes about shifts the gas giant’s gravitational field.

By using the famous rings like a seismograph, scientists studied processes in the planet’s interior and determined that its core must be “fuzzy.” Instead of a solid sphere like Earth’s, the core of Saturn appears to consist of a ‘soup’ of rocks, ice and metallic fluids that slosh around and affect the planet’s gravity.

…Not only does the planet’s core seem sludgy, it also appears to extend across 60% of the planet’s diameter, making it much larger than previously estimated. The analysis showed that Saturn’s core might be about 55 times as massive as the entire planet Earth. Of the total mass of the core, 17 Earth masses are made of ice and rock, with the rest consisting of a hydrogen and helium-based fluid, the study suggests.

The image above was taken in 2017, and shows both a density wave in the rings (the parallel lines in the center) caused by a Saturn moon, and numerous “propellers”, small distortions in the rings caused by slightly larger objects.

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Ingenuity’s 12th flight successful

9:15 am

Ingenuity's shadow just before landing.

According to the Perseverance science team, the Mars helicopter Ingenuity successfully completed its twelfth flight on Mars early yesterday, making a short scouting round trip over an area called South Seitah to provide images that the team can use to plan the rover’s future route.

All told, Ingenuity flew just under 1,500 feet flying about 30 feet above the ground for just under three minutes. The picture to the right was taken just before landing, and shows the helicopter’s shadow on the ground. It is one of six so far downloaded. The remaining images will follow later.

The announcement was made on Twitter, and included some embarrassingly over-the-top prose:

The #MarsHelicopter’s latest flight took us to the geological wonder that is the “South Séítah” region.

South Seitah is hardly a “geological wonder”. It is a sandy area with some rocks and interesting geology.

I’m not sure why, but the Perseverance rover team seems prone to do this with their press releases and announcements. The claim they make over and over that Perseverance’s prime mission is to look for ancient life is junk Now they call a relatively undistinguished and small area on a crater floor a “wonder.”

Makes one think they somehow feel a need to justify what they are doing, something that is patently absurd. They are controlling a robotic rover and helicopter tens of millions of miles away as both explore a place on another planet no one had ever visited before. That certainly is spectacular enough, and does not need purple prose to justify.

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Regional Martian dust storms help suck water from Mars

2:55 pm

Orbital data now shows that both global and regional dust storms on Mars help remove the planet’s water, allowing it to reach higher atmospheric elevations where solar radiation breaks it up and it escapes into space.

Scientists have long suspected that Mars, once warm and wet like Earth, has lost most of its water largely through this process, but they didn’t realize the significant impact of regional dust storms, which happen nearly every summer in the planet’s southern hemisphere. Globe-enveloping dust storms that strike typically every three to four Martian years were thought to be the main culprits, along with the hot summer months in the southern hemisphere when Mars is closer to the Sun.

But the Martian atmosphere also gets heated during smaller, regional dust storms, according to a new paper published August 16 in the journal Nature Astronomy. The researchers, an international team led by Chaffin, found that Mars loses double the amount of water during a regional storm as it does during a southern summer season without regional storms.

This conclusion is based on data gathers from three different orbiters during a regional dust storm in early 2019.

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A Martian river of ice

12:59 pm

Glacial flow on Mars?
Click for full image.

Cool image time! The photo to the right, rotated, cropped and reduced to post here, was taken on May 13, 2021 by the high resolution camea on Mars Reconnaissance Orbiter (MRO). It spans the entire 4.7 mile width of the southern hemisphere canyon dubbed Reull Vallis. The white arrow indicates the direction of the downhill grade

The scientists title this image “Lineated Valley Fill.” The vagueness of this title is because they have not yet confirmed that this lineated valley fill is a glacier flowing downhill to the west.

Nonetheless, the material filling this valley has all the features one expects glaciers to exhibit. Not only is the the lineation aligned with the flow, it varies across the width of the canyon as glaciers normally do. At the edge the parallel grooves are depressed, probably because they are torn apart by the canyon walls as the glacier flows past. In turn, at the center of the flow the grooves are thinner and more tightly packed, and appear less disturbed. Here, the flow is smooth, less bothered by surrounding features.

This pattern also suggests the merging of two flows somewhere upstream.

A glance at the spectacular Concordia glacier in the Himalayas near the world’s second highest mountain, K2, illustrates the similarity of this Martian feature to Earth glaciers.

Reull Vallis itself flows down to Hellas Basin, the deepest basin on Mars. As it meanders downhill along its 650 mile length it steadily gets wider and less distinct as it drops into Hellas. Along its entire length MRO has photographed numerous similar examples of this lineated fill, all suggesting that under a thin layer of debris is a thick glacier, slowerly carving this canyon out.

The overview map below illustrates these facts nicely, while further reinforcing these glacial conclusions.
» Read more

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Ingenuity’s next flight

1:17 pm

Ingenuity's flight plane for 12th flight
Click for full image.

The Ingenuity engineering team today announced their plans for the helicopter’s twelfth flight on Mars, scheduled for early tomorrow.

Ingenuity will climb to an altitude of 10 meters and fly approximately 235 meters east-northeast toward the area of interest in Séítah. Once there, the helicopter will make a 5-meter “sidestep” in order to get side-by-side images of the surface terrain suitable to construct a stereo, or 3D, image. Then, while keeping the camera in the same direction, Ingenuity will backtrack, returning to the same area from where it took off. Over the course of the flight, Ingenuity will capture 10 color images that we hope will help the Perseverance science team determine which of all the boulders, rocky outcrops and other geologic features in South Séítah may be worthy of further scrutiny by the rover.

The map above shows South Seitah in the yellow oval. The yellow line marks Ingenuity’s past flights. The white line marks the path Perseverance has taken south since landing. The dashed lines mark Perseverance’s planned route.

Thus, the helicopter will be obtaining aerial photos of the region in Seitah where the scientists want to send Perseverance, in order to help them pick the best route.

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Curiosity looks backwards

12:40 pm

Curiosity panorama looking southeast
Click for full resolution version. For original images go here and here.

Overview map
Click for interactive map.

Cool image time! The mosaic above was created from two photos taken on August 13, 2021 by Curiosity’s right navigation camera. It looks to the southeast, at the mountainous Martian terrain that the rover had been traveling just below for the past two months.

The overview map to the right shows with the yellow lines the approximate area covered by this mosaic. The white mountain at the top is the highest visible flank of Mount Sharp, and is beyond the right/bottom edge of the overview map. Mt. Sharp’s peak itself is not visible, as it is higher up and to the right. It is presently blocked by these mountainous foothills.

The science team probably took this image partly to provide another view of these mountains for comparison with earlier views. They can use this new data to look for changes as well as obtain better three-dimensional data.

They also took the image for the same reason I post it here. Having now climbed more than 1,500 feet from the floor of Gale Crater, Curiosity’s view is routinely spectactular. Why not enjoy it?

Mt. Sharp’s peak however is still about 13,000 feet above the rover. The climb up the mountain has just begun.

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A chain of Martian sinkholes

3:19 pm

Chain of sinkholes on Mars
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on June 17, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a somewhat straight depression with several wider and deeper pits along it.

The feature immediately suggests sinkholes that exist because the ground is sagging into voids below ground. Yet, both the straight and circular depressions also appear filled, showing no evidence that they connect to any below ground cavities.

Are the sinks the result of a fissure produced by a graben, when two large blocks shift relative to each other to cause a fissure to appear? Or are they evidence of an underground lava tube? Or maybe they are the filled remains of a now mostly buried canyon carved by water or ice?

As always, a wider view helps clarify things, though whether it answers the question is uncertain.
» Read more

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China to fly asteroid sample mission in ’24

9:19 am

The new colonial movement: Chinese scientists have revealed that China is now building an asteroid sample mission to launch in ’24 and grab samples in ’25 from the near Earth asteroid dubbed Kamoʻoalewa.

According to a correspondence in Nature Astronomy, there are two typical approaches to sampling asteroids like Kamoʻoalewa, namely anchor-and-attach and touch-and-go.

The former requires delicate and dangerous interactions with the planetary body but allows more controllable sampling and more chances for surface analysis. The latter, used by Hayabusa 2 and OSIRIS-Rex, is a quick interaction facilitated by advanced navigation, guidance and control and fine control of thrusters.

China’s mission will use both architectures in order to “guarantee that at least one works.” The paper states that there is “still no successful precedent for the anchor-and-attach architecture,” meaning a possible deep space first. A 2019 presentation reveals that China’s spacecraft will attempt to land on the asteroid using four robotic arms, with a drill on the end of each for anchoring.

The attempt to do both these approaches is audacious, especially because the evidence from both OSIRIS-REx and Hayabusa-2 is that it will be difficult to safely land and hold onto a rubble pile asteroid. The material is too loosely held together.

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Confirmed: Perseverance sample was too crumbly and poured away

8:58 am

Perseverance scientists have confirmed that the reason their sample container was empty once stored on the rover was because the material that they had drilled into was more crumbly than expected, and when the core was extracted from the ground the powder simply poured out of the core tube.

The team has decided to move on.

Rather than try again with the cratered floor fractured rough, Perseverance has already departed the area and is heading towards a region named South Séítah, which likely contains layered sedimentary rocks that are more similar to the Earth rocks that engineers drilled during tests before the mission’s launch. “We are going to step back and do something we are more confident of,” says Trosper. The rover will try to drill a core there, perhaps in early September. When it does, engineers will pause the automated drilling process to check whether a core has been extracted before the rover takes the next steps of sealing the tube and storing it away.

While it makes sense to find a different place to drill for a core sample, it appears that Perseverance is designed in a manner that it can do no analysis of any drill hole material:

Curiosity and Perseverance are similar in many respects — Perseverance was actually built using much of the leftover hardware from Curiosity — but there is one major difference in how they drill into the Martian surface. Curiosity intentionally grinds rock into powder, which it then places inside analytical instruments it has onboard to conduct scientific studies. NASA designed Perseverance to extract intact cores that slide into its sampling tubes. So crumbly rocks are good for Curiosity, but not for Perseverance.

If Perseverance can do no analysis of any drillholes, this limits the science it can do significantly. While putting aside samples for later return to Earth is an excellent idea, to make this the priority so that Perseverance can analyze nothing seems a terrible decision. What if that sample return mission never gets built?

If my supposition here is correct it also means NASA’s repeated claim that Perseverance is searching for ancient life on Mars is even more of a lie than I had assumed. It isn’t merely that this claim is a distortion of Perseverance’s actual research goals — to study the geology of Mars — the rover can’t look for ancient life. It has no way of looking at any samples it digs up.

I am not sure if my conclusions here are entirely correct. For example, maybe they hope to find this alien evidence by looking at the sealed core samples they store. Unfortunately, I have no idea, because I am somewhat handicapped in describing Perseverance’s day-by-day operations because, unlike Curiosity, the Perseverance team is providing no regular updates of their operations at their blog. While the Curiosity team posts something at least twice a week, the Perseverance team has posted nothing since just after landing in February. I’ve emailed NASA about this, but have gotten no response.

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OSIRIS-REx scientists refine Bennu’s future Earth impact possibilities

1:28 pm

Using the orbital and gravity data compiled during OSIRIS-REx’s visit to the asteroid Bennu, scientists have refined its future orbits as well as the most likely moments it might impact the Earth.

In 2135, asteroid Bennu will make a close approach with Earth. Although the near-Earth object will not pose a danger to our planet at that time, scientists must understand Bennu’s exact trajectory during that encounter in order to predict how Earth’s gravity will alter the asteroid’s path around the Sun – and affect the hazard of Earth impact.

Using NASA’s Deep Space Network and state-of-the-art computer models, scientists were able to significantly shrink uncertainties in Bennu’s orbit, determining its total impact probability through the year 2300 is about 1 in 1,750 (or 0.057%). The researchers were also able to identify Sept. 24, 2182, as the most significant single date in terms of a potential impact, with an impact probability of 1 in 2,700 (or about 0.037%).

Although the chances of it hitting Earth are very low, Bennu remains one of the two most hazardous known asteroids in our solar system, along with another asteroid called 1950 DA.

This paper’s conclusions are confirming what had been found earlier in the mission, while OSIRIS-REx was still flying in formation with the asteroid. Nonetheless, it is essential to refine these numbers as precisely as possible, so this confirmation is excellent news.

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Glacial ice sheets on Mars?

1:10 pm

Glacial ice sheets on Mars?
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on June 29, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The location is in Mars’ glacier country, that strip of chaos terrain that runs about 2,000 miles along the transition zone between the northern lowland plains and the southern cratered highlands at 30 to 47 degrees north latitude. This particular feature is located in Deuteronilus Mensae, the westernmost region of that strip of chaos.

I call this glacier country because practically every image taken by MRO’s high resolution camera in this region suggests the presence of glacial material covered by a protective layer of debris. The photo to the right is typical, though a bit more puzzling because of the depressions that appear to run along highpoints.

As usual, the overview map below helps explain what we are looking at.
» Read more

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