Tag: science

Lava cones, fissures, and channels from Olympus Mons

9:11 am

A lava cone, fissure, and channel on Mars
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on June 29, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). In this one spot we see three obvious volcanic features, all however formed by different processes.

The location of this image is west of Olympus Mons. It sits on the vast lava plain that was laid down by that volcano, the largest in the solar system.

In order of likely occurrence, the cone probably came first. It likely indicates a past eruption coming up from below to create a small volcano.

The shallow meandering channel that sweeps around it to the north and east probably marks a later lava flow coming down from Olympus Mons.

The deeper straight fissure to the south probably came last. It is a graben, a crack caused by the uplift of the entire surface because of pressure from a magma chamber below, causing cracks to form as the surface is stretched.

Three different volcanic events, each probably taking thousands of years, with maybe thousands to millions of years between them. The context map below adds weight to the scale of time and size represented by this one Martian photo.
» Read more

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Juno science team proposes fly-bys of Jupiter’s moons

8:30 am

The Juno science team has proposed doing fly-bys of three of Jupiter’s moons, should NASA extend the mission beyond ’21.

Juno’s five-year primary mission phase ends in July 2021, and mission managers have proposed an extension that would continue operations until September 2025. The spacecraft’s additional orbits around Jupiter will bring Juno closer to the planet’s moons, allowing for a more diversified set of scientific targets.

…The moon flybys would begin in mid-2021 with an encounter with Ganymede, Jupiter’s largest moon, at a distance of roughly 600 miles (1,000 kilometers), according to Bolton.

After a series of distant passes, Juno would swoop just 200 miles (320 kilometers) above Europa in late 2022 for a high-speed flyby. Only NASA’s Galileo spacecraft, which ended its mission in 2003, has come closer to Europa.

There are two encounters with Jupiter’s volcanic moon Io planned in 2024 at distances of about 900 miles (1,500 kilometers), according to the flight plan presented by Bolton last month.

The extended mission would also allow scientists to get a better look at Jupiter’s north pole.

NASA will decide on the extension by the end of the year. From a cost and scientific perspective, it makes perfect sense to extend this mission for as long as possible. Compared to launching a new mission, extending an active one is far cheaper. It is also already in place.

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A massive Martian glacier that looks just like a glacier on Earth

2:06 pm

Massive glacier on Mars
Click for full image.

If you ever had any doubt about the existence of glaciers on Mars, today’s cool image should ease those doubts. The photo to the right, taken on August 27, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and rotated, cropped, and reduced to post here, shows many features that are appear identical to features found on typical massive glaciers on Earth.

Downhill is to the northwest. The many parallel grooves or fractures running along the length of the glacier resemble what are seen in many similar Earth glaciers. Some of these fractures are caused by the glaciers slow drift downward, with different sections moving at slightly different rates, thus causing a separation along the flow. Hence the parallel fractures.

These fractures also show evidence of some erosion. Because these Martian glaciers are no longer getting more snowfall, they are no longer growing. However, if the thin layer of dust and debris that protects the ice gets blown off or removed by motion, the ice is exposed and can then sublimate into gas so that the glacier erodes.

On the flow’s edges the darker parallel lines also resemble features seen on Earth, showing the exposed layers of the glacier’s past levels. The same thing can be seen on either side of the canyon’s walls.

The wide smooth section near the center of the parallel lines could very well be an impact crater that landed on this glacier sometime in the far past, and has since been distorted in shape as the glacier flowed downward.

If you still have doubts, the context image below, taken by MRO’s wide angle context camera, should help further allay those doubts.
» Read more

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Astronomers watch star’s destruction as supermassive black hole eats it

10:27 am

Astronomers, using a number of ground-based and orbiting telescopes, successfully observed a star’s destruction as it was ripped apart and eaten by a supermassive black hole at the center of a galaxy 215 million light years away.

The team carried out observations of AT2019qiz, located in a spiral galaxy in the constellation of Eridanus, over a 6-month period as the flare grew in luminosity and then faded away. “Several sky surveys discovered emission from the new tidal disruption event very quickly after the star was ripped apart,” says Wevers. “We immediately pointed a suite of ground-based and space telescopes in that direction to see how the light was produced.”

Multiple observations of the event were taken over the following months with facilities that included X-shooter and EFOSC2, powerful instruments on ESO’s VLT and ESO’s NTT, which are situated in Chile. The prompt and extensive observations in ultraviolet, optical, X-ray and radio light revealed, for the first time, a direct connection between the material flowing out from the star and the bright flare emitted as it is devoured by the black hole. “The observations showed that the star had roughly the same mass as our own Sun, and that it lost about half of that to the monster black hole, which is over a million times more massive,” says Nicholl, who is also a visiting researcher at the University of Edinburgh.

Astronomers have seen similar events previously, but never so close and never so early in the event.

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CDC study: Masks do nothing to stop COVID-19 infection

10:52 pm

A new CDC study shows that masks appear to have zero effect in stopping the spread of the COVID-19 virus.

An underreported, recently-published CDC study adds to the pile of evidence that cloth masks or other forms of mandated face coverings only contribute negatives to our COVID-19 problem. The study also displays — despite the constant accusations of widespread misbehavior from public health officials — that Americans are adhering to mask wearing, but mask wearing is not doing us any good.

The CDC study, which surveyed symptomatic COVID-19 patients, has found that 70.6% of respondents reported “always” wearing a mask, while an additional 14.4% say they “often” wear a mask. That means a whopping 85% of infected COVID-19 patients reported habitual mask wearing. Only 3.9% of those infected said they “never” wear a face covering.

The graph below from the study is damning. It shows that wearing a mask made no difference between those who got the disease (left column) and those in the control group.

CDC study graph: masks made no difference.

In either case, the number of cases remained the same no matter how much you wore the mask.

I suspect however that a larger study will find more infections among full-time mask wearers, especially if that study delineates between those medical professionals who are trained to wear the mask properly and with care, keeping it anti-septic, and the general public who fingers their mask continually and then sticks it in their pocket between uses.

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A lunar landslide

10:03 am

Landslide on the Moon
Click for full image.

Cool image time! The image to the right was posted by the Lunar Reconnaissance Orbiter (LRO) science team on October 9, 2020, and shows a spectacular landslide almost a mile and a half long that had occurred on the interior rim of a crater on the Moon.

The top of the rim is on the left, with the landslide breaking out onto the floor of the crater on the right.

The walls of Kepler crater (30 kilometer diameter) exhibit numerous landslides. In this example, a landslide of dark material begins about 100 meters below the rim from a narrow box canyon. The box canyon is about 50 meters wide and 300 meters long. Overall, the slide is extends some 2300 meters (from the end of the canyon to its base). The base of the slide is on a fault block that lies some 1800 meters below the rim. The wall slope is about 33 degrees.

This slide is actually composed of a series of narrow landslides 20-30 meters wide. Along most of the slope, the individual slides overrun each other forming a band of debris up to about 180 meters wide. At the base of the slope, the individual slides can be recognized as they move apart forming a fan of material. A few individual isolated slides also occur adjacent to the main mass. The overlapping nature of these small slides indicate that the overall feature may have formed over a period of time, rather than all at once.

From above and at this resolution, the landslide looks almost like frozen flowing liquid. It allso looks like it began with a scattering of boulders breaking free at the top all at once that quickly consolidated into a single massive avalanche.

At the link you can zoom in or out to look at the entire image, at full resolution.

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A mile-long trail of human footprints about 12,000 years old

9:41 am

Scientists have found in New Mexico a mile-long trail of human footprints from about 12,000 years ago that was probably left by a woman and toddler.

Even more interesting, the tracks show that the woman (or male adolescent) retraced her route, without the child.

Unlike many other known footprint trackways, this one is remarkable for its length – over at least 1.5km [almost a mile] – and straightness. This individual did not deviate from their course. But what is even more remarkable is that they followed their own trackway home again a few hours later.

Each track tells a story: a slip here, a stretch there to avoid a puddle. The ground was wet and slick with mud and they were walking at speed, which would have been exhausting. We estimate that they were walking at over 1.7 metres per second – a comfortable walking speed is about 1.2 to 1.5 metres per second on a flat dry surface. The tracks are quite small and were most likely made by a woman, or possibly an adolescent male.

At several places on the outward journey there are a series of small child tracks, made as the carrier set a child down perhaps to adjust them from hip to hip, or for a moment of rest. Judging by the size of the child tracks, they were made by a toddler maybe around two years old or slightly younger. The child was carried outward, but not on the return.

There is also evidence of a mammoth and sloth crossed the tracks in-between the outward and return journey, with the sloth apparently sensing the human tracks or presence.

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More Martian pits!

2:28 pm

Pit #1
Click for full image.

Pit #2
Click for full image.

Though the number of new pictures showing pits and possible caves from the high resolution camera on Mars Reconnaissance Orbiter (MRO) has significantly tailed off in the past year, as I noted in my previous post on Martian pits in September, the pictures are still rolling in. This post will highlight five new photos and the pits therein.

The first two, on the right, are both located on the southern flanks of the giant volcano Arsia Mons, where many such pits are found. They were taken respectively on August 16, 2020 and August 27, 2020. The first was a captioned image from MRO’s science team:

In this image, the ceiling of the lava tube collapsed in one spot and made this pit crater. The pit is about 50 meters (150 feet) across, so it’s likely that the underground tube is also at least this big (much bigger than similar caves on the Earth). HiRISE can’t see inside these steep pits because it’s always late afternoon when we pass overhead and the inside is shadowed at that time of day.

What I find most interesting about both images is that the skylights do not occur where you’d expect. In image #1, the meandering rill that suggests an underground lava tube is about 1,000 feet south of the pit. The pit itself seems unrelated to that rill. In image #2, the surface shows no obvious evidence of an underground tube matching the three aligned pits. There is the hint of a narrow depression along the alignment of the three pits, but this could just as easily be evidence of wind-blown dust along that alignment.

In the full image all three pits appear to sit inside a very wide and very shallow northwest-to-southwest depression, but this is hardly certain, and regardless the three pits align in a different direction.

The overview map below provides some context.
» Read more

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Flying over Jupiter

11:02 am

Cool movie time! Using images produced by Juno in orbit around Jupiter, citizen scientist Kevin Gill has produced a very nice movie of the spacecraft’s 27th fly-by on June 2, 2020.

During the closest approach of this pass, the Juno spacecraft came within approximately 2,100 miles (3,400 kilometers) of Jupiter’s cloud tops. At that point, Jupiter’s powerful gravity accelerated the spacecraft to tremendous speed — about 130,000 mph (209,000 kilometers per hour) relative to the planet.

I have embedded the movie below the fold. The choice of a piece of music by Vangellis might seem hokey, but I think in this case it works very nicely. I also was impressed with the addition of some 3D depth near the movie’s beginning.
» Read more

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A typical mid-latitude Martian crater with glacial features

2:22 pm

Typical mid-latitude Martian crater with glacial fill
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Cool image time! The crater on the right, the image cropped and reduced to post here, is a great example of many craters scientists have found in the mid-latitudes on Mars containing a variety of features that suggest buried glaciers. In this case we are looking at what they have dubbed a concentric crater fill, material that resembles glacial material that fills the crater’s interior and floor, and appears often to erode in a series of rings. You can see another example here.

The photo was taken on June 29, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The crater itself is located in a region of chaos terrain dubbed Nilosyrtis Mensae, located in the transition zone between the cratered southern highlands and the lowland northern plains.

Nilosyrtis Mensae is part of a region of Mars I call glacier country. When you include the mensae regions Protonilus and Deuteronilus to the west, this transition zone of random mesas, knobs, and criss-crossing canyons stretches about 2,000 miles. The context map below focuses in on Nilosyrtis Mensae, where this crater is located.
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Radio astronomers claim negative impact from satellite constellations

10:35 am

Put them on the Moon! Radio astronomers have released a paper claiming that the coming large communication satellite constellations, such as Starlink and OneWeb, will seriously impact observations with the Square Kilometer Array (SKA) of radio telescopes being built in the remote western outback of Australia.

Saturation of the instruments: very strong interfering signals can saturate the receiver systems and thereby drown out all other signals seen by the Band 5b receivers. As a consequence, all data in that frequency band would be lost, rendering these receivers useless for a portion of the time. For the first phase of the constellation deployments (about 6,400 satellites in total), saturation is predicted to occur for a few percent of the time assuming there is no direct illumination of the dishes by the satellites. For significantly larger constellation sizes (up to more than 100,000 satellites), saturation would be essentially continuous without significant mitigation measures implemented by the satellite operators.

Based on this conclusion, the astronomers estimate that for observations in this particular band they will need to look about 70% longer to get the same data, thereby cutting the number of observations by about half.

The astronomers propose this solution:

One of these mitigation techniques is for the satellite transmitters not to point their beams near the SKAO dishes. SKAO would require operators to steer their satellites’ beams away from the telescope site, a measure which would require a simple software modification with no repercussion on the constellation’s deployment, positioning or hardware. While a cost-effective implementation of this solution does depend on the hardware and software deployed on the satellites, operators already use this technique to comply with international regulations when their satellites cross the path between geostationary satellites in higher orbit and their receiving ground stations, for example to avoid affecting telecommunications and TV transmissions.

This mitigation could reduce the impact on the SKA by a factor of 10 over that noted previously and result in a 7% increase of integration time for SKA observations within the satellite transmission range 4. While any loss of sensitivity is regrettable, SKAO recognises the need for compromise between the competing scientific and commercial drivers.

The solution seems reasonable, but in truth it is only a temporary one. The permanent and smart solution for the astronomical community is to move their telescopes, in all wavelengths, off the Earth. For radio astronomy the far side of the Moon would be ideal.

And with SpaceX now developing a reusable big rocket, Starship, to put such payloads in orbit at low cost, the astronomers need to start thinking about taking advantage of this engineering. The situation for ground-based astronomer will only get worse.

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China releases images of Tianwen-1 on way to Mars

10:12 pm

Tianwen-1 on its way to Mars

China has released several images taken of its Tianwen-1 orbiter/lander/rover by a camera ejected by the spacecraft on its way to Mars.

The images released by the China National Space Administration on Oct. 1 show the Tianwen 1 spacecraft traveling through the blackness of space. Tianwen deployed a small camera to take the self-portrait as it tumbled away from the mothership.

Two wide-angle lenses on the deployable camera were programmed to one image every second. The images were transmitted back to Tianwen via a wireless radio link, then downlinked back to ground teams in China.

In the images, Tianwen 1’s solar array wings and dish-shaped high-gain communications antenna are prominently visible. The white section of the spacecraft is the mission’s entry module and heat shield, which contains a Chinese rover designed to land on Mars and explore the surface.

The spacecraft is about halfway to Mars, and will arrive in Mars orbit in February. It will then spend several months surveying its candidate landing sites, of which there appear to be two, before releasing the lander/rover to the surface.

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Cliffs of Martian ice

12:01 pm

southern hemisphere Martian ice scarp
Click for full image.

Today’s cool image to the right, cropped to post here, shows an ice scarp located in the high southern latitudes south of Hellas Basin. It was taken on August 15, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and was released today as a captioned image. From the caption:

Scientists have come to realize that, just below the surface, about one third of Mars is covered in ice. We study this ice to learn about Mars’ ancient climate and astronauts’ future water supplies.

Sometimes we see the buried ice because cliffs form like the one in this image. On the brownish, dusty cliff wall, the faint light-blue-colored ice shows through. [emphasis mine]

This ice scarp is one of about two dozen [pdf] that have so far been found within the latitude bands of approximately 45 to 65 degrees latitude in both the north and south hemispheres. The data so far obtained suggests that the scarp exists because of a pure water ice layer just below the surface. Over time this pole-facing cliff retreats away from the pole towards the equator, leaving behind it an extended pit. In the cliff wall scientists think they have detected evidence of that water ice layer.

Blue in MRO hi-res images can indicate both water as well as very rough surfaces. While much of the blue here could be ether, the blocky cracks suggest it is ice. As explained by Colin Dundas of the U.S. Geological Survey’s Astrogeology Science Center in Arizona and lead author of the pdf above,

The crack patterns are likely thermal contraction cracks, which form in shallowly buried ice due to seasonal temperature changes causing it to expand and contract. When that repeats over many years it creates regular patterns of cracks that organize themselves into polygons.

The overview image below gives the location of all known such scarps, as of March of 2020, taken from the pdf paper that I linked to above.
» Read more

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Two dozen exoplanets superior to Earth for life?

8:45 am

The uncertainty of science: A team of scientists have now identified 24 exoplanets from the Kepler telescope archive that they propse might actually be better for life than Earth itself.

All the exoplanets are rocky and terrestrial, like the Earth. All are in the habitable zone, meaning that they orbit their star at a distance that makes their general temperature comparable to Earth.

What makes them superior, according to these scientists, are three factors. First, their stars are not G-type stars, like the Sun, but K-types. K-types have much longer lifespans, 70 billion years compared to the Sun’s 8 to 10 billion, allowing more time for life to develop.

Second, the planets have a slightly greater mass than Earth.

Part of the reason the Earth is habitable is because it’s large enough to be geologically active, giving it a protective magnetic field, and has enough gravity to retain an atmosphere. According to the team, if a planet was 10 percent larger, it would have more surface area to live on. If it was 1.5 times as massive as the Earth, its interior would retain more heat from radioactive decay, would remain active longer, and hold onto its atmosphere for a longer time.

Finally, the orbits of these two dozen exoplanets makes them just slighter warmer than Earth, which is thought to be beneficial to life.

This is interesting, but it is pure guesswork. These factors might make our Earth life happier, but these scientists have no idea if such conditions are beneficial or harmful to the creation of life. At present we have zero data on what the ideal conditions would be.

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“N-Word Science” Proves You’re a Racist!

6:44 pm

Link here. The author delves into the so-called “science” of some of the most hyped “white supremacy” academic research, and finds it not only wanting, he finds it downright garbage and not worth the recycled paper it is written on.

No surprise. Race and gender studies are all lies and bigotry, designed not to improve the knowledge of the human race, but to slander all whites, to dehumanize them, and to make it justifiable to treat them as second-class citizens.

I liked his opening however:

With summer 2020 finally in the rearview mirror, and after seven months of “two weeks to flatten the curve,” I’m getting a little sick of “the science.” Not science, mind you, but theee science, the thing that leftists keep assuring us exists—a singular, canonical truth we all must obey. Mind you, it sure seems like there’s not a great deal of agreement about “the science” regarding COVID: You don’t need masks/You do need masks. Hydroxychloroquine doesn’t work/Hydroxychloroquine totally works. Sunlight doesn’t help/Sunlight helps. COVID doesn’t linger in the air/COVID totally lingers in the air/COVID doesn’t linger after all.

Large crowds spread COVID/Large crowds don’t spread COVID (if it’s a BLM crowd).

Theee science is whatever today’s CNN home page says it is. If that happens to contradict yesterday’s home page, well, that’s your fault for having a memory. [emphasis in original]

The number of lies and inconsistencies coming from the “We’re all gonna die from COVID-19” crowd is legion. In this one short quote he sums the worst up quite succinctly.

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Criss-crossing Martian ridges hit by new impacts

9:41 am

Criss-crossing Martian ridges hit by new impacts
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The image to the right, cropped to post here, is a captioned photo from the high resolution camera on Mars Reconnaissance orbiter and released today. From the caption:

The black spots [recent impacts] form because the craters exposed cleaner materials in the subsurface beneath the bright, dusty surface.

Our image is also interesting because the surface has a criss-cross pattern formed by wind activity. Bright ripples that are oriented from the upper right to the lower left are perpendicular to the wind flow. In contrast, outcrops that have been eroded by the wind are oriented perpendicular to the ripples to produce the criss-cross pattern we now observe.

The overview map below might also help explain this criss-cross pattern.
» Read more

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A donut on the Moon

8:58 am

A donut crater on the Moon
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In this case the donut is a crater dubbed Bell E Crater, with a second concentric rim in its interior. The photo to the right, reduced to post here, was taken by Lunar Reconnaissance Orbiter (LRO) as part of its high resolution survey of the entire Moon. As noted at the first link:

Craters not only vary in shape but also in complexity. There are simple craters and complex craters with ring structures and mountains at the center. Somewhere in between is Bell E, a small crater located within the larger Bell crater. These donut-shaped formations are commonly known as concentric craters. Many questions remain on the origin of donut craters. While there have been several ideas about their origin, including double impacts, the currently favored hypotheses involve volcanic processes and compositional variations.

The article outlines four hypotheses for explaining this crater’s formation, a perfectly aligned double impact, ripples at impact into thick warm lava, layers of different densities, and later volcanic activity. None do a good job of explaining all of the concentric craters found on the Moon, and thus suggest that these craters might have formed from some combination of more than one theory.

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Sunspot update: Practically no sunspots for a month

11:49 am

It is sunspot update time again! NOAA today updated its monthly graph for tracking the Sun’s monthly sunspot activity, and I have posted it below, with additional annotations by me to show the past solar cycle predictions.

July and August had seen sunspot numbers higher than the new NOAA prediction (shown by the red curve on the graph below). September however was almost totally blank, with only two weak sunspots for the entire month, as shown on the SILSO graph below.
» Read more

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Hubble creates time lapse movie of fading supernova

10:42 am

Using the Hubble Space Telescope, astronomers have created a time lapse movie showing the fading of a supernova in a nearby galaxy over a year.

The supernova is captured by Hubble in exquisite detail within this galaxy in the left portion of the image. It appears as a very bright star located on the outer edge of one of its beautiful swirling spiral arms. This new and unique time-lapse of Hubble images created by the ESA/Hubble team shows the once bright supernova initially outshining the brightest stars in the galaxy, before fading into obscurity during the year of observations. This time-lapse consists of observations taken over the course of one year, from February 2018 to February 2019.

The video of that time lapse is embedded below the fold.

The galaxy itself is located 70 million light years away. That the supernova of this single star initially outshone the entire galaxy indicates the almost unimaginable power of the explosion.
» Read more

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Parker completes record-setting sixth Sun fly-by

9:51 am

The Parker Solar Probe has successfully completed its sixth close fly-by of the Sun, flying as close as 8.4 million miles, the closest any spacecraft has ever gotten to the Sun, while also moving at a record speed of 289,927 miles per hour.

Flight controllers at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, received a “Status A” signal from the spacecraft through NASA’s Deep Space Network at 4:45 a.m. EDT; Status A is the best of four possible status signals, and indicates that the spacecraft is operating nominally.

The beacon comes after a six-day stretch when communications with the spacecraft were not possible as it wheeled around the Sun. This is the first sign of a successful solar encounter; this sixth solar encounter began Sept. 21 and continues through Oct. 2.

Future fly-bys will likely break this record as well.

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On the rim of Mars’ Grand Canyon

9:35 am

The rim of Valles Marineris
Click for full image.

Cool image time! Mars has many grand geological features that will surely attract tourists in the far future, when the planet has been successfully colonized and humans live there with the same ease that we today live in what was the New World wilderness several hundred years ago.

Of those features, none probably compare with Valles Marineris, the largest known canyon in the solar system. When compared to it, the Grand Canyon — at about a mile deep, about ten miles wide, and about 280 miles long — is a mere pothole, hardly noticeable. Valles Marineris averages a depth of five miles, a width of 370 miles, and a length of 1,900 miles. You could fit many Grand Canyons within it.

The photo to the right, cropped to post here, was taken on July 13, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows only a tiny section of this gigantic canyon’s rim. At this spot the depth from rim to floor is about 4.3 miles, or about 22,700 feet. In the image itself I estimate the cliff at the rim to be somewhere between 6,000 to 8,000 feet high, more than the depth of the entire Grand Canyon. And that’s only this top cliff.

The three overview maps below show the context of this location within Valles Marineris.
» Read more

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Big scallops in the Martian southern latitudes

12:11 pm

Big scallops on Mars
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, shows an example of some large scalloped depressions in the high southern latitudes of Mars.

Taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on June 27, 2020, these scallops resemble in many ways the ice scarps that scientists have previously found at this same latitude, both to the east and west of where these scallops are located. With those scarps, the data suggests that a very pure layer of ice is visible in the cliff face, and that over time the cliff retreats northward due to sublimation of that ice.

The scallops in the photo to the right suggest the same process, though the differences raise questions. As explained by Colin Dundas of the U.S. Geological Survey’s Astrogeology Science Center in Arizona,
» Read more

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The liquids in Titan’s lakes stratify into different density layers

9:50 am

Using the data archive from the Cassini mission to Saturn, scientists now think that the liquids in Titan’s lakes can stratify into different density layers.

Lakes on Saturn’s moon Titan, composed of methane, ethane, and nitrogen rather than water, experience density driven stratification, forming layers similar to lakes on Earth. However, whereas lakes on Earth stratify in response to temperature, Titan’s lakes stratify solely due to the strange chemical interactions between its surface liquids and atmosphere, says a paper by Planetary Science Institute Research Scientist Jordan Steckloff.

Stratification occurs when different parts of a lake have different densities, with the less dense layer floating atop the denser layer. On Earth, lakes in temperate climates often stratify into layers in the summer as the Sun heats the surface of the lake, causing this water to expand and become less dense, forming a layer of warm water that literally floats upon the cooler water below. This density-driven stratification can occur on Titan as well; however it happens due to the amount of atmospheric nitrogen that Titan’s surface liquids can dissolve, rather than the liquids warming up and expanding.

…Because liquid methane is less dense than liquid ethane, it has been long assumed that Titan’s methane would generally float atop its liquid ethane. However, when methane’s affinity for atmospheric nitrogen is accounted for, methane can dissolve sufficient nitrogen at low temperatures to become denser than ethane.

This result has a great deal of uncertainty, mostly because of the relatively small dataset available of Titan. What it really shows is the possibility of this phenomenon. To confirm it will require some in situ measurements.

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UAE leader confirms goal to land rover on Moon by ’24

9:15 am

The new colonial movement: The ruler of the United Arab Emirates (UAE) has confirmed the initiation of a project to land a rover on the Moon by 2024, and have it built entirely by UAE engineers.

The Emirates Lunar Mission will be a 100 percent Emirati-built lunar rover that will land on the moon by 2024, according to a series of tweets by Sheikh Mohammed bin Rashid Al Maktoum, the UAE Prime Minister and Vice President and Ruler of Dubai.

The lunar rover has been named “Rashid” in honour of Sheikh Rashid bin Saeed Al Maktoum who ruled Dubai for 32 years from 1958 until his death in 1990 and who “sparked” the emirate’s advancement.

This is an ambitious goal, but not completely unreasonable. Their engineers were closely involved in the construction of their Hope Mars orbiter, mostly built by U.S. universities and subcontractors. That knowledge can now be applied to their own spacecraft. I also suspect that their 2016 agreement with India to invest billions there in exchange for space-related engineering assistance included technical information about India’s own lunar rover missions.

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New study confirms liquid water under Mars’ south pole

3:02 pm

A new study has confirmed earlier work that suggested there were liquid lakes of water under the Martian south pole.

The data appears to indicate that the bodies are “hypersaline solutions” –a brine in which high concentrations of salt are dissolved in water – which is perhaps the reason they are able to stay liquid despite the very cold conditions of Mars’s south pole.

The fact that there is a whole set of lakes suggests that they have probably formed relatively easily, and that versions of them may therefore have been present throughout the history of the planet. [emphasis mine]

There is one problem with hypothesis indicated by the highlighted words. Mars’ rotational tilt (its obliquity) shifts significantly, from 0 to 60 degrees. Right now it is tilted about 25 degrees, similar to Earth. The south pole as we see it today will have been very different at different obliquities, which means there is no way to assume these posited underground lakes would have been there.

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Martian channels formed by water? by ice? by lava?

1:37 pm

Meandering channels on Mars
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Many of the pictures from Mars show meandering channels, all of which suggest an erosion process related to some form of flow. For most of the last half century, since the first images of these channels were beamed back by Mariner 9 in 1972, scientists had believed that liquid water must have caused them. The accumulating recent photos from Mars now tentatively suggest that these channels might have instead been caused by glacial processes, creeping frozen water instead of liquid.

The image to the right, rotated, cropped, and reduced to post here, was taken on July 17, 2020 by the high resolution camera on Mars Reconnaissance Orbiter. The channels suggest some form of flow going downhill to the northwest, but was it caused by water or ice? There is no obvious visual evidence of glaciers in this image, nor is there any such evidence that I can spot in any of the nearby high resolution images of this same region, despite the fact that at 35 degrees north latitude it is in the mid-latitude band where scientists have identified many glacial features.

The region itself is called Mareotis Fossae, an area of southwest-to-northeast trending parallel fissures and ridges, as shown in the two overview maps below.
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German instrument on Chang’e-4 documents dangerous radiation levels

2:07 pm

This result is not a surprise: A German instrument on China’s Chang’e-4 lander, located now on the Moon’s far side, has measured the radiation levels there, and found them to be much worse than found on Earth.

DLR radiation physicist Thomas Berger from the DLR Institute of Aerospace Medicine, who participated in the publication explains: “The radiation exposure we measured is a good indication of the radiation inside a spacesuit. The measurements give us an equivalent dose rate – the biologically weighted radiation dose per unit of time – of around 60 microsieverts per hour. For comparison, during a long-haul flight from Frankfurt to New York, the dose rate is five to 10 times lower than this. On Earth’s surface, it is some 200 times lower. In other words, a long-term stay on the Moon will expose astronauts’ bodies to high doses of radiation.”

“Human bodies are simply not made to be exposed to space radiation,” adds Robert Wimmer-Schweingruber of the Christian-Albrecht University (CAU) in Kiel, whose team developed and built the LND instrument . “On longer missions to the Moon, astronauts will have to protect themselves from it – by covering their habitat with a thick layer of lunar rock, for example. This could reduce the risk of cancer and other illnesses caused by long periods of time spent on the Moon.”

Previous instruments had only measured the cumulative radiation for the entire mission. This instrument took multiple readings lasting one, ten, or sixty minutes, which gives a more realistic measure of what an astronaut would actually experience, once there.

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An ice-covered mountain on Mars?

2:00 pm

Ice-covered mountain on Mars?
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Grinnell Crater in Glacier National Park in 2017

Today’s cool image, taken on July 1, 2020 by the high resolution camera on Mars Reconnaissance Orbiter, is of a mound-like mountain on Mars that to all intents and purposes appears covered by glacial ice, some eroded, some not.

The image to the right, rotated, cropped, and reduced to post here, shows this mound. Both the flow coming down from the mountain top down the north slope as well as the flow in the north that appears to begin in a small crater suggest glacial features.

Even more convincing are what appear to be patches of glacial ice on the southern slopes, resembling the kind of glacial patches you see everywhere in Glacial National Park. The second photo to the right, taken by me on our visit to Glacier National Park in 2017, shows similar patches hugging the mountainside at Grinnell Glacier.

This Martian mountain is located in the southern hemisphere inside Hellas Basin on its eastern interior rim. (See the overview map below, with the location of this photo the small white box south of Harmakhis Valles.) Thus, you would expect the north-facing slope to get more sunlight (and more heat) than the south-facing slopes. Yet, from this image there appears to be greater erosion on the south-facing slopes. A puzzle indeed.
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OSIRIS-REx team confirms date for sample grab from Bennu

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Nightingale landing site on Bennu
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The OSIRIS-REx science team has confirmed October 20, 2020 as the date the spacecraft will attempt a sample grab from the asteroid Bennu.

OSIRIS-REx is charged with collecting at least 2 oz. (60 grams) of Bennu’s rocky material to deliver back to Earth – the largest sample return from space since the Apollo program – and the mission developed two methods to verify that this sample collection occurred. On Oct. 22, OSIRIS-REx’s SamCam camera will capture images of the TAGSAM head to see whether it contains Bennu’s surface material. The spacecraft will also perform a spin maneuver on Oct. 24 to determine the mass of collected material. If these measures show successful collection, the decision will be made to place the sample in the Sample Return Capsule (SRC) for return to Earth. If sufficient sample has not been collected from [the primary landing site] Nightingale, the spacecraft has onboard nitrogen charges for two more attempts. A TAG attempt at the back-up Osprey site would be made no earlier than January 2021.

The press release at the link provides a lot of technical and interesting details about the sample-grab-and-go attempt, expected to put the spacecraft in contact with the asteroid’s surface for no more than sixteen seconds.

The maneuver itself is quite risky, as the available smooth landing area, as shown in the image above, is only half the size the equipment was designed for, and surrounded by large boulders.

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Corroding glacier in crater rim gully?

9:45 am

Gully in crater rim
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Today’s cool image to the right, rotated and cropped to post here, shows a gully flowing down the north facing rim of a 30-mile-wide crater in the southern cratered highlands. It was taken on June 30, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

To my eye the corroded ridges and pits running down the western side of this gully look like a corroded ice, as if we are looking at a glacier that the light of the Sun, which in the southern hemisphere hits this north-facing slope more directly and for longer periods of time, is causing it to sublimate away with time.

The wider shot below shows the entire rim, flowing downhill from the south to the north.
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