Tag: science

Scientists: First data from Europe’s Proba-3 satellites suggest the Sun’s slow solar wind is faster and more chaotic than expected

3:20 pm

Figure 4 showing variable speeds of slow solar wind
Click for original image.

The uncertainty of science: According to the first published paper [pdf] from Europe’s two Proba-3 satellites, scientists have found the slow solar wind that comes from the Sun is sometimes far faster than expected, and is also far more chaotic. From the second link above:

Just like wind on Earth, solar wind can be fast or slow, smooth or gusty. Fast solar wind usually flows in a smooth current from magnetic structures called coronal holes. In contrast, slow solar wind is variable and gusty, making understanding how it works more difficult.

Scientists think that slow solar wind is generated by the Sun’s magnetic field lines changing how they are connected, merging and separating again. This process pushes out blobs of plasma (electrically charged gas) in so-called ‘streamers’: large, bright rays in the corona.

…Previously, scientists found that close to the Sun’s surface, slow solar wind should have speeds around 100 km/s. Instead, Andrei’s team tracked some blobs of plasma moving at 250–500 km/s.

The graph to the right, Figure 4 in the paper, shows Proba-3’s tracking of a variety of these blobs. Not only did some move faster than expected (the arrows above the gray line marking earlier data), their speeds changed with time, with some actually speeding up.

The reason the Sun’s fast wind is relatively stable is that it emanates from magnetic structures dubbed coronal holes because the magnetic field lines there are is somewhat calm and stable. The slow wind meanwhile comes out through much more active and unstable regions of the magnetic field, with its field lines jumping about as well as connecting and unconnecting from the field’s structure in a chaotic manner.

This research suggests that the slow wind is chaotic and thus unpredictable, almost like the weather on Earth.

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Orion’s risky return-to-Earth happens tonight at 8:07 pm (Eastern)

9:47 am

The Earth as seen by the Artemis-2 astronauts, from behind the Moon
The Earth and Moon during the lunar fly-by on April 6, 2026.
Click for original image.

After spending ten days in space, including a swing around the back of the Moon, the four-person Artemis-2 crew is now preparing for its return-to-Earth this evening, splashing down off the Pacific coast near San Diego.

At 10:53 p.m. EDT [last night], the Orion spacecraft ignited its thrusters for 9 seconds, producing an acceleration in velocity of 5.3 feet-per-second and pushing the Artemis II crew toward Earth. The crew is now more than halfway home.

About two hours before the burn, there was an unexpected return link loss of signal during a data rate change affecting the transmission of communications and telemetry from the spacecraft to the ground. Two-way communications were reestablished, and flight controllers resumed preparing for the upcoming burn with the crew shortly after.

…The third return trajectory correction burn is scheduled for April 10 at about 1:53 p.m. ahead of re-entry procedures.

This is I think the second time Orion has had a short loss of communications with ground control. In addition, the crew had to cancel a planned manual piloting demonstration of Orion while it flew past the Moon because of a leak in an internal helium tank, used to maintain pressure in the oxygen tank as the propellant is used. The leak was inside the European-built service module, which will be jettisoned before re-entry and burn up in the atmosphere.

Mission managers say this leak has not impacted any engine burns, but it will require attention before the next flight.

The return to Earth however carries the biggest risk of the entire mission. Orion’s heat shield is questionable. During its first use in the 2022 unmanned Artemis-1 flight around the Moon, it did not behave as expected, with large chunks breaking off instead of thin layers ablating away. Though mission engineers have adjusted the flight path through the atmosphere to mitigate stress, there is great uncertainty about that solution.

I have embedded NASA’s live stream of the return-to-Earth below. It begins at 6:30 pm (Eastern), though the first return event, jettison the service module, doesn’t occur until 7:33 pm (Eastern).
» Read more

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Martian mountains on Mount Sharp

11:45 am

Panorama looking up Mount Sharp
Click for larger full resolution image. For original images go here and here.

Overview map
Click for interactive map.

Cool image time! The panorama above was created using two pictures taken by the high resolution camera on the rover Curiosity on Mars (here and here).

The overview map to the right gives the context. The blue dot marks Curiosity’s position on the day before these pictures were taken, climbing through the foothills on the flanks of Mount Sharp. I do not know if it traveled again before taking these two pictures above. The white dotted line its past travels, while the red dotted line its planned future route. At present Curiosity has climbed about 3,500 feet up the mountain. It is still about 15,000 feet below the peak, which is about 25 miles away and not visible from here.

The yellow lines indicate where I think the panorama is looking, though I admit that I am not sure. The view is distant, since this is high resolution camera. This panorama might actually be looking in a completely different direction, downhill at one of the hills that Curiosity previously drove past. The air is very dusty, which means if the rim of Gale Crater is in the background, 20-30 miles away, we can’t see it.

Regardless, the science team has finally finished its many nine-month-long survey of the boxwork geology, and has sent Curiosity climbing again. I think these pictures are part of their review of the future terrain, as they plan the rover’s route through the lighter-colored sulfate terrain higher on the mountain. If instead they are looking downhill, they were taken both to review previously viewed geology as well as to measure the dustiness of the atmosphere.

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Feathery eroding layers on Mars

11:01 am

Feathery layers on Mars
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and enhanced to post here, was taken on February 23, 2026 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team calls “layers exposed around [a] streamlined feature”.

The elevation difference between the mesa top on the left and the canyon floor on the right is about 1,000 feet. The layers are the terraces stepping downward along that drop.

What makes these layers interesting is how they have been exposed. The material that makes up the layers appears very sandy and delicate, so it breaks away it very small pieces, just like sand on a beach. The result is this feathery look. If you look close you can see that some small craters have been partly obliterated by that erosion, with their existence only marked by their remaining rim, on the high side.
» Read more

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Cracked bedrock on Mars?

2:01 pm

Cracked Martian landscape
Click for full image.

For today’s cool image we return to Mars. The picture to the right, cropped and brightened to post here, was taken on December 3, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The focus of the picture was a strange crater in the floor of Mawrth Vallis, a channel that drains northward from Mars’ cratered southern highlands to its northern lowland plains. You can see the crater in the full image if you click on the picture. It is intriguing because its rim is strangely abrupt and flat on all sides, something that is not seen with impact craters, which have a raised rim of material plowed out by the impact.

In the picture to the right I have however focused on the two small 50-70-foot-high mesas and cracked ground that surrounds them. What struck me was the dry appearance of this landscape. Located at 23 degrees north latitude, it is in the dry tropics of Mars, where little near surface ice is found. The cracks emphasize this conclusion, as they so well resemble the cracks you see in dried mud on Earth.
» Read more

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Avio delays next Vega-C launch due to “technical issue”

8:40 am

The Italian rocket company Avio announced yesterday that is has postponed the May 9, 2026 launch of the European Space Agency’s (ESA) Smile solar wind spacecraft due to “a technical issue” discovered by a subcontractor in a component used by the Vega-C rocket.

The press release provided little information:

The launch of the Smile satellite has been postponed, due to a technical issue occurred on a subsystem component production line after VV29 launcher integration. Additional investigations are needed to exclude any relation between such issue and the VV29 launcher in order to safeguard flightworthiness. The new launch date will be announced following the completion of these activities, as agreed with the supplier.

This launch will be the first entirely managed by Avio since it regained control of its rockets from ESA’s Arianespace division. The rocket itself was grounded for two years in 2023 and 2024 due to nozzle issues. It has since flown four times successfully.

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Voyager-2’s most detailed look at Neptune’s moon Triton

3:10 pm

Triton
Click for original image.

Today we conclude our tour of the Voyager-2 fly-bys of Uranus in 1986 and Neptune in 1989 with what is the most detailed look at the alien surface of Neptune’s moon Triton, taken on August 25, 1989 and shown to the right, cropped, rotated, reduced, and sharpened to post here.

Taken from a distance of only 25,000 miles, the frame is about 140 miles across and shows details as small as [a half mile in width]. Most of the area is covered by a peculiar landscape of roughly circular depressions separated by rugged ridges. This type of terrain, which covers large tracts of Triton’s northern hemisphere, is unlike anything seen elsewhere in the solar system. The depressions are probably not impact craters: They are too similar in size and too regularly spaced. Their origin is still unknown, but may involve local melting and collapse of the icy surface.

A conspicuous set of grooves and ridges cuts across the landscape, indicating fracturing and deformation of Triton’s surface. The rarity of impact craters suggests a young surface by solar system standards, probably less than a few billion years old.

What this photograph as well as the handful of other Voyager-2 images of Triton tell us is that we only have gotten a tiny taste of what’s there, only enough to tell us we don’t understand what we are seeing in the slightest. This is a truly alien world, cold, dark, and composed of materials far different then that found in the inner solar system. Its formation is a mystery, and its subsequent geological history a cypher. Scientists have made some guesses, but to get a real understanding we need to go back, and be there for a long time.

In fact, this is the final conclusion of all of the Voyager-2 images from both Uranus and Neptune. That probe gave humanity its first good close look at these distant worlds, but the look was still a quick and very superficial one. The images and data left us with far more questions than answers.

Unfortunately, there is at present no mission approved and under development to go to either Uranus or Neptune, though several have been proposed. Thus, it will likely be at least two decades before any mission gets there, if that soon.

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Neptune’s rings, as seen by Voyager-2 in 1989

2:05 pm

The rings of Neptune as seen by Voyager-2
Click for original image.

Cool image time! The picture to the right, cropped, reduced slightly, and sharpened to post here, was taken by Voyager-2 on August 26, 1989 shortly after it had completed its close fly-by of Neptune, looking back at the planet from a distance of about 175,000 miles.

The two main rings are clearly visible and appear complete over the region imaged. … Also visible in this image is the inner faint ring at about 25,000 miles from the center of Neptune, and the faint band which extends smoothly from the 33,000 miles ring to roughly halfway between the two bright rings. Both of these newly discovered rings are broad and much fainter than the two narrow rings.

These long exposure images were taken while the rings were back-lighted by the sun at a phase angle of 135 degrees. This viewing geometry enhances the visibility of dust and allows fainter, dusty parts of the ring to be seen. The bright glare in the center is due to over-exposure of the crescent of Neptune. The two gaps in the upper part of the outer ring in the image on the left are due to blemish removal in the computer processing. Numerous bright stars are evident in the background. Both bright rings have material throughout their entire orbit, and are therefore continuous.

While Voyager-2 took other pictures of these rings (here, here, here, here, and here), I think this picture shows the rings best, if not terrible well. Images using the Hubble and Webb space telescopes as well as others have not been better.

The rings were first confirmed to exist in the mid-1980s, shortly before Voyager-2’s fly-by. We now think there are five rings total, all made of dark material, likely a mix of carbon-based molecules, much of it the equivalent of dust and soot.

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The new Rubin telescope discovers over 11,000 new asteroids in first observations

11:07 am

Rubin's first asteroid discoveries
Click for full animation.

The new Rubin Observatory, a ground-based telescope in Chile, has discovered over 11,000 new asteroids in its first preliminary observations, with most in the main asteroid belt but a large number in the Kuiper Belt beyond Neptune and 33 previously unknown near-Earth asteroids.

The graphic to the right, annotated by me to post here, shows all of Rubin’s asteroid detections in light blue.

The submission to MPC [Minor Planet Center] comprises approximately one million observations, taken over the span of a month and a half, of over 11,000 new asteroids and more than 80,000 already known asteroids, including some that had previously been observed but were later “lost” because their orbits were too uncertain to predict their future locations. You can interact with all of Rubin’s asteroid discoveries in the Rubin Orbitviewer, which uses real data to provide an intuitive way to explore the structure of our cosmic backyard in three dimensions and in real time. Also, visit the Rubin Asteroid Discoveries Dashboard to learn about the new objects Rubin has uncovered.

…Among the newly identified objects are 33 previously unknown near-Earth objects (NEOs), which are small asteroids and comets whose closest approach to the Sun is less than 1.3 times the distance between Earth and the Sun. None of the newly discovered NEOs pose a threat to Earth, and the largest is about 500 meters wide.

Astronomers predict that Rubin will eventually find 90,000 new near-Earth objects, with some expected to pose a risk of hitting the Earth. It does this by repeatedly surveying the southern sky with its large mirror, then identifying new objects with its sophisticated software.

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Voyager-2 discovered Neptune to be a planet of quickly changing weather

10:53 am

Neptune's fast changing weather
Click for source.

Cool image time! When Voyager-2 flew past Uranus in 1986, the data showed the gas giant’s weather to be relatively sedate and quiet, with little changing during the fly-by. Scientists expected this: Uranus’s distance from the Sun meant it got little energy to fuel an active climate, with any activity produced by internal heating due to the gravitational pressure of its mass. And Uranus did not produce that much heat internally.

When Voyager-2 passed Neptune three year later, the scientists expected something similar, or even less, due to Neptune’s greater distance from the Sun. Instead, Voyager-2’s data showed Neptune’s weather patterns to be changing constantly and quickly, as illustrated by the three images of the Great Dark Spot to the right, the biggest storm on Neptune at that time and located in the planet’s southern mid-latitudes.

The bright cirrus-like clouds of Neptune change rapidly, often forming and dissipating over periods of several to tens of hours. In this sequence spanning two rotations of Neptune (about 36 hours) Voyager 2 observed cloud evolution in the region around the Great Dark Spot at an effective resolution of about 60 miles per pixel. The surprisingly rapid changes which occur over the 18 hours separating each panel shows that in this region Neptune’s weather is perhaps as dynamic and variable as that of the Earth. However, the scale is immense by our standards — the Earth and the [Great Dark Spot] are of similar size.

In Neptune’s frigid atmosphere, where temperatures are as low as 55 degrees Kelvin (-360 F), the cirrus clouds are composed of frozen methane rather than Earth’s crystals of water ice.

Subsequent observations by the Hubble Space Telescope in 1994 found this Great Dark Spot was gone, replaced by a comparable storm in the northern hemisphere. Further Hubble observations found Neptune’s storms tend to last about two years, fading as they drifted towards the equator. Those observations however also detected storms drifting away from the equator. Other research suggested the storms might be influenced by the Sun’s sunspot cycle.

All of the data post-Voyager-2 remains very coarse and uncertain, as we are looking at Neptune at a great distance. Thus, no theory about what is happening carries much weight, especially because we do not know why Neptune produces so much more internal heat than Uranus, fueling this fast-changing weather. For example, Neptune gets 1/20th of the energy received by Jupiter, yet its atmosphere appears even more active and variable.

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Voyager-2’s view of clouds on top of clouds on Neptune

11:45 am

Neptune's upper clouds
Click for original image.

Time to continue our cool image tour this week of the Voyager-2 archive of Neptune, taken during the spacecraft’s August 25, 1989 close fly-by of the gas giant, zipping only 2,700 miles above the cloud-tops. This remains the only mission to visit Neptune so far.

The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken two hours before Voyager-2’s closest approach. From the caption:

These clouds were observed at a latitude of 29 degrees north near Neptune’s east terminator. The linear cloud forms are stretched approximately along lines of constant latitude and the sun is toward the lower [right]. The bright sides of the clouds which face the sun are brighter than the surrounding cloud deck because they are more directly exposed to the sun. Shadows can be seen on the side opposite the sun.

These shadows are less distinct at short wavelengths (violet filter) and more distinct at long wavelengths (orange filter). This can be understood if the underlying cloud deck on which the shadow is cast is at a relatively great depth, in which case scattering by molecules in the overlying atmosphere will diffuse light into the shadow. Because molecules scatter blue light much more efficiently than red light, the shadows will be darkest at the longest (reddest) wavelengths, and will appear blue under white light illumination.

The resolution of this image is 6.8 miles per pixel and the range is only 98,000 miles. The width of the cloud streaks range from 30 to 125 miles, and their shadow widths range from 18 to 30 miles. Cloud heights appear to be of the order of 31 miles.

Of all the high resolution images taken of Neptune by Voyager-2, this is the only one that clearly shows some dimensionality. Later photographs taken by Hubble and other ground- and space-based telescopes can only show global views that are far less sharp than the global views produced by Voyager-2.

This picture hints at Neptune’s very complex weather patterns, which has no well-defined surface and is made up mostly of gas and liquid. Though scientists have used Hubble to roughly track those weather patterns, they can only glean the most basic facts. For example, its fast-changing weather appears to be driven by high winds, thought to move as fast as 1,300 miles per hour. This fact however is woefully incomplete and very uncertain, as we have no way to track detailed weather patterns at multiple depths.

Our tour will continue tomorrow.

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A soft barred galaxy with an active nucleus

9:56 am

A barred galaxy with an active galactic nucleus
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope as part of two different surveys aimed at studying galaxies with what scientists call active galactic nuclei.

IC 486 lies right on the edge of the constellation Gemini (the Twins), around 380 million light-years from Earth. Classified as a barred spiral galaxy, it features a bright central bar-shaped structure from which its spiral arms unfurl, wrapping around the core in a smooth, almost ring-like pattern.

…At the galaxy’s center a noticeable white glow outshines the starlight around it. This is light given off by IC 486’s active galactic nucleus (AGN), powered by a supermassive black hole more than 100 million times the mass of the Sun. Every sufficiently large galaxy hosts a supermassive black hole at its center, but some of these black holes are particularly ravenous, marshaling vast amounts of gas and dust into swirling accretion discs from which they feed. The intense heat generated by the orbiting disc of material generates intense radiation up to and including X-rays, which can outshine the entire rest of the galaxy. In these cases, the galaxy is known as an active galaxy, with an AGN at its center.

For comparison, the relatively inactive supermassive black hole at the center of the Milky Way has a mass of about four million Suns, considerably smaller than IC 486’s. Why one is active and the other not however is not yet truly understood, though their different masses might provide part of the explanation.

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Astronaut Mike Fincke finally reveals details of his medical emergency on ISS

9:33 am

Astronaut Mike Fincke, who had an undisclosed medical issue on ISS in January 2026 that forced the early return of his crew, has finally provided details of what happened.

Four-time space flier Mike Fincke said he was eating dinner on Jan. 7 after prepping for a spacewalk the next day when it happened. He couldn’t talk and remembers no pain, but his anxious crewmates jumped into action after seeing him in distress and requested help from flight surgeons on the ground. “It was completely out of the blue. It was just amazingly quick,” he said in an interview with The Associated Press from Houston’s Johnson Space Center.

Fincke, 59, a retired Air Force colonel, said the episode lasted roughly 20 minutes and he felt fine afterward. He said he still does. He never experienced anything like that before or since. Doctors have ruled out a heart attack and Fincke said he wasn’t choking, but everything else is still on the table and could be related to his 549 days of weightlessness. He was 5 ½ months into his latest space station stay when the problem struck like “a very, very fast lightning bolt.”

Fincke hopes he can fly in space again, but I doubt NASA would agree if the cause of this incident is not identified. His other option then would be to get hired by one of the commercial space station companies to fly to their stations, but even they might be reluctant to hire him.

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Neptune as seen by Voyager-2 in 1989, four days before closest approach

2:46 pm

Neptune as seen by Voyager-2 on approach
Click for original image.

Cool image time! In two earlier posts I highlighted the pictures taken by Voyager-2 of Neptune’s two largest moons, Triton and Proteus, when it made its close fly-by of Neptune in 1989. Other than a very distant low resolution picture of 105-mile-wide Nereid, Voyager-2 took no other good images of Neptune’s other known moons.

So today, let’s begin a tour of some of Voyager-2’s imagery of Neptune itself. The picture to the right, reduced slightly to post here, was taken on August 20, 1989 as the spacecraft was beginning its approach to Neptune. It shows the full daylight hemisphere of the gas giant. From the caption:

The images were taken at a range of 4.4 million miles from the planet, 4 days and 20 hours before closest approach. The picture shows the Great Dark Spot and its companion bright smudge; on the west limb the fast moving bright feature called Scooter and the little dark spot are visible. These clouds were seen to persist for as long as Voyager’s cameras could resolve them. North of these, a bright cloud band similar to the south polar streak may be seen.

Next week I will post some of the other good shots taken of Neptune, as well as one or two close-ups of Triton that need highlighting. Sadly, at that point we will have more or less reviewed most of the best data now available of this distant world. Astronomers have used the Hubble Space Telescope in subsequent years to attempt to track its weather patterns, but even Hubble really can’t provide enough resolution to really make that research substantive.

But stay tuned. The Voyager-2 images to come are worth viewing.

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Proteus, Neptune’s second largest moon, discovered by Voyager-2 in 1989

3:02 pm

Proteus, Neptune's second largest moon
For original images go here and here.

Our tour continues of the only close visit to Neptune on August 25, 1989 by Voyager-2. The two pictures to the right were taken by the spacecraft during that fly-by of Neptune’s second largest moon, dubbed Proteus. Both pictures are shown as Voyager-2 took them.

The top picture was taken from a distance of about 540,000 miles, and has a resolution of about five miles per pixel.

The satellite has an average radius of about 120 miles and is uniformly dark with an albedo of about 6 percent. The irregular shape suggests that 1989N1 has been cold and rigid throughout its history and subject to significant impact cratering.

The bottom picture was taken from a distance of about 91,000 miles, and can resolve objects as small as 1.7 miles in size.

Hints of crater-like forms and groove-like lineations can be discerned. The apparent graininess of the image is caused by the short exposure necessary to avoid significant smear.

Proteus was not known prior to Voyager-2’s fly-by, because it orbits so close to Neptune (about 73,000 miles) that the ground-based telescopes of the time could not see it in the glare of the gas giant. It was discovered in early global pictures of Neptune as Voyager-2 approached.

While planetary scientists have made some educated guesses about the moon’s origin and geology based on these two images, they are simply guesses. These are the only detailed images we have of Proteus, and neither is particularly good.

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Astronomers detect the first comet whose nucleus’ reversed its rotation

11:28 am

Astronomers using data collected by the orbiting Gehrels Swift and Hubble space telescopes now think the nucleus of a small comet reversed its rotation sometime in 2017, caused by the force of the material sublimated off its surface.

From the abstract of their paper [pdf]:

The rotations of cometary nuclei are known to change in response to outgassing torques. The nucleus of the Jupiter-family comet 41P/Tuttle–Giacobini–Kresak exhibited particularly dramatic rotational changes when near perihelion in 2017 April. Here, we use archival Hubble Space Telescope observations from 2017 December to study the postperihelion lightcurve of the nucleus and to assess the nucleus size.

From both Hubble photometry and nongravitational acceleration measurements, we find a diminutive nucleus with effective radius 500 ± 100 meters. Systematic optical variations are consistent with a two-peaked (i.e., rotationally symmetric) lightcurve with period 0.60 ± 0.01 days, substantially different from periods measured earlier in 2017. The spin of the nucleus likely reversed between perihelion in 2017 April and December as a result of the outgassing torque.

In plain English: the thrust of the material being thrown from the surface as the comet made its close approach to the Sun was sufficient to slow and then reverse the nucleus’s rotation. This process was helped by the relatively small size of the nucleus compared to the material being sublimated from it.

The data also suggests the nucleus was once much larger, and has been whittled down to its present small size as it made its multiple close fly-bys of the Sun during the past 1,500 years. Rather than break-up, as most comets do at some point as their nucleus gets smaller, this comet’s nucleus simply kept shrinking, to the point that the thrust of that material could change its rotation.

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Webb and Hubble take a look at Saturn

9:37 am

Saturn seen by Webb and Hubble

Astronomers using both the Hubble Space Telescope and the Webb Space Telescope have produced new complementary views of the ringed planet Saturn.

Those photographs are shown above, with Webb’s false-color infrared image to the left and Hubble’s optical image to the right. From the press release:

In the Webb image, a long-lived jet stream known as the “ribbon wave” meanders across the northern mid-latitudes, influenced by otherwise undetectable atmospheric waves. Just below that, a small spot represents a lingering remnant from the “Great Springtime Storm” of 2010 to 2012. Several other storms dotting the southern hemisphere of Saturn are visible in Webb’s image, as well. All these features are shaped by powerful winds and waves beneath the visible cloud deck, making Saturn a natural laboratory for studying fluid dynamics under extreme conditions.

…In Webb’s infrared image, the rings are extremely bright because they are made of highly reflective water ice. In both images, we’re seeing the sunlit face of the rings, a little less so in the Hubble image, hence the shadows visible underneath on the planet.

There are also subtle ring features such as spokes and structure in the B ring (the thick central region of the rings) that appear differently between the two observatories. The F ring, the outermost ring, looks thin and crisp in the Webb image, while it only slightly glows in the Hubble image.

The press release says little about the Hubble image, mostly because it shows little new by itself. It however is part of an on-going decade-long survey using Hubble to track Saturn’s changing weather patterns.

While both images are valuable, they also highlight our present limits in observing Saturn. Views from Earth can only see so much. It is like trying to watch a football game from ten miles away, with binoculars. And sadly, no mission is presently planned to return to Saturn.

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Triton: Neptune’s largest moon

11:19 am

The southern mid-latitudes of Neptune's moon Trident
Click for original image.

Triton

Today’s cool image begins a new tour I plan on doing over the next week or so of the few close-up photographs we have of Neptune and its moons, sent back by Voyager-2 when it did its close fly-by of this distant planet on August 25, 1989. That fly-by was almost 37 years ago, and it remains our only close look. While at the time it shined a quick flashlight of new knowledge on Neptune, its moons, and its ring system, we remain generally in the dark about what’s there, despite some good imagery produced in subsequent years by Hubble and some ground-based telescopes.

The image above, cropped and enhanced to post here, shows a portion of the southern mid-latitudes of Triton, Neptune’s largest moon, as Voyager-2 made its closest pass at a distance of about 25,000 miles. The photo to the right, cropped and reduced, shows a more global view to provide some context, with the box indicating the approximate area covered by the upper image. It was taken when Voyager-2 was on approach, at a distance of about 330,000 miles. The top picture captures several dozen black plumes that appear to vent material from below. From the caption:

The plumes originate at very dark spots generally a few miles in diameter and some are more than 100 miles long. The spots which clearly mark the source of the dark material may be vents where gas has erupted from beneath the surface and carried dark particles into Triton’s nitrogen atmosphere. Southwesterly winds then transported the erupted particles, which formed gradually thinning deposits to the northeast of most vents.

It is possible that the eruptions have been driven by seasonal heating of very shallow subsurface deposits of volatiles, and the winds transporting particles similarly may be seasonal winds. The polar terrain, upon which the dark streaks have been deposited, is a region of bright materials mottled with irregular, somewhat dark patches. The pattern of irregular patches suggests that they may correspond to lag deposits of moderately dark material that cap the bright ice over the polar terrain.

As we only have a few images of this planet, and those provided views of only about 40% of its surface, any theory that tries to explain the weird geology here is certain to be wrong to some degree.

More to come in the next few days. As much as we think we know, these pictures are going instead highlight how sparse that knowledge really is.

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Intuitive Machines wins $180.4 million new NASA lunar lander contract

8:46 am

Intuitive Machines' Nova-D lunar lander
Click for original.

The lunar lander startup Intuitive Machines announced yesterday that it has won its fifth contract from NASA, a $180.4 million deal to place its larger upgraded Nova-D lander near the Moon’s south pole.

The IM-5 mission will target Mons Malapert, a ridge near the Lunar South Pole that offers continuous Earth visibility, stable illumination conditions, and access to permanently shadowed regions. These characteristics make the site a compelling location for future communications, navigation, and surface infrastructure.

The artist’s rendering to the right shows this Nova-D lander. What stands out immediately is its low-slung appearance. Intuitive Machines’ smaller Nova-C lander was tall (see this image), with a high center of gravity. In its only two landing attempts on the Moon it tipped over both times after touchdown. It appears the company has finally recognized the issue and reworked this new lander to make it more stable after touchdown.

This contract award appears to be part of the accelerated program by NASA administrator Jared Isaacman to land 30 unmanned rovers on the moon in three years, beginning in 2027. Mons Malapert is a plateau that Intuitive Machines second lander tipped over on. It is also the landing site for Astrobotics’ Griffin lander, as well as a candidate landing site for the first Artemis manned missions.

Note the small rover on the right in the graphic. While the mission will carry seven NASA science instrument payloads, it will also carry this commercial rover, built by Honeybee Robotics, a subsidiary of Blue Origin. As the company states above, the lander on this mission also has additional available payload capacity for more commercial customers.

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Juno data suggests lightning on Jupiter is a hundred to a million times more powerful than lightning on Earth

11:08 am

The uncertainty of science: Using data from the orbiter Juno as it passed multiple times above a storm on Jupiter, scientists now believe lightning bolts on Jupiter could be a hundred to a million times more powerful than lightning bolts on Earth.

Juno made 12 passes over isolated storms during that period, and was close enough on four of them to measure microwave static from lightning. The flashes averaged three per second during these passes; on one flyover, Juno detected 206 separate pulses of microwave radiation. Of a total of 613 pulses measured, Wong calculated that the power ranged from about that of a lightning bolt on Earth to 100 or more times the power of an Earth bolt. Because he compared Earth lightning emissions at one radio wavelength to Jupiter lightning emissions at a different wavelength, there’s some uncertainty in the comparison, Wong cautioned. Based on one study of lightning radio emissions on Earth, Jupiter’s bolts could have been a million times more powerful than those on Earth.

Lots of uncertainty and assumptions in these conclusions, but they are not only not surprising, they fit earlier data collected before Juno.

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Changes to the Crab Nebula after a quarter century

9:44 am

The Crab Nebula, changes after a quarter century
For original images go here and here.

Using the Hubble Space Telescope, astronomers have obtained a new high resolution image of the Crab Nebula, and by comparing it with earlier Hubble images taken in 1999/2000 have been able to track the continuing expansion and evolution of this supernova remnant over a period now covering almost a quarter century.

The supernova itself became visible on Earth in 1054, though it actually erupted about 6,500 years earlier, as the Crab Nebula is 6,500 light years away. In the 25 years Hubble has been tracking the remnant’s expansion astronomers estimate it is expanding at about 3.4 million miles per hour.

[William Blair of Johns Hopkins University] noted that filaments around the periphery of the nebula appear to have moved more compared to those in the center, and that rather than stretching out over time, they appear to have simply moved outward. This is due to the nature of the Crab as a pulsar wind nebula powered by synchrotron radiation, which is created by the interaction between the pulsar’s magnetic field and the nebula’s material. In other well-known supernova remnants, the expansion is instead driven by shockwaves from the initial explosion, eroding surrounding shells of gas that the dying star previously cast off.

The new, higher-resolution Hubble observations are also providing additional insights into the 3D structure of the Crab Nebula, which can be difficult to determine from a 2D image, Blair said. Shadows of some of the filaments can be seen cast onto the haze of synchrotron radiation in the nebula’s interior. Counterintuitively, some of the brighter filaments in the latest Hubble images show no shadows, indicating they must be located on the far side of the nebula.

A movie showing the changes between these two images can be seen here. It is worth your while to take a look. These optical images will be further enhanced as the Webb Space Telescope gathers infrared data.

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Growing damage to the wheels of the Curiosity Mars rover

9:19 am

Close-up of the wheel in the worst condition
Images cropped and reduced to post here. For the original images go here and here.

Survey of wheels

Every few months or so the Curiosity science team uses one of the rover’s cameras to do a survey of the rover’s wheels to track their condition. Since early in the mission they had found the wheels were not holding up as well as expected as they rolled over the rough terrain in Gale Crater and on Mount Sharp, and so they take great care in how they move the rover as well as review the wheels regularly.

A year ago it had appeared that the damage to one particular wheel had increased, to a point where its outer section might even break off.

Yesterday the science team did another survey, as shown in the picture to the right.

The two photos above (found here and here) focus on one particular wheel of that survey, which I suspect is the same wheel that was the focus of last year’s post. After taking the first image on the left the team moved Curiosity so that the other side of the wheel could be photographed. As you can see, the damage is extensive, so much so that it is possible the wheel could collapse entirely in the not-to-distant future.

It also looks like another wheel is beginning to see similar damage (see here and here), though not yet as extreme.

The good news is that Curiosity has six wheels, and that it can continue to travel even with the loss of one or maybe two wheels. It also appears that future terrain might not be so rocky.

The bad news is that this wheel damage is likely the one problem that will likely end the mission, possibly sooner than anyone would like. And from these photographs, that end might be sooner rather than later.

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Canada cancels small lunar rover that was to fly on Firefly’s Blue Ghost lander in ’29

2:13 pm

Even as Canada has increased its government space spending in Europe and in Canada — mostly it appears to prop up bureaucracies or failing businesses — its space agency has at the same time cancelled its first lunar rover project, scheduled to brought to the south pole of the Moon by a Firefly Blue Ghost lander in 2029.

As part of its 2026-2027 departmental plan, the Canadian Space Agency (CSA) has cancelled its ambitious lunar rover mission. The lunar rover was announced in 2022. It would have been Canada’s first rover, built by Canadensys, and hitching a ride to the moon on a commercial launch vehicle built by a private U.S. company, Firefly Aerospace.

…The principal investigator of the mission, Gordon Osinski, a planetary geologist from Western University, said that he found out about a month ago, and that he was “devastated” by the news.

Note that this rover was hardly “ambitious.” It was a small unmanned rover comparable to similar rovers deployed by India, Japan, and others, mostly aimed at testing the engineering for later larger rovers.

The real issue however is how this decision illustrates Canada’s leftist government misplaced priorities. Increasingly it appears it is canceling actual space research or planetary missions and shifting the money to other uses, either European projects or bureaucracies in Canada or failing Canadian businesses.

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Private mission to Apophis gets another customer, two student-built landers

1:43 pm

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

The orbital tug startup Exlabs has signed up a second payload customer to fly on its private ApophisExL mission to rendezvous with the potentially dangerous asteroid Apophis when it makes its April 13, 2029 close fly-by of the Earth.

ExLabs has announced its partnership with Japan’s Chiba Institute of Technology (ChibaTech) and its Planetary Exploration Research Center (PERC) to send university-led payloads to the surface of asteroid Apophis during its rare near-Earth flyby in 2029. ApophisExL is the world’s first commercial deep-space rideshare and is supported by mission design and operations collaboration with NASA’s Jet Propulsion Laboratory (JPL) operated by Caltech.

Under the leadership of planetary scientist and PERC Director, Dr. Tomoko Arai, ChibaTech students and researchers are developing two landing payloads to be deployed on the asteroid’s surface.

An Australian satellite startup, Fleet Space Technologies, had already signed on to fly a mapping instrument on ApophisExL.

Though the press release at the link calls this private mission “a new model,” using private enterprise rather than relying on the government for doing planetary missions, it actually harks back to the way things were done in the U.S. before World War II, when the private sector did most of this pure research. In fact, as late as the 1960s there was at least one company, American Science and Engineering, doing the first X-ray astronomical observations flying suborbital rockets. It later won contracts from NASA and other agencies to help build several later orbiting X-ray telescopes.

Over time the government space agencies became dominant, so that most of this design work was either done by them or by universities, with private companies relegated to the roles of minor subcontractors.

This new model is simply an extension of the capitalism model that is taking over the entire space industry, shifting power and ownership from big, expensive, and inefficient government programs to small, cheap, and economical private missions. Those space agencies can still do missions, but they do it by buying payload space on these private missions.

Below is a list of the missions going to Apophis in 2029:
» Read more

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Uranus: one glimpse and that was forty years ago

12:27 pm

Uranus as seen by Voyager-2, natural colors on left, false color on right
Uranus as seen by Voyager-2, natural colors on left, false color on right. Click for original.

I close today our week-long tour of Voyager-2’s fly-by of Uranus in January 1986 with three cool images, the two images of the planet itself above and a close-up of its rings. All three illustrate that though Voyager-2 gave us our first very good first close-up view of this distant world, it also gave us only a tiny glimpse, very superficial and lacking in any larger context.

The two images above were taken on January 17, 1986 when Voyager 2 was till 5.7 million miles away, on approach.

The picture at left has been processed to show Uranus as human eyes would see it from the vantage point of the spacecraft. The picture is a composite of images taken through blue, green and orange filters. The darker shadings at the upper right of the disk correspond to the day-night boundary on the planet. Beyond this boundary lies the hidden northern hemisphere of Uranus, which currently remains in total darkness as the planet rotates. The blue-green color results from the absorption of red light by methane gas in Uranus’ deep, cold and remarkably clear atmosphere.

The picture at right uses false color and extreme contrast enhancement to bring out subtle details in the polar region of Uranus. Images obtained through ultraviolet, violet and orange filters were respectively converted to the same blue, green and red colors used to produce the picture at left. The very slight contrasts visible in true color are greatly exaggerated here. In this false-color picture, Uranus reveals a dark polar hood surrounded by a series of progressively lighter concentric bands. One possible explanation is that a brownish haze or smog, concentrated over the pole, is arranged into bands by zonal motions of the upper atmosphere. The bright orange and yellow strip at the lower edge of the planet’s limb is an artifact of the image enhancement. In fact, the limb is dark and uniform in color around the planet.

The third cool image below of Uranus’s rings was taken just after the closest approach, when Voyager-2 was in Uranus’s shadow and looking back at its rings from a distance of 142,000 miles.
» Read more

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SLS/Orion have begun 12-hour trip from VAB to launchpad

8:59 am

Artemis-2 mission flight path
The Artemis-2 flight path. Click for full animation.

NASA engineers today began the long and slow 12-hour trip of the SLS rocket from the Vehicle Assembly Building (VAB) to the launchpad in preparation for a targeted April 1, 2026 launch date of this Artemis-2 mission around the Moon.

NASA’s Artemis II SLS (Space Launch System) rocket and Orion spacecraft slated to send four astronauts around the Moon began rolling to Launch Pad 39B at 12:20 a.m. EDT on Friday, March 20. Rollout operations at the agency’s Kennedy Space Center in Florida were delayed earlier in the day due to high winds in the area.

The trek to the pad is expected to take up to 12 hours, as NASA’s crawler-transporter 2 carefully carries the rocket on top of the mobile launcher approximately 4 miles along the crawlerway.

The launch will send four astronauts on a ten-day mission swinging around the Moon and back to Earth, using a questionable heat shield and a life support system not yet been tested in space. On the first unmanned Artemis-1 mission around the Moon in 2022, the shield experienced far more damage than predicted, with large chunks breaking off. NASA engineers think they understand why this happened, and have decided that they can mitigate the problem by using a less stressful flight path upon return into Earth’s atmosphere.

They don’t really know if this is so, but they hope so. As for the life support system, the plan is to remain in a high Earth orbit for the mission’s first day to test it. If it has problems then, the crew will be able to return to Earth somewhat quickly. If it has problems after heading to the Moon, however, that won’t be possible.

If a private company tried to convince NASA to do this mission with these issues, the agency would say “Hell no!” It is proceeding because, like the Challenger and Columbia failures, it is a NASA-built project and politics and schedule have superseded safety and good engineering procedures

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Engineers regain contact with Proba-3’s Coronagraph probe

8:36 am

The Proba-3 mission
The Proba-3 mission. Click for original.

A month after all contact was lost with the Coronagraph probe of Europe’s two-spacecraft Proba-3 solar observatory, engineers have regained contact with it this week, and have been able to place it in safe mode in preparation for re-establishing science operations.

After more than a month of silence, ESA’s ground station in Villafranca, Spain, received telemetry from the Coronagraph spacecraft. Telemetry is a package of data sent by a spacecraft including information on its temperature, voltages, and health of onboard systems.

The Coronagraph is now in safe mode and stable, and the mission team and operators are running health checks on the spacecraft to understand if any parts of it have been damaged.

The spacecraft’s solar panel is facing the Sun, powering the essential electronics on board, and charging the battery with the remaining power.

Before it can resume observations engineers need to get the spacecraft back up to operating temperature after a month without power.

As shown in the graphic to the right, the Coronograph satellite is the heart of this mission. It records the data, available because the Occulter blocks the Sun from view so that the corona, the Sun’s atmosphere, can be seen. It is almost a miracle that it has survived that month, and can soon resume observations.

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Scientists compile catalog of the 69 known rocky exoplanets in the habitable zone

12:49 pm

Graph of the 45 most habitable known exoplanets
Credit: Gillis Lowry / Pablo Carlos Budassi.
Click for original at full resolution.

Scientists reviewing the more than 6,000 exoplanets so far discovered have now compiled a detailed catalog describing the 69 known rocky exoplanets that are also in the habitable zone.

The graph to the right, cropped and reduced to post here, shows the 45 exoplanets most likely to be habitable, with the amount of energy they get from their star measured relative to that of Earth and the Sun (shown center top). You can read their paper here. From the press release:

The researchers pinpointed 45 rocky worlds that may support life in the habitable zone, and another 24 in a narrower 3D habitable zone that makes a more conservative assumption of how much heat a planet can take before it loses its habitability.

They include some famous exoplanets, including Proxima Centauri b, TRAPPIST-1f and Kepler 186f, as well as others that are not as well known, such as TOI-715 b. The most interesting planets of those listed, according to the authors, are TRAPPIST-1 d, e, f and g, which are 40 light-years from Earth, as well as LHS 1140 b, which is 48 light-years away. Whether these planets could have liquid water depends in part if they can hold an atmosphere.

The worlds that get light from their stars most similar to what modern Earth receives from the Sun are the transiting planets TRAPPIST-1 e, TOI-715 b, Kepler-1652 b, Kepler-442 b, Kepler-1544 b and the planets Proxima Centauri b, GJ 1061 d, GJ 1002 b, and Wolf 1069 b, which make their stars wobble.

The paper includes tables listing the best exoplanets that do transits of their stars, the best with the oldest estimated ages, and the best for testing the limits of the habitable zone itself. As the researchers say in their abstract:

The resulting list of rocky exoplanet targets in the HZ will allow observers to shape and optimize search strategies with space- and ground-based telescopes – such as the James Webb Space Telescope (JWST), Extremely Large Telescope (ELT), Habitable Worlds Observatory (HWO), and Large Interferometer For Exoplanets (LIFE) – and design new observing strategies and instruments to explore these worlds, addressing the question of the limits of exoplanet surface habitability.

In other words, the focus of exoplanet research is now shifting from simply finding these planets to studying them directly, with the potentially habitable worlds listed above the most interesting of all. Astronomers might not find alien life or civilizations on these worlds, but at a minimum they will be doing the first preliminary scouting for humanity’s the first interstellar missions, with the Trappist-1 solar system appearing to head the list.

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Uranus’s moon Oberon, of which we know little

11:38 am

Uranus' five biggest moonsThe historically known moons of Uranus. Click for original NASA press release.

Oberon, as seen by Voyager-2
Click for original image.

Today we finish our week-long tour of the five largest moons of Uranus, all discovered by astronomers before the start of the space age, and imaged successfully if not very completely by Voyager-2 when it did its fly-by of the planet on January 24, 1986. The gallery of these moons above was taken by the spacecraft when it was on approach, still about three million miles from Uranus, and shows them in order from the innermost on the left to the outermost on the right. They are also scaled to show their relative sizes. To see Voyager-2’s close-up images of the four inner moons, posted earlier this week, go here, here, here, and here.

The picture to the right, cropped slightly to post here, is Voyager-2’s only high resolution image of Oberon, the outermost moon of this group. From NASA’s press release:

This Voyager 2 picture of Oberon is the best the spacecraft acquired of Uranus’ outermost moon. The picture was taken shortly after 3:30 a.m. PST on Jan. 24, 1986, from a distance of 410,000 miles. The color was reconstructed from images taken through the narrow-angle camera’s violet, clear and green filters.

The picture shows features as small as 7 miles on the moon’s surface. Clearly visible are several large impact craters in Oberon’s icy surface surrounded by bright rays similar to those seen on Jupiter’s moon Callisto. Quite prominent near the center of Oberon’s disk is a large crater with a bright central peak and a floor partially covered with very dark material. This may be icy, carbon-rich material erupted onto the crater floor sometime after the crater formed. Another striking topographic feature is a large mountain, about 6 km (4 mi) high, peeking out on the lower left limb.

Oberon is about 946 miles in diameter, making it the tenth-largest moon in the solar system. Because of the quickness of Voyager-2’s fly-by, it could get no closer images, and none of the planet’s nightside. Thus, only 40% of the surface has been photographed, and at not very high resolution.

Later spectroscopy from Hubble and other telescopes suggests there is water ice on the surface. Other data suggests Oberon may have a liquid underground ocean, but that conclusion is highly uncertain. Other than these vague facts and the image to the right, we essentially know almost nothing about this moon. Like Titiania, Uranus’s largest moon, Voyager-2’s data merely gave us a tantalizing glimpse, and that glimpse is now forty years old. No other mission has been there since, and none is planned in the near future.

Tomorrow, to summarize this tour, I will outline further what little we know of Uranus and its moons

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Scientists: Shadowcam images suggest there is little water in permanently shadowed lunar craters

8:58 am

Shadowcam-LRO mosaic
The floor of Shackleton Crater showing no obvious ice deposits,
as seen by Shadowcam, imposed on a Lunar Reconnaissance Orbiter
image. The black cross marks the south pole. Click for original image.

In a new paper published yesterday, the science team for the low-light Shadowcam instrument on South Korea’s lunar orbiter Danuri confirmed their earlier conclusion from 2024, that there appears to be far less water ice than expected in the permanently shadowed lunar craters near the Moon’s south pole. From their abstract:

We used the high-reflectance and forward-scattering optical properties to search for water ice in lunar PSRs [permanently shaded regions]. We found no evidence of widespread water ice in PSRs at abundances above the detection limit of 20 to 30 wt % but could not rule out widespread low-content water ice. A few small locations with both high reflectance and forward-scattering behavior were observed, which could be consistent with >10 wt % ice.

And from their conclusion:

Our manual examination of ShadowCam radiance images that cover all lunar PSRs suggests either that most of the lunar PSRs lack surface ice exposures or that their ice concentration is below the detection limit, approximately 20 to 30 wt % on the basis of the visible reflectance enhancement, which aligns well with previous ShadowCam findings. Only a few candidate high-reflectance anomalies were seen, which, if they are water ice, is consistent with previous sparse detections of lunar surface water ice.

There is still a chance there is water ice in these permanently shadowed craters, but it appears once again that if it exists, it will likely require processing to extract it from the soil, and there won’t be that much available regardless.

These results are not conclusive, but they do suggest that the south pole of the Moon will not be as ideal a location for a lunar base as previously imagined.

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