Tag: science

The damp southern latitudes of Mars

11:01 am

Impact craters on the southern permafrost of Mars
Click for the full image.

Cool image time! The image on the right, cropped to post here, was part of the monthly image release from the high resolution camera on Mars Reconnaissance Orbiter (MRO). The release came with no caption, and was merely titled Aonia Terra, indicating that it was part of the vast cratered region ranging from 30 to 81 degrees latitude south of Valles Marineris.

These craters are at the high latitude of 73 degrees, so they are relatively close to the south pole. Based on what I have recently learned about the Martian poles, the higher the latitude the more water you will find saturated in the ground. In many ways one could refer to this ground as a kind of permafrost.

The lander Phoenix landed at about 68 degrees north latitude, slighter farther from the north pole, and was able to find water by merely scraping off a few inches of ground.

Thus, we should not be surprised by the muddy look of these craters. Their bolides landed on ground that was likely saturated with water, and went splat when they hit.

The scientific puzzle is why one crater seems to sit above the general surface, as if the ground resisted the impact, while the other seems to be mostly sunken, as if the ground was so soft that when the bolide hit, it sunk as if it landed on quicksand, leaving only a vague trace of an impact crater.

Don’t ask me for an explanation. I only work here.

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Museum decides T-Rex skeleton has no gender

3:48 pm

The coming dark age: Officials at the Field Museum in Chicago have decided that since scientists were never able to determine the sex of their most famous T-Rex skeleton, they will now refer to it as if was gender neutral.

According to Arc Digital, “Sue,” Field Museum’s Tyrannosaurus Rex — one of the most complete and largest T-Rex skeletons ever discovered — is working on becoming a “gender neutral” icon by adopting gender-neutral pronouns in her new private exhibit on the museum’s second floor.

Sue is not, in fact, gender neutral or gender fluid. The T-Rex skeleton, discovered in South Dakota in the 1990s, was either male or female. The scientists who discovered Sue believed the skeleton belonged to a female because female T-Rexes are larger than male T-Rexes, and Sue was one of the largest dinosaur skeletons ever found; she’s named “Sue” after Susan Hendrickson, who led the team that unearthed her.

But back in March 2017, Arc Digital reports, the museum decided to have a little fun, and in response to a question lobbed during a Twitter Q&A, Sue claimed that she was “gender neutral” because her sex was unknown, and that she preferred the pronouns they/their/them.

By March 2017, though, Sue, who had graced the museum’s central rotunda for more than a decade, was due to move upstairs to make room for an even larger dinosaur skeleton, and when constructing her pernament home in the museum’s dinosaur exhibit, museum officials adopted Sue’s social media gender-neutral tendencies and made them official. “In her new suite, some of the signage describing the fossil has adopted non-binary pronouns,” Arc Digital says. “One sign does make the distinction between SUE the museum ambassador/Twitter star and the fossil itself, noting that the fossil is properly referred to as ‘it.’ But some of the rest of the signage uses ‘their’ pronouns and seems more interested in teaching museum-goers about the trendy movement for acceptance of non-binary identity than it does about paleontology.”

Our society is truly becoming delusional. This dinosaur was not gender neutral. It goes against every principle of science that a science museum is supposed to be teaching to make believe it is.

Worse, this is a form of political pandering that is disgraceful. It is not the job of the Field Museum to take sides in this sexual political battle. Not only is it inappropriate, it assumes all who enter the museum will agree with them, something that is decidedly a false assumption.

In a sane world I would expect donations to the museum to drop because of this. Unfortunately, I am not convinced we live in a sane world.

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First confirmed Ebola case in Uganda

2:57 pm

Officials have now confirmed the first case of Ebola in Uganda since the present outbreak of the contagious disease in the Congo.

The confirmed case is a 5-year-old child from the Democratic Republic of the Congo who travelled with his family on 9th June 2019. The child and his family entered the country through Bwera Border post and sought medical care at Kagando hospital where health workers identified Ebola as a possible cause of illness. The child was transferred to Bwera Ebola Treatment Unit for management. The confirmation was made today by the Uganda Virus Institute (UVRI). The child is under care and receiving supportive treatment at Bwera ETU, and contacts are being monitored.

The Ministry of Health and WHO have dispatched a Rapid Response Team to Kasese to identify other people who may be at risk, and ensure they are monitored and provided with care if they also become ill. Uganda has previous experience managing Ebola outbreaks. In preparation for a possible imported case during the current outbreak in DRC, Uganda has vaccinated nearly 4700 health workers in 165 health facilities (including in the facility where the child is being cared for); disease monitoring has been intensified; and health workers trained on recognizing symptoms of the disease. Ebola Treatment Units are in place.

In response to this case, the Ministry is intensifying community education, psychosocial support and will undertake vaccination for those who have come into contact with the patient and at-risk health workers who were not previously vaccinated.

There also remain questions about how effective the vaccine is. It seems to work to protect from ebola, but only if you haven’t already become infected. Since the vaccine has not been fully tested, the real scientific questions remain.

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Ghost dunes on Mars

9:10 am

A ghost dune
Click for full image.

Cool image time! The Mars Reconnaissance (MRO) science team today released a captioned image of several ghost dunes on Mars. The image on the right is cropped and reduced to highlight one of those ghosts, which the scientists explain as follows.

Long ago, there were large crescent-shaped (barchan) dunes that moved across this area, and at some point, there was an eruption. The lava flowed out over the plain and around the dunes, but not over them. The lava solidified, but these dunes still stuck up like islands. However, they were still just dunes, and the wind continued to blow. Eventually, the sand piles that were the dunes migrated away, leaving these “footprints” in the lava plain.

The location of these ghost dunes is inside the southeast edge of Hellas Basin, what I call the bottom of Mars.

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The big water volcano on Ceres

8:38 am

Scientists have proposed a new detailed model to explain the formation of the large mountain Ahuna Mons on the asteroid Ceres.

The new theory doesn’t change the generally accepted idea that this mountain is a ice volcano, formed by the rise of a brine from below. It simply provides some details about the process.

A study involving scientists from the German Aerospace Centre (DLR) has now solved the mystery of how Ahuna Mons, as the mountain is called, was formed, using gravity measurements and investigations of the geometrical form of Ceres. A bubble made of a mixture of salt water, mud and rock rose from within the dwarf planet. The bubble pushed the ice-rich crust upwards, and at a structural weak point the muddy substance, comprising salts and hydrogenated silicates, was pushed to the surface, solidified in the cold of space, in the absence of any atmosphere, and piled up to form a mountain. Ahuna Mons is an enormous mud volcano.

The bubble would be the equivalent of a magma chamber of lava here on Earth.

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New analysis throws wrench in formation theory of spirals in galaxies

8:29 am

The uncertainty of science: A new analysis of over 6000 galaxies suggests that a long-held model for the formation of spirals in galaxies is wrong.

[Edwin] Hubble’s model soon became the authoritative method of classifying spiral galaxies, and is still used widely in astronomy textbooks to this day. His key observation was that galaxies with larger bulges tended to have more tightly wound spiral arms, lending vital support to the ‘density wave’ model of spiral arm formation.

Now though, in contradiction to Hubble’s model, the new work finds no significant correlation between the sizes of the galaxy bulges and how tightly wound the spirals are. This suggests that most spirals are not static density waves after all.

Essentially, we still have no idea why spirals form in galaxies.

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Land of stucco and lava-filled cracks

5:27 pm

Stucco and filled cracks on Mars
Click for full image.

Cool image time! The picture on the right, cropped and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter in December 2018 and released earlier this year. It shows a filled fault/fissure in a region dubbed Cereberus Palus, located south of the giant volcano Elysium Mons and to the west of Olympus Mons. This region is also biggest and most extensive sections of the transition zone between Mars’s southern highlands and the northern lowlands. This area however is so far from the lowlands its geology is more likely influenced more by the volcanism that created Elysium Mons to the north.

Overview map

The overview map to the right illustrates this geography, with the black square indicating the location of this image.

The image itself strengthens my uneducated conclusion. This region of Cereberus Palus is filled with many faults, cracks caused as the terrain was stretched by the rising volcano. In some cases, as shown here, the cracks became filled with lava from below, as indicated by the lighter color of the material in those filled cracks..

What struck me most about this image was the terrain on the picture’s right. Looks exactly like the stucco on the outside of my house. It is as if a plasterer came by before the lava solidified and ran his putty knife over the surface to create the multiple small ridges.

It is worthwhile checking out the full resolution image. The details are especially intriguing.

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The Martian North Pole

1:23 pm

The Martian North Pole

Since the very beginning of telescopic astronomy, the Martian poles have fascinated. Their changing sizes as the seasons progressed suggested to the early astronomers that Mars might be similar to Earth. Since the advent of the space age we have learned that no, Mars is not similar to Earth, and that its poles only resemble Earth’s in a very superficial way.

Yet, understanding the geology and seasonal evolution of the Martian poles is critical to understanding the planet itself.

This post will focus on the Martian north pole. The map on the right of the north polar regions is based on many satellite images supplemented by a lot of research by planetary scientists. The black circle in the middle is an area with relatively poor image coverage. The green areas are regions of higher elevation where the bulk of the permanent ice cap is located, surrounded by the blue northern lowlands that cover much of Mars’s northern hemisphere and are thought to have once harbored an intermittent ocean.

Olympia Undae dune field
Click for full image.

The reddish regions encircling the permanent ice cap are large seas of sand dunes, with Olympia Undae the largest and most sand-dune-packed. The image on the right, posted initially here on March 25, 2016, was taken by Mars Odyssey and shows the endlessness of this dune sea. Olympia Undae, spanning 120 degrees of longitude, is about 700 miles long, making it bigger than the Grand Canyon. As I noted in that post, “Just imagine trying to travel though this area. It is the epitome of a trackless waste. And without some form of GPS system getting lost forever would be incredibly easy.”

The polar cap itself, surrounded by those sand seas, is 600 miles across and a little less than 7,000 feet deep. It is made up of many seasonal layers, like the icecaps on Earth, with the bulk a mixture of water ice and cemented dust and sand. The very top layers, dubbed the residual icecap, is about three to six feet thick made up of frozen water having a volume about half of Greenland’s icecap. While this water could sublimate away, data suggests it is, like the icecaps on Earth, in a steady state, neither gaining or losing volume with each Martian year.

Above the residual icecap of water is the seasonal icecap made up of carbon dioxide. Unlike the other layers, this seasonal cap of dry ice, also less than six feet thick, comes and goes with the seasons. During the Martian summer it is gone, the carbon dioxide having sublimated away into the atmosphere. As the weather chills however that carbon dioxide begins to freeze again, falling as CO2 snow on the surface at the poles to create a thin cap of dry ice extending down to about 60 degrees latitude and covering practically everything seen in the first map above.

These facts suggest that future Martian colonists will have an interest in this region. While harsher than the rest of the planet, the conditions at the poles are not so much different that it will be impossible to work here. And here they will find a ready supply of carbon dioxide to help their plants grow, as well as a ready supply of water, all easily mined and near the surface.

In order to understand how this dry ice cap comes and goes, scientists have been using the high resolution camera of Mars Reconnaissance Orbiter (MRO) to repeatedly monitor some of the same locations in these sand seas to track the seasonal changes. In my routine review of the new images downloaded from MRO in May, I came across more than a dozen such images, all of which had been requested by Dr. Candice Hansen of the Planetary Science Institute in Tucson, Arizona, and taken just as the Martian winter was ending and spring was beginning. As she explained to me, “The images I’m requesting now follow-up on many of our earlier study sites so that we can study interannual variability. We’re also looking at more places to get a sense of what is similar/different depending on where you are.”

Below are two of these recent images, showing one example of the springtime changes that can be seen on these dunes.
» Read more

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Ebola epidemic continues to grow

9:17 am

The Ebola epidemic in Africa has continued to grow in the past year, with indications that it is accelerating.

The number of Ebola cases in the Democratic Republic of the Congo (DRC) has doubled in just over two months and has now passed 2,000, according to the World Health Organization (WHO).

An estimated 2,008 people have been infected with Ebola in the North Kivu and Ituri provinces since the start of the outbreak in late July 2018, and 1,346 of those individuals have died. The numbers represent a rapid escalation of the crisis since the outbreak passed the 1,000-case mark on 24 March (see ‘Escalating crisis’).

Part of the cause for the disease’s spread is political tensions. The Congo government and the people in North Kivu have been in conflict:

Violence has plagued North Kivu for decades, and the region is home to dozens of armed groups and communities who oppose the government. Political tensions grew late last year during elections, when the [Congo’s] former president banned more than a million people in North Kivu from voting because of Ebola. The measure led many people to suspect that the outbreak was a political invention to marginalize the opposition, and not a real disease.

But authorities cannot tackle Ebola if people mistrust their intentions. Health workers must convince people to send their family members to treatment centres, for instance, and persuade people to receive an experimental Ebola vaccine. Despite continuous outreach, many people remain suspicious of Ebola responders — who are often not from the region — and a small fraction assault health workers.

If things don’t change, none of this will end well, for anyone.

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A look at future missions to Venus

12:47 pm

Link here. The article gives a nice summary of what we presently know about Venus, as well as outlining the various proposed missions to it.

First off the starting line, and as far as I know the only mission actually approved, is an orbiter from India, scheduled for launch in 2023. After this are a number of proposals in the U.S. Europe, and Russia.

It appears that the discovery of many exoplanets with features somewhat similar to Venus is one of the factors generating the new interest in going back there.

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On the precipice on Bennu

10:00 am

Truck-sized boulder on a crater rim on Bennu
Click for full image.

Cool image from OSIRIS-REx. The picture on the right, cropped to post here, was taken by OSIRIS-REx and shows a square boulder about the size of a 15-passenger van, precariously perched on the rim of a large crater on the asteroid Bennu. The picture was taken April 11 from about 2.9 miles distance.

This scale is human-sized. If that rock is a 15 passenger van, then the small rocks around it are about the size of a person and that cliff is about 20-30 feet high. I can imagine strolling down the slope to check out the cliff face, though I would make sure I gave a wide berth to the part of the cliff directly below that boulder.

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Update on effort to resume drilling of heat probe on InSight

9:38 am

Link here. It appears InSight’s camera cannot see the hammer drill, called “the mole,” that pushes the heat probe down, and to get a look and assess the problem they are going to use InSight’s robot arm to remove the equipment in the way.

The lifting sequence will begin in late June, with the arm grasping the support structure (InSight conducted some test movements recently). Over the course of a week, the arm will lift the structure in three steps, taking images and returning them so that engineers can make sure the mole isn’t being pulled out of the ground while the structure is moved. If removed from the soil, the mole can’t go back in.

They also have a theory as to what has stopped the drilling.

Team members now believe the most likely cause is an unexpected lack of friction in the soil around InSight – something very different from soil seen on other parts of Mars. The mole is designed so that loose soil flows around it, adding friction that works against its recoil, allowing it to dig. Without enough friction, it will bounce in place.

They can’t see it, as designed? It depends on the soil for friction? I am very puzzled at these design decisions.

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Sunspot update May 2019: The long ramp down

12:18 pm

NOAA yesterday released its May update for the Sun’s sunspot cycle. The graph is posted below, annotated by me to give it some context.

The Sun in May continued to show the exact same amount of activity as it had shown for March and April. This steady uptick in sunspot activity once again shows that the ramp down to full solar minimum will be long and extended.

May 2019 sunspot activity

The graph above has been modified to show the predictions of the solar science community for the previous solar maximum. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction, extended in November 2018 four years into the future.

That we are definitely ramping downward to minimum, even with the slight increase in the past three months, is shown by the fact that the Sun has shown no sunspots for the past fifteen days. In fact, all the activity shown in May comes from the first half of the month. This pattern is actually a reflection of the Sun’s 27-day rotation period. As I noted in my February 2017 update,

January’s activity however illustrated a statistical phenomenon that is typical of the sunspot count. That count is determined not by the numbers of sunspots on the entire surface of the Sun, but on the sunspots visible on the side of the Sun facing the Earth. Since it is not unusual for one face to be more active than the other, as we transition from maximum to minimum the sunspot counts will often show a more pronounced up-and-down curve reflecting this fact. Since the Sun’s day equals about 27 Earth days, this means that about every two weeks the active side will dominate our view until it rotates away and the inactive side reveals itself for two weeks.

In 2017 the number of spots were greater, so the period of inactivity was generally less. Now, it is not unusual for the Sun to be blank for weeks at a time. When it does become active, it is also not unusual for that activity to be confined to one hemisphere, so we get two weeks or less of activity, followed by two weeks or more of blankness.

So far there have been no sunspots in June. Expect that to continue for at least another week, when the more active hemisphere of the Sun returns to face us. I would not be surprise however if that other hemisphere arrives with its sunspots gone, so that the present streak of blankness continues unabated.

Meanwhile, solar scientists struggle to figure out what is going to happen next. Unlike climate scientists, who know as little about the climate, the solar science community admits to its ignorance about the Sun, and the uncertainty of its solar models.

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VLT snaps image of double asteroid zipping past Earth

9:04 am

Double asteroid imaged by VLT

The Very Large Telescope (VLT) in Chile was successfully able to photograph the double asteroid that flew past the Earth on May 25 at a distance of 3.2 million miles and a speed of 43 thousand miles per hour.

The left image on the right is the raw image, while the right image is their reconstruction after applying adaptive-optics (AO) to the raw image. From the press release:

Bin Yang, VLT astronomer, declared “When we saw the satellite in the AO-corrected images, we were extremely thrilled. At that moment, we felt that all the pain, all the efforts were worth it.” Mathias Jones, another VLT astronomer involved in these observations, elaborated on the difficulties. “During the observations the atmospheric conditions were a bit unstable. In addition, the asteroid was relatively faint and moving very fast in the sky, making these observations particularly challenging, and causing the AO system to crash several times. It was great to see our hard work pay off despite the difficulties!”

To put it mildly, that right image is a fantasy. Astronomers love to tout the wonders of adaptive optics, but no matter how good it might be, it still is garbage-in-garbage-out, a computer simulation based on their guess at what the object would look like if there was no atmosphere in the way. In this particular case, they are being especially fantastic, and guaranteed to be wrong. It is impossible for them to extrapolate such minute surface details from the fuzzy image on the left.

Still, getting an image of this asteroid as it zipped by at that speed using such a large telescope is an achievement, and bodes well for the use of ground-based astronomy of near Earth asteroids.

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Solar scientists struggle to predict the next sunspot cycle

9:10 am

Link here. This is a detailed article describing the meeting in March where the solar science community gathered to formulate its prediction for the next solar cycle.

What stands out about the meeting is the outright uncertainty the scientists have about any prediction they might make. It is very clear that they recognize that all their predictions, both in the past and now, are not based on any actual understanding the Sun’s magnetic processes that form sunspots and cause its activity cycles, but on superficial statistics and using the past visual behavior of the Sun to predict its future behavior.

“There’s not very much physics involved,” concedes panelist Rachel Howe of the University of Birmingham in the United Kingdom, who has been tasked with reviewing the mishmash of statistical models. “There’s not very much statistical sophistication either.”

Panelist Andrés Muñoz-Jaramillo of the Southwest Research Institute in Boulder agrees with Howe. “There is no connection whatsoever to solar physics,” he says in frustration. McIntosh, who by now has walked downstairs from his office and appears in the doorway, is blunter. “You’re trying to get rid of numerology?” he says, smirking.

The result, as I repeatedly note in my monthly sunspot updates, is that the last prediction failed, and that there is now great disagreement among these scientists about what will happen in the upcoming cycle.

[They] dutifully tabulate the estimates, and come up with a peak sunspot range: 95 to 130. This spells a weak cycle, but not notably so, and it’s marginally stronger than the past cycle. [They do] the same with the votes for the timing of minimum. The consensus is that it will come sometime between July 2019 and September 2020. Maximum will follow sometime between 2023 and 2026.

The range of predictions here is so great that essentially it shows that there really is no consensus on what will happen, which also explains why the prediction has still not been added to NOAA’s monthly sunspot graph. For past cycles the Sun’s behavior was relatively consistent and reliable, making such statistical and superficial predictions reasonably successful.

The situation now is more elusive. For the past dozen or so years the Sun has not been behaving in a consistent or reliable manner. Thus, the next cycle might be stronger, it could be weak, or we might be heading into a grand minimum, with no sunspots for many decades. These scientists simply do not know, and without a proper understanding of the Sun’s dynamo and magnetic field, they cannot make a sunspot prediction that anyone can trust.

And so they wait and watch, as we all. The Sun will do what the Sun wants to do, and only from this we will maybe be able to finally begin to glean an understanding of why.

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Astronauts recover towel left on outside of ISS ten years ago

8:01 am

During a spacewalk this week Russian astronauts recovered a towel that had been left on the outside of ISS during an earlier spacewalk ten years ago.

The towel was originally meant to clean astronauts’ spacesuits during their work in outer space. It was left by a Russian cosmonaut about a decade ago. Mr Kononenko and Mr Ovchinin removed the towel from the station’s surface and placed it in a special container. It will be sent back to Earth and delivered to a group of experts for further examination.

Though unplanned, this towel will provide some good data on the ability of microorganism to survive in space. It almost certainly had such things within it when it was taken outside a decade ago, and the question now will be whether they survived or not, and their condition in either case.

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Rover update: May 30, 2019

12:28 pm

Summary: Curiosity confirms clay in the clay unit. Yutu-2 begins its sixth day on the far side of the Moon. Three other rovers move towards completion and launch.

For the updates in 2018 go here. For a full list of updates before February 8, 2018, go here.

Clouds over Gale Crater
Clouds over Gale Crater

Curiosity

For the overall context of Curiosity’s travels, see my March 2016 post, Pinpointing Curiosity’s location in Gale Crater.

Curiosity’s journey up the slopes of Mount Sharp in Gale Crater goes on! On the right is one of a number taken by the rover in the past week, showing water clouds drifting over Gale Crater.

These are likely water-ice clouds about 19 miles (31 kilometers) above the surface. They are also “noctilucent” clouds, meaning they are so high that they are still illuminated by the Sun, even when it’s night at Mars’ surface. Scientists can watch when light leaves the clouds and use this information to infer their altitude.

While these clouds teach us something about Martian weather, the big rover news this week was that the data obtained from the two drill holes taken in April show that the clay formation that Curiosity is presently traversing is definitely made of clay, and in fact the clay there has the highest concentration yet found by the rover.

This clay-enriched region, located on the side of lower Mount Sharp, stood out to NASA orbiters before Curiosity landed in 2012. Clay often forms in water, which is essential for life; Curiosity is exploring Mount Sharp to see if it had the conditions to support life billions of years ago. The rover’s mineralogy instrument, called CheMin (Chemistry and Mineralogy), provided the first analyses of rock samples drilled in the clay-bearing unit. CheMin also found very little hematite, an iron oxide mineral that was abundant just to the north, on Vera Rubin Ridge. [emphasis mine]

That two geological units adjacent to each other are so different is significant for geologists, because the difference points to two very different geological histories. The formation process for both the clay unit and Vera Rubin Ridge must have occurred at different times under very different conditions. Figuring out how that happened will be difficult, but once done it will tell us much about both Gale Crater and Mars itself.

With the success of their clay unit drilling campaign, the Curiosity science team has had the rover begin its trek back from the base of the cliff below Vera Rubin Ridge to its planned travel route up the mountain.

An updated description of that route was released by the Curiosity science team last week, while I was in Wales. Below is their image showing that route, with additional annotations by me and reduced to post here.
» Read more

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First movie of solar eclipse rediscovered

9:56 am

The first movie ever made of a solar eclipse, taken in 1900, has been rediscovered and restored.

The film was taken by British magician turned pioneering filmmaker Nevil Maskelyne on an expedition by the British Astronomical Association to North Carolina on 28 May, 1900. This was Maskelyne’s second attempt to capture a solar eclipse. In 1898 he travelled to India to photograph an eclipse where succeeded but the film can was stolen on his return journey home. It was not an easy feat to film. Maskelyne had to make a special telescopic adapter for his camera to capture the event. This is the only film by Maskelyne that we know to have survived.

I have embedded the movie below the fold.
» Read more

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Hayabusa-2 successfully places reference target at man-made crater

8:48 am

Close-up during Hayabusa-2's close approach

Hayabusa-2 has successfully dropped a small reference target at the man-made crater on Ryugu, getting within 10 meters of the surface.

The image to the right is the last image taken by the spacecraft’s navigation camera during the operation. Unfortunately, the science team did not provide any further information, such as the height from which this image was taken, nor the scale of the features. Based on the sequence of images, it clearly occurred at the moment of closest approach.

I have tried to see if I could pinpoint the crater in the image by comparing it to the planning image post here. Unfortunately, I have been unable to identify comparable features.

Either way with the successful placement of the reference target on the surface, they can now begin planning the sample grab touch-and-go at this location.

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The mysterious slope streaks of Mars

12:10 pm

Massive flow on Mars
A typical Martian slope streak.

The uncertainty of science: In the past decade or so scientists have documented in detail a number of features on the Martian surface that evolve or change over time. From the constantly changing poles to the tracks of dust devils to landslides to the appearance of seasonal frost, we have learned that Mars is far from a dead world. Things are happening there, and while they are not happening as quickly or with as much energy as found on Earth, geological changes are still occurring with regular frequency, and in ways that we do not yet understand.

Of the known changing features on Mars, two are especially puzzling. These are the two types of changing streaks on the slopes of Martian cliffs, dubbed recurring slope lineae (referred as RSLs by scientists) and slope streaks.

Lineae are seasonal, first appearing during the Martian summer to grow hundreds of feet long, and then to fade away with the arrival of winter. Their seasonal nature and appearance with the coming of warm temperatures suggests that water plays a part in their initiation, either from a seep of briny water or an avalanche of dust. Or a combination of both. The data however does not entirely fit these theories, and in fact is downright contradictory. Some studies (such as this one and this one) say that the seasonal lineae are caused by water. Other studies (such as this one and this one) say little or no water is involved in their seasonal formation.

The answer remains elusive, and might only be answered, if at all, when Curiosity takes a close look at two lineae in the coming years.

Slope streaks however are the focus of this post, as they are even more puzzling, and appear to possibly represent a phenomenon entirely unique to Mars. I became especially motivated to write about these mysterious ever newly appearing features when, in reviewing the May image release from the high resolution camera on Mars Reconnaissance Orbiter (MRO), I found four different uncaptioned images of slope streaks, all titled “Slope Stream Monitoring.” From this title it was clear that the MRO team was re-imaging each location to see if any change had occurred since an earlier image was taken. A quick look in the MRO archive found identical photographs for all four slope streak locations, taken from 2008 to 2012, and in all four cases, new streaks had appeared while older streaks had faded. You can see a side-by-side comparison of all four images below the fold.
» Read more

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NASA IG finds both Europa missions a mess

10:25 am

Our incompetent federal government: A report released today [pdf] by NASA’s inspector general has found that the management of the Europa Clipper orbiter and the later Europa lander missions, both mandated by Congress, are facing serious budget and schedule risks, despite being given more than three-quarters of a billion dollars more than requested.

Congress has taken a strong interest in the project and since fiscal year (FY) 2013 has appropriated about $2.04 billion to NASA for a Europa mission—$1.26 billion more than the Agency requested.

…Despite [this] robust early-stage funding, a series of significant developmental and personnel resource challenges place the Clipper’s current mission cost estimates and planned 2023 target launch at risk. In addition, although Congress directed NASA to use the SLS to launch the Clipper, it is unlikely to be available by the congressionally mandated 2023 date and therefore the Agency continues to maintain spacecraft capabilities to accommodate both the SLS and two commercial launch vehicles, the Delta IV Heavy and Falcon Heavy. [emphasis mine]

The lander meanwhile is in even worse shape, especially because its congressionally-mandated launch date on SLS in 2025 seems impossible.

It seems to me that this entire project could be the poster boy for the overall incompetence of our so-called “betters” in Washington, who in the past three decades have failed spectacularly in practically every major project they have undertaken. The project was mandated on NASA by Congress, led by former congressman John Culberson (R-Texas), who was then the chairman of the House subcommittee that was in charge of funding the agency. It was his pet project. Though the planetary science community were glad to have this mission, it was listed as their second priority in their 2011 decadal survey. Culberson made it first, and also made sure it got a lot of money, far more than NASA ever requested.

Despite this strong support, the inspector general has now found that the project is being badly mismanaged and faces budget overruns and scheduling problems. The scheduling problems partly result from the project’s bad management, but mostly because of Congress’s demand that the spacecraft fly on SLS. Our vaunted elected officials wanted to give that boondoggle (they own pet project) a mission, something it didn’t have, and Europa Clipper and Lander were therefore given that task.

The problem, as I have documented endlessly, is that SLS is woefully behind schedule. It appears it will likely not be ready for Europa Clipper’s launch window in 2023.

But hey, let’s give our federal government more responsibility and power! Let’s go socialist!

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Hayabusa-2 has begun approach to Ryugu

9:05 am

Ryugu during approach

Hayabusa-2 has begun its approach to the man-made impact site on Ryugu in order to drop a reflective reference target there in preparation for a later touch-and-go landing.

The link provides real time delivery of the images taken by the spacecraft’s navigation camera, released approximately once every thirty minutes. The image on the right, brightened slightly to post here, is the most recent image as I write this post.

The approach will take almost twenty-four hours, so viewing the changes at the link will be somewhat equivalent to watching paint dry. I suggest returning every few hours to see the closer images of the asteroid.

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Chang’e-4 and Yutu-2 wake up for sixth lunar day

8:29 am

China’s Chang’e-4 lander and Yutu-2 rover have been reactivated this week to begin observations during their sixth lunar day on the far side of the Moon.

According to the Chinese news source,

For the sixth lunar day, the lander’s neutron radiation detector and low-frequency radio detector will be restarted to conduct scientific tasks including particle radiation observation and low-frequency radio astronomical observation.

The rover’s panoramic camera, detection radar, infrared imaging spectrometer and neutral atom detector will be restarted during the sixth lunar day.

That’s about all we know. They have not released much information about the rover’s travels, nor have they released any detailed information about the data they have obtained.

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Scientists propose planetary orbital alignments cause the sunspot cycle

10:15 am

The uncertainty of science: Scientists today proposed a new model that says the orbital alignments of the planets, most especially Venus-Earth-Jupiter, act to initiate the eleven-year solar sunspot cycle.

As with the gravitational pull of the Moon causing tides on Earth, planets are able to displace the hot plasma on the Sun’s surface. Tidal forces are strongest when there is maximum Venus-Earth-Jupiter alignment; a constellation that occurs every 11.07 years. But the effect is too weak to significantly perturb the flow in the solar interior, which is why the temporal coincidence was long neglected. However, the HZDR researchers then found evidence of a potential indirect mechanism that may be able to influence the solar magnetic field via tidal forces: oscillations in the Tayler instability, a physical effect that, from a certain current, can change the behavior of a conductive liquid or of a plasma. Building on this concept, the scientists developed their first model in 2016; they have since advanced this model in their new study to present a more realistic scenario.

More details at the link. To put it mildly, this theory is far from proven. While they mention how it might also cause grand minimums and double-peaked maximums, they are somewhat vague in explaining this process. If valid, however, they should be able to use this model to predict future cycles, including the possible arrival of a new grand minimum in the coming decades.

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Future lunar colonies at Shackleton Crater at the Moon’s south pole

9:52 am

The rim of Shackleton Crater
Click for full image.

The Lunar Reconnaissance Orbiter (LRO) science team has released a new image of the rim of Shackleton Crater, reduced slightly in resolution to post here on the right. The Moon’s south pole is located on the crater’s rim near the top right of this image. As they note at the link, the interior of Shackleton never gets any sunlight, making it what scientists call a Permanently Shadowed Region (PSR), while a ridgeline running south to de Gerlache Crater gets sunlight 90% of the time.

An elevated ridge runs roughly between Shackleton and de Gerlache craters, and the relatively high elevation of this landscape means that some portions are illuminated up to 90% of the time, but nowhere is permanently illuminated. Future explorers could take advantage of this persistent illumination by setting up solar panels in several closely spaced locations providing nearly constant solar generated electricity.

The proximity to Permanently Shadowed Regions in and around Shackleton crater adds scientific value to this destination, as PSRs are often home to compounds such as water ice that are not found elsewhere on the Moon, but which contain clues to the history of of inner Solar System water and other volatile elements. A nearby, ready source of water-ice would also be of benefit to human surface activities, either as a consumable (air or water) or as spacecraft fuel.

Below is a more detailed map they provide showing this area, with the permanently shadowed regions shaded in blue. The green dot indicates the location of the south pole. The green arrows indicate regions in sunlight in the full image.

The region around Shackleton

Sadly, I expect we are looking at the locations of future Chinese and Indian lunar bases. Though the U.S. has done all the proper legwork to find out the exact locations to build a lunar base at Shackleton, our government has decided we will instead twiddle our thumbs in lunar orbit while other countries use our legwork to land and establish bases on the Moon itself.

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OSIRIS-REx moves into new science phase

9:01 am

The OSIRIS-REx science team has shifted the spacecraft’s operation into a new phase aimed at carefully mapping the surface of the asteroid Bennu in preparation for an eventual touch-and-go sample grab.

During Detailed Survey: Equatorial Stations phase, the spacecraft’s instruments will make the scientific observations needed to help the team home in on the best location on Bennu to collect a sample of regolith (loose surface material). To obtain these data, the spacecraft will execute a series of slews between Bennu’s north and south poles while taking observations from seven different stations above the equator. These data will be studied to understand the geology of Bennu. The spacecraft will also conduct searches for dust and gas plumes.

During this phase, planned to last through mid-June, they are asking for the public’s help in mapping the surface and its innumerable rocks.

For this effort, NASA is partnering with CosmoQuest, a project run out of the Planetary Science Institute that supports citizen science initiatives. Volunteers will perform the same tasks that planetary scientists do – measuring Bennu’s boulders and mapping its rocks and craters – through the use of a simple web interface. They will also mark other scientifically interesting features on the asteroid for further investigation.

The boulder mapping work involves a high degree of precision, but it is not difficult. The CosmoQuest mapping app requires a computer with a larger screen and a mouse or trackpad capable of making precise marks. To help volunteers get started, the CosmoQuest team provides an interactive tutorial, as well as additional user assistance through a Discord community and livestreaming sessions on Twitch.

Seems like fun!

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Hayabusa-2 aborts close-in drop of visual marker on Ryugu

3:09 pm

Japan’s asteroid probe Hayabusa-2 automatically aborted a planned drop of a visual markee on the asteroid Ryugu at the site where the probe created a crater in April.

Thursday’s mission was to observe the targeted area in detail and drop a marker from an altitude of 10 meters. But officials say the probe automatically suspended the operation after it descended to about 50 meters above the surface. It then headed toward its standby position of 20 kilometers above Ryugu. Hayabusa2 is designed to automatically abort its landing if it detected any irregularity. The agency is looking into the cause of the arrested descent.

Once the marker is eventually in place, they will use it for guidance during a a second touchdown to grab further samples, this time hopefully of material churned up by the explosion that created the crater.

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The floor of Marineris Valles

12:02 pm

Close-up of the floor of Marineris Valles

Larger view
Click for the full image.

To the right is small section cropped out of an image, taken by the high resolution camera of Mars Reconnaissance Orbiter (MRO) on March 30, 2019, of one very tiny area of the floor of the 2,500 mile long Marineris Valles, the biggest known canyon in the solar system.

Below this on the right is a larger section of the full image, with the white box showing the part covered by the top photograph. The general flow direction is to the east.

The photograph, uncaptioned, is titled “Terminus of Pitted Materials Emanating from Oudemans Crater.” Oudemans Crater is about 55 miles across and is located near the head of Marineris Valles to the east of the giant volcanic region dubbed the Tharsis Bulge. The meteorite that caused this crater is estimated to have been a little less than 3 miles in diameter. It is believed by some scientists that the impact heated up subsurface carbon dioxide permafrost which then explosively flooded down the Valles Marineris into the Northern Plains of Mars, pushing a lot of pulverized debris in front of it..

Instead of liquid water, what is stored underground on Mars is liquid CO2 and when a collapse occurs, this boils almost instantly and explosively to CO2 vapour, blasting the rock and regolith to dust, except for the most resistant fragments such as igneous rocks. The rest of the regolith is composed of dust and gravel, weakly cemented by water ice. On Mars, water is not a fluid, but behaves as a mineral in most situations. Grains of ice would be tumbled along in the cryogenic flows, and transported as passive solids just like quartz grains are transported as sand by rivers on Earth.

This theory, if correct, would eliminate the need for liquid water on the surface, and would explain many of the planet’s geological surface features.

Overview

The overview thumbnail to the left shows the location of both Oudemans Crater and this MRO image, indicated by the very tiny blue rectangle near the thumbnail’s center..

The “pitted materials” in the image’s title refers to that flowing avalanche of pulverized ice, rock, and dust, shown in the picture by the curved terraced cliffs descending to the east. This is where this material settled as it flowed eastward, pushed by that explosive CO2 flood.

You can see another example of this eastward flow in another MRO image taken just to the west. The canyon floor is pitted, confused, and rough, but there is an obvious flow trend to the east.

In fact, much of the floor of Marineris Valles that has been photographed at high resolution is similarly rugged. It will be a challenge to explore this place, especially because we have only imaged a small percentage at high resolution. There is much there that remains unseen and unknown.

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Fractured and collapsed Martian crater floor

4:06 pm

Fractured and collapse Martian crater floor
Click for full image.

Time for some puzzling Martian geology. The image on the right, rotated, cropped, and reduced to post here, comes from the Mars Reconnaissance Orbiter (MRO) high resolution archive, and shows a strangely collapsed and fractured crater floor. In fact, like a number of other Martian craters, rather than having a central peak, the center of the crater floor, shown at the image’s center right, seems depressed.

The crater is located in a region dubbed the Cerberus Plains, in a hilly subregion called Tartarus Colles. Of the transition zone between the northern lowlands and the southern highlands these plains comprise the second largest region.

Being in the transition zone I would guess that the geology here is strongly influenced by the ebb and flow of the slowly retreating intermittent ocean that is thought to have once existed in the nearby lowlands. As water came and went, it created a variety of shoreline features scattered about, but not in a single sharp line as we would expect on Earth. Think more like tidal pools, where in some areas water gets trapped and left behind only to sublimate away at at later time.

We can see some hints of these processes in the images of the floors of two other craters that I have previously highlighted, here and here.

With this geological overview in mind, the broken plates here remind me of features I’ve seen in caves. Mud gets washed into a passage, partly filling it. Over time a gentle water flow over the surface of the mud deposits a crust of calcite flowstone on top of the mud. Should the water flow suddenly increase, it will wash out the mud below the crust. If the crust is not very strong or thick, it will crack into pieces as it falls, and thus resemble what we see here in this Martian crater.

There are cases where the crust becomes thick enough to remain standing, which produces some spectacular hanging calcite draperies that seem to defy explanation.

The collapse in the center of the crater is more puzzling, but suggests, based on comparable-looking Earth geology, that any perched water in this canyon might have actually drained out through underground drainage, accessed through the depression.

Be warned: All my explanations above are based on what exists on Earth, and Mars is very different from Earth. The lower gravity, colder temperatures, and different chemistry guarantee that the geological processes there will not be identical. We start by using what we know here, but recognize that we need to learn more about Mars to truly understand what goes on there.

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