Tag: science

All instruments check out on the Parker Solar Probe

9:24 am

The initial check out of the Parker Solar Probe, now on its way to the Sun, has shown all instruments are functioning properly.

“All instruments returned data that not only serves for calibration, but also captures glimpses of what we expect them to measure near the Sun to solve the mysteries of the solar atmosphere, the corona,” said Nour Raouafi, Parker Solar Probe project scientist at the Johns Hopkins University Applied Physics Lab in Laurel, Maryland.

The mission’s first close approach to the Sun will be in November 2018, but even now, the instruments are able to gather measurements of what’s happening in the solar wind closer to Earth.

The spacecraft will make its first fly-by of Venus in October.

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A Martian shoreline?

11:52 am

Collapsing cliff in Tempe Fossae

Cool image time! The image on the right, reduced and cropped to post here, was part of the August 31 image release from the high resolution camera of Mars Reconnaissance Orbiter (MRO). (Click on the image to see the full image.) It shows a slowly separating cliff feature in a region dubbed Tempe Fossae

As part of that monthly mass release, no caption was provided for this image. However, we can gain some understanding by looking at the larger context.

Tempe Fossae is located at the margins between the low flat northern plains and the high southern highlands. The location is also part of the vast drainage region to the east of Mars’ gigantic volcanoes. This is obvious from the overview image below and on the right. The location of this image is indicated by the white cross.

Mars overview

In this area of that drainage the canyons appear to follow southwest to northeast trending fault lines. Tempe Fossae is one of the smaller of these canyon complexes. All however appear to drain out into the northern plains.

Most of the MRO images of features in this area focus on the canyon cliffs. This image however focused on this one isolated small cliff in the middle of the canyon. To my eye it appears that these features document the slow drying of that vast intermittent ocean in Mars’s northern plains. The cliff is actually two steps, with the higher one appearing to mark an older shoreline. The lower cliff is abutted by a low flat area where it appears as if there had once been ponded water, now dried.

close-up of cracked area

The cracks in the cliff itself suggest it is slowly breaking apart and falling down towards that low flat area. In fact, the entire feature reminds me of the sand cliffs that are sometimes found along shorelines. The sand is not very strong structurally, and with time sections will separate and then fall down. The image to the right zooms in on this cracked region. The presence of sand dunes reinforces my impression.

I imagine that as the water drained down from the glaciers on the sides of the volcanoes and filled that intermittent sea, the shoreline regions would have had the most water. At Tempe Fossae the canyons might have been partly filled. As the water level drained out and lowered, first the upper cliff edge was exposed, then the lower. The draining water probably helped created these cracks as it flowed down through them.

Finally, the last remaining pits of water ponded at the base of the cliff, eventually drying out. With time, the weakly structured sand cliffs, already carved partly by the flowing water, began to slump apart and fall downward, producing the cracks we now see. I expect that some time in the near future, on geological time scales, there will be a landslide and the outer section will collapse downward.

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Vulcan found?

9:51 am

Scientists have found a super-earth orbiting 40 Eridani-A, a star located sixteen light years away and proposed by Gene Roddenberry in 1991 as the home star for his race of logical Vulcans.

It turns out the letter authors’ prediction was right — a world really does orbit the primary star of the three-star 40 Eridani system. (Whether it’s home to a logic-based alien society, though, is anyone’s guess!)

The world is a super-Earth, the most common type of planet in the galaxy (though a type that’s missing from our solar system). At twice Earth’s radius and eight to nine times its mass, 40 Eridani b sits on the line that divides rocky super-Earths from gaseous ones. The planet orbits its star every 42 days, putting just inside the system’s habitable zone — in other words, where it’s nice and hot. At 16 light-years away, it’s the closest super-Earth known and therefore a good potential target for followup observations.

The discovery was made by a survey taking place using a relatively small telescope right here in the Tucson area, on top of Mount Lemmon. Most cool!

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Instrument on GRACE-FO fails

9:45 am

The U.S/German science two-satellite constellation, launched in May, has not gathered any science data since July because one instrument on one satellite has shut down.

It appears the problem is related to an electrical problem. The article provides little information, though they say they will switch to a back up system later this month. I wonder why this has taken so long.

The article at the link calls this “a glitch.” That is a lie and bad journalism. Any failure that shuts down a spacecraft for months and requires the use of a back up is a major failure, not a mere “glitch.” I wish news organizations would stop using that word, as it only exists to help minimize the seriousness of a problem.

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Curiosity fails again to drill into Vera Rubin Ridge

9:13 am

For the third time Curiosity has failed to drill into the rock on top of Vera Rubin Ridge.

Last night we learned that our drill attempt on “Inverness” was not successful, reaching only 4 mm into the rock.

The only successful drill attempt on the ridge occurred when they moved down off the top of the ridge to a slightly lower geological layer.

They are moving Curiosity to another candidate drill site on the ridge, where they will try again. While they imply in their reports that it is solely the hardness of the ground that is stopping them, I still wonder if the improvised drill technique, using the robot arm to push down rather than the drill’s jammed feed mechanism, is partly to blame. I would think that they have placed limits on how hard the arm can push to protect it.

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Cryo-volcanism had less influence on shaping Ceres than predicted

10:23 am

The uncertainty of science: A careful analysis of the Dawn data has found that though cryo-volcanism has occurred repeatedly on Ceres, it had less influence on the dwarf planet’s surface than previous models had predicted.

At the same time, the data also suggests that Ceres has been more active throughout its history than predicted. They found about 22 domes that are apparently past cryo-volcanoes that have flattened out.

“Given how small Ceres is, and how quickly it cooled off after its formation, it would be exciting to identify only one or two possible cryovolcanoes on the surface. To identify a large population of features that may be cryovolcanoes would suggest a long history of volcanism extending up to nearly the present day, which is tremendously exciting,” said Sizemore. “Ceres is a little world that ought to be ‘dead,’ but these new results suggest it might not be. Seeing so much potential evidence for cryovolcanism on Ceres also lends more weight to discussions of cryovolcanic processes on larger icy moons in the outer solar system, where it’s likely more vigorous.”

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Cassini’s last view of Titan

11:25 am

The Cassini science team today released a mosaic of the last images Cassini took of Titan before it crashed into Saturn’s atmosphere four days layer.

The mosaic shows Titan’s north polar region, and shows seas, lakes, and spotty clouds. The lack of clouds is a puzzle to scientists, as they had expected the north polar region to be cloud-covered at this time as summer arrived there, as had been seen at the south pole.

During Titan’s southern summer, Cassini observed cloud activity over the south pole.

However, typical of observations taken during northern spring and summer, the view here reveals only a few small clouds. They appear as bright features just below the center of the mosaic, including a few above Ligeia Mare. “We expected more symmetry between the southern and northern summer,” said Elizabeth (“Zibi”) Turtle of the Johns Hopkins Applied Physics Lab and the Cassini Imaging Science Subsystem (ISS) team that captured the image. “In fact, atmospheric models predicted summer clouds over the northern latitudes several years ago. So, the fact that they still hadn’t appeared before the end of the mission is telling us something interesting about Titan’s methane cycle and weather.”

The truth is we haven’t the slightest idea whether the clouds over the south pole during its previous summer were normal or an aberration. We have barely seen a full year of seasons at Saturn and Titan. To confidently extrapolate any pattern from this slim data is silly.

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Dress rehearsal of Hayabusa-2’s landing scrapped

9:22 am

The dress rehearsal of Hayabusa-2’s eventual landing on the asteroid Ryugu was cut short yesterday when the spacecraft found it could not get a reliable distance reading of the surface once it descended to 600 meters.

The problem was apparently due to the pitch black surface of the carbon-rich asteroid that made laser distance measurements difficult. JAXA says the Hayabusa 2 is in good condition, and the agency is considering changing landing procedures such as adjusting the configuration of measuring devices.

Despite the suspension, the altitude of 600 meters the explorer has descended to the asteroid is the closest ever recorded. JAXA had planned to bring down the probe to 30 meters and make detailed observations of a landing spot.

Just to clarify, this was a height record for Hayabusa-2 only.

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Astronomers use radio emissions from distant galaxy to observe asteroid

9:03 am

The wonders of science: Astronomers have successfully used the faint radio emissions from very distant galaxy to roughly determine the shape and size of a nearby asteroid.

In an unusual observation, astronomers used the National Science Foundation’s Very Long Baseline Array (VLBA) to study the effects on radio waves coming from a distant radio galaxy when an asteroid in our Solar System passed in front of the galaxy. The observation allowed them to measure the size of the asteroid, gain new information about its shape, and greatly improve the accuracy with which its orbital path can be calculated.

When the asteroid passed in front of the galaxy, radio waves coming from the galaxy were slightly bent around the asteroid’s edge, in a process called diffraction. As these waves interacted with each other, they produced a circular pattern of stronger and weaker waves, similar to the patterns of bright and dark circles produced in terrestrial laboratory experiments with light waves. “By analyzing the patterns of the diffracted radio waves during this event, we were able to learn much about the asteroid, including its size and precise position, and to get some valuable clues about its shape,” said Jorma Harju, of the University of Helsinki in Finland.

The amount of information is not great, and there is an enormous amount of uncertainty in the data. Nonetheless, this is an amazing and fascinating observation.

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Is mercury release cause of New Mexico solar observatory shutdown?

1:28 am

Story here. From the link:

The issue may be related to Mercury (the metal, not the planet). On a tip from a science journalist friend who covers telescopes and who has been there, I verified the observatory uses a vat of liquid mercury as a float bearing for the giant solar telescope. According to an internal NSO/NMSU document, that bearing is “high-risk” during maintenance. If there was a major mercury spill, it might explain why the Feds are there, with FBI providing security. The amount of Mercury is said to be in the “tens of gallons” range, which is next to impossible to come by in the commercial market these days, and if it were weaponized, it would make a very nasty dirty bomb. Perhaps there’s some security issue with the mercury on-site.

This is third hand, so it should be taken with a great deal of skepticism.

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Scientists identify molecule linked to anti-aging effects

2:18 pm

Scientists have identified a molecule produced by the body during fasting that then acts to delay aging.

In this study, the research team explores the link between calorie restriction (eating less or fasting) and delaying aging, which is unknown and has been poorly studied. The findings are published in the journal Molecular Cell.

The researchers identified an important, small molecule that is produced during fasting or calorie restriction conditions. The molecule, β-Hydroxybutyrate, is one type of a ketone body, or a water-soluble molecule that contains a ketone group and is produced by the liver from fatty acids during periods of low food intake, carbohydrate restrictive diets, starvation and prolonged intense exercise.

“We found this compound, β-Hydroxybutyrate, can delay vascular aging,” Zou said. “That’s actually providing a chemical link between calorie restriction and fasting and the anti-aging effect. This compound can delay vascular aging through endothelial cells, which line the interior surface of blood vessels and lymphatic vessels. It can prevent one type of cell aging called senescence, or cellular aging.”

Senescent cells can no longer multiple and divide. The researchers found β-Hydroxybutyrate can promote cell division and prevent these cells from becoming old. Because this molecule is produced during calorie restriction or fasting, when people overeat or become obese this molecule is possibly suppressed, which would accelerate aging.

It appears that there is still a lot of work to create an artificially produced version of this molecule, but to know it exists is a significant discovery. For the body to produce it requires you to fast for at least 24 hours.

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Solar observatory closed for unstated security reasons

10:38 am

The National Solar Observatory facility at Sacramento Peak in New Mexico, managed by a consortium of universities, has been shut down temporarily for unstated security reasons.

The Sunspot Observatory is temporarily closed due to a security issue at the facility that’s located 17 miles south of Cloudcroft in the Sacramento Mountains Friday, an Association of Universities for Research in Astronomy (AURA) spokeswoman Shari Lifson said.

“The Association of Universities for Research in Astronomy who manages the facility is addressing a security issue at this time,” Lifson said. “We have decided to vacate the facility at this time as precautionary measure. It was our decision to evacuate the facility.”

She said she cannot comment on the specifics of the security issue.

This is a very strange story, especially because of the lack of information being released. What could have happened that required them to evacuate? And why can’t they release more details?

I can’t deny that my first thought was aliens, but this is a laughable and ridiculous idea. The facility merely looks up at the Sun, and is also a somewhat minor research facility. More likely they have had a serious employee problem, and are trying to take steps to prevent anyone from getting hurt.

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Science paper slams IAU planet definition

10:26 am

Worlds without end! A paper published August 29 in the science journal Icarus has hurled serious criticisms of the definition of planets imposed on the world by International Astronomical Union in 2006 that also robbed Pluto of planetary status.

“The IAU’s definition was erroneous since the literature review showed that clearing orbit is not a standard that is used for distinguishing asteroids from planets, as the IAU claimed when crafting the 2006 definition of planets,” said Dr. Kirby Runyon, from the Johns Hopkins University Applied Physics Laboratory. “We showed that this is a false historical claim. It is therefore fallacious to apply the same reasoning to Pluto.”

According to the team, the definition of a planet should be based on its intrinsic properties, rather than ones that can change, such as the dynamics of a planet’s orbit. “Dynamics are not constant, they are constantly changing. So, they are not the fundamental description of a body, they are just the occupation of a body at a current era,” Dr. Metzger said. “We recommend classifying a planet based on if it is large enough that its gravity allows it to become spherical in shape.”

I must also note that the IAU’s definition had ignored the recommendations of its own committee on coming up with a new planetary definition and was voted on at the very end of a conference when almost everyone had left.

In other words, the IAU’s actions in 2006 were purely political, were bad science, and should be dumped as quickly as possible. And now the scientists are saying this, in peer-reviewed papers.

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Jupiter’s weird magnetic field

11:34 am

New data from Juno has revealed that Jupiter’s magnetic field acts like it has three poles, one at each pole and another near the equator.

If Earth’s magnetic field resembles that of a bar magnet, Jupiter’s field looks like someone took a bar magnet, bent it in half and splayed it at both ends. The field emerges in a broad swath across Jupiter’s northern hemisphere and re-enters the planet both around the south pole and in a concentrated spot just south of the equator, researchers report in the Sept. 6 Nature.

“We were baffled” at the finding, says study coauthor Kimberly Moore, a graduate student at Harvard University.

They think the multiple poles are a result of the complexity of Jupiter’s inner core, which likely does not have the same kind of organization as a rocky terrestrial planet.

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Hayabusa-2 scientists release updated landing schedule

10:20 am

The science team for Hayabusa-2 has released an updated landing schedule.

Two of the landers developed by the Japanese space agency will be deployed together by Hayabusa 2 on Sept. 21, and another landing probe provided by German and French scientists is set for its descent to Ryugu on Oct. 3.

Those landing attempts will be preceded by a landing rehearsal using the Hayabusa 2 spacecraft to approach within 100 feet (30 meters) of Ryugu next week. The spacecraft is scheduled to reach its closest point to the asteroid Sept. 12, low enough to fire and test its laser range finder, a navigation sensor to be used on future touch-and-go maneuvers to snag a sample of Ryugu for return to Earth.

Below is the very busy planetary probe schedule through January:

  • Week of September 12: Hayabusa-2 will do dress rehearsal of its Ryugu landing
  • September 21: Two of Hayabusa-2’s three Minerva-II mini-landers will land on Ryugu
  • October 3: Another Hayabusa-2 mini-lander, MASCOT, will land on Ryugu
  • October 3: The Parker Solar Probe makes first fly-by of Venus
  • Late October: Hayabusa-2 itself will land and grab a sample of Ryugu
  • November 26: The U.S. lander InSight will land on Mars.
  • December 3: OSIRIS-REx will arrive at the asteroid Bennu.
  • December: Chang’e-4 will land on the Moon’s far side.
  • January 1: New Horizons will fly past the Kuiper Belt object Ultima Thule.

During this time period Curiosity will also make two more drill attempts, and then resume its climb up Mount Sharp.

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TESS releases its first batch of exoplanet candidates

9:59 am

The science team for the U.S.’s exoplanet space telescope TESS this week released its first batch of exoplanet candidates.

TESS scientists released the list so that other astronomers could make an initial determination as to whether these candidates are planets. There are 73 objects in this first batch, including some planets previously known from ground-based searches, says George Ricker, the mission’s principal investigator at the Massachusetts Institute of Technology in Cambridge. Perhaps 5 to 20% of the objects on the list will turn out to be false alarms, he says. Others, if confirmed, will join the ranks of newly discovered exoplanets.

Researchers expect TESS to find as many as 10,000 large planets. But its main goal is to discover and measure the masses of at least 50 small worlds no more than four times the size of Earth.

Meanwhile, Kepler has resumed operations despite being almost out of fuel. The science team there is attempting to squeeze every last ounce of data it can before the spacecraft’s fuel runs out.

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Update on the Parker Solar Probe

8:49 am

Link here. The press release notes that the spacecraft’s instruments are one by one being made operational without problem and that it has also successfully completed a second course adjustment.

The release also provided a link to a page which will shows the probe’s present location. This is useful, as it also shows the probe’s position in relation to the Sun, Venus, and the Earth.

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Curiosity to drill twice more on Vera Rubin Ridge

3:45 pm

Before they will resume the journey up Mount Sharp the Curiosity science team now plans two more drilling attempts on Vera Rubin Ridge.

The rover has never encountered a place with so much variation in color and texture, according to Ashwin Vasavada, Curiosity’s project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. JPL leads the Mars Science Laboratory mission that Curiosity is a part of.

“The ridge isn’t this monolithic thing — it has two distinct sections, each of which has a variety of colors,” Vasavada said. “Some are visible to the eye and even more show up when we look in near-infrared, just beyond what our eyes can see. Some seem related to how hard the rocks are.”

Part of this drilling campaign will also include gaining a better understanding better their improvised drilling technique.

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New study: Forest cover has blossomed since 1980s

4:43 pm

The uncertainty of science: According to new research the world’s tree canopy has grown by almost a million square miles since 1982.

While the area of bare ground and short vegetation is diminishing, forest area is growing. As Ronald Bailey notes in Reason, “Forests in montane regions are expanding as climate warming enables trees to grow higher up on mountains.”

The greatest increase in tree canopy occurred in Europe, including European Russia, where it exploded by 35%. A close second was found in China, where tree canopy gained 34%. In the U.S., tree canopy increased by 15%.

This study confirms numerous other forest and agricultural research that has shown that increased carbon dioxide in the atmosphere encourages plant growth. Numerous other studies have also found that the Earth has been greening in the past century.

My review of the scientific literature on this subject also matches this finding, having found that if global warming is happening, research looking at what has actually happened generally show that increased CO2 and warming have tended to have beneficial effects, despite the endless doomsday predictions by global warming scientists of what might happen.

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Saturn’s polar hexagonal vortex might tower high above clouds

3:35 pm

The uncertainty of science: A long term analysis of data from the probe Cassini suggests that Saturn’s north polar hexagonal vortex might tower many miles high above the planet’s clouds.

A new long-term study has now spotted the first glimpses of a northern polar vortex forming high in the atmosphere as Saturn’s northern hemisphere approached summertime. This warm vortex sits hundreds of kilometres above the clouds, in a layer of atmosphere known as the stratosphere, and reveals an unexpected surprise. “The edges of this newly-found vortex appear to be hexagonal, precisely matching a famous and bizarre hexagonal cloud pattern we see deeper down in Saturn’s atmosphere,” says Leigh Fletcher of the University of Leicester, UK, lead author of the new study.

“While we did expect to see a vortex of some kind at Saturn’s north pole as it grew warmer, its shape is really surprising. Either a hexagon has spawned spontaneously and identically at two different altitudes, one lower in the clouds and one high in the stratosphere, or the hexagon is in fact a towering structure spanning a vertical range of several hundred kilometres.”

There are many uncertainties here. For one thing, we have not yet even observed Saturn from up close through a complete year. We might be seeing random weather events having nothing to do with the gas giants overall planetary weather patterns.

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Sunspot update for August 2018: The slide to minimum

12:28 pm

As it does the first Sunday of each month, yesterday NOAA posted its monthly update of the solar cycle, covering sunspot activity for August 2018. And as I do every month, I am posting it below, annotated to give it some context.

The Sun in August had a slight uptick in sunspot activity, but not a very significant one. As such, the slide to solar minimum continues. Right now the lack of sunspot activity in 2018 is heading to match or even exceed 2007, the year in which the previous solar minimum began.

August 2018 sunspot activity

The graph above has been modified to show the predictions of the solar science community. 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.

If you look at the original graph at NOAA, you will see that we are getting very close to the right edge of the graph. I expect that sometime in the next few months NOAA will update the graph, a necessary act that will in one sense be a shame, as they have been adding monthly updates to this graph since the beginning of the last solar minimum. This has allowed everyone to see a standard visual, month to month, for comparing solar activity. It has also allowed me to annotate the graph properly to show how the 2007 and 2009 predictions held up against actual activity. Once the graph changes it will be more difficult to do this.

Anyway, it is very clear we are entering solar minimum, and that the solar cycle we are now completing will be both a short and weak cycle. What happens next is really the big question. Will the Sun sunspot activity recover? Or will we enter the first grand minimum since the 1600s? Either way, for solar scientists the coming years are going to be very exciting.

Posted on interstate 10 going from Tucson to Phoenix, on the way to the wooded northern forests of Arizona, where Diane and I will spend a couple of days visiting friends at their upstate cabin/home.

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Some debate at NASA over Opportunity

8:58 am

This story yesterday had the following interesting paragraph:

Members of Opportunity’s engineering team recommended a different plan, the person close to the mission says. Their idea was to actively try to communicate with Opportunity until the end of January 2019 — the end of the seasonal cleaning period. After that, they suggested passive listening until the end of 2019. But these recommendations were ignored by management in order to save money, this person says, meaning the agency could be risking abandoning a still-functioning rover. The Opportunity team reportedly didn’t receive formal notice of the plan until “minutes before JPL published its press release,” according to The Atlantic.

It appears that some on the science team do not feel that the present plan to listen closely for only 45 days, through mid-October, is sufficient, as it will likely require a dust devil to clear Opportunity’s solar panels, and dust devil season will not begin until November.

However, it is very likely wrong to blame the resistance by NASA management to this plan solely to a desire to save money. There are other considerations, such as tying up the Deep Space Network for this one rover when, as I noted yesterday, the October to January time period will be a very very very busy time for that network, with many important new planetary probe events. Seven different spacecraft will either be landing or doing fly-bys on four different solar system targets during that time. Tying the network up to listen for Opportunity will likely not work.

It seems to me that Opportunity should be recovered, if possible, but it also must receive a lower priority during this time period. After New Horizons’ January 1st fly-by of Ultima Thule it might be possible to devote more time then to listening, but I can see the logic, at least in this context, for reducing the listening time from October to January.

Hat tip Kirk Hilliard.

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The upcoming very busy planetary probe season

12:08 pm

The next few months are going to be very busy and exciting for the planetary science community. Seven different probes will be either flying past or landing on four different solar system objects, with interesting events happening every few weeks:

  • September 21: One of Hayabusa-2’s mini-landers, Minerva-II-1, will land on the asteroid Ryugu
  • October 3: Another Hayabusa-2 mini-lander, MASCOT, will land on Ryugu
  • Late October: Hayabusa-2 itself will land and grab a sample of Ryugu
  • November 26: The U.S. lander InSight will land on Mars.
  • December 3: OSIRIS-REx will arrive at the asteroid Bennu.
  • December: Chang’e-4 will land on the Moon’s far side.
  • January 1: New Horizons will fly past the Kuiper Belt object Ultima Thule.

In addition, another Hayabusa-2 mini-lander will also land on Ryugu, sometime after Hayabusa-2’s landing. Moreover, as OSIRIS-REx and New Horizons approach their targets we shall see daily new and increasingly sharper images of both Bennu and Ultima Thule, prior to their arrival.

I expect from September to January there will be many many very cool images coming from space, on almost a daily basis.

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How the Curiosity science team found soft rock for drilling

10:15 am

Link here. They very much wanted drill samples on Vera Rubin Ridge, but had twice found the rock too hard for Curiosity’s drill. So how did they pinpoint the spot, dubbed Stoer, where the drill finally worked?

In the absence of direct data on rock mechanical properties, we came up with three criteria that we could use to try to find a softer rock. (1) Did the bristles of the DRT brush leave scratches on the rocks’ surfaces? While not necessarily a direct indicator of what the rock strength would be when we drilled into it, we could at least say rocks that got scratched with the DRT had a softer surface than those that didn’t. (2) How well exposed are the white calcium sulfate veins? On some rock targets, like Stoer, we clearly see veins. On other targets, like Voyageurs, the veins are recessed into the rock. Recessed veins erode much faster than the surrounding bedrock because the surrounding bedrock is harder. Non-recessed veins tells us the bedrock may be similar in strength to the veins, or, if the veins stick out, the bedrock may be lower in strength. (3) What does the large-scale topography tell us? Broadly, Vera Rubin Ridge is a ridge because it is composed of hard rocks that are more resistant to erosion than their surroundings. We realized we might use this same logic to find softer rocks within the ridge by trying to drill in local topographic lows or at bases of scarps where the bottom of the scarp is eroding more quickly than the hard rocks on top.

The successful drill hole, Stoer, was thus down somewhat from to top of the ridge. As they prepare to move on, it appears they want to try again to drill at the top of the ridge. It also appears that the work described above has maybe found another location there where the rock might be soft enough for the drill.

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As Mars dust storm clears, Opportunity remains silent

10:04 am

The Opportunity science team today provided a new update on the rover, noting that it remains silent even as the Martian dust storm is clearing.

With skies clearing, mission managers are hopeful the rover will attempt to call home, but they are also prepared for an extended period of silence. “If we do not hear back after 45 days, the team will be forced to conclude that the Sun-blocking dust and the Martian cold have conspired to cause some type of fault from which the rover will more than likely not recover,” said Callas. “At that point our active phase of reaching out to Opportunity will be at an end. However, in the unlikely chance that there is a large amount of dust sitting on the solar arrays that is blocking the Sun’s energy, we will continue passive listening efforts for several months.”

The additional several months for passive listening are an allowance for the possibility that a Red Planet dust devil could come along and literally dust off Opportunity’s solar arrays. Such “cleaning events” were first discovered by Mars rover teams in 2004 when, on several occasions, battery power levels aboard both Spirit and Opportunity increased by several percent during a single Martian night, when the logical expectation was that they would continue to decrease. These cleaning dust devils have even been imaged by both rovers on the surface and spacecraft in orbit (see https://mars.nasa.gov/resources/5307/the-serpent-dust-devil-of-mars/).

It appears however that if nothing is heard from Opportunity by sometime in mid-October, they will be very prepared at that time to begin shutting down ground-based operations here on Earth.

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Dates set for first landings on Ryugu

9:10 am

The science team for the Japanese probe Hayabusa-2 have set the dates for the first two landings on the asteroid Ryugu.

On 21 September, it will despatch the first of these piggybacked packages. A 3.3kg container known as Minerva II-1, which is mounted on the spacecraft, will deploy two robots known as Rover 1A and Rover 1B.

The 1kg “rovers” will actually move by hopping under the asteroid’s low gravity. Each one contains a motor-powered internal mass that rotates to generate force, propelling the robot across the surface. The rovers are equipped with wide-angle and stereo cameras to send back pictures from Ryugu.

Then, on 3 October, the mothership will deploy a lander called Mascot, which has been developed by the German Aerospace Center (DLR) in conjunction with the French Space Agency (CNES). Mascot, otherwise known as the Mobile Asteroid Surface Scout, is a 10kg instrument package that will gather a range of scientific data from the surface. It carries a wide-angle camera, a microscope to study the composition of minerals, a radiometer to measure temperature and a magnetometer to measure the magnetic field.

After it reaches the surface, Mascot can move its position only once, by jumping.

An earlier report had said that Hayabusa-2 would itself land late in October, but this report today leaves that landing date unstated.

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The aurora of Saturn

10:11 am

Cool movie time! Using the Hubble space telescope scientists have compiled an animation showing the changes in Saturn’s north pole aurora over time.

In 2017, over a period of seven months, the NASA/ESA Hubble Space Telescope took images of auroras above Saturn’s north pole region using the Space Telescope Imaging Spectrograph. The observations were taken before and after the Saturnian northern summer solstice. These conditions provided the best achievable viewing of the northern auroral region for Hubble.

…The images show a rich variety of emissions with highly variable localized features. The variability of the auroras is influenced by both the solar wind and the rapid rotation of Saturn, which lasts only about 11 hours. On top of this, the northern aurora displays two distinct peaks in brightness — at dawn and just before midnight. The latter peak, unreported before, seems specific to the interaction of the solar wind with the magnetosphere at Saturn’s solstice.

The animation of all the images is embedded below. At the link is a second video showing the aurora in close-up

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Lunar scientist Paul Spudis had passed away

10:03 am

R.I.P.: Paul Spudis, lunar scientist and strong advocate for the human exploration of space, passed away yesterday at the age of 66.

Spudis was one of the best lunar scientists we have had. He also saw past petty budget battles and his personal planetary research to recognize the need for human exploration and settlement on the Moon and elsewhere. This is a premature loss for us all.

Leonard David at Space News has written a fine obituary, which gives only a hint at how important Spudis was to the recent resurgence of the U.S. in the exploration of space.

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Looking for Marsquakes

1:24 pm

After eight and a half years of study of one particular very young fault system on Mars using high resolution images from Mars Reconnaissance Orbiter, scientists have found no evidence that any quakes occurred there in that time.

The team studied images of Mars’s surface over nearly a decade to look for changes that might have been caused by marsquakes. The researchers used images of Mars’s surface from the High Resolution Imaging Science Experiment (HiRISE) and applied Co-registration of Optically Sensed Images and Correlation (COSI-Corr)—software that has been validated to track terrestrial glaciers, landslides, and quakes on Earth, as well as dune movement on Mars itself—to hunt for signs of displacement near fault zones.

The researchers focused on the Cerberus Fossae fault system, the youngest fault system on the Red Planet and thus the most likely to still be active. They used the average coregistration performance of each study image to determine that this method should be able to detect fault slip rates of 0.1–10 millimeters a year.

The team identified only one displacement signal that could have been interpreted as evidence of a marsquake—but dismissed it as the result of a topographic artifact. Their results suggest that no seismic movement occurred in the Cerberus Fossae area over the course of the study, which spanned 8.5 Earth years’ worth of images from the planet.

This suggests, but does not prove, that Mars has very few quakes. We shall know more when InSight lands on Mars on November 26.

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