Tag: science

More glaciers in Mars’ glacier country

2:24 pm

Overview map

glacial layering in Clasia Vallis
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on June 18, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what appear to be layered glacial features on the floor of what at first glance appears to be a crater.

It is not a crater however. The depression in the lower right of this image is the rim and floor of a 77-mile-long meandering canyon on Mars dubbed Clasia Vallis. The red cross in the overview map above marks its location, at 34 degrees north latitude. This channel drains downward from the southern cratered highlands into the 2,000-mile-long mid-latitude strip of mensae terrain that I dub glacier country because almost every hi-res image from this region shows glacial features.

Below is a wider view of Clasia Vallis, taken by the context camera on MRO on March 19, 2014.
» Read more

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First ground-based telescope view of DART impact on Dimorphus

10:10 am

LICIACube Explorer image of DART impact

We now have the first ground-based images of the DART impact on the 525-foot-wide asteroid Dimorphus yesterday, captured by the Hawaiian telescope ATLAS.

You need to watch the video of the full sequence of images, available here, to get a true sense of the impact. The cloud of material quickly expands to about twice the asteroid’s size, then dissipates away, with the remaining asteroid now appearing larger (?). That larger size could be caused by a remaining cloud of material that still needs to settle back to the surface.

More images have been released by a Chinese telescope. Also, the first images from the Italian cubesat LICIACube Explorer, flying in parallel with DART, have been released. I have posted one to the right. The large blob near the center is the parent half-mile-wide asteroid, Didymos. Dimorphus is buried in the debris cloud above and slightly to the right.

Hat tip stringer Jay for the links to these images.

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Radar data from Zhurong finds no ice to a depth of 260 feet

9:46 am

Zhurong's ground-penetrating radar data

Overview map

Chinese scientists today finally published their results from the ground-penetrating radar instrument on their Mars rover Zhurong, revealing that to a depth of 260 feet (80 meters), it detected no clear signal of water ice.

Figure 2 of their paper, posted above, summarizes their results. It shows the radar profile to 328 feet (100 meters) depth along Zhurong’s route, as shown in the map to the right, with the last bit of its recent travels ending somewhere in the blue circle. From the paper:

Our low-frequency radar imaging profile shows radar signals within the depth range of 0–80 m (Fig. 2a), precluding the existence of a water-rich layer within this depth range as the existence of water would strongly attenuate the radar signals and diminish the visibility of deeper reflections. The estimated low (less than 9) dielectric permittivity (Fig. 2c) further supports the absence of a water-rich layer as water-bearing materials typically have high (greater than 15) dielectric permittivity.

We further tested this assessment with thermal considerations by conducting a heat conduction simulation based on available thermal parameters estimated from previous studies (Methods). Our thermal simulation results … show that the Zhurong landing area has an annual average temperature of around 220K in the RoPeR detection depth range, which is much lower than the freezing point of pure water (273K), and also lower than the eutectic temperatures of typical sulfate and carbonate brines, but slightly above those of perchlorate brine systems. This observation suggests that the shallow subsurface of the Zhurong landing area could not stably contain liquid water nor sulfate or carbonate brines, consistent with the radar imaging result.

The data suggests that below the surface topsoil layer, the regolith, there are two distinct layers of material that the scientists interpret as possible evidence of past catastrophic floods. That conclusion however is very very uncertain. The main take-away is that in the northern lowland plains of Utopia Planitia at 25 degrees north latitude, where Zhurong landed, Mars is definitely a dry desert, with no water close to the surface.

This data also suggests that if you establish a colony anywhere in Mars’ dry equatorial regions within 30 degrees latitude of the equator, you will likely have to travel north or south a considerable distance to get to easily accessible ice. The global map of Mars below shows the regions where ice is most evident, north and south of 30 degrees latitude.
» Read more

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DART hits Dimorphus

4:42 pm

Didymos and Dimorphus

Dimorphus

The surface of Dimorphus

The probe DART today successfully impacted the small 525-foot-wide asteroid Dimorphus. From the data produced engineers will calculate how much that impact changed Dimorphus’ orbit around it parent asteroid, half-mile-wide Didymos.

The three images to the right give a sense of the approach and impact.

The first, at 2 minutes and 30 seconds from impact, shows Didymos in the left bottom corner. You can actually see individual boulders on its surface. At this distance and resolution is is unclear whether it is a rubble pile or a more solid body. Dimorphus is no longer a mere dot, but no surface features can yet be discerned.

The second image, only seventeen seconds before DART crashed into Dimorphus, shows us the entire asteroid. Though it appears to be a pile of rocks, it also appears less of a rubble pile than both Ryugu and Bennu, visited by probes in 2019 and 2020. Those rubble-piles had almost no smooth surface areas. Dimorphus however at this distance and resolution does appear to have a lot of areas where the surface is relatively smooth, suggesting its structure is more solid than a rubble pile.

At only 525 feet across, some of those bigger boulders are about 50 to 60 feet in diameter.

The white dot in the center of Dimorphus marks the rocks seen in the third image, taken about five seconds before impact. At this resolution so close to the surface, it appears the smooth areas are actually made up of many tiny pebbles and dust.

The biggest rock in the center of the picture is probably between ten to twenty feet in diameter.

The primary data from this mission will not be available for a few weeks. Scientists have to observe both asteroids to see how much, if at all, Dimorphus’s orbit was shifted by the impact. Also, the images from the Italian cubesat, LICIACube Explorer, which was flying parallel to DART and taking pictures of the impact, plume, and back side of Dimorphus, won’t be available until later this week. Those images should give us a measure of the spacecraft’s effect on the asteroid. They will also reveal a lot more about the asteroid’s geology.

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Zig-zag ridges on Mars

2:26 pm

Zig-zag ridges on Mars
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on April 9, 2022v by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a series of parallel zig-zag ridges in a flat, knobby terrain.

I don’t presume to explain this at all. According to one research paper,

This interplana region consists of extensive networks of ridges—the eponymous Aeolis Dorsa—and is interpreted as having formed by topographic inversion of fluvial and alluvial deposits.

Why these ridges zig-zag however does not seem to fit into either a fluvial or alluvial explanation, both of which involve the flow of water. The quote implies these could be inverted stream channels (where the compacted streambed becomes a ridge when the surrounding terrain erodes away), but once again, the distinct zig-zag pattern seems wrong. Rivers meander, but they don’t generally turn right and left so sharply. And why should we see parallel zig-zags? This doesn’t seem to fit with a river channel origin.

The particular location, as shown on the overview map below, is close to the dry Martian equator, on the edge of Medusae Fossae Formation, the largest field of volcanic ash dust on Mars.
» Read more

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A galaxy slowly being eaten by its black hole

10:16 am

Spiral galaxy
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Cool image time! The photo to the right, rotated and reduced to post here, was taken by the Hubble Space Telescope. From the caption:

NGC 5495, which lies around 300 million light-years from Earth in the constellation Hydra, is a Seyfert galaxy, a type of galaxy with a particularly bright central region. These luminous cores — known to astronomers as active galactic nuclei — are dominated by the light emitted by dust and gas falling into a supermassive black hole. This image is drawn from a series of observations captured by astronomers studying supermassive black holes lurking in the hearts of other galaxies.

Essentially Seyfert galaxies are galaxies whose central supermassive black hole has become dominant, large enough that its gravity is slowly eating up the rest of the galaxy. As it increasingly swallows stars and gas, the black hole emits more and more energy, thus becoming an active galactic nuclei.

Two stars from our own galaxy also dominate this picture, one inside and to the right of the galaxy’s center, and the other the bright star at the bottom of the picture, both identified by the diffraction spikes.

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Watch DART smash into asteroid today

9:27 am

At 7:14 pm (Eastern) the NASA’s Double Asteroid Redirection Test (DART) spacecraft will crash into the small and harmless asteroid Dimorphus to see if such an impact could be used in the future to change the path of another asteroid aimed at Earth.

Dimorphus is 525 feet in diameter, and is a small moon of the larger half-mile-wide asteroid Didymos. Both are presently about 7 million miles away from Earth.

I have embedded the live streams below, one from a DART camera, dubbed DRACO, that will view the asteroid as the spacecraft approaches, and the other from NASA’s official live stream. From the DRACO live stream webpage:
» Read more

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Ganymede as seen by Juno

10:29 am

Ganymede as seen by Juno
Click to see full image.

Cool image time! The picture to the right, cropped and reduced to post here, was taken on June 7, 2021 when Juno made a close fly-by of Jupiter’s moon Ganymede. It has been reprocessed to bring out the details by citizen scientist Brian Swift.

Note the bands and parallel light and dark ridges that criss-cross the planet. Scientist as yet do not understand what caused them. Note also the bright impact craters, suggesting the release of water ice from below.

This image anticipates Juno’s upcoming September 29, 2022 fly-by of Europa, one of Jupiter’s other Galilean moons. The orbiter will pass only 221 miles above its surface, and get the best images in decades, since the Galileo mission in the 1990s.

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Above ground and underground Martian drainages

2:28 pm

Overview map

Cool image time! Today we are going to zoom into our cool image. The overview map to the right provides us the context. Our target is the small white rectangle inside the small box just below the north rim of 185-mile-wide Newton Crater, located 200 to 800 miles from the southwest edge of the lava plains dubbed Daedalia Planum that flowed down from Mars’s biggest volcanoes.

Newton Crater has a number of interesting features. Only two weeks ago I featured 4-mile-wide Avire Crater in Newton’s western quadrant, long known to have many gullies on its interior slopes as well as glacier features on its floor. Scientists have been monitoring those gullies now for more than a decade to see if they change seasonally, in a attempt to figure out their cause.

Today’s cool image looks at the very intriguing meandering canyons that appear to flow south from Newton’s north rim.
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A hot wave in Jupiter’s upper atmosphere has been discovered, flowing away from the pole

9:59 am

Jupiter heat wave

Using data obtained by ground-based telescopes, scientists have discovered a hot wave, with temperatures in the range of 700 degrees Celsius (about 1,300 degrees Fahrenheit), rolling outward from Jupiter’s hot polar atmospheric regions, believed caused by the gas giant’s intense aurora.

Jupiter’s atmosphere, famous for its characteristic multicoloured vortices, is also unexpectedly hot: in fact, it is hundreds of degrees hotter than models predict. Due to its orbital distance millions of kilometres from the Sun, the giant planet receives under 4% of the amount of sunlight compared to Earth, and its upper atmosphere should theoretically be a frigid -70 degrees Celsius. Instead, its cloud tops are measured everywhere at over 400 degrees Celsius.

…Just like the Earth, Jupiter experiences auroras around its poles as an effect of the solar wind. However, while Earth’s auroras are transient and only occur when solar activity is intense, auroras at Jupiter are permanent and have a variable intensity. The powerful auroras can heat the region around the poles to over 700 degrees Celsius, and global winds can redistribute the heat globally around Jupiter.

The graphic above, adapted from the research presentation [pdf], shows that wave propagating away from the pole. The wave’s width is about the size of the Earth, with different sections moving from about 1,000 feet per second to 8,000 feet per second.

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Watching DART impact asteroid on September 26, 2022

9:35 am

A NASA planetary probe, dubbed DART, is on course for a planned impact of the asteroid Dimorphos this coming Monday, September 26, 2022, at 4:14 PM (Pacific).

DART was launched from Vandenberg Space Force Base, CA on November 23, 2021 PST (November 24 EST) headed to the asteroid Didymos and its tiny moon Dimorphos 7 million miles away. The plan is for DART to ram itself into Dimorphos while scientists on Earth measure whether its orbit around Didymos changes.

Dimorphos is about 525 feet in diameter, while Didymos is much larger, about a half mile in width. The goal is to see if this method can be used in the future to adjust an asteroid’s orbit enough to shift it away from hitting the Earth.

The impact will be observed by a camera on DART, as well as an Italian cubesat dubbed LICIACube.

NASA TV will be live streaming the event, and I will embed that live stream here when it goes live. Once DART gets close, its camera will record the asteroid’s approach through impact.

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Martian layers everywhere!

1:38 pm

Layers in Argyre Basin
Click for full image.

Cool image time! The photo to the left, rotated, cropped, and reduced to post here, was taken on June 1, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the rim edge to a fifteen-mile-wide canyon, with many apparent layers exposed on the high plateau.

The layers are intriguing in that they suggest several things. First, they give us a glimpse into the top and youngest layers that make up the interior canyon wall. Second, they tell us that erosion has removed much of those top and youngest layers, resulting in the mesas on that plateau.

Finally, the gullies flowing down into the canyon indicate further erosion processes, eating away at the canyon wall over time.

The location of this canyon is also intriguing.
» Read more

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Another model attempts to show how liquid water could have once existed on Mars

11:07 am

The uncertainty of science: Scientists today published a new model that attempts to show how it was possible in the distant past for liquid water to have existed on the surface of Mars.

New research published in Earth and Planetary Science Letters suggests that Mars was born wet, with a dense atmosphere allowing warm-to-hot oceans for millions of years. To reach this conclusion, researchers developed the first model of the evolution of the Martian atmosphere that links the high temperatures associated with Mars’s formation in a molten state through to the formation of the first oceans and atmosphere. This model shows that — as on the modern Earth — water vapor in the Martian atmosphere was concentrated in the lower atmosphere and that the upper atmosphere of Mars was “dry” because the water vapor would condense out as clouds at lower levels in the atmosphere. Molecular hydrogen (H2), by contrast, did not condense and was transported to the upper atmosphere of Mars, where it was lost to space. This conclusion – that water vapor condensed and was retained on early Mars whereas molecular hydrogen did not condense and escaped – allows the model to be linked directly to measurements made by spacecraft, specifically, the Mars Science Laboratory rover Curiosity.

As a model, this theory proves nothing, though it is very intriguing. The scientists propose that the heat from the planet’s interior replaces the known lack of energy that came from the Sun in Mars’ far past. While this could work, what makes it very uncertain is that its surface data is based on a single measurement from Curiosity, hardly a deep and convincing baseline.

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Ingenuity completes 32nd flight

10:21 am

According to a tweet from JPL, Ingenuity successfully completed its 32nd flight on Mars on September 18, 2022.

The 55.3-second flight covered 93.74m at a max speed of 4.75 meters per second.

That is about 308 feet distance, comparable to the helicopter’s previous flight. Though it probably continued to the west, as with that last flight, JPL’s tweet did not provide any directional information.

This second short hop in a row however suggests that the team’s focus has definitely shifted from scouting for Perseverance to practicing precision landings, thus gathering data to help build the future Martian helicopter that will be used to pick up Perseverance’s core samples some time in the future.

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Want to do a virtual hike in Jezero Crater on Mars? You can!

10:01 am

Using data from Mars orbiters, Perseverance, and Ingenuity, scientists have now created a virtual hiking map of Jezero Crater, allowing anyone to explore in detail the same places that the rover and helicopter have visited.

You can view the map here. From the press release:

The map allows virtual hikers to zoom in and out, and pan rapidly across scenes, so that they can explore the landscape from large scales down to centimetre-detail. Some of the 360° panoramas integrated with the waypoints have been synthetically rendered from orbital image data. Others are real panoramas stitched together from a multitude of single images taken by the Mastcam-Z camera instrument onboard the Mars 2020 Rover Perseverance, which have been provided by the University of Arizona. The sounds have been recorded by the SuperCam instrument on that same rover mission.

I’ve played with the map only a little, but find it quite amazing and useful, especially because it seems to work well on my relatively ordinary desktop Linux computer.

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Webb’s first infrared image of Neptune

9:30 am

Webb's infrared view of Neptune
Click for full image.

The science team for the James Webb Space Telescope today released that telescope’s first infrared image of Neptune.

That image is to the right, cropped and reduced slightly to post here. It is, as the press release touts, the best view in decades of Neptune’s rings. From the caption:

The most prominent features of Neptune’s atmosphere in this image are a series of bright patches in the planet’s southern hemisphere that represent high-altitude methane-ice clouds. More subtly, a thin line of brightness circling the planet’s equator could be a visual signature of global atmospheric circulation that powers Neptune’s winds and storms. Additionally, for the first time, Webb has teased out a continuous band of high-latitude clouds surrounding a previously-known vortex at Neptune’s southern pole.

The dots around the gas giant are the heat signatures of seven of its fourteen moons.

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InSight’s power level holding steady

9:57 pm

InSight's on-going power levels

The Energizer bunny of Mars, the InSight lander, continues to hold on. The engineering team tonight issued another status report, as shown in the graph to the right. For the past week the lander continued to produce 420 watt-hours per day, even though the tau level of dust in the atmosphere increased from 0.8 to 0.85.

The tau level of dust outside of the winter dust season is normally between 0.6 and 0.7. Even though Mars is moving out of winter, that level has increased slightly above InSight. And yet, even with a higher dust content and thus less sunlight, the lander’s dust-covered solar panels are generating power, at a very slightly higher level.

The InSight team had expected the lander to die in early September, at the latest. Instead, it keeps running, thus allowing it to detect on September 5th an impact created by a cluster of three asteroids, the first time scientists have ever pinpointed exactly when such a new impact occurred on Mars.

For the lander to survive for even longer, all it needs is one gust of wind across the solar panels to clean them off. The science team had expected this to happen periodically, based on past experience with the Spirit and Opportunity rovers. Unfortunately for InSight, it has not yet happened even once since it arrived on Mars in 2018. Nonetheless, it only has to happen once to save the lander.

Stay tuned. All is not yet lost.

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Jupiter’s endless interweaving storms

1:01 pm

Jupiter's endless interweaving storms

Cool image time! The photo to the right, rotated so that north is up and then reduced slightly to post here, was created by citizen scientist Thomas Thomopoulos from a raw photo taken by Juno during its 44th orbit of Jupiter.

To bring out the details Thomopoulos enhanced the colors, then enlarged the entire photo and cropped the area of interest.

Unfortunately, the Juno team that releases these photos does not provide information for easily establishing scale. In an email to me Thomopoulos noted that the largest circular storm in the northern half of the image is likely a vortex, which on Jupiter tend to range from 600 to 3,500 miles in diameter. He also noted that Juno was a little less than 27,000 miles away from Jupiter when this photo was snapped on August 17, 2022. Thus, I suspect this particular vortex sits on the larger end of that size range, which makes it a little less than half the size of the Earth.

As for the colors, as with many similar Juno images, the white clouds appear to almost always sit at the top of these storms and jets, almost like thunderheads.

Though the largest feature here is that large vortex to the north, most of the gigantic Jupiter storms visible seem instead to form as bands, the storms churning about madly as they are driven along the gas giant’s very fast ten hour rotation period.

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The strange scattered rocks of Gediz Vallis on Mars

10:28 am

The strange rocks of Gediz Vallis
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Cool image time! The photo to the right, reduced to post here, was taken on August 20, 2022 by Curiosity’s high resolution camera. It shows some of the scattered and very delicate rocks that it is finding on the floor of Gediz Vallis, the valley the rover had been striving for since landing more than a decade ago and finally entered in mid-August.

Because of Mars weak gravity, about 39% of Earth’s, and very thin atmosphere, about 1% of Earth’s, it is possible for surface rocks to erode into such delicate shapes. The shapes appear to be further encouraged by the many layers that exist in Mars, with each layer having different characteristics. In the case of the hanging flakes to the right, these layers were more resistant to erosion and thus remains intact while material above and below was slowly blown away.

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Some scientists make educated guess as to the number of ants on Earth

9:38 am

It’s time for junk science! By combing through thousands of research papers, a team of scientists have estimated the Earth’s population of ants numbers approximately 20 quadrillion.

So for the work, researchers combed through 12,000 reports from databases in many languages, including Bulgarian and Indonesian, finding 489 studies with rigorous enough methods of collecting and counting ants to be included. Most of the studies were not focused on ants per se but on larger questions of biodiversity and evolution and just happened to sample ants. The team was surprised to find how concentrated ants are in the tropics, being most plentiful there in savannas and moist forests.

This estimate is 2 to 20 times higher than previous guesses. It is also a somewhat pointless exercise, mostly because there is no way to check the number. It is simply an educated guess, from which little real knowledge can be gleaned.

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Webb instrument has technical issue partly preventing its use

9:31 am

Because a an issue with the mid-infrared instrument (MIRI) on the James Webb Space Telescope, the telescope’s engineering team has paused use of that instrument while it reviews the situation.

On Aug. 24, a mechanism that supports one of these modes, known as medium-resolution spectroscopy (MRS), exhibited what appears to be increased friction during setup for a science observation. This mechanism is a grating wheel that allows scientists to select between short, medium, and longer wavelengths when making observations using the MRS mode. Following preliminary health checks and investigations into the issue, an anomaly review board was convened Sept. 6 to assess the best path forward.

The Webb team has paused in scheduling observations using this particular observing mode while they continue to analyze its behavior and are currently developing strategies to resume MRS observations as soon as possible. The observatory is in good health, and MIRI’s other three observing modes – imaging, low-resolution spectroscopy, and coronagraphy – are operating normally and remain available for science observations.

I am quoting almost entirely NASA’s short announcement. The announcement is vague, confusing, and (quite typically) written to minimize the reality of the issue. I can’t figure out how MIRI’s other observing modes are available if they have paused use of a mechanism that allows them to choose modes.

Regardless, Webb is awful young to have this kind of problem.

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Interstellar clouds backlit by nearby massive star

1:27 pm

Interstellar clouds backlit by nearby massive star
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Cool image time! The photo to the right, cropped and reduce to post here, was taken by the Hubble Space Telescope of what astronomers believe is a newly formed massive star about 9,000 light years away that has periodically spewed out material during eruptions.

The scientists hope to use Hubble to determine the speed in which this material is flying away from the star by taking pictures at intervals and then measuring the amount of change from image to image. This data will also allow the scientists to better gauge the distance to this star, as well as its actual mass, information that will help them better understand what is happening.

I highlight this picture however simply because of its beauty. The interstellar clouds on the left are all apparently backlit by the brightest star on the right, and thus their shape is easy to perceive.

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InSight’s seismometer detects its first new impact on Mars

1:13 pm

Martian impact discovered by InSight
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Using data from InSight’s seismometer that suggested a new impact had occurred at a specific location on September 5, 2022 on Mars, scientists used the high resolution camera on Mars Reconnaissance Orbiter (MRO) to search and find that impact.

The photo to the right, reduced to post here, is that MRO photo.

The initial impact itself created a small marsquake that was detected by InSight’s seismometer. The instrument recorded seismological data that showed the moment the meteoroid entered Mars’ atmosphere, its explosion into pieces in the atmosphere, and finally, the impact that created a series of at least three craters in the surface.

MRO then flew over the approximate site where the impact was “felt” to look for darkened patches of ground using its Context Camera. After finding this location, HiRISE captured the scene in color. The ground is not actually blue; this enhanced-color image highlights certain hues in the scene to make details more visible to the human eye – in this case, dust and soil disturbed by the impact.

This was thus the first new Martian impact detected based on its actual occurrence, rather than simply finding a change between two photos taken at different times. The latter only tells you a time period when the impact occurred. InSight’s detection here marks the impact’s exact moment.

Nor is this the only such discovery. It appears that InSight detected at least two other impacts (here and here), that only subsequently were linked to MRO impacts. In those cases, the new impact had already been found by MRO, and only afterward were scientists able to identify its seismic vibration in InSight data, thus pinpointing the exact date it took place.

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Valeri Polykov, holder of the record’s longest stay in space, passes away

10:00 am

Valeri Polykov
Valeri Polykov

Russian astronaut Valeri Polykov, who holds the record for the longest spaceflight yet of any human in history, has passed away at the age of 80.

In 1994 and 1995 Polykov spent 437 days on Russia’s space station Mir, the equivalent of fourteen months and two weeks. His thoughts at launch, as he told me personally when I interviewed him while writing Leaving Earth, were not so confident:

“What if something goes wrong?” [he explained]. “I had sacrificed so much time. The government has spent so much, more than they can afford. And I’ve learned so much for them myself, for them.

“Better I die if something went wrong,” he thought. “Better if I had a gun to shoot myself.”

Nothing went wrong however. Polykov, a doctor, had pushed for this long mission to find out if it would be possible for a person to function after a year-plus of weightlessness upon arrival on Mars. Originally planned to last 18 months, circumstances eventually shortened it to 14 months-plus. When Polykov came home in March 1995, he managed to walk a few steps on his own, shortly after being removed from the capsule. To his mind, he had proved that a person could function on their own on Mars after such a long flight.

Others disagreed. As I wrote in Leaving Earth, though he was almost normal within a week of landing,

Polykov had come back to Earth very weak. For at least those first few hours, he needed help from those around him. Any spacefarer arriving on Mars after a year in space must be prepared to face that same challenge.

Regardless, Polykov, like Brian Binnie, was one of the early giants in space exploration. His contribution must not be forgotten.

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Webb takes its first infrared image of Mars

9:12 am

Webb's first infrared image of Mars
Click for full image.

Astronomers have now released the the James Webb Space Telescope’s first infrared image of Mars, taken on September 5, 2022.

The image to the right, cropped and reduced to post here, shows some of the data obtained. Because Mars is so close, it is actually too bright for Webb’s instruments. To get any data, the exposures were very very short, and still the brightest areas — as indicated by large areas of yellow — are overexposed. The cause of the different brightness of Hellas Basin, however, is not simply because the basin — the deepest point on Mars — is cooler.

As light emitted by the planet passes through Mars’ atmosphere, some gets absorbed by carbon dioxide (CO2) molecules. The Hellas Basin – which is the largest well-preserved impact structure on Mars, spanning more than 1,200 miles (2,000 kilometers) – appears darker than the surroundings because of this effect. “This is actually not a thermal effect at Hellas,” explained the principal investigator, Geronimo Villanueva of NASA’s Goddard Space Flight Center, who designed these Webb observations. “The Hellas Basin is a lower altitude, and thus experiences higher air pressure. That higher pressure leads to a suppression of the thermal emission at this particular wavelength range [4.1-4.4 microns] due to an effect called pressure broadening. It will be very interesting to tease apart these competing effects in these data.”

The NASA press release says the scientists are preparing a paper analyzing the spectral data and what it revealed about “dust, icy clouds, what kind of rocks are on the planet’s surface, and the composition of the atmosphere,” I suspect however that Webb’s capabilities for studying Mars are much more limited than implied, and that it will over time take much fewer images of the red planet, compared to Hubble.

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Deep inside the youngest flood lava event on Mars

1:30 pm

Deep inside the youngest flood lava event on Mars
Click for full image.

Cool image time! Today we return to the Athabasca Valles flood lava event, believed to be the youngest major lava event on Mars that I highlighted in a cool image last week.

Then, I showed two meandering lava flows near the edge of this Great Britain-sized flood lava plain, produced 600 million years ago in only a matter of weeks. Today, we take a look deep within the lava plain. The photo to the right, rotated, cropped, and reduced to post here, was taken on May 6, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label “a lava-crater interaction.”

In plain English, we are looking at a crater that has been inundated by the flood lava, filling it.
» Read more

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Starlink being tested in Antarctica

9:33 am

Capitalism in space: The National Science Foundation (NSF) has begun testing a single Starlink terminal at its McMurdo station in Antarctic, with the hope that the service can improve communications at the station significantly.

Everyone at the base shares a 17 Mbps link, according to the United States Antarctic Program, which severely limits what people can do. The station actually blocks people from using high-bandwidth apps like Netflix, cloud backups, and video calls, with the exception of once-weekly Skype or FaceTime sessions at a public kiosk or mission-critical communications.

The addition of Starlink probably doesn’t mean that McMurdo residents will be able to hold a Netflix movie night or anything — the terminals can handle around 50-200 Mbps, which still isn’t a ton to go around, even during the winter when far fewer people are at the base — but it could help make transferring important scientific data off of the icy continent easier.

According to SpaceX’s plans, this new service in Antarctica means that by year’s end Starlink will be available on all seven continents.

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New theory: Saturn’s rings came from a lost and destroyed moon

9:24 am

The uncertainty of science: According to a new computer simulation, scientists have proposed that the reason Saturn’s rings are tilted 27 degrees is because they were created by the destruction of a moon 160 million years ago, an event that was also linked to the way the orbits of Saturn and Neptune interact, combined with the on-going slow evolutionary changes in Titan’s orbit around Saturn.

Wisdom and his colleagues believe Saturn acquired its tilt because of a peculiar synchronicity: the precession of Saturn’s spin axis—the way it wobbles like a top with a particular rhythm—is suspiciously in tune with a precession in Neptune’s orbit. If Saturn and Neptune were trapped in this resonance, Saturn’s tilt would be “kind of vulnerable to other forces that could cause it to change,” says Rola Dbouk, an MIT graduate student in planetary science. In 2020, Cassini scientists discovered what the study team thinks is that external stimulus: Titan, Saturn’s largest moon, is migrating away from Saturn by 11 centimeters a year. In a study published today in Science, Dbouk, Wisdom, and colleagues show how Titan’s migration, in combination with the Saturn-Neptune resonance, could have ratcheted up Saturn’s tilt over the course of 1 billion years.

The work also yielded a potential explanation for the origin of Saturn’s rings. Using Cassini’s measurements of Saturn’s gravitational fields to model the planet’s interior structure, the researchers refined calculations for the wobble of Saturn’s spin axis and found it is no longer in sync with Neptune. “Something kicked it out of the resonance,” Dbouk says. They first ruled out the possibility that chaotic changes in the orbits of some of the largest of Saturn’s dozens of moons could be responsible. But when they added another moon to the mix, things got interesting.

In simulations, the researchers included an object about the size of Iapetus, Saturn’s third largest moon, orbiting about 43 Saturn radii out—between the orbits of Titan and Iapetus. They found this moon could have provided the necessary nudge to the resonance if it were suddenly knocked from its orbit because of chaotic interactions with its neighbors about 160 million years ago.

To say that this theory is uncertain is no different that saying the sky is blue. It is so uncertain that it is difficult to take it seriously. It could be right, but as one scientist quoted at the article noted, there is no way to test it.

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September 15, 2022 Quick space links

3:44 pm

Courtesy of BtB’s stringer Jay, who trolls Twitter so I don’t have to.

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Overlapping galaxies

9:22 am

Overlapping galaxies, as seen by Hubble
Click for full image.

Cool image time! The picture to the right, cropped and reduced to post here, was taken by astronomers using the Hubble Space Telescope, and captures two galaxies that happen to overlap in their line of sight to Earth.

The two galaxies, which have the uninspiring names SDSS J115331 and LEDA 2073461, lie more than a billion light-years from Earth. Despite appearing to collide in this image, the alignment of the two galaxies is likely just by chance — the two are not actually interacting.

This image was taken as part of the citizen-scientist project dubbed Galaxy Zoo, whereby volunteers review lower resolution images of strange-looking galaxies and propose the best for Hubble higher resolution imaging.

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