Tag: science

OSIRIS-REx preps for final rehearsal of sample grab

9:40 am

The OSIRIS-REx science and engineering team is getting ready for its August 11th final rehearsal of the sample grab-and-go at the asteroid Bennu that it plans to do in October.

If the rehearsal goes right, the spacecraft will descend to within 131 feet of the surface of Bennu as it deploys its equipment as if it would continue down to the surface. It will also fly in formation above the Nightingale sample site when it does this, taking the highest resolution images yet of the surface of the asteroid.

It will then back off, returning to its home orbit farther from Bennu. Engineers will then review what happened, and use that data to prepare for the actual sample grab-and-go, set for October 20, 2020.

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Slushy floor of southern Martian crater?

1:45 pm

Knobby floor of southern crater
Click for full image.

The cool image to the right, rotated, cropped, and reduced to post here, shows the northwest section of the floor of a crater in the southern cratered highlands of Mars, in a mountainous region dubbed Claritus Fossae, located south of Valles Marineris. The photo was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on May 14, 2020.

The entire crater floor appears to be covered by these strings of closely-packed knobs, reminiscent of the brain terrain found in the mid-latitude glacial regions of Mars and thought to be the result of underground ice sublimating upward.

Below is the area in the white box, in full resolution.
» Read more

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Study: Lava tubes on Mars and the Moon will be gigantic

9:34 am

A new study comparing lava tubes on the Earth with those detected from orbit on Mars and the Moon now suggests that tubes on those other worlds will be many times larger than on Earth.

Researchers found that Martian and lunar tubes are respectively 100 and 1,000 times wider than those on Earth, which typically have a diameter of 10 to 30 meters. Lower gravity and its effect on volcanism explain these outstanding dimensions (with total volumes exceeding 1 billion of cubic meters on the Moon).

Riccardo Pozzobon adds: “Tubes as wide as these can be longer than 40 kilometres, making the Moon an extraordinary target for subsurface exploration and potential settlement in the wide protected and stable environments of lava tubes. The latter are so big they can contain Padua’s entire city centre”.

Moreover, the data suggests their roofs, even at this size, will be very stable because of the lower gravity, making them excellent locations for large human colonies.

The researchers also suggest that there are many intact such lava tubes under the mare regions on the Moon, their existence only hinted at by the rare skylights created due to asteroid impact.

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Astronomers use Hubble to detect ozone on Earth

8:57 am

Using the Hubble Space Telescope, scientists have shown that it will be possible to detect ozone in the atmospheres of exoplanets, using larger telescopes while observing transits of those exoplanets across the face of their star.

What the scientists did was aim Hubble at the Moon during a lunar eclipse. Moreover, they timed the observations so that the sunlight hitting the Moon and reflecting back to Earth (and Hubble) had also traveled through the Earth’s atmosphere on its way to the Moon.

They then looked at the spectrum of that light, and were able to glean from it the spectral signal of ozone in the Earth’s atmosphere. When giant ground-based telescopes under construction now come on line in the coming decades they will have the ability to do this with transiting exoplanets.

The measurements detected the strong spectral fingerprint of ozone, a key prerequisite for the presence – and possible evolution – of life as we know it in an exo-Earth. Although some ozone signatures had been detected in previous ground-based observations during lunar eclipses, Hubble’s study represents the strongest detection of the molecule to date because it can look at the ultraviolet light, which is absorbed by our atmosphere and does not reach the ground. On Earth, photosynthesis over billions of years is responsible for our planet’s high oxygen levels and thick ozone layer. Only 600 million years ago Earth’s atmosphere had built up enough ozone to shield life from the Sun’s lethal ultraviolet radiation. That made it safe for the first land-based life to migrate out of our oceans.

“Finding ozone in the spectrum of an exo-Earth would be significant because it is a photochemical byproduct of molecular oxygen, which is a byproduct of life,” explained Allison Youngblood of the Laboratory for Atmospheric and Space Physics in Colorado, USA, lead researcher of Hubble’s observations.

Ozone does not guarantee the presence of life on an exoplanet, but combined with other detections, such as oxygen and methane, would raise the odds significantly.

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Filled and distorted craters on Mars

9:12 pm

A very distorted and filled crater on Mars
Click for full image.

Cool image time! The photo to the right, rotated and cropped to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on May 25, 2020. The entire image was dubbed “Cluster of Filled Craters”, but I decided to highlight the crater of the cluster that was most strangely distorted of them all. The material that fills all the craters in the full image is almost certainly buried ice and is dubbed concentric crater fill by scientists.

This crater is located in the northern lowland plains the mid-latitudes between 30 and 60 degrees, where planetary scientists have found ample evidence of many such filled craters and glaciers.

Not only does the crater’s interior seemed filled with glacial material, its distorted rim suggests that it has been reshaped by glacial activity that might have covered it entirely over the eons as the mid-latitude glaciers of Mars waxed and waned with the extreme shifts that happen regularly to Mars’ rotational tilt. Moreover, there is strong evidence that in these lowland northern plains an underground ice table exists close to the surface, allowing for more distortion over time.

The overview map below provides some location context.
» Read more

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Lightning and mushballs on Jupiter

3:49 pm

Artist's illustration of Jupiter lightning
Click for full illustration.

Using data from Juno, scientists now theorize that Jupiter produces what they dub “shallow lightning” as well as ammonia-water hailstones dubbed “mushballs.”

The image to the right, cropped and reduced to post here, is only an artist’s illustration of the lightning. Sadly Juno’s camera doesn’t have the resolution to capture such flashes.

An unexpected form of electrical discharge, shallow lightning originates from clouds containing an ammonia-water solution, whereas lightning on Earth originates from water clouds.

Other new findings suggest the violent thunderstorms for which the gas giant is known may form slushy ammonia-rich hailstones Juno’s science team calls “mushballs”; they theorize that mushballs essentially kidnap ammonia and water in the upper atmosphere and carry them into the depths of Jupiter’s atmosphere.

As with the InSight results below, there is much uncertainty with these results, especially the hypothesis of mushballs. These features fit their present data from Juno, but we must remember that the data is still somewhat superficial.

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Scientists make first rough estimate of Mars’ internal structure

3:33 pm

Artist's cutaway showing theorized Martian interior
Artist’s cutaway of theorized Martian interior

Using data from InSight’s seismometer, scientists have made their first approximation of the internal structure of Mars.

The first boundary Deng and Levander measured is the divide between Mars’ crust and mantle almost 22 miles (35 kilometers) beneath the lander.

The second is a transition zone within the mantle where magnesium iron silicates undergo a geochemical change. Above the zone, the elements form a mineral called olivine, and beneath it, heat and pressure compress them into a new mineral called wadsleyite. Known as the olivine-wadsleyite transition, this zone was found 690-727 miles (1,110-1,170 kilometers) beneath InSight. “The temperature at the olivine-wadsleyite transition is an important key to building thermal models of Mars,” Deng said. “From the depth of the transition, we can easily calculate the pressure, and with that, we can derive the temperature.”

The third boundary he and Levander measured is the border between Mars’ mantle and its iron-rich core, which they found about 945-994 miles (1,520-1,600 kilometers) beneath the lander. Better understanding this boundary “can provide information about the planet’s development from both a chemical and thermal point of view,” Deng said.

Because they only have one seismometer on the planet, this approximation has a great deal of uncertainty. Only when we have multiple such seismic instruments, scattered across the entire Martian globe, will scientists be able to hone their models more accurate of the planet’s interior.

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The dry barren plains of Tyrrhena Terra

12:20 pm

Tyrrhena Terra badlands
Click for full image.

In a sense today’s cool image is a replay of one I posted in March, showing the dry barren terrain in the vast rough cratered highlands of Tyrrhena Terra, located along the equator of Mars between the giant basins of Isidis and Hellas.

Today’s image on the right, cropped to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter on March 26, 2020, and shows well the barrenness of this region. The surface appears quite solid, like bedrock, rather than the squishy soft surface of the northern lowland plains. Moreover, there is a lot of dust trapped in the low areas between the ridges, forming ripples that new data suggest move slowly across the surface. If you click on the full image, you will see that this terrain is far from local, and goes on in this manner for quite a distance in all directions.

This is a dry and forbidding place, about the size of the American southwest, from Texas to California.

The overview map below provides some context of Tyrrhena Terra’s location on Mars.
» Read more

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Masks, social distancing, and mass hysteria

4:34 pm

This past weekend Diane and I went hiking, as we try to do at least once a week. With the gyms closed by our petty dictator governor, Republican Doug Ducey, we need to find a way to get out and exercise, both for our sanity and to strengthen our immune systems, since outdoor exercise is probably the most effective way to prevent yourself from getting sick from any respiratory illness.

As we were hiking along a single male hiker, probably in his mid- to late- twenties, approached us from the other direction. When he saw me in the lead, he immediately cringed off to the side of the trail in what seemed literal terror, holding a bandana to his face.

I looked at him in irritation. “You don’t need the mask, we don’t have cooties and we won’t make you sick.”

“I don’t want to make you sick,” he said as I passed him.

“What makes me sick,” I responded as I continued past him down the trail, “is the irrational terror and fear I see in everyone’s eyes, over something that really is not much more different than the flu.”

I will admit to have become somewhat of a cranky grump these days when I see everyone wearing masks. And I feel this way because of the utter mindlessness of mask-wearing. This healthy young hiker, who almost certainly was not contagious in any way with any illness, including COVID-19, was only within four feet of me for about one second. Even if he had COVID-19 and was infectious to me and tried to pant in my face as I went by it would have been almost impossible for him to infect me. We were just not in close enough contact for long enough.

Moreover, he stood there holding the bandana to his mouth and nose, with his hand. That its exactly the wrong thing to do if you want to protect yourself, as your hands are the most likely transmission point for infection, and by pressing his bandana against his face with his hand he risked placing that infection at the very place he breathed.

He might have reduced my chances of getting infected by an infinitesimal amount, but he increased his own risk substantially.

Mask-wearing is just plain irrational, and for intelligent Americans to go along with this silliness is beyond shameful, especially because in almost every jurisdiction, even those that mandate mask use, you can opt out by simply stating you have medical reasons for not wearing a mask, and are not required under HIPPA regulations to even show documentation proving that statement in any way. It must be accepted on its face, without question.

Let’s review the absurdity of this situation, and maybe remind people why it is foolish.
» Read more

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Sunspot update: Hints of the next maximum

11:07 am

It’s time for another monthly sunspot update! NOAA yesterday updated its monthly graph for tracking the Sun’s monthly sunspot activity, and as I do every month, I am posting it below with additional anotations by me to show the past and new solar cycle predictions.

July 2020 sunspot activity

The graph above has been modified to show the predictions of the solar science community for both the previous and upcoming solar maximums. The green curves show the community’s two original predictions from April 2007 for the previous maximum, with half the scientists predicting a very strong maximum and half predicting a weak one. The blue curve is their revised May 2009 prediction. The red curve is the new prediction, first posted by NOAA in April 2020.

July continued the trend from June, with a slight uptick in activity. The SILSO graph below for July illustrates this.
» Read more

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Study: Mars’ meandering canyons formed under ice

9:23 am

A new study comparing Mars’ meandering canyons with those found in the Arctic regions on Earth suggests that the Martian valleys were formed by water melting under large ice sheets, not flowing water on the surface.

A large number of the valley networks scarring the surface of Mars were carved by water melting beneath glacial ice, not by free-flowing rivers as previously thought, according to new research published in Nature Geoscience. The findings effectively throw cold water on the dominant “warm and wet ancient Mars” hypothesis, which postulates that rivers, rainfall and oceans once existed on the red planet.

To reach this conclusion, lead author and postdoctoral research scholar Anna Grau Galofre of Arizona State University’s School of Earth and Space Exploration developed and used new techniques to examine thousands of Martian valleys. She and her co-authors also compared the Martian valleys to the subglacial channels in the Canadian Arctic Archipelago and uncovered striking similarities. The western edge of the Devon ice cap on the Canadian Arctic Archipelago.

I have noted previously on Behind the Black my sense that the planetary science community was beginning to shift away from the hypothesis of flowing liquid surface water on Mars as an explanation for the planet’s riverlike and oceanlike features to some form or ice/glacial activity. For a half century the scientists have tried and failed to come up with some scenario that could allow water to flow on the surface in Mars’ cold climate and thin atmosphere.

Ice or glacial activity rather than flowing liquid water might solve this problem, and today’s paper is a push in this direction.

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New model predicting solar flares is 56% accurate

1:01 pm

The uncertainty of science: Using observations from the space-based Solar Dynamics Observatory (SDO), solar scientists have developed a new model for predicting the biggest solar flares, and have found it to able to predict a big flare about 56% of the time.

Kusano and his team looked at the seven active regions from the last solar cycle that produced the strongest flares on the Earth-facing side of the Sun (they also focused on flares from part of the Sun that is closest to Earth, where magnetic field observations are best). SDO’s observations of the active regions helped them locate the right magnetic boundaries, and calculate instabilities in the hot spots. In the end, their model predicted seven out of nine total flares, with three false positives. The two that the model didn’t account for, Kusano explained, were exceptions to the rest: Unlike the others, the active region they exploded from were much larger, and didn’t produce a coronal mass ejection along with the flare. [emphasis mine]

What they did was apply their model to active regions on the Sun during the last solar maximum to see if it would accurately predict the events we know did happen. The model predicted that big flares would spout from ten of twelve active regions on the Sun during the last solar cycle. In reality, only seven of those twelve active regions produced flares.

The press release minimizes the three false positives, making believe they don’t count in the total. That’s hogwash. The model got it wrong, and so these false positives must be counted just like the two false negatives.

A prediction rate of 56% is barely above random, so this model needs a lot of work. Nonetheless, it is a major step forward, because it is not based on simple statistics — counting the number of big sunspots and the number of big flares and then calculating the percentage that flare — which is how most solar science models are structured, and thus are really meaningless. Instead, this model is based an actual analysis of the behavior of the Sun’s magnetic field in big active regions when solar flares erupt. They are trying to pinpoint the precise conditions that cause the big flares, and appear to be narrowing the conditions successfully.

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Jupiter’s south pole

10:59 am

The storms at the south pole of Jupiter
Click for full image.

Cool image time! The photo to the right, rotated and reduced to post here, was taken by Juno during its 28th close orbital fly-by of Jupiter, and then processed by citizen scientist Hemant Dara.

While not the first Juno image of the poles of Jupiter, this photo illustrates very well the evolution of the gas giant’s deep atmosphere as you move from the equator to the pole. From the equator to the high mid-latitudes the planet’s rotation, producing a day only 10 hours long, organizes that atmosphere into jet streams that form the bands that astronomers have spied from Earth since the first telescopes.

At the pole the influence of that rotation seems to wane, or at least influence the atmosphere differently, so that the storms seem to form randomly and incoherently.

The image also shows that there appear to be several types of storms at the south pole. Some appear as tight spirals, similar to hurricanes. Others appear chaotic, with no consistent shape, almost like clouds on Earth.

The processes that would explain all this are not yet understood, in the slightest, and won’t be until we get orbiters at Jupiter able to watch the atmosphere continuously, as we do here on Earth. Then it will be possible to assemble movies of the formation and dissipation of these storms, and begin (only begin) to decipher what causes them.

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Yutu-2 completes 20th lunar day on Moon

10:28 am

The new colonial movement: The Chinese lunar rover Yutu-2 has completed its 20th lunar day on the farside of the Moon, and has now been put in sleep mode for the long lunar night.

Yutu 2 continued on its planned journey to the northwest of the lander, according to the China Lunar Exploration Program (CLEP). The rover covered 90 feet (27.64 meters) during the lunar day to make a total of 1,610 feet (490.9 m) of roving since setting down on the far side of the moon in January 2019.

The article at the link includes some images, including visual data from the ground-piercing radar that suggests at least four layers in the lunar subsurface.

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Midnight repost: A scientist’s ten commandments

11:59 pm

The tenth anniversary retrospective of Behind the Black continues: The post below, from September 27, 2010, reports on one of the simplest but most profound scientific papers I have ever read. Its advice is doubly needed today, especially commandment #3.

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A scientist’s ten commandments

Published today on the astro-ph website, this preprint by Ignacio Ferrín of the Center for Fundamental Physics at the University of the Andes, Merida, Venezuala, is probably the shortest paper I have ever seen. I think that Dr. Ferrin will forgive me if I reprint it here in its entirety:

1. Go to your laboratory or your instrument without any pre-conceived ideas. Just register what you saw faithfully.

2. Report promptly and scientifically. Check your numbers twice before submitting.

3. Forget about predictions. They are maybe wrong.

4. Do not try to conform or find agreement with others. You may be the first to be observing a new phenomenon and you may risk missing credit for the discovery.

5. Criticism must be scientific, respectful, constructive, positive, and unbiased. Otherwise it must be done privately.

6. If you want to be respected, respect others first. Do not use insulting or humiliating words when referring to others. It is not in accord with scientific ethics.

7. Do not cheat. Cheating in science is silly. When others repeat your experiment or observation, they will find that you were wrong.

8. If you do not know or have made a mistake, admit it immediately. You may say, “I do not know but I will find out.” or “I will correct it immediately.” No scientist knows the answer to everything. By admitting it you are being honest about your knowledge and your abilities.

9. Do not appropriate or ignore other people’s work or results. Always give credit to others, however small their contribution may have been. Do not do unto others what you would not like to be done unto you.

10. Do not stray from scientific ethics.

It seems that some scientists in the climate field (Phil Jones of East Anglia University and Michael Mann of Pennsylvania State University are two that come to mind immediately) would benefit by reading and following these rules.

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Perseverance’s planned journey in Jezero Crater

1:34 pm

Jezero Crater delta
Jezero Crater delta

If all goes right, on February 18, 2021 the rover Perseverance will gently settle down onto the floor of Jezero Crater on Mars. The image to the right is probably the most reproduced of this site, as it shows the spectacular delta that some scientists believe might be hardened mud that had once flowed like liquid or lava from the break in the rim to the west.

They hope to put Perseverance down to the southeast of that delta, as shown in the overview map below.
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Astronomers find freshly fallen meteorites based on tracking their fall

11:36 am

Australian astronomers have found two meteorites on the ground after spotting them in the sky before they fell, with one found only

The first had been spotted in the sky only a few weeks earlier, while the second had been spotted back in November 2019. They had had to postpone the search for the second until the restrictions for the Wuhan flu were lifted.

The discovery of the first was amusing:

Astronomer Dr Hadrien Devillepoix and planetary geologist Dr Anthony Lagain originally went on a reconnaissance mission to assess the latest fall site near Madura, taking drone imagery of the area. Dr Devillepoix said that as they were walking back to their car along the old telegraph track near Madura Cave, they spotted what appeared to be a real meteorite on the ground just in front of them.

“I thought Anthony was playing a prank on me, that he planted one of the fake meteorites we were using for the drone training session. But after a closer inspection, it was evident that the fist-sized, 1.1 kilogram rock we just found was indeed the meteorite we were after,” Dr Devillepoix said. Dr Devillepoix explained that although the rock was very close to the predicted fall position, the team was not expecting to find it that quickly in this bushy terrain.

Based on its track as it fell, the astronomers think it might be from the Aten family of asteroids, which orbit the Sun between Venus and Earth. Such asteroids are hard to find because of the glare of the Sun, and are thus not as well studied. This makes this find even more significant.

Finds like this, which are beginning to happen more and more, are important because, first, the meteorite doesn’t spend much time in the Earth environment, and second, they can precisely identify where the asteroid came from. Both facts allow scientists a much better understanding of the asteroids themselves.

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Neutron star left over from Supernova 1987A?

8:24 am

The uncertainty of science: Two different teams of astronomers are now suggesting that, based on evidence recently obtained by the Atacama Large Millimeter/submillimeter Array (ALMA), a neutron star is what is left over from the star that caused Supernova 1987A, the only naked eye supernova in the past four hundred years.

Recently, observations from the ALMA radio telescope provided the first indication of the missing neutron star after the explosion. Extremely high-resolution images revealed a hot “blob” in the dusty core of SN 1987A, which is brighter than its surroundings and matches the suspected location of the neutron star.

..The theoretical study by Page and his team, published today in The Astrophysical Journal, strongly supports the suggestion made by the ALMA team that a neutron star is powering the dust blob. “In spite of the supreme complexity of a supernova explosion and the extreme conditions reigning in the interior of a neutron star, the detection of a warm blob of dust is a confirmation of several predictions,” Page explained.

These predictions were the location and the temperature of the neutron star. According to supernova computer models, the explosion has “kicked away” the neutron star from its birthplace with a speed of hundreds of kilometers per second (tens of times faster than the fastest rocket). The blob is exactly at the place where astronomers think the neutron star would be today. And the temperature of the neutron star, which was predicted to be around 5 million degrees Celsius, provides enough energy to explain the brightness of the blob.

They haven’t actually gotten any direct evidence of this stellar remnant, so some healthy skepticism is required. At the same time, the data favors this solution, which means the star did not collapse into a black hole when it exploded.

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Glacier country on Mars

12:47 pm

Glacial flow in Protonilus Mensae
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on May 24, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and provides a wonderful example of the kind of evidence of buried glaciers found extensively in the mid-latitudes of Mars.

This particular region, called Protonilus Mensae, is a region of chaos terrain at the transition zone between the southern cratered highlands and the northern lowland plains. I have featured a number of cool images in Protonilus, all of which show some form of buried glacial flow, now inactive.

The last cool image above was one that the MRO science team had picked to illustrate how to spot a glacier on Mars.

In this particular image are several obvious glacier features. First, we can see a series of moraines at the foot of each glacier in the photo, each moraine indicating the farthest extent of the glacier when it was active and growing. It also appears that there are two major layers of buried ice, the younger-smaller layer near the image’s bottom and sitting on top of a larger more extensive glacier flow sheet. This suggests that there was more ice in the past here, and with each succeeding ice age the glaciers grew less extensive.

Second, at the edges of the flows can be seen parallel ridges, suggestive also of repeated flows, each pushing to the side a new layer of debris.

Third, the interior of the glacier has parallel fractures in many places, similar to what is seen on Earth glaciers.

Protonilus Mensae, as well as the neighboring chaos regions Deuteronilus to the west and Nilosyrtis to the east, could very well be called Mars’ glacier country. Do a search on Behind the Black for all three regions and you will come up with numerous images showing glacial features.

Below is an overview of Protonilus, the red box showing the location of this image. Also highlighted by number are the locations of the three features previously posted and listed above.
» Read more

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Martian eroding ridges amid brain terrain

12:09 pm

Brain terrain and bisected ridges on Mars
Click for full image.

Today’s very cool image is cool because of how inexplicable it is. To the right, cropped to post here, is a photo taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) of an area of what they call “Ribbed Terrain and Brain Terrain”.

I call it baffling.

Nor am I alone. At the moment the processes that create brain terrain (the undulations between the ridges) remain a complete mystery. There are theories, all relating to ice sublimating into gas, but none really explains the overall look of this terrain.

Making this geology even more baffling are the larger ridges surrounding the brain terrain, all of which appear to have depressions along their crests. Here too some form of sublimation process appears involved, but the details remain somewhat mysterious.
» Read more

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Another university researcher arrested for spying for China

2:18 pm

The FBI yesterday arrested a researcher who had been working at the University of California-Davis and had lied about here contacts with the Chinese communist party and its military.

Juan Tang, 37, who had been a visiting cancer researcher at UC Davis for several months, left her Davis apartment in June after FBI agents questioned her about evidence that she lied concerning whether she was a member of the Chinese military or Communist Party when she applied for a visa, according to federal court papers.

…U.S. authorities have no authority to enter the consulate without permission, and it was not immediately clear Friday whether she had voluntarily surrendered. Jail records show the FBI arrested her overnight and booking was still in progress Friday morning.

She is one of four Chinese researchers charged by the Justice Department this week for spying. The other three have already been arrested.

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Slip-sliding away – on Mars

1:00 pm

Faults on Mars
Click for full image.

Today’s cool Martian image, rotated, cropped, and reduced to post here, comes from the camera on Mars Odyssey and was taken on May 18, 2020. It shows an area on Mars where faults and cracks in the ground have caused criss-crossing depressions. In this particular case we can see that the north-south trending fissure at some point got cut in half by east-west trending fault, its northern and southern halves thus getting shifted sideways from each other. For scale the straight section of the northern canyon is about five miles long, with the sideways shift about a mile in length.

As the caption notes, “With time and erosion this region of fault blocks will become chaos terrain,” regions of canyons often cutting at right angles to each other with flat-topped mesas and buttes in between.

Now for the mystery.
» Read more

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A July 4th Hubble image of Saturn

10:27 am

Saturn as seen by Hubble on July 4, 2020
Click for full image, annotated.

Cool image time! The photo to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope on July 4, 2020, and shows Saturn, its rings, plus several moons, in all their glory.

The dot near the bottom center is Enceladus. The dot at center right is Mimas. If you click on the annotated full image it will show the locations of several other smaller moons much harder to see.

This new Saturn image was taken during summer in the planet’s northern hemisphere.

Hubble found a number of small atmospheric storms. These are transient features that appear to come and go with each yearly Hubble observation. The banding in the northern hemisphere remains pronounced as seen in Hubble’s 2019 observations, with several bands slightly changing color from year to year. The ringed planet’s atmosphere is mostly hydrogen and helium with traces of ammonia, methane, water vapor, and hydrocarbons that give it a yellowish-brown color.

Hubble photographed a slight reddish haze over the northern hemisphere in this color composite. This may be due to heating from increased sunlight, which could either change the atmospheric circulation or perhaps remove ices from aerosols in the atmosphere. Another theory is that the increased sunlight in the summer months is changing the amounts of photochemical haze produced.

The distance across from one end of the rings to the other is about 150,000 miles, about two thirds the distance from the Earth to the Moon.

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First image of multi-exoplanets around young sunlike star

10:00 am

Two exoplanets in one image

Worlds without end: Using the Very Large Telescope (VLT) in Chile, astronomers have taken the first image that captures two different exoplanets circling a young sunlike star.

The star’s light is partly blocked in the upper left of the photo to the right, cropped slightly to post here.

You can read the paper here [pdf]. The star itself, though similar in mass to the Sun, is thought to be only seventeen million years old.

But the system, dubbed TYC 8998-760-1, is nothing like our solar system. One of the star’s companions straddles the line that defines planets, with a mass 14 times Jupiter’s; the other has a mass of six Jupiters. Both orbit far from the star, about 160 and 320 times the average distance between Earth and the Sun. That puts them more than four times farther out than Pluto is from the Sun.

The size and distance of these giant planets were why they could be imaged from the ground.

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Moving ripples on Mars

9:37 am

Using Mars Reconnaissance Orbiter (MRO) high resolution images, scientists have now determined that the giant ripples seen from space are actually moving, albeit very slowly.

Megaripples are found in deserts on Earth, often between dunes. Waves in the sand spaced up to tens of meters apart, they’re a larger version of ripples that undulate every 10 centimeters or so on many sand dunes. But unlike dunes, megaripples are made up of two sizes of sand grains. Coarser, heavier grains cap the crests of megaripples, making it harder for wind to move these features around, says Simone Silvestro, a planetary scientist at Italy’s National Institute of Astrophysics in Naples.

Since the early 2000s, Mars rovers and orbiters have repeatedly spotted megaripples on the Red Planet. But they didn’t seem to change in any measurable way, which led some scientists to think they were relics from Mars’s past, when its thicker atmosphere permitted stronger winds.

Now, using images captured by NASA’s Mars Reconnaissance Orbiter, Silvestro and his colleagues have shown that some megaripples do creep along—just very slowly.

They found that the ripples shift position about four inches per year, which astonished them since they had not believed the winds of Mars were strong enough to move them at all.

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Tianwen-1 successfully launched, on its way to Mars

9:27 pm

UPDATE: According to news reports, China tonight successfully launched Tianwen-1 towards Mars, with arrival expected in February 2021.

Below the fold is a live stream of the launch of the Long March 5 rocket. It is not in English, and since it was not linked to China’s mission control, it only covers the first two minutes or so, after which the rocket went out of sight.

The leaders in the 2020 launch race:

17 China
11 SpaceX
7 Russia
3 ULA
3 Japan

The U.S. still leads China 18 to 17 in the national rankings.
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