Tag: science

Want to look at every planetary map ever made? You can!

9:25 am

Two Polish academics have created a web-available catalog intended to contain every planetary map ever created, beginning in 1600 through the present.

“Our catalogue is being updated regularly with both newly resurfaced historic maps and new additions. For the future, we plan to add maps that have been published in journal articles and digitize maps that do not yet include GIS formats,” added Hargitai. “We live in a transition period where static maps that characterized the last 400 years may become extinct, replaced by dynamic digital map services and tools. In the digital platforms it is becoming difficult even to define what we consider to be a ‘map’, and not just layers of spatial data. Maps are used for mission planning, surface operation, and post-mission analysis. In the near future, they will be key components of planning and operating new human missions.”

The website is here. At the moment the catalog seems significantly incomplete, with only several hundred maps available. Hopefully this will expand with time.

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Creeping into Ryugu

10:16 pm

Ryugu

Cool images! As Hayabusu-2 creeps to its closest approach to Ryugu in preparation to releasing its first two mini-landers, dubbed MINERVA-II-1 and 2, the images coming down about once every half hour show the asteroid increasingly closer, with the spectacular shadow of Hayabusa-2 with its solar panels clearly visible.

The image on the right was downloaded about 10 pm (Pacific) tonight. The boulder-strewn field of Ryugu is also clearly visible. The black areas are where data has not yet been downloaded. The bright area under the shadow is merely an optical illusion.

UPDATE: A look at this webpage provides some details. When this image was taken the spacecraft was about 60 100 meters above the surface, its closest approach yet. This was also when the MINERVA-II landers were to be deployed.

All later images at the first link above were from a greater distance.

UPDATE: I have corrected the post. They released both MINERVA-II rovers, and they did it about 100 meters distance from the asteroid, not 60. We will not know the mini-landers’ status until late today.

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Hayabusa-2 sees its shadow

9:24 am

Ryugu, with Hayabusa-2's shadow

During its aborted landing rehearsal last week Hayabusa-2 imaged its own shadow as it approached within 600 meters of Ryugu.

The shadow is only a little dot on the surface of the asteroid, but to have resolved it is quite impressive. The image on the right has been annotated by me to indicate the shadow.

They have not said when they will do another landing rehearsal. Meanwhile, two of the spacecraft’s mini-landers are expected to be released sometime in the next few days.

Update: Based on the raw navigation images being released in real time from Hayabusa-2, the release of the MINERVA-II-1 has begun, with Hayabusa-2 moving in towards Ryugu in preparation for that release.

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Astronomers detect matter falling into black hole at 30% of the speed of light

9:05 am

Using the XMM-Newton X-ray space telescope astronomers have detected matter falling into the central supermassive black hole at 30% of the speed of light in a galaxy a billion light years away.

Using data from XMM-Newton, Prof. Pounds and his collaborators looked at X-ray spectra (where X-rays are dispersed by wavelength) from the galaxy PG211+143. This object lies more than one billion light years away in the direction of the constellation Coma Berenices, and is a Seyfert galaxy, characterised by a very bright AGN [active galactic nucleus] resulting from the presence of the massive black hole at its nucleus.

The researchers found the spectra to be strongly red-shifted, showing the observed matter to be falling into the black hole at the enormous speed of 30 per cent of the speed of light, or around 100,000 kilometres per second. The gas has almost no rotation around the hole, and is detected extremely close to it in astronomical terms, at a distance of only 20 times the hole’s size (its event horizon, the boundary of the region where escape is no longer possible).

Astronomers have theorized for several decades that the reason Seyfert galaxies have such active nuclei is exactly because matter is falling into the central black hole. This observation appears to confirm that theory.

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The volcano Llullaillaco

11:18 am

Llullaillaco volcano in South America

Cool image time! The image on the right, cropped and reduced to post here, shows a volcano not on Mars or the Moon or any of the moons of Jupiter or Saturn, but here on Earth in South America!

Llullaillaco is a stratovolcano at the border of Argentina and Chile. It lies on a high plateau close to the Atacama Desert. At an elevation of 6723 m ASL, it is the second highest active volcano in the world. About 150,000 years ago the volcano’s southeastern flank collapsed, producing a debris avalanche that traveled 25 kilometers. The youngest dated rocks are about 5600 years old; but there are local reports of activity from the 1800s. The perspective image looking east was acquired December 19, 2014.

If you click on the link you can see the full image. It was taken by one of the instruments on the Earth-observation satellite Terra, launched in December 1999. Though the website for this image does not state so, I suspect that some of the colors we see here are false colors, as some of the data comes from the infrared.

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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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