Tag: science

More evidence of recent active volcanism on Venus

11:37 am

In a just published paper, scientists using archive data from the Magellan radar orbiter that circled Venus from 1990 to 1994, combined with data from Europe’s Venus Express that orbited from 2006 to 2015, have detected more evidence of recent volcanic activity in a canyon dubbed Ganis Chasma located in a rift zone called Atla Regio.

From the paper’s conclusion:

The pattern of the radar emissivity in these regions is consistent with relatively young and unweathered materials. The transient IR-bright spots in these regions detected 20 years after Magellan, provide independent corroboration of active volcanism in Ganis Chasma since the 1990’s.

As a possible site of current tectonic and volcanic activity, Atla Regio represents one important science target for the upcoming missions to Venus.

There are presently four missions planned for Venus, Europe’s EnVision orbiter, NASA’s VERITAS and DAVINCI+ probes, and Russia’s Venera-D missoin. All will certainly take a closer look at this region to see if there is active volcanism going on there now.

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Dust and clouds in the Martian atmosphere, as seen by UAE’s Al-Amal orbiter

11:18 am

Two new science papers have just been released detailing results from the Al-Amal (Hope) Mars orbiter that was designed and built by American universities for the United Arab Emirates (UAE).

Both papers used data obtained from the orbiter’s infrared spectrometer, dubbed the Emirates Mars Infrared Spectrometer (EMIRS).

Daily cloud cover changes on Mars
Figure 1 from paper. Click for full image.

First, the instrument tracked the daily changes in the planet’s cloud cover.

A prominent region of clouds that is commonly observed near the equator during Mars’ cold season—known as the aphelion cloud belt—was observed to reach a minimum near midday, with more clouds typically observed in both the morning and afternoon. Distinct differences were found in clouds observed near volcanoes, which tended to reach a minimum before local noon and increase throughout the afternoon.

The figure to the right shows this. In the morning and afternoon (LTST’s 7 and 17), there is a high concentration of clouds in the equatorial region above the Tharsis Bulge where the highest Martian volcanoes are located. During the middle of the day (LTSTs 11 and 13) this cloud cover largely dissipates, with a corresponding increase in cloud cover in Hellas Basin, in the southern hemisphere.

The second paper took a more general look at the data, including the change in temperature depending on elevation as well as dust and water content during the Martian northern spring and summer. From the abstract:
» Read more

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Cones south of Starship’s prime landing sites on Mars

3:55 pm

Cones near Phlegra Mountains
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on May 7, 2022 by the high resolution camera on Mars Reconnaissnace Orbiter (MRO). It shows what the scientists have labeled as “Cones in Phlegra.”

Cones such as these are one of the prime geological mysteries of Mars’ northern lowland plains. Scientists do not know yet whether they are either mud or lava volcanoes, or even if they are sedimentary mesas that resisted subsequent erosion. In fact, it was hoped by some American scientists that the Chinese would send its Zhurong rover north towards a nearby cone to find out, but alas, the Chinese decided to head south instead.

Zhurong however was on the other side of Mars. The overview map below shows us where these cones are located.
» Read more

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A distant cliff and a rocky path forward

11:11 am

Mosaic of Gediz Vallis
Click for full image.

Close-up of distant cliff face
Click for full image.

Two cool images arrived today from Curiosity, as it is about to enter the Martian canyon of Gediz Vallis. The mosaic above, cropped, reduced, and annotated to post here, was assembled from photos taken by the rover’s right navigation camera on August 15, 2022. The photo to the right, cropped and reduced to post here, was taken the same day by the rover’s Chemistry camera, normally designed to take very close-up pictures of nearby features. In this case the science team aimed it at a distant cliff face, marked by the arrow in the panorama above, to get a preview of some of the many layers in that mesa.

And has become quite expected from Mars, the number and types and variety of layers is astonishing. The layer that forms the flat bright area at the center of this image is what scientists have dubbed “the marker layer”, since they have found it at similar elevations in many places on the flanks of Mount Sharp. (See the annotated overview map from a post last week.)

Curiosity’s planned route is to head to the right of this mesa, circling around it to get into the upper reaches of Gediz Vallis. First however engineers are going to have to figure out how to get the rover past the somewhat large scattered rocks on the ground directly ahead, without further damaging Curiosity’s already tattered wheels. At first glance there does not appear to be any clear path.

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Curiosity finally looks out into Gediz Vallis

12:56 pm

First look into Gediz Vallis
Click to view full mosaic.

Overview map
Click for interactive map.

Cool image time! Curiosity’s right navigation camera today produced the mosaic above, cropped and reduced to post here, taking its first good look into Gediz Vallis, the canyon that the rover has been aiming for since it landed on Mars ten years ago.

The green dot on the overview map to the right marks the approximate location of a recurring slope lineae, a streak that comes and goes depending on the seasons whose cause remains uncertain. The yellow lines show the approximate area covered by the mosaic. The red dotted lines show Curiosity’s upcoming route. According to previously announced plans, the rover will not head straight into Gediz Vallis, but circle to the west or right of the mesa to the right of Kukenan.

The valley of course looks spectacular. For scale, the cliff face of Kukenan is estimated to be about 1,500 feet high.

The most important revelation from this image however is the ground terrain. It looks like Curiosity will have no problem moving forward into the canyon from this point, something the science team could not know for sure until the rover reached the saddle and could look down and actually see ahead.

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InSight seismometer data suggests no underground ice at landing site

9:25 am

Using a computer model combined with seismometer data gathered by the Mars lander InSight, scientists have concluded that there is little or no underground ice in the equatorial region where InSight sits.

From the paper’s abstract:

We use rock physics models to infer cement properties from seismic velocities. Model results confirm that the upper 300 m of Mars beneath InSight is most likely composed of sediments and fractured basalts. Grains within sediment layers are unlikely to be cemented by ice or other mineral cements. Hence, any existing cements are nodular or formed away from grain contacts. Fractures within the basalt layers could be filled with gas, 2% mineral cement and 98% gas, and no more than 20% ice. Thus, no ice- or liquid water-saturated layers likely exist within the upper 300 m beneath InSight. Any past cement at grain contacts has likely been broken by impacts or marsquakes.

As the lander sits just north of the equator in the red planet’s equatorial zone, which ample orbital data has suggested is a dry region (as shown in the global map below), this result is not a surprise. It does provide further confirmation however of this conclusion, that if there is any water on Mars within 30 degrees latitude of the equator, it will be deep underground, and likely only in certain regions.
» Read more

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A typical Martian rock on Mount Sharp

10:03 am

Panorama of pass
Click for full 360 degree panorama.

Typical Martian rock
Click for full image.

Cool image time! The photo to right, taken by the Mars rover Curiosity on August 9, 2022, provides a nice close-up of what might be a somewhat typical rock on the flanks of Mount Sharp in Gale Crater, many layered with some of those layers extending outward to the side for somewhat ridiculous distances as thin flakes.

The scientists call it a float rock, because they think it actually fell from the cliff dubbed Bolivar in the panorama above. Thus, it gives geologists data on the layers higher up that are not easily accessible from Curiosity’s present position.

The panorama is a mosaic created from images taken by the rover’s right navigation camera on August 8, 2022. The white arrow marks the rock. The green dot marks the approximate location on the cliff face of a previously observed recurring slope lineae, streaks that appear to come and go seasonally whose origin is still not understood.

The red dots mark my guess as to the route engineers will pick for Curiosity as it weaves its way around the other float rocks ahead.
» Read more

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Fractures in the Martian northern lowland plains

1:35 pm

Fractures in the northern lowland plains
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on April 21, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) of a spot in the Martian northern lowland plains.

Generally the surface of these lowland plains — especially at high latitudes above 30 degrees — tends to appear very water saturated, producing blobby features and what look like mud volcanoes. This picture however features something different, what the scientists have labeled fractures, geological features that appeared caused by dry conditions and sudden quake-like events. The break in the fracture near the top of the photo illustrates why water flow had little if anything to do with its formation. Other fractures in the full image show the same thing. Also the stippled surface along the picture’s right edge also suggest there is little near surface water or ice at this location.

The location, as shown by the overview map below, suggests that water might still have played a part, but only a long time ago.
» Read more

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InSight’s power status holding steady on Mars

9:47 am

InSight's status as of August 9, 2022

Yesterday the InSight science team posted the lander’s ongoing power status, as it has been doing about every week since in June the team announced that they expected power to run out sometime in August, ending the mission.

I have created the graph to the right, showing the data from all those updates, to try to glean the overall trends. The red line indicates the tau level of dust in the atmosphere, essentially telling us how much that dust is blocking light from the Sun. Normally outside of dust season this number should range from 0.6 to 0.7. Since May 17 that dust level has been steadily declining, which thus increases the amount of sunlight reaching the panels.

The blue line marks the amount of power the lander’s panels have been able to produce. The lack of change in this line reveals both good and bad news. The good news is that the power level is holding steady, at a level that allows InSight’s one operating instrument, its seismometer, to continue to function. Should this power level continue to remain stable, that seismometer should be able to operate past August, thus extending the instrument’s life longer than expected.

The bad news is that the power levels are not going up as the dust level is dropping. This suggests that the dust layer on the panels that is preventing them from generating power is actually getting thicker. InSight has still not experienced any puff of Mars’ weak wind capable of blowing dust off those panels. Instead, as the dust settles out of the atmosphere with the end of dust season, some is settling on the panels themselves.

As new updates arrive I will update this graph. Stay tuned. InSight is not yet dead, though the vultures are unfortunately circling overhead.

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Mapping the break-up and impact of one of the first asteroid’s tracked from space to the ground

11:33 am

Computer simulation of asteroid break-up
Click for full figure.

By analyzing 600 scattered pieces recovered from a 20-foot wide asteroid that broke-up and landed in the Sudan in 2008, scientists have discovered that some surface pieces were able to reach the ground unscathed because they were on the asteroid’s protected aft as it plowed through the atmosphere.

This asteroid was one of the first ever discovered shortly before impact and then tracked as it hit the atmosphere and broke up, the pieces falling as meteorites. The image to the right, figure 4 of the paper, shows the computer simulation of the asteroid’s break-up, based on the data obtained by mapping the location of its pieces on the ground. From the press release:

“Because of the high speed coming in, we found that the asteroid punched a near vacuum wake in the atmosphere,” says Robertson. “The first fragments came from the sides of the asteroid and tended to move into that wake, where they mixed and fell to the ground with low relative speeds.”

While falling to the ground, the smallest meteorites were soon stopped by friction with the atmosphere, falling close to the breakup point, while larger meteorites were harder to stop and fell further downrange. As a result, most recovered meteorites were found along a narrow 1-km wide strip in the asteroid’s path. “The asteroid melted more and more at the front until the surviving part at the back and bottom-back of the asteroid reached a point where it suddenly collapsed and broke into many pieces,” said Robertson. “The bottom-back surviving as long as it did was because of the shape of the asteroid.”

No longer trapped by the shock from the asteroid itself, the shocks from the individual pieces now repulsed them, sending these final fragments flying outwards with much higher relative speed. “The largest meteorites from 2008 TC3 were spread wider than the small ones, which means that they originated from this final collapse,” said Jenniskens. “Based on where they were found, we concluded that these pieces stayed relatively large all the way to the ground.”

The location of the large meteorites on the ground still reflects their location in the back and bottom-back part of the original asteroid.

While there is a certain randomness in how any asteroid breaks up, this data will help scientists better understand the make-up of future meteorites they find. The bigger more widely scattered pieces likely came from the asteroid’s rear surface.

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Further damage to Curiosity’s wheels

10:14 am

Curiosity wheel comparison of damage
For the original images, click here for the top photo and here and here
for the bottom photo.

The photo comparison to the right, created from high resolution images taken by Curiosity on Mars two months apart, provides us a new update on the state of the rover’s damaged wheels. It shows damage on the same wheel that I have been tracking for several years.

The numbers indicate the same treads, or grousers as termed by the science team. The “+” sign indicates spots where new damage has occurred since the previous photo.

The top photo was taken on June 3, 2022, and was the first to show new damage in more than five years. The bottom photo was taken on August 6, 2022, and shows that another small piece on the same grouser has broken off during the past two months.

Other than this change, however, the rest of the grousers appear unchanged. Moreover, a comparison with an earlier image of this same wheel taken in the summer of 2021 shows that grouser #6 as well as the unnumbered one just below appear also unchanged.

The damage in grouser #5 however is still concerning, and reflects the increasing roughness of the terrain as Curiosity climbs higher and higher on Mount Sharp. Though the science team has been very careful since the rover’s first few years on Mars to travel around obstacles that could damage the wheels, it apparently is becoming harder to do so.

However, even if this wheel eventually loses all the metal between the zig-zag grouser treads, the science team has said it has “proven through ground testing that we can safely drive on the wheel rims if necessary.” The team as also said they do not think that is likely, at least not for a long time, and based on the rate of damage documented by these pictures, this appears very true.

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Strange terrain southwest of Jezero Crater

1:17 pm

Strange terrain near Jezero Crater

Cool image time! The photo to the right, cropped and reduced to post here, was taken on June 16, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists have merely label “landforms.”

I instead call them strange. Clearly we are seeing exposed layering that surrounds the mesa in the middle of the image. This in turn suggests that the mesa top was once the surface of this whole region, and that region had been formed by the repeated placement of multiple sedimentary layers. Then, over time the surrounding terrain was eroded away, exposing those underlying layers.

Even so, some of the parallel lines do not appear to be layers, but striations etched into the ground. To get a better look, the white box marks the area covered by a full resolution close-up below.
» Read more

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