Tag: science

The canyon that Curiosity will eventually climb

11:36 am

The canyon that Curiosity will eventually climb
Click for full resolution. For original images go here and here.

Overview map
Click for interactive map.

Cool image time! The panorama above, created from two photographs taken on May 23, 2025 by the left navigation camera (here and here) on the Mars rover Curiosity, looks south uphill into the canyon that Curiosity is eventually going to climb.

The overview map to the right provides the context. The blue dot marks Curiosity’s present position, the white dotted line its past travels, the red dotted line its initial planned route, and the green dotted line its future route. The yellow lines indicate the approximate area seen in the panorama above.

If you look on the horizon to the left, you can see very bright terrain higher up the mountain. This is the pure sulfate-bearing unit that is Curiosity’s next major geological goal. It won’t reach that terrain for quite some time however because first the scientists want to spend some time studying the boxwork geology that Curiosity is now approaching. That boxwork suggests two past geological processes, as yet unconfirmed. First it suggests the ground dried like mud, forming a polygon pattern of cracks that then hardened into rock. Second, lava seeped up from below and filled those cracks. The lava, being more resistant to erosion, ended up becoming the boxwork of ridges as the material around eroded away.

This proposed history however is not proven. They hope to find out when Curiosity gets there.

Meanwhile, despite having traveled almost 22 miles, the rover is more than 25 miles from the peak of Mount Sharp, which remains out of sight. That peak is also about 15,000 feet higher.

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Scientists: Jezero Crater’s theorized lake overflowed intermittently four times in the past

10:42 am

The inlet and outlet valleys of Jezero Crater
Click for original image.

Scientists analyzing the Martian geology of the meandering outflow canyon from Jezero Crater, now think it was formed by four different very short-lived events when the theorized lake inside the crater overflowed the crater rim.

The map to the right, figure 1 of the paper (cropped and annotated to post here), provides the context. Two canyons, Sava Vallis and Neretva Vallis feed into Jezero Crater, and one canyon, Pliva Vallis, flows out. From the abstract:

By examining the shape of the valley, we noticed that Pliva Vallis was not like valleys carved by continuous rivers on Earth and propose instead that the valley was carved by at least four episodes of lake overflow. To give a minimum estimate of the duration of these events, we use a numerical model to simulate the overflow of a lake and the incision of a valley. Modeling suggests that the four (or more) episodes identified each incised part of the valley and that each episode lasted a few weeks at maximum.

The researchers also considered whether Pliva Vallis could have been carved by glacial flows, but rejected that possibility partly because “the general morphology of the valley shows a decrease in depth and width downstream, while subglacial channels [on Earth] tend to remain of similar width or become larger, as the flow regime does not decrease downstream.”

These conclusions of course carry a great deal of uncertainty. For one, they are based solely on orbital data. No ground truth exists as yet. Secondly, they assume the geology on Mars behaves in the same manner as on Earth. It could very well be for example that the reason the valley shrinks in size is because its Martian glacier sublimated away as flowed downhill, something that doesn’t happen on Earth.

Regardless, the data strongly suggests that water shaped Jezero in some manner.

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Astronomers discover a star radiating in X-rays and radio in ways that fit no known explanation

10:14 am

ASKAP J1832 circled. Note the red arc denoting the supernovae remnant
ASKAP J1832 circled. Note the red arc denoting
the supernovae remnant. Click for original image.

Using both the Chandra X-Ray Observatory and the Square Kilometer Array in Australia, astronomers have discovered a star that pulses in both X-rays and and radio frequencies in a manner previously unseen and that fit no known theory.

ASKAP J1832 belongs to a class of objects called “long period radio transients,” discovered in 2022, that vary in radio wave intensity in a regular way over tens of minutes. This is thousands of times longer than the length of the repeated variations seen in pulsars, which are rapidly spinning neutron stars that have repeated variations multiple times a second. ASKAP J1832 cycles in radio wave intensity every 44 minutes, placing it into this category of long period radio transients.

Using Chandra, the team discovered that ASKAP J1832 is also regularly varying in X-rays every 44 minutes. This is the first time that such an X-ray signal has been found in a long period radio transient.

…However, that is not all ASKAP J1832 does. Using Chandra and the SKA Pathfinder, the team found that ASKAP J1832 also dropped off in X-rays and radio waves dramatically over the course of six months. This combination of the 44-minute cycle in X-rays and radio waves in addition to the months-long changes is unlike anything astronomers have seen in the Milky Way galaxy.

The false-color X-ray/radio image to the right shows the star (circled). Based on the data, it is unlikely that the star is a neutron star or a pulsar. Its properties also do not fit with a magnetar (a pulsar with a very strong magnetic field). Though located within a supernova remnant, the astronomers determined this to be a coincidence, the star unrelated to the remnant.

The best explanation so far is that this is a white dwarf with a companion and the strongest magnetic field ever conceived. The astronomers however do not appear enthused by that explanation either.

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Engineers pinpoint and bypass fuel line problem on Psyche

9:00 am

Psyche's flight path to the asteroid Psyche
Psyche’s flight path to the asteroid Psyche.
Click for original image.

In troubleshooting a significant drop in pressure in the xenon gas fuel lines to the ion engines of the Psyche asteroid probe, engineers have now pinpointed the problem to a failed valve and have switched to a back-up fuel line.

Powered by two large solar arrays, Psyche’s thrusters ionize and expel xenon gas to gently propel the spacecraft, which gradually picks up speed during its journey. The team paused the four electric thrusters in early April to investigate an unexpected drop in pressure. They determined that a mechanical issue in one of the valves, which open and close to manage the flow of propellant, caused the decrease. Through extensive testing and diagnostic work, the team concluded that a part inside one of the valves is no longer functioning as expected and is obstructing the flow of xenon to the thrusters.

Now that the swap to the backup fuel line is completed, engineers will command the spacecraft’s thrusters to resume firing by mid-June.

This issue had to be resolved before that scheduled firing in June or else Psyche would have fallen off its course to reach the metal asteroid Psyche by August 2029.

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The Sun’s surface, in high resolution

9:41 am

The Sun's surface in high resolution
Click for movie (though not of this image)

Cool image time! The picture to the right, reduced and sharpened to post here, was one of a number of pictures released today by the science team operating the new adaptive optics at the 60 inch Goode Solar Telescope (GST) at the Big Bear Solar Observatory (BBSO) in California. It shows the fluffy surface of the Sun, made of many needle-like threads called spicules, with larger bits of plasma (in the center) flung upward and back along the Sun’s magnetic field lines.

If you click on the image, you can watch a 42-second movie produced by many images of a different plasma blob as it changes and evolves. Other short movies produced show bits of this material falling back quickly along those field lines as well as that fluffy surface of needles waving almost like tall prairie grass. The width of the image covers approximately 25,000 miles, which means you could fit about three Earth’s in this space.

To create these images from a ground-based telescope required new technology:

The GST system Cona uses a mirror that continuously reshapes itself 2,200 times per second to counteract the image degradation caused by turbulent air. “Adaptive optics is like a pumped-up autofocus and optical image stabilization in your smartphone camera, but correcting for the errors in the atmosphere rather than the user’s shaky hands,” says BBSO Optical Engineer and Chief Observer, Nicolas Gorceix.

Using this refined imagery, solar scientists will be better able to track and observe the Sun’s small scale behavior (actually quite large on human scales).

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A galactic pinwheel

8:39 am

A galactic pinwheel
Click for original image.

It’s cool image time, partly because we have a cool image and partly because there is little news today due to the holiday. The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope and was released today as the science team’s picture of the week. It shows us a classic pinwheel galaxy located approximately 46 million light years away. From the caption:

A spiral galaxy seen face-on. Its centre is crossed by a broad bar of light. A glowing spiral arm extends from each end of this bar, both making almost a full turn through the galaxy’s disc before fading out.

The bright object with the four spikes of light is a foreground star inside the Milky Way and only 436 light years away. The bright orange specks inside the spiral arms are likely star forming regions, with the blue indicating gas clouds.

As for the holiday, I’ll have more to say about Memorial Day later today.

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Astronomers discover a perfect sphere in radio

1:20 pm

Radio object Teleios

Using the array of radio dishes dubbed the Australian Square Kilometre Array, astronomers have made the serendipitous discovery of what appears to be a perfect sphere of radio emissions tens of light years in diameter and tens of thousands of light years away and near the galactic center.

The scientists have dubbed the object Teleios, Greek for ‘complete’ or ‘perfect’. The image to the right is that radio image. Though the astronomers posit that it must have been formed from a supernova explosion, there are problems with that conclusion. From their paper [pdf]:

Unfortunately, all examined scenarios have their challenges, and no definitive Supernova origin type can be established at this stage. Remarkably, Teleios has retained its symmetrical shape as it aged even to such a diameter, suggesting expansion into a rarefied and isotropic ambient medium. The low radio surface brightness and the lack of pronounced polarisation can be explained by a high level of ambient rotation measure (RM), with the largest RM being observed at Teleios’s centre.

In other words, this object only emits in radio waves, is not visible in optical or other wavelengths as expected, and thus doesn’t really fit with any theories describing the evolution of supernova explosions. Yet its nature fits all other possible known space objects even less, such as planetary nebulae, nova remnants, Wolf-Rayet stars, or even super-bubbles of empty space (such as the Local Bubble the solar system is presently in).

Baffled, the scientists even considered the possibility that they had discovered an artificially built Dyson Sphere, but dismissed that idea because Teleios emits no infrared near its boundaries, as such a sphere is expected to do.

At present the best theory remains a supernova remnant, though this remains a poor solution at best.

Hat tip to reader (and my former editor at UPI) Phil Berardelli.

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Astronomers discover another object in an orbit so extreme it reaches the outskirts of the theorized Oort Cloud

12:45 pm

Orbits of known Trans-Neptunian Objects

Astronomers analyzing a dark energy survey by a ground-based telescope have discovered what might be another dwarf planet orbiting the Sun, but doing so in an orbit so extreme that it reaches the outskirts of the theorized Oort Cloud more than 151 billion miles out.

This object, dubbed, 2017 OF201, was found in 19 different observations from 2011 to 2018, allowing the scientists to determine its orbit. The map to the right is figure 2 from their paper [pdf], with the calculated orbit of 2017 OF201 indicated in red. As you can see, this new object — presently estimated to be about 450 miles in diameter — is not the first such object found in the outer solar system with such a wide eccentric orbit. However, the object also travels in a very different region than all those other similar discoveries, suggesting strongly that there are a lot more such objects in the distant outer solar system.

Its existence also contradicts a model that proposed the existence of a larger Planet X. That theory posited that this as-yet undetected Planet X was clustering the orbits of those other distant Trans-Neptunian objects shown on the map.

As shown in Figure 2, the longitude of perihelion of 2017 OF201 lies outside the clustering region near π ≈ 60◦ observed among other extreme TNOs [Trans-Nepturnian Objects]. This distinction raises the question of whether 2017 OF201 is dynamically consistent with the Planet X hypothesis, which suggests that a distant massive planet shepherds TNOs into clustered orbital configurations. Siraj et al. (2025) computed the most probable orbit for a hypothetical Planet X by requiring that it both reproduces the observed clustering in the orbits of extreme TNOs.

…These results suggest that the existence of 2017 OF201 may be difficult to reconcile with this particular instantiation of the Planet X hypothesis. While not definitive, 2017 OF201 provides an additional constraint that complements other challenges to the Planet X scenario, such as observational selection effects and the statistical robustness of the observed clustering.

Planet X might exist, but if so it is likely simple one of many such objects in the outer solar system. It is also likely to be comparable in size to these other objects, which range from Pluto-sized and smaller, making it less unique and less distinct.

In other words, our solar system has almost certainly far more planets than nine (including Pluto).

Hat tip to BtB’s stringer Jay.

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Perseverance moves across the barren outer rim of Jezero Crater

10:46 am

Looking back at the rim of Jezero Crater
Click for full resolution. For original images go here and here.

Overview map
Click for interactive map.

Cool image time! While most of the mainstream press will be focusing today on the 360 degree selfie that the Perseverance science team released yesterday, I found the more natural view created above by two pictures taken by the rover’s right navigation camera today (here and here) to be more immediately informative, as well as more evocative.

After spending several months collecting data at a location dubbed Witch Hazel Hill on the outer slopes of the rim of Jezero Crater, the science team has finally had the rover move south along its planned route. The overview map to the right provides the contest. The blue dot marks Perseverance’s present location, the red dotted line its planned route, and the white dotted line its actual travels. The yellow lines mark what I think is the approximate area viewed in the panorama above.

That panorama once again illustrates the stark alienness of Mars. It also shows the startling contrast between the rocky terrain that the rover Curiosity is seeing as it climbs Mount Sharp versus this somewhat featureless terrain traveled so far by Perseverance. Though Perseverance is exploring the ejecta blanket thrown out when the impact occurred that formed Jezero Crater, that event occurred so long ago that subsequent geological processes along with the red planet’s thin atmosphere have been able to smooth this terrain into the barren landscape we now see.

And barren it truly is. There is practically no place on Earth where you could find the surface so completely devoid of life.

Some would view this as a reason not to go to Mars. I see it as the very reason to go, to make this terrain bloom with life, using our fundamental human ability to manufacture tools to adapt the environment to our needs.

Meanwhile, the science team operating Perseverance plans to do more drilling, as this ejecta blanket probably contains material thrown out from the impact that is likely quite old and thus capable of telling us a great deal about far past of Mars’ geological history.

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Terraced Martian butte

12:44 pm

Terraced Martian butte
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on April 1, 2025, by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The scientists label this as a “Layered Butte.” Seems like a good description. From top to bottom there appear to at a minimum about a dozen terraces, each of which represents a specific geological era on Mars.

I post this mostly because I think it shows us another example of the alien beauty of the Martian landscape. The scientific question of course is what do these layers represent. In a general sense, they indicate that over a long time period one by one these layers were laid down, and then over a likely equally long time period the top layers were worn away, one by one. The mesa is just a random spot where that erosion process was not complete, leaving behind this terraced 400-foot-high tower.
» Read more

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Astronomers detect evidence of exoplanet in weird orbit

9:13 am

Perpendicular planet
Click for original image.

Though there is much uncertainty in their data, astronomers now believe they have discovered an exoplanet orbiting a binary system of two brown dwarfs, but doing so tilted 90 degrees to the ecliptic of the orbits of those brown dwarfs.

The graphic to the right illustrates the theorized system, with the orbits of the brown dwarfs indicated in blue and the exoplanet’s orbit in orange. While sixteen exoplanets have been found orbiting outside a binary pair of stars, this is the first doing so at such an inclination.

The detection has great uncertainty however.

The candidate planet cannot be detected the way most exoplanets – planets around other stars – are found today: the “transit” method, a kind of mini-eclipse, a tiny dip in starlight when the planet crosses the face of its star.

Instead they used the next most prolific method, “radial velocity” measurements. Orbiting planets cause their stars to rock back and forth ever so slightly, as the planets’ gravity pulls the stars one way and another; that pull causes subtle, but measurable, shifts in the star’s light spectrum. Add one more twist to the detection in this case: the push-me-pull-you effect of the planet on the two brown dwarfs’ orbit around each other. The path of the brown dwarf pair’s 21-day mutual orbit is being subtly altered in a way that can only be explained, the study’s authors conclude, by a polar-orbiting planet.

The radial velocity method however requires the scientists to make a number of assumptions, and provides limited information that can result in a misinterpretation of the data. It is for this reason this exoplanet is described as a “candidate planet.” Its theorized existence must be confirmed by other measurements before it is considered real.

I think this was posted as a quick link back in early May, when the scientists first announced their work, but can’t find it now.

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China reports discovery of new microbe on its Tiangong-3 space station

8:52 am

China’s state-run press yesterday announced the discovery of a new microbe on its Tiangong-3 space station that appears designed to survive in the harsh environment of space.

In May 2023, the Shenzhou-15 crew collected surface microbial samples using sterile wipes, preserving them at low temperatures in orbit. Subsequent ground analysis revealed the novel Niallia tiangongensis species, confirmed through multidisciplinary methods including morphological analysis, genome sequencing, phylogenetic studies and metabolic profiling, the CMSA said.

…Niallia tiangongensis demonstrates exceptional stress resistance, maintaining cellular redox balance and ensuring robust growth in extreme conditions by regulating bacillithiol (BSH) biosynthesis to counteract space-induced oxidative stress, according to the CMSA. It exhibits distinctive capabilities in biofilm formation and radiation damage repair, making it a highly adaptable “all-rounder” for space environments.

More information here. This new microbe has characteristics both different and similar to microbes found on ISS. Its discovery is also not that unique, a it appears such unusual and new biology has been found in other space-related environments, such as the clean rooms on Earth used to build spacecraft. For example, dozens were found in clean room for the Phoenix Mars lander in the early 2000s.

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More missions to Apophis when it flies past Earth in 2029?

11:45 am

Apophis' path past the Earth in 2029
A cartoon (not to scale) showing Apophis’s
path in 2029

There were two stories today that heralded the addition of one real and two potential new spacecraft to rendezvous with the potentially dangerous asteroid Apophis when it flies past the Earth on April 13, 2029.

First, the European Space Agency (ESA) awarded a 1.5 million euro contract to the Spanish company Emxys to build a small cubesat that will fly on ESA’s Ramses mission to Apophis. This is the second cubesat now to fly attached to Ramses, with the first designed to use radar to study Apophis’ interior.

The second CubeSat, led by Emxys, will be deployed from the main spacecraft just a few kilometres from Apophis. It will study the asteroid’s shape and geological properties and will carry out an autonomous approach manoeuvre before attempting to land on the surface. If the landing is successful, it will also measure the asteroid’s seismic activity.

Second, American planetary scientists have been lobbying NASA to repurpose the two small Janus spacecraft for a mission to Apophis. These probes were originally built to go to an asteroid as a secondary payload when the Pysche asteroid mission was launched, but when Pysche was delayed they could no longer go that that asteroid on the new launch date. Since then both Janus spacecraft have been in storage, with no place to go.

The scientists say they could easily be repurposed to go to Apophis, but NASA will have to commit to spending the cost for launch, approximately $100 million. NASA officials were not hostile to this idea, but they were also non-committal. I suspect no decision can be made until the new administrator, Jared Isaacman, is confirmed by the Senate and takes office.

Time however is a factor. The longer it takes to make a decision the fewer options there will be to get it to Apophis on time.

At the moment there is only one spacecraft in space and on its way to Apophis, and that is the repurposed Osiris-Rex mission, now called Osiris-Apex. Japan might also send a craft past Apophis as part of its mission to another asteroid.

Learning as much as we can about Apophis is critical, as there is a chance it will impact the Earth sometime in the next two hundred years.

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New research suggests the two types of streaks on Mars are caused by dry events

9:35 am

A Martian slope streak caused by a dust devil?
A Martian slope streak caused by a dust devil? From
data taken in 2023. Click for original image.

Scientists using a computer machine learning algorithm to assembly and analyze global maps of all known slope streaks and recurring slope lineae (RSL) — the two different types of streaks found on Mars whose cause as yet remain unexplained — have concluded that these streaks are likely caused by dry processes, not wet brine seeping from underground.

Slope streaks can occur randomly throughout the year, can be bright or dark, can occur anywhere, and fade with time. Recurring slope lineae instead appear seasonally in the same locations and are always dark.

You can read the published paper here. It essentially provides further details on research that was first announced at a conference in March. From its conclusion:

[O]ur observations suggest that slope streak and RSL formation may be predominantly controlled by two independent, dry drivers, 1) the seasonal delivery of dust onto topographic inclines, and 2) the spontaneous activation of accumulated dust by energetic triggers – wind and impacts for slope streaks, as well as dust devils and rockfalls for RSL.

…Our results underline the fundamental differences between slope streaks and RSL, despite their visual resemblance. Streak and RSL populations occur on opposite hemispheres (north vs south), at different topographic elevations (mostly lowlands vs mostly highlands), in opposite thermal inertia terrain (low vs high), in different wind speed regimes (above-average vs below-average), in dissimilar diurnal thermal amplitude and heat flux terrain (above-average vs average), in different WEH, H2O, H, and water vapor column terrain (average vs below-average), and in terrain that provides suitable (theoretical) conditions for liquid water at different seasons (Ls ~90° vs Ls ~ 270°).

This data suggests both types of streaks form in connection with very fine Martian dust, but the researchers also admit that the actual method in which these avalanche-type streaks form remains unclear. In both cases the streaks cause no change in the topography (sometimes even traveling uphill for short distances), produce no debris piles at their base, as avalanches typically do, and do not appear to have an obvious cause or source at the top of the streak.

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Astronomers detect evidence of numerous protoplanetary disks in three molecular clouds near the galactic center

11:58 am

Using the ground-based ALMA telescope in Chile, astronomers have detected evidence of the existence of numerous protoplanetary disks in three molecular clouds near the galactic center.

The findings suggest that over three hundred such systems may already be forming within just these three CMZ clouds [Central Molecular Zone]. “It is exciting that we are detecting possible candidates for protoplanetary disks in the Galactic Centre. The conditions there are very different from our neighbourhood, and this may give us a chance to study planet formation in this extreme environment,” said Professor Peter Schilke at the University of Cologne.

You can read the paper here.

These results once again suggest that the formation of stars, solar systems, and planets is more ubiquitous than ever expected, that they can all form in very extreme and hostile environments, of which the center of the Milky Way is one of the most hostile.

And if planets can form here, they can likely form everywhere else. This increases the likelihood of many planets throughout the galaxy capable of supporting the development of life.

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Curiosity looks uphill at boxwork and future travels

11:06 am

Curiosity's view uphill
Click for original image.

Overview map
Click for interactive map.

Cool image time! The panorama above, taken on May 14, 2025 by the left navigation camera on the Mars rover Curiosity, takes a look uphill at the canyon that the rover is now entering.

The overview map to the right gives the context. The blue dot marks the rover’s location when the picture was taken, and the yellow lines indicate approximately the view of the panorama above. If you look closely at the ground at the base of the cliff on the right, you can see the boxwork ridges indicated on the overview map.

The red dotted line marks the original planned route of the rover. The science team abandoned that plan several months ago in order to get to the boxwork geology as quickly as possible. It expects to reach that boxwork sometime in the next month or so.

Based on the proposed route posted in September 2023, after the scientists have completed their observations of the boxwork the rover will continue uphill within this canyon, bearing east as it parallels that 100-foot-high cliff seen on the horizon. The green dotted line indicates roughly that future route.

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NASA: Perseverance observed the first visible-light aurora in March 2024

10:15 am

According to a NASA/JPL press release today, Perseverance successfully observed the first visible-light aurora on another world when in March 2024 it photographed a faint aurora overhead, caused by a strong solar flare.

The images at the link are quite unexciting, so much so that I don’t see a reason to include it here. The aurora observed is barely noticeable. Moreover, this is not really a new discovery. Previous observations in the ultraviolet had determined that Mars does have a weak aurora. That in rare circumstances a strong solar event can have it also appear in visible wavelengths is hardly news.

Normally I would have considered this story unimportant enough to list merely as a quick link at the end of the day, but I post it now because of how the mainstream propaganda press has latched onto it as if it is a big deal. The New York Times, the Washington Post, and the Associated Press all posted stories, giving it far more play than it deserves.

My impression from all these articles is that their reporters know almost nothing about Mars and the research that is going on there, and were easily bamboozled by the press people at NASA and JPL to report this relatively minor story loudly. They no longer have anyone who covers science and space on a regular basis and thus understand the larger context, so therefore their coverage is often shaped entirely by the public relations departments at NASA.

More proof that in today’s internet world, if you want good information the last place you should go is the old dinosaur press.

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Engineers reactivate thrusters on Voyager-1 that have been out of commission since 2004

11:58 am

The Voyager missions
The routes the Voyager spacecraft have
taken since launch. Not to scale.

Because of an anticipated pause in communications due to upgrade work on the antennas of NASA’s Deep Space Network — used to communicate with interplanetary missions — the engineers operating the two Voyager spacecraft that are now in interstellar space after almost a half century of travel have improvised a repair that reactivated thrusters on Voyager-1 that were deemed inoperable in 2004.

Since then the spacecraft had been dependent solely on its backup thrusters. The engineers wanted the spacecraft to have two sets of thrusters again in case something went wrong during that pause in communications, running from May 2025 to February 2026.

The repair required getting two heaters switched back on, and carried with it the risk of an explosion that would destroy Voyager-1. The command to reactivate the heaters was sent on March 20, 2025, and two days later (after the command traveled at the speed of light for 23 hours to reach Voyager-1 and then 23 hours to return) the spacecraft signaled that all was well and that the heaters and thrusters were now working again.

Both Voyagers are expected to run out of power sometime in the next two years. The goal now is try to make both last at least until 2027, so that they will mark a full half century of operation since their launch in 1977.

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Astronomers observe cloud changes above the northern polar lakes of Titan

10:15 am

Changes seen in Titan's atmosphere
Click for full resolution image.

Using data from both ground- and space-based telescopes, astronomers have now observed clouds rising in the thick atmosphere of the Saturn moon Titan.

The team observed Titan in November 2022 and July 2023 using both Keck Observatory and the James Webb Space Telescope. Those observations not only showed clouds in the mid and high northern latitudes on Titan — the hemisphere where it is currently summer — but also showed those clouds apparently rising to higher altitudes over time. While previous studies have observed cloud convection at southern latitudes, this is the first time evidence for such convection has been seen in the north. This is significant because most of Titan’s lakes and seas are located in its northern hemisphere and evaporation from lakes is a major potential methane source. Their total area is similar to that of the Great Lakes in North America.

The image to the right shows these methane clouds, indicated by the arrows, as seen by Webb on July 11, 2023 and then three days later by Keck. The clouds appear to have shifted downward during these observations.

The data suggests we are seeing one small aspect of Titan’s atmospheric methane cycle, where the liquid methane in the lakes evaporates to form clouds, which later than condense to rain back down. Though superficially similar to the water cycle here on Earth, the details suggest it will be very different on Titan.

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The global distribution of dust devils on Mars

4:13 pm

Global map of dust devils on Mars
Click for original image.

Scientists reviewing the dust devil tracks in orbital images produced by Mars Reconnaissance Orbiter (MRO) have now created a global map that also provides insight into the ground conditions that cause the dust devils to form. From the abstract:

In the first global study of these tracks using high-resolution satellite images from 2014 to 2018, we find tracks in 4% of the images, mostly near 60° north and south latitudes. These tracks are more common during local summers, especially in the southern hemisphere, coinciding with the peak of Mars’ dust storm season, when active dust devils are also more common. Surprisingly, dust devil track (DDT) formation does not depend on elevation, indicating it is not related to the ambient atmospheric pressure. Instead, they occur in darker areas where surface dust covers coarser material, which is revealed as the dust devil moves past.

The white dots on the map above, figure 5 of the paper, shows those MRO images where dust devil tracks were seen. The redish-orange regions are where the data suggests more dust devils should occur, while the blue areas of regions of few dust devils.

The map also notes the locations where Spirit, Opportunity, and InSight landed. Opportunity clearly landed in a region that had more dust devil activity, which explains why its solar panels were cleaned off so regularly by wind. Spirit did not land in such a region, but somehow it was lucky in getting wind events that cleared its panels of dust. InSight had no such luck, and having landed in a region with little dust devil activity, its panels steadily became covered with dust, eventually forcing the end of the mission.

As the paper notes, “To maximize mission lifetimes, future solar powered assets should favor regions where we have identified numerous [dust devil tracks] and where many active [dust devils] are present.” This proposal makes sense, for many reasons. For one, it shifts missions to higher latitudes where many glacial and near-surface ice features are found. Up until now the science community has sent all the landers and rovers to the Martian dry tropics, which has no such near surface ice. For future colonies it is imperative we begin studying Mars’ wetter regions.

This study provides another practical reason for doing so.

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