Tag: science

Update on coronavirus spread

1:08 pm

Link here. As expected, the situation in China continues to be serious and somewhat out of control. The key data point however is this:

The number of confirmed infections across China has risen to 7,711, resulting in 170 deaths. By comparison, there were 5,327 cases of severe acute respiratory syndrome (SARS) in China during the 2002-2003 outbreak, although that virus was more deadly, claiming 349 lives.

In about a week the number of those infected has grown exponentially, far far faster than the previous SARS epidemic. In one week it just about passed SARS, which took a year to accumulate the same numbers.

At the same time, coronavirus still appears relatively mild, having produced half the deaths, about 2% of all those infected. This number however can easily rise, as the disease is still in its early stages for the majority of those infected.

So far the detected cases outside of China remain small, but they are also on the rise, including the first detected human-to-human transmission entirely within the U.S.

Once again, it is essential that no one panic over this virus. Its potential danger should also not be poo-pooed. Until we know more, it poses a threat that must be faced.

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A new Juno flyover movie above Jupiter

10:01 am

Citizen scientist Brian Swift has created a new movie from images taken by Juno during its December 25th close pass of Jupiter, the 24th such flyby of the spacecraft’s mission.

I have embedded the movie below. While it isn’t as spectacular as previous movies (see here, here, here, and especially here and here), as it appears that either Juno did not get quite as close, or Swift did not shape it to give that impression, it is still most breathtaking.

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Parker completes fourth solar flyby; sets new record

9:19 am

The Parker Solar Probe yesterday completed its fourth orbital close fly-by of the Sun, setting a new speed record.

The spacecraft traveled 11.6 million miles from the Sun’s surface at perihelion, reaching a speed of 244,225 miles per hour. These achievements topple Parker Solar Probe’s own previous records for closest spacecraft to the Sun — previously about 15 million miles from the Sun’s surface — and fastest human-made object, before roughly 213,200 miles per hour.

Parker will continue to break these records with each orbit.

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First images from Inouye Solar Telescope

3:36 pm

Close-up of the Sun by Inouye Telescope

Scientists have released the first images of the Sun taken by the new Daniel K. Inouye Solar Telescope on the island of Maui in Hawaii.

The image to the right, cropped to post here, is today’s released image, a close-up of the Sun’s surface granular structure, with each cell about the size of Texas.

Right now most of the telescope’s instruments are not yet on line. It is expected the telescope will become fully operational in July.

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Voyager 2 in safe mode

8:41 am

After forty years of operation and successfully leaving the solar system, Voyager 2 has experienced a technical issue that caused it to go into safe mode.

According to NASA, Voyager 2 failed to perform a scheduled maneuver on Saturday January 25. The craft was due to rotate a full 360 degrees to calibrate its magnetic field instrument, but for some reason the action was delayed. That in turn meant that two particularly power-hungry systems were left running at the same time, which overdrew the available power supply.

…As of January 28, the team managed to turn off one of those high-power systems, allowing some scientific instruments to be switched back on. Engineers are currently analyzing data to figure out the status of the rest of the systems, to work out how to turn off the second one and return the craft to normal operations.

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Inexplicable ridges on Mars

1:06 pm

Inexplicable ridges on Mars
Click for full image.

Don’t ask me to explain the geology on today’s cool image, rotated, cropped and reduced above. Taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on August 16, 2019, the image’s uncaptioned website merely calls these “Convergent and Overlapping Narrow Curved Ridges.”

I don’t know why the sand in the hollows appears light blue, or even if it is sand. I don’t know what created the ridges, or why they seem to overlap each other randomly, or why they seem to peter out to the south.

I am sure there are planetary scientists out there who have theories that might explain these features. I also know that they would forgive me if I remained skeptical of those theories. This geology is a puzzle.

Hellas Basin, the basement of Mars

The location of these ridges is in the southeast corner of Hellas Basin, which I like to call the basement of Mars as it is the equivalent of the United States’ Death Valley, having the lowest relative elevation on the planet. As I have noted previously, the geology in this basin can be very strange. To my eye it often invokes a feeling that we are looking at Mars’s “uttermost foundation of stone” (to quote Tolkien), frozen lava that flowed in many ways and then froze in strange patterns.

Or not. Your guess is as good as mine.

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Two abandoned satellites might collide

11:52 am

According to a company that monitors objects in low Earth orbit, two abandoned satellites might actually collide on January 29..

The two satellites, NASA’s IRAS space telescope and the experimental U.S. Naval Research Lab satellite GGSE-4, will swing past each other at 6:39 p.m. EST at an altitude of about 559 miles in the skies above Pittsburgh, Pennsylvania. They’ll be hurtling along their orbit at a relative velocity of about 32,880 miles per hour and could swing within 50 feet of each other.

LeoLabs noted that, at the time of the tweet, the odds of a collision were about 1 in 100 and said the relatively large size of the two spacecraft increased the risk of a collision.

IRAS was the first infrared space telescope ever launched, and operated for ten months after its launch in 1983. The other spacecraft was a National Security Agency test satellite of surveillance technology.

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More evidence of ample shallow ice in Martian mid-latitudes

11:12 am

In a new paper released this week, scientists using instruments on both Mars Odyssey and Mars Reconnaissance Orbiter have found more evidence that there is a large amount of widespread ice close to the surface in the Martian mid-latitudes. As the scientists note in their abstract:

We show that water ice is present sometimes just a few centimeters below the surface, at locations where future landing is realistic, under mobile material that could easily be moved around. This ice could be exploited on‐site for drinking water, breathable oxygen, etc., at a much lower cost than if brought from Earth.

They deduced this by looking at how that ice would change the seasonal temperatures in the atmosphere directly above. Cooler regions suggested more ice close to the surface, while warmer regions suggested either no ice or ice deep below the surface. While this approach is indirect and did not directly detect ice, their conclusions match perfectly with all previous research. Below is a global map of Mars taken from the paper’s the supplementary material [docx file], reduced and annotated by me, showing the regions that seem to have ample shallow ice. Regular readers of Behind the Black will instantly recognize these locations.
» Read more

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The beginning of chaos on Mars

12:30 pm

The beginning of a chaos canyon
Click for full image.

Cool image time! The photo on the right, rotated, cropped, and reduced to post here, was taken by the high resolution camera of Mars Reconnaissance Orbiter (MRO) on October 7, 2019. In one image it encapsulates the process that forms one of the more intriguing and major Martian geological features, dubbed chaos terrain.

Chaos terrain is typically a collection of mesas separated by straight-lined canyons. It is found in many places on Mars, most often in the transition zone between the southern highlands and the northern lowlands where an intermittent ocean might once have existed. It is believed to form by erosion, possibly caused by either flowing water or ice, moving along fault lines. As the erosion widened the faults, they turned into canyons separating closely packed mesas. With time, the canyons widened and the mesas turned into a collection of hills.

This image shows the beginning of this process. It is centered on a fault line running from south to north. In the south all we can see is the fault expressing itself as a very shallow small depression in the plains. As we move north the depression widens and deepens. The material inside the depression near the top of the photo could very well be a buried inactive ice glacier. Several million years ago, when the inclination of Mars was much higher and the mid-latitudes were much colder than the poles, the water ice at the poles was sublimating from the poles to those mid-latitudes where it fell as snow. At that time this glacier was likely active, helping to grind out this canyon.

The image was taken at the south border of a chaos region dubbed Nilosytis Mensae, as shown by the overview maps below.
» Read more

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Martian pimples

1:48 pm

Pimples on Mars!
Click for full image.

Cool image time! The image to the right, cropped and reduced to post here, is one of those terrain sample images the science team of the high resolution camera of Mars Reconnaissance Orbiter (MRO) takes periodically when they have a gap in their observation schedule with no specific requests for images of the terrain below. Still, they need to use the camera regularly to keep its temperature maintained, so they then take a somewhat random picture over that terrain, based partly on information from lower resolution images but without a strong sense of what they will find.

In this case, they found what I dub pimples, raised mounds with small holes at their peaks. The image, taken on November 30, 2019, is located is in the northern lowlands, at a latitude (45 degrees) where subsurface ice is possible. Thus, we could be looking at water ice volcanoes.

Very few high resolution images have been taken of this area, with no others close by. Thus, the overall context of these mounds is hard to gauge. They could be widespread, or very localized.

The unknowns here and general lack of research suggests this location and these mounds are ripe research for some postdoc student interested in planetary geology.

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OSIRIS-REx completes close fly-over of Bennu touchdown site

9:38 am

OSIRIS-REx has successfully completed the first of a series of increasingly closer fly-overs of its primary sample grab sites on the asteroid Bennu.

The spacecraft got as close as about 2,000 feet in order to take more high resolution images of the Nightingale landing site where they hope in August to do a touch-and-go sample grab.

A similar flyover of the backup sample collection site, Osprey, is scheduled for Feb. 11. Even lower flybys will be performed later this spring – Mar. 3 for Nightingale and May 26 for Osprey – as part of the mission’s Reconnaissance C phase activities. The spacecraft will perform these two flyovers at an altitude of 820 feet (250 m), which will be the closest it has ever flown over asteroid Bennu’s surface.

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An update on the new virus outbreak originating from China

9:51 pm

Link here. The numbers of people so far infected is hardly gigantic, less than 450 worldwide, with almost all confined to one province in China.

You can also find out some general information about this particular virus as well as other related viruses, such as SARS and MERS, in this separate article. All are far less threatening that press reports make them appear. For example, SARS only infected 8,000 people total, killing a little less than 10% of those infected.

This new virus appears so far to be even less deadly, with nine deaths total, about 5%.

While under no condition should this outbreak be ignored or poo-pooed, it is very important to recognize that, at least so far, it is hardly an epidemic that will wipe out civilization. This could change with time, but I doubt it.

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Animal life thriving in Fukushima radioactive zone

9:27 pm

The uncertainty of science: Despite fears that the radioactivity released from the Fukushima nuclear accident would make life difficult if not impossible within the 80-mile radius exclusion zone surrounding the reactor, animals are thriving there, in large unexpected numbers.

Now, nearly a decade after the nuclear accident, the wildlife populations appear to be thriving. Animals are most abundant in areas still devoid of humans, with more than 20 species captured in the UGA’s camera study.

Particular species that often find themselves in conflict with humans, especially Fukushima’s wild boar, were most often photographed in human-evacuated areas. Without the threat of humankind, wildlife is flourishing. In the years since the nuclear accident, Japan’s wild boar seems to have taken over abandoned farmland — even moving into abandoned homes. The government hired boar hunters to cull the population prior to re-opening parts of the original exclusion zone in 2017.

This phenomenon has happened before. Life inside the Chernobyl exclusion zone in Ukraine became an accidental wildlife preserve after humans left following the nuclear disaster there in April 1986. [emphasis mine]

This story, and that of Chernobyl, does not prove that radioactivity is harmless. Not at all. What it shows is that we know diddly-squat about its effects on life. For example, one study has shown changes in the weight and size of one species of monkey at Fukushima has shrunk, but have flourished nonetheless.

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The oldest known meteorite strike?

9:09 pm

The uncertainty of science: Scientists think they have identified the oldest meteorite strike known on Earth, dated at 2.33 billion years ago, located in a known impact site in Yarrabubba, Western Australia.

Lead author Dr Timmons Erickson, from Curtin’s School of Earth and Planetary Sciences and NASA’s Johnson Space Center, together with a team including Professor Chris Kirkland, Associate Professor Nicholas Timms and Senior Research Fellow Dr Aaron Cavosie, all from Curtin’s School of Earth and Planetary Sciences, analysed the minerals zircon and monazite that were ‘shock recrystallized’ by the asteroid strike, at the base of the eroded crater to determine the exact age of Yarrabubba.

The team inferred that the impact may have occurred into an ice-covered landscape, vaporised a large volume of ice into the atmosphere, and produced a 70km diameter crater in the rocks beneath.

Professor Kirkland said the timing raised the possibility that the Earth’s oldest asteroid impact may have helped lift the planet out of a deep freeze. “Yarrabubba, which sits between Sandstone and Meekatharra in central WA, had been recognised as an impact structure for many years, but its age wasn’t well determined,” Professor Kirkland said. “Now we know the Yarrabubba crater was made right at the end of what’s commonly referred to as the early Snowball Earth – a time when the atmosphere and oceans were evolving and becoming more oxygenated and when rocks deposited on many continents recorded glacial conditions”.

Associate Professor Nicholas Timms noted the precise coincidence between the Yarrabubba impact and the disappearance of glacial deposits. “The age of the Yarrabubba impact matches the demise of a series of ancient glaciations. After the impact, glacial deposits are absent in the rock record for 400 million years. This twist of fate suggests that the large meteorite impact may have influenced global climate,” Associate Professor Timms said. [emphasis mine]

I truly believe they have determined the approximate age of this impact, making it one of the oldest known impacts. Implying however a “precise” linkage to other only vaguely known climate events, and inferring that the former was the cause of the latter seems to me to be a very large overstatement. Their data might suggest this conclusion, but the uncertainties here demand a bit less certitude..

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Undulations on Mars

1:07 pm

Undulations in Dokka Crater
Click for full image.

Time for a cool image that makes no sense. The photo on the right, cropped to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on November 15, 2019 of the floor of a crater, dubbed Dokka Crater, located in the high latitudes of the Martian northern lowlands. Uncaptioned but labeled “Undulations on Dokka Crater Ice Dome,” it shows a region of weird complex wave features, reminiscent of another weird Martian geological feature called brain terrain.

The problem is that brain terrain is generally found in the mid-latitudes, not the high latitudes. Both this feature and brain terrain however appear to associated with ice. In this case, these undulations are occurring on the ice dome that apparently sits inside Dokka crater, which is also likely to be related to the islands of ice found in many high latitude craters on Mars in the southern hemisphere..

In the case of the southern hemisphere ice-filled craters, scientists have found evidence suggesting that global wind patterns might affect their shape and placement within the craters. One wonders if this same factor is a part cause for these undulations in this northern hemisphere crater.

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Six Martian summers at a polar impact crater

1:28 pm

Crater on Martian north polar ice cap
Click for full image.

Cool image time! The science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO) last week released a very neat short movie compiled from images taken of an impact crater located on top of the northern polar ice cap of Mars. As noted by planetary scientist Alfred McEwen of the Lunar & Planetary Laboratory in Arizona in the image caption,

Shown here is an impact crater on the north polar ice cap, which contains an icy deposit on the crater floor. These inter-crater ice deposits shrink and expand or change shape or surface texture from year to year,

The image on the right, cropped and reduced to post here, is the most recent of these six images. The crater, which is about 200 feet in diameter, is the black speck in the center. The white streaks to the south of the crater, similar on all six photos, indicate that the prevailing winds come from the pole.

The animation zooms in on the crater so that you can see the details on its crater floor. And though the animation is fun, below the fold is a collage of all six photos, which I think makes it easier to see how the inter-crater ice deposits changed from summer to summer.
» Read more

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Tadpole on Mars

1:37 pm

Tadpole on Mars
Click for full image.

Cool image time! The image on the right, cropped and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on October 7, 2019, and shows a crater on the northern fringe of Arabia Terra, one of the largest transitional regions between the Martian northern lowlands and the southern highlands. It shows a crater with an inlet canyon that makes the entire crater resemble a wiggling tadpole.

This is certainly not first tadpole-resembling crater found on Mars. See for example this press release from February 2018, showing a tadpole crater with the tail being an outlet channel. In today’s image however the channel feeds the crater.

In fact, take a look at the full image. This crater apparently occurred right at the edge of a large mesa cliff, with this impact cutting into the cliff near its bottom. The canyon might have actually existed before the impact, with the crater merely obliterating the canyon’s outlet.

If you look along that escarpment to the east you can see similar southwest-to-northeast flows. One is a canyon flowing downhill through the escarpment, probably resembling what the first canyon might have once looked like before the impact. To the east of this is another tadpole crater. This second tadpole impact however took place on top of the mesa, so the channel flows out from the crater and then down off the mesa, the reverse of the tadpole crater above.

These flow features are consistent with the nature of this transitional zone, a region with many features suggesting it was once the shoreline of an intermittent ocean. That ocean, if it had existed, is long gone, though scattered across the Martian surface are geological ghost features like these that speak of its past existence.

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Wolf puppies play fetch with humans

9:40 am

An experiment raising wolf puppies in close contact with humans has surprisingly found that some of those puppies learn how to play fetch with humans, even strangers.

Playing fetch with your dog isn’t as simple as it seems. Your pooch must be perceptive enough to realize you want the ball back—and social enough to want to play with you in the first place. It’s such an advanced skill, in fact, that many scientists think it could have arisen only over thousands of years of domestication.

But a new study reveals that some gray wolves—the ancestors of dogs—can also play fetch. The work supports the idea that the roots of many of the traits and behaviors we see in domesticated animals, from cats to chickens, may be present in their wild relatives.

…As the pups grew, the scientists noticed that some would retrieve a tennis ball thrown across the room. Intrigued, they tested all the wolves for the ability. When the pups were 8 weeks old, Hansen Wheat brought each one into a large, barren room with someone the animals had never met before. Then she left, and after a few minutes, the stranger threw a tennis ball.

Most of the wolves ignored the ball. But two pups—Lemmy and Elvis—returned the ball twice, the team reports today in iScience. One pup named Sting returned it all three times it was thrown, as seen in the video above. (All the wolves were named after musicians.)

What this study has discovered is likely the very process that produced the first dogs, from wolves. Early humans culled out of the wolf pack the puppies that responded to human behavior, and interbred those puppies to produce a new species that was closely linked to its human masters. And apparently this process can be quicker than some scientists previously believed.

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Strange things at center of Milky Way

9:31 am

Astronomers have discovered an additional four more weird objects orbiting the supermassive black hole, dubbed Sagittarius A* (pronounced A-star) for a total of six, all of which display behavior that is inexplicable.

Part of a new class called G objects, they look compact most of the time and stretch out when their orbits bring them closest to the black hole. Those orbits range from about 100 to 1000 years. “These objects look like gas and behave like stars,” says Andrea Ghez, director of the Galactic Centre Group at the University of California, Los Angeles (UCLA) and co-author of a paper in the journal Nature.

The new discoveries are known simply as G3 to G6. G1 was discovered by Ghez’s research group back in 2005, and G2 by astronomers in Germany in 2012. “The fact that there are now several of these objects observed near the black hole means that they are, most likely, part of a common population,” says co-author Randy Campbell, from the Keck Observatory in Hawaii.

It is not surprising that the intense gravitational field of Sagittarius A* rips these objects into elongated stretched objects as their orbits bring them close to the black hole. What is very very puzzling is their apparent ability to spring back to compact form as their orbits take them away from the black hole.

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A second exoplanet orbiting Proxima Centauri?

9:32 am

Worlds without end: Astronomers think they have found evidence of a second exoplanet orbiting the nearest star, Proxima Centauri.

The planet, a super-Earth called Proxima Centauri c (Proxima c for short), has at least six times more mass than Earth and orbits its star every 5.2 years.

…“Stars like Proxima Centauri are rather restless and continuously present eruptions and spots on their surface, which make the detection of a planetary-induced oscillation very complicated,” says coauthor Fabio Del Sordo (University of Crete and Foundation for Research and Technology-Hellas in Heraklion, Greece). Because the observations span almost two decades, the scientists have confidently ruled out those sources of noise, but they caution that follow-up observations are needed to confirm that the signal comes from a planet.

There is a lot of uncertainty here, requiring an independent confirmation of this result. It would not be surprising if this exoplanet vanished when others took a look, finding it a creation not of a periodic gravitation wobble but of the random fluctuations of the star itself.

If it does exist, it will not likely be a place where life exists. Too far from this very dim red dwarf star to get enough energy. However, as a super-Earth it might someday in the far future be a great mining world.

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Spitzer SpaceTelescope shutdown in a week

9:20 am

After sixteen years in orbit, NASA will shut down the Spitzer Space Telescope on January 22, 2020,

The telescope is still functional in a somewhat limited manner but NASA wishes to save the annual budget of $14 million to operate it. Moreover, it will become redundant and significantly superseded once the infrared James Webb Space Telescope launches and becomes operational next year.

NASA had hoped a private organization would take over Spitzer’s operation, but apparently got no takers.

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Martian dry ice frost on glacial remains?

10:18 am

Frost on ridgelines and inside crater
Click for full image.

Close-up of frost

Cool image time! The photo on the right, rotated, cropped, and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter on November 30, 2019. Located just east of Hellas Basin in southern mid-latitudes, the color strip shows dry ice frost both in the crater as well as on the ridgelines to the north. As noted in the caption, written by Candy Hansen of the Planetary Science Institute in Tucson, Arizona,

When we acquired this image, it was [winter in the southern hemisphere] on Mars, but signs of spring are already starting to appear at latitudes not far from the equator. This image of Penticton Crater, taken at latitude 38 degrees south, shows streamers of seasonal carbon dioxide ice (dry ice) only remaining in places in the terrain that are still partially in the shade.

The turquoise-colored frost (enhanced color) is protected from the sun in shadowed dips in the ground while the sunlit surface nearby is already frost-free.

Note for example how the frost disappears in the southern half of the crater floor, the part exposed to sunlight.

What immediately struck me however were the underlying features. The entire northeast quadrant of the crater’s rim appears to have been breached by some sort of catastrophic flow, as if there had been a glacial lake inside the crater that at some point smashed through suddenly, wiping that part of the rim out as it ripped its way through.

To the right is a full resolution inset, indicated by the white box above, of the dry ice frost on the outside of the crater. I find myself however drawn more to the underlying features, which once again have a chaotic aspect suggesting a sudden violent event, coming from the south and moving north.

I have no idea if my visceral conclusions here have any validity. At this latitude, 38 degrees, scientists have found a lot of buried inactive glaciers of ice, so I could be right. Or not. Your guess is as good as mine.

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First asteroid discovered that circles Sun closer than Venus

9:33 am

Astronomers have detected the first asteroid circling the Sun in an orbit that lies entirely inside Venus’s orbit.

In addition to being the first known asteroid with this orbit, the space rock, called 2020 AV2, has the smallest aphelion, or distance from the sun, of any known natural object in the solar system, excluding Mercury. Moreover, by traveling around the sun in a mere 151 days, 2020 AV2 has the shortest orbital period of any known asteroid, according to The Virtual Telescope Project, an online observatory based in Italy.

The reason this is a first is because it is very hard to find such small objects orbiting closer to the Sun than Earth. The glare of the Sun limits what can be spotted. This fact is also why the scientists are unsure of the size of 2020 AV2.

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Gully on Mars

12:47 pm

Gully in crater on Mars
Click for full image.

Cool image time! If we were told that the photo on the right was taken by an airplane over some southwest desert gully, no one should be surprised if we were to accept that description entirely. The gully sure looks like a lot of drainages one can routinely see when flying over the American southwest, dry, treeless, but showing the typical dendritic pattern seen for most desert water drainages.

Of course my readers all know that this is not in the American southwest, but on Mars, in a crater located in the transition zone between the southern highlands and the northern lowland plains. The image, cropped to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter on October 12, 2019.

It appears that this particular gully has been subject to repeated monitoring, since November 2015. A rough and very quick comparison of the earlier image with today’s image does not show any obvious change. This does not mean there hasn’t been any evolution, as my look was cursory, and I could easily be missing changes. Seasonal variations might also be occurring that I could be missing.

The reasons for the monitoring are of course obvious. This gully strongly suggests the flow of liquid downhill. Is that occurring today, or are we seeing the evidence of a past flow from long ago? Only some long term monitoring can tell.

There is also the possibility that we are looking at a buried glacier. The crater is located at 42 degrees north latitude, well within that mid-latitude band where scientists have located many buried Martian glaciers. If so, then the monitoring is to see if that glacier is active in any way.

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More superEarth exoplanets found circling nearby stars

9:41 am

Worlds without end: Among a new bunch of thirteen exoplanets, astronomers have discovered two more superEarth-sized exoplanets circling nearby red dwarf stars.

The two potentially habitable planets are orbiting GJ180 and GJ229A, which are among the nearest stars to our own Sun, making them prime targets for observations by next-generation space- and land-based telescopes. They are both super-Earths with at least 7.5 and 7.9 times our planet’s mass and orbital periods of 106 and 122 days respectively.

The Neptune-mass planet—found orbiting GJ433 at a distance at which surface water is likely to be frozen—is probably the first of its kind that is a realistic candidate for future direct imaging. “GJ 433 d is the nearest, widest, and coldest Neptune-like planet ever detected,” Feng added.

For a lot of reasons it is likely that life as we know it probably does not exist on these planets. Nonetheless, their close proximity makes it possible to study them, and since we have no such planets in our own solar system they can teach us a lot about planetary formation and evolution.

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Stardust found in meteorite older than Earth

9:12 am

Scientists studying what they think is grains of stardust in a meteorite the hit the Earth in 1969 have discovered the oldest material ever found on Earth, material that is actually older than the Earth itself.

The meteorite, dubbed the Murchison meteorite after the nearest city in Australia where it landed, has been a treasure trove of information for planetary scientists because so much of it was recovered right after impact.

About 30 years ago it was found that the rocks housed “presolar grains” – tiny grains of silicon carbide older than the Sun. But their exact age hadn’t been determined until now.

To figure that out, the researchers on the new study measured how long these presolar grains had been exposed to cosmic rays. These high-energy particles flit around space and can pass through solid matter, creating new elements inside the existing minerals as they interact with them. That means the scientists can measure the amount of these new elements in the grains to determine how long they were floating around in space – and, ultimately, how old they are.

In doing so, the team found that most of the grains were between 4.6 and 4.9 billion years old. The Sun itself is at the younger end of that range, at 4.6 billion years old, while the Earth didn’t form until 4.5 billion years ago.

But the oldest of the grains were dated to more than 5.5 billion years, making them the oldest known material on Earth. The team says that the history of these grains could be traced back even further, to the stars that birthed them some 7 billion years ago. According to the researchers, this finding suggests that our galaxy went through a period of intense star formation around that time.

Obviously there are uncertainties with this result, though their age estimates are quite reasonable and largely robust.

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Curiosity climbs a hill

5:07 pm

Overview map of Curiosity's journey through sol 2643

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

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

Since my last Curiosity update on November 6, 2019, the science team has sent the rover climbing up what they call Western Butte, the butte directly to the west of Central Butte and part of the slope/escarpment that separates the clay unit from the Greenheugh Piedmont and the sulfate unit above that.

The overview map to the right gives a sense of the journey. The thick yellow line indicates its route since it climbed up from the Murray Formation onto Vera Rubin Ridge in 2017. The thick red line indicates their planned route, which they have only vaguely been following since their arrival in the clay unit.

Below the fold are two panoramas that I created from a sequence of images taken by Curiosity’s left navigation camera from the high point on Western Butte, the first looking north across the crater floor to the Gale Crater rim approximately 30 miles away and indicated by the thin yellow lines on the overview map. The second looks south, up hill towards Mount Sharp, and is indicate by the thin red lines.
» Read more

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No trend in hurricanes since 1970

4:35 pm

The uncertainty of science: A new study has found no trend, up or down, in hurricanes that made landfall since the 1970s, despite many global warming predictions that said the numbers of catastrophic hurricanes would increase.

Key quote:

There are a lot of ups and downs in the data, but no obvious trends.

The scientists note that though they see no obvious trends, it is difficult to pin anything down because the variability from year to year is so great.

That large variability in occurrence means – as a simple matter of mathematics – that our ability to detect changes in tropical cyclones one or two magnitudes smaller (or more) on similar time scales is obviously made difficult, if not impossible.

So, when next you hear a global warming expert, either a teenager not attending school or a Democratic politician who doesn’t remember anything from school, claiming we are all going to die from giant hurricanes caused by human-caused global warming, remember this study. It demonstrates that those “experts” have no idea what they are talking about.

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