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To listen to all of John Batchelor’s podcasts, go here.
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Courtesy of BtB’s stringer Jay. This post is also an open thread. I welcome my readers to post any comments or additional links relating to any space issues, even if unrelated to the links below.
Click for original image.
Cool image time! The picture to the right, rotated, cropped, and reduced to post here, was taken on December 12, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
The science team labels this a “crater interrupted by flow.” And what a flow! This unnamed 1.4-mile wide crater was not only filled and partly buried by the flow, that flow was so strong it cut through the crater’s rim at two points, refusing to let that rim block it in any way.
The flow in this case is lava, coming down from the Tharsis Bulge where four of Mars’ biggest volcanoes arose. And that flow was quite vast, as the nearest of those volcanoes, Arsia Mons, is almost 800 miles away. Because of Mars’ relative light gravity, about 39% that of Earth’s, lava on Mars can flow across large distances in a very short time. It might have only taken a few weeks for that flow to cover that 800 miles.
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A researcher reviewing the text of a 16th century printing of Claudius Ptolemy’s most famous book, The Almagest (in which he outlined his theory that the Earth stood at the center of the universe), was astonished this January to discover previously unidentified notes in the handwriting of Galileo in the book’s margins.
As [historian Ivan Malara flipped through the pages, he spotted something out of place. Someone had transcribed Psalm 145 on an otherwise blank page—in handwriting reminiscent of a very, very famous Tuscan astronomer.
That book, Malara came to realize, had been extensively annotated by none other than Galileo Galilei. Malara’s discovery, described in a paper now under review at the Journal for the History of Astronomy, promises new insights into one of the most famous ideological transitions in the history of science: the moment when Earth was thrust from the center of our universe.
The article at the link tries to makes the absurd and false claim that “many historians’ typical portrayal of Galileo as being motivated by philosophy or even political savvy, not careful math. ‘He has been presented as a big-picture sort of guy—not interested in the nitty-gritty technical details of astronomy,’ says James Evans, a historian of astronomy at the University of Puget Sound.” The article does this to suggest these newly discovered notes will profoundly change that interpretation.
That interpretation is wrong however. Anyone who has read any histories or biographies of Galileo (as I have) knows this portrayal is false. It is very clear from all his work that Galileo was very evidence-based, focused on the data and facts — the nitty-gritty technical details — to determine the larger picture. And these newly discovered notes confirm this:
Galileo’s notes, perhaps written around 1590, or roughly 2 decades before his groundbreaking telescope observations of the Moon and Jupiter, reveal someone who both revered and critically dissected Ptolemy’s work. And they imply, Malara argues, that Galileo ultimately broke with Ptolemy’s cosmos because his mastery of the traditional paradigm’s reasoning convinced him that a heliocentric system would better fulfill Ptolemy’s own mathematical logic.
Fascinating stuff. I can’t wait to read the final paper.
Japanese spaceports indicated by red dots
The Japanese rocket startup Space One has now scheduled the third launch attempt of its Kairos rocket for this coming Sunday, March 1, 2026, lifting off from its private Spaceport Kii launchpad.
Space One said Friday that it would launch the No. 3 unit of its Kairos small rocket carrying artificial satellites on Sunday morning. The Tokyo-based space development startup canceled the initially scheduled launch on Wednesday, citing a forecast for unfavorable weather conditions.
According to Space One, the Kairos No. 3 unit is set to lift off from the company’s Spaceport Kii launch site in the town of Kushimoto, Wakayama Prefecture, between around 11 a.m. and 11:20 a.m. on Sunday. The rocket will carry five satellites, including one developed by the Taiwan Space Agency.
The two previous launch attempts, in March and December 2024, both failed almost immediately after launch.
A success now by this private company is crucial for Japan, as its government-owned H3 and Epsilon rockets are both grounded due to launch failures.
China’s state-run press today outlined a short update on the status of its manned space station program as well as its planned manned lunar landing, still targeting a 2030 launch.
For the space station, these are its upcoming plans:
China is scheduled to launch two crewed missions and one cargo spacecraft mission for its space station operation in 2026, according to the China Manned Space Agency (CMSA). An astronaut from the Hong Kong or Macao special administrative region is expected to carry out a space station flight mission as early as this year, the CMSA noted.
One astronaut from the Shenzhou-23 crew will conduct a year-long in-orbit stay experiment, the CMSA said.
I am willing to bet that China is planning an even longer station mission that will break Valeri Polyakov’s 14.5 month record mission, set in the 1990s on Mir.
As for China’s lunar landing plans, nothing new was announced:
China is targeting a crewed lunar landing by 2030. The development of major flight products, including the Long March-10 carrier rocket, the Mengzhou crewed spacecraft, and the Lanyue lunar lander, is proceeding smoothly. Key tests have been completed, including the zero-height abort test for the Mengzhou spacecraft, the landing and takeoff test for the Lanyue lunar lander, the static fire test and the low-altitude demonstration and validation test for the Long March-10 rocket system, and the maximum dynamic pressure escape test for the Mengzhou spacecraft system.
In 2026, the country will intensify efforts to advance the construction of supporting facilities and equipment for the lunar mission at the Wenchang Spacecraft Launch Site in southern Hainan Province, as well as the development of ground support systems.
China has not yet outlined a program of missions leading up to that lunar landing. Like Apollo and now Artemis, it makes sense to do low orbit rendezvous and docking tests of these various spacecraft before heading to the Moon. It also makes sense to do these same tests first in lunar orbit, before landing. Expect China to announce such a program soon, for launch in the 2027-2029 timeframe.
The program is being changed
During a update press conference today on the status of SLS, NASA administrator Jared Isaacman announced some major changes to the next three Artemis missions.
Isaacman began his remarks by blasting the slow launch cadence of the SLS rocket, noting that all previous NASA launch vehicles averaged about three months between launches, not three years. In order to shorten the SLS cadence to as short as ten months, he has eliminated the upgraded upper stage for SLS, required for the Artemis-3 lunar landing mission. They will standardize the equipment now being used for all further missions. It also suggests the upgraded mobile launcher — needed for that upgraded upper stage — is being canceled, though the officials refused to confirm this. It is far behind schedule and over budget.
Second, Artemis-3 will no longer be a lunar landing. It will instead fly in ’27 as a manned low-Earth-orbit mission to test rendezvous and docking with one or both of the lunar landers being built by SpaceX and Blue Origin. The flight will also test the spacesuits the astronauts will use on the later lunar mission, including possibly a spacewalk.
This change also appears to eliminate the need for Lunar Gateway, though this decision was not stated. Without that upgraded first stage, SLS cannot reach lunar orbit as intended. It appears the plan is to launch crew in Orion and transfer them to the lander in Earth orbit, and transport them to the Moon in those vehicles.
Third, the goal will then be to do two lunar landings in ’28 on Artemis-4 and Artemis-5. It was also clear that this is merely a target, and things could change after the ’27 mission.
These changes all make great sense and face basic reality. It never made sense to attempt the lunar landing after only one manned Artemis mission. The changes also shift focus from SLS and Orion to the rockets and spacecraft being made by the private sector. It attempts to meet Trump’s goal of landing on the Moon by ’28, but also gives the last three budgeted SLS missions a better and more realistic program. Whether SLS as designed can do this remains unclear, but no matter what, this clearly lays the groundwork for that shift from SLS to the private sector.
The officials also made it clear that this plan is still in flux, and will change depending on what happens in the next year or so.
Click for original image.
The European Space Agency’s (ESA) probe Juice, presently on its way to Jupiter, yesterday released its first image of interstellar comet 3I/Atlas from the data it gathered in November 2025 but only now has been able to send back to Earth.
That picture is to the right, cropped and reduced to post here. From the press release:
[T]he science camera on ESA’s Jupiter Icy Moons Explorer (Juice) shows interstellar comet 3I/ATLAS spewing dust and gas. The tiny nucleus of the comet (not visible) is surrounded by a bright halo of gas known as the coma. A long tail stretches away from the comet, and we see hints of rays, jets, streams and filaments. The inset in the image shows the same data, but processed to highlight the coma structure.
As also noted in the release, though this comet is from outside our solar system, “its behaviour is completely in line with that expected from a ‘normal’ comet.”
The picture was taken on November 6, 2025, just seven days after the comet made its closest pass to the Sun. At that time Juice took 120 images, which could not be sent back until now because the Sun was in the way. The science team is presently analyzing that data, and plans a full release of its work next month.
SpaceX early this morning successfully launched another 29 Starlink satellites, its Falcon 9 rocket lifting off from Cape Canaveral Space Force Station in Florida.
The first stage (B1069) completed its 30th flight, landing on a drone ship in the Atlantic. With this flight, B1069 becomes the fourth SpaceX first stage to fly thirty times:
39 Discovery space shuttle
33 Atlantis space shuttle
33 Falcon 9 booster B1067
31 Falcon 9 booster B1063
30 Falcon 9 booster B1071
30 Falcon 9 booster B1069
28 Columbia space shuttle
The 2026 launch race:
25 SpaceX
8 China
2 Rocket Lab
2 Russia
1 ULA
1 Europe (Arianespace)
As it did in both ’24 and ’25, SpaceX in ’26 so far has more launches than the entire rest of the world combined.
Rocket Lab’s suborbital launch from two days ago had been scrubbed due to weather, and is now scheduled for later today, lifting off from Wallops Island in Virginia and carrying an Australian hypersonic test vehicle. This won’t count in the totals above, but I will report the results after launch.
Courtesy of BtB’s stringer Jay. This post is also an open thread. I welcome my readers to post any comments or additional links relating to any space issues, even if unrelated to the links below.
Orion’s damaged heat shield after 2022 flight.
ASAP “Move along! Nothing to see here.”
NASA’s Aerospace Safety Advisory Panel (ASAP) today released its annual report, and once again it demonstrated why I have been calling it corrupt and a waste of money for years.
The report can be read here [pdf], but let me warn you that its findings have nothing to do with ASAP’s original purpose (created after the 1967 Apollo 1 launchpad fire that killed three astronauts), to look at NASA projects to make sure the agency is not ignoring specific safety issues.
Instead, as it has done repeatedly in recent years, the panel focused on management goals and larger strategic issues, and as usual concluded that the best way to do things is to make NASA bigger with more control over the entire space industry.
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The European Space Agency:
home of dead-end projects
The European Space Agency (ESA) today announced that it has successfully completed a static fire test program of a new rocket engine, dubbed Greta, that uses alternative fuels in order to save the environment.
Greta uses hydrogen peroxide and ethanol as propellants, a more sustainable alternative with a lower carbon footprint compared to monomethyl hydrazine propellant used by most traditional rocket engines in this thrust range.
Greta was ignited multiple times from July to November 2025 and showed stable operations, including controlled shutdowns. During the test campaign the engine fired continuously for over 40 seconds at a time. Greta was tested on a new, low-cost and versatile mobile test stand with instruments measuring data such as pressure and temperature, which will be used to further optimise the engine.
The problem is that this engine is not being built for any specific rocket or spacecraft. As the press release notes vaguely, “This type of engine could be used on lunar landers or on kick stages, such as Astris that is being developed for Europe’s Ariane 6 rocket.”
In other words, this is a test program only, and could very well end up on the scrap heap once completed, because it belongs to no private company aimed at making profits.
NASA did these kinds of projects for decades, all for naught. The agency would make a splash with its press release, the propaganda press would extol blindly the wonders that have been achieved, and then the project would complete and get quietly shelved, stored somewhere in the government archives (possibly in the same place they put Indiana Jones’ Ark of the Covenant).
ArianeGroup is building this engine for ESA, so there is a small chance the company might decide to use it in a future rocket or spacecraft, but only if it makes sense financially. And there is no indication that this engine’s development is tied to financial concerns, in the slightest. For example, the program only calls for another round of static fire engine tests — using “parts for the flight-like motor design” — in 2027, more than a year hence. At that pace the engine will be obsolete before tests are completed.
The uncertainty of science: A new analysis of Apollo lunar samples suggests that the Moon’s magnetic field actually shifted back and forth from strong to weak, with it being weak most of the time.
The problem scientists have had since the Apollo missions is that the Apollo samples, which all came from the relatively flat mare regions, tended to exhibit evidence of a strong past magnetic field, even though the Moon’s size and make-up suggested its field should have always been weak. This new research offers a solution:
The research team analysed the chemical makeup of a type of lunar rock – known as the Mare basalts – and found a new correlation between their titanium content and how strongly magnetised they are. Every lunar sample which had recorded a strong magnetic field also contained large amounts of titanium – and the samples containing less than 6 wt.% titanium were all associated with a weak magnetic field.
This suggests that the formation of high-titanium rocks and the generation of a strong lunar magnetic field are linked. The researchers believe that both were caused by melting of titanium-rich material deep inside the Moon, temporarily generating a very strong magnetic field.
Because the Mare basalts were an ideal landing site for the Apollo missions, due to being relatively flat, the astronauts brought back far more of the titanium-rich basalts (containing evidence for a strong magnetic field) than are representative of the lunar surface. As a result, large numbers of these rocks have been analysed by scientists back on Earth, and this was previously interpreted to mean that the lunar magnetic field was strong for long periods of its history.
Instead, the limited number of samples, all from the same regions, biased the conclusions. The scientists predict that future missions to more places on the Moon will confirm their findings.
Last night NASA yesterday successfully completed the roll back of its SLS rocket back to the Vehicle Assembly Building (VAB).
The SLS (Space Launch System) rocket and Orion spacecraft for NASA’s Artemis II mission arrived at the Vehicle Assembly Building from Launch Pad 39B at approximately 8 p.m. EST Feb. 25, at NASA’s Kennedy Space Center in Florida. While in the assembly building, technicians will troubleshoot the helium flow issue to the rocket’s upper stage, replace batteries on the rocket’s upper stage, core stage, and solid rocket boosters as well as service its flight termination system.
NASA officials have not said what will happen next, once that helium flow problem is resolved. I suspect NASA administrator Jared Isaacman will insist on another wet dress rehearsal to not only test the rocket’s troublesome fueling system, but to also test the helium system used to drain the tanks afterward.
If so, it is very unlikely a launch can occur prior to April 6th, when the present launch window closes. The odds of there being no issues on the next dress rehearsal are slim, based on SLS’s past record, and even if all goes well, the time margins are very very tight, allowing for no delays of any kind.
Space Force officials yesterday made it official, that it has suspended all further military launches using ULA’s Vulcan rocket, due to the nozzle failure in one of the rocket’s solid-fueled strap-on boosters during the last launch on February 12, 2026.
The Space Force is pressing pause on all military launches on United Launch Alliance’s Vulcan rocket as officials investigate a recent anomaly they say could take “many months” to resolve.
That means launch plans for a GPS III satellite slated to fly on the brand new rocket next month are in flux, according to Col. Eric Zarybinsky, program executive officer for assured access to space. “I’m going to look for every flexibility I have to make sure that I can deliver warfighter capability as quickly as possible,” Zarybinsky told reporters at AFA’s Air Warfare Symposium here. “I’ve got a number of tools in my toolkit to do that, but until this anomaly is all over, we will not be launching National Security Space Launch missions on Vulcan.”
Though the rocket was able to get the payload to its proper orbit, despite the problem, this was the second Vulcan launch where a strap-on booster, built by Northrop Grumman, experienced a nozzle failure. In addition, another nozzle failure had occurred during a static fire test in 2025.
Prior to the February launch the Space Force had already shifted two launches from ULA’s Vulcan to SpaceX’s Falcon 9. At the moment ULA has seven military Vulcan launches scheduled for this year. Expect a considerable number to shift to SpaceX.
Blue Origin’s New Glenn rocket might also become an option, but the company must complete two more launches before the Space Force will certify it for national security launches. Considering that company’s slow pace in doing anything, it does not appear it will be able to take advantage of this situation.
ULA meanwhile had hoped to complete 18 to 22 launches in 2026, the majority using Vulcan. This decision by the Space Force likely means the company won’t complete more than five launches this year, most of which using its soon-to-be-retired Atlas-5 rocket.
Embedded below the fold in two parts.
To listen to all of John Batchelor’s podcasts, go here.
» Read more
An eveing pause: More young talent. This is different in that he improvises his own piano version based on only hearing a portion of the original.
Hat tip Cotour.
Courtesy of BtB’s stringer Jay. This post is also an open thread. I welcome my readers to post any comments or additional links relating to any space issues, even if unrelated to the links below.
Click for full resolution. For original
images go here and here.
Cool image time! In my continuing exploration of the New Horizons’ image archive, I keep finding things that I do not remember ever seeing before. The two New Horizon pictures used to create the panorama to the right (here and here) were taken by the spacecraft only thirteen minutes before its closest approach to Pluto at 7,800 miles on July 14, 2015. It shows the Al-Idrisi mountains — thought to be made up of frozen ice as hard as granite — and the frozen nitrogen sea that pushes against those mountains and squeezes them into their jumbled shape. For scale, the image is estimated to be fifty miles wide.
In December 2015 the science team released a small section of one of two images, focused specifically at that nitrogen sea shoreline, noting:
Great blocks of Pluto’s water-ice crust appear jammed together in the informally named al-Idrisi mountains. Some mountain sides appear coated in dark material, while other sides are bright.
The team however did not release this wider panorama produced by both images, which I think gives a better perspective of what we are looking at.
I posted an even wider shot of this shoreline on January 29, 2026. If you look closely at that picture, you can spot the features to the right, but much smaller seen from a greater distance.
For the larger context, below is a wide shot of Pluto indicating the part of the planet where this image is located.
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NASA’s SLS rocket today began its long slow journey from the launchpad back to Vehicle Assembly Building (VAB) so that engineers can safely troubleshoot the failure of helium to properly flow into the tanks of the rocket’s upper stage following the dress rehearsal countdown last week.
NASA’s SLS (Space Launch System) rocket and Orion spacecraft for the Artemis II mission began rolling off the launch pad at 9:38 a.m. EST, Feb. 25, at NASA’s Kennedy Space Center in Florida.
Rolling from Launch Pad 39B to the Vehicle Assembly Building at NASA Kennedy is expected to take up to 12 hours.
At this time NASA officials have not yet determined whether they will need another wet dress rehearsal countdown. There are concerns however that the movement to and from the VAB might be contributing to the fuel leaks that have plagued previous rehearsals and countdowns, and if so, those concerns almost guarantee the need to do another countdown rehearsal once the helium issue is fixed and the rocket is back on the launchpad.
Officials are also reviewing potential future launch dates both in late April as well as May and June. The present window closes on April 6, though there is one launch opportunity on April 30th. Nothing has been decided as yet.
The beat goes on! Since yesterday SpaceX completed two Starlink launches, placing a total of 54 Starlink satellites in orbit on opposite coasts.
First, the company yesterday afternoon launched 29 Starlink satellites, its Falcon 9 rocket lifting off from Cape Canaveral in Florida. The first stage completed its 10th flight, landing on a drone ship in the Atlantic.
Then early this morning SpaceX placed another 25 Starlink satellites in orbit, its Falcon 9 rocket lifting off from Vandenberg Space Force Base in California. The first stage completed its 11th flight, landing on a drone ship in the Pacific.
The 2026 launch race:
24 SpaceX
8 China
2 Rocket Lab
2 Russia
1 ULA
1 Europe (Arianespace)
As it did in both ’24 and ’25, SpaceX in ’26 so far has more launches than the entire rest of the world combined.
Rocket Lab has a suborbital launch scheduled for later today, lifting off from Wallops Island in Virginia and carrying an Australian hypersonic test vehicle. This won’t count in the totals above, but I will report the results after launch.
Starlab design as of December 2025
The medical company LambdaVision announced yesterday that has booked payload slots and commercial space on Starlab in order to manufacture “protein-based artificial retinas.”
LambdaVision leverages microgravity to improve the layer-by-layer production process of their artificial retina through alternating layers of the protein bacteriorhodopsin and a polymer, supported by a membrane of a synthetic fiber that has long been used by the medical community. Reduced gravity in an LEO environment improves homogeneity, stability, and performance of thin films like the protein-based artificial retina. By using proteins similar to the visual pigment rhodopsin naturally found in our eyes, LambdaVision’s protein-based artificial retina mimics the light-absorbing properties of human photoreceptors replacing the function of these damaged cells in the retinas of blind patients.
Starlab is the giant single module space station being built by a consortium led by Voyager Technologies that will be placed in orbit by a Superheavy/Starship launch.
While NASA allowed this kind of medical research on ISS, it never allowed the companies to manufacture any products on ISS for later sale on Earth. The new private space stations are decidedly opposed to that government restriction, and thus they are attracting customers like LambdaVision because they will allow it to make money on what it produces. The press release notes that while this first project is aimed at producing artificial retinas to restore vision in patients, the technology will be applicable to “sensitive biosensors, optical systems, tissue engineering, and drug delivery applications.”
In my rankings below of the five commercial American space station projects under development, the first three are basically tied, the fourth is simply late to the game, and the last, Blue Origin’s Orbital Reef, is hardly out of the starting gate.
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An evening pause: Hat tip Mike Nelson, who adds, “by a group of kids that make me jealous as I never had ANY musical aptitude whatever.”
Courtesy of BtB’s stringer Jay. This post is also an open thread. I welcome my readers to post any comments or additional links relating to any space issues, even if unrelated to the links below.
Click for original image.
Cool image time! The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on October 28, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
The science team labels this “bands near mesa,” an apt description. What we are looking at is a geological feature unique to Mars, but also unique to only one particular place on Mars, the planet’s death valley, the place in Hellas Basin with the lowest relative elevation of any spot on Mars.
The feature is called taffy terrain. According to a 2014 paper, the scientists posit that this material must be some sort of “a viscous fluid,” naturally flowing downward into “localized depressions.” Those localized depressions however happen to also be at the very basement of Mars.
Note how in some spots the bands appear to have been stripped off, exposing small hollows in which dust has become trapped over time to form ripple dunes.
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The Basilica towering over Barcelona
The exterior of the Basílica de la Sagrada Família in Barcelona, Spain, was finally completed this week, 144 years after construction began on architect Antoni Gaudí’s greatest creation.
Last week saw the upper arm of this roughly 56-ft (17-m) tall cross fitted with the help of a giant crane. That final piece, which is nearly 15 ft (4.5 m) tall, completes the grouping of the six central towers of the church – and brings the basilica’s height to a dizzying 566 ft (172.5 m).
Interestingly, the cross was built in Germany using white enameled ceramic tiles, stone interior and glass that were made in the Spanish region of Catalonia. It was then transported in parts back to Barcelona by ferry and trucks, and finally assembled at the church.
Though more work is required in the interior of the church, for the first time in its history all outside cranes will be removed and it will be visible unobstructed.
More information about Gaudi and this church can be found here. I also posted an evening pause about this monumental work of art in 2023.
Shenzhou-20 after its return to Earth. The damaged
window can be seen on the right. Click for original image.
The Chinese Shenzhou-20 crew this week gave a detailed interview describing their discovery and inspection of the cracks in the window of their Shenzhou-20 capsule.
Chen Dong, commander of the Shenzhou-20 crew, first noticed the damage to the window while conducting final checks on the return capsule. The believed culprit: space debris striking the window. …As mission commander for Shenzhou-20, Chen said he was the one who went for checking out the return craft. During that work, “I spotted something like a triangular on the viewport,” he said. “My first thought was whether a small leaf had somehow stuck to the outside of the window,” said Chen. “But then I quickly realized that couldn’t happen because we were in space. How could there possibly be a fallen leaf there?”
Chen pointed out the window anomaly to his two other colleagues also in ready mode for the return trek to Earth. Wang, who served as the flight engineer on the Shenzhou-20 mission, had previously worked as an aerospace technician involved in the construction of China’s space station before becoming an astronaut. “I wasn’t really nervous, actually. The outermost layer of the viewport is a protective layer, and inside it there are two pressure-bearing layers, and we are safe as long as the cabin pressure doesn’t change,” said Wang.
Using a 40x microscope, they determined that some of the cracks had penetrated through the window’s outermost layer.
As of today however China has yet to release images of the cracks, or if they have, no western media source has found and released them.
Click for original image.
Using the Webb Space Telescope, astronomers on January 19, 2025 were able to observe Uranus for fifteen straight hours, tracking the atmosphere’s temperature and structure more completely than ever before.
You can read the peer-reviewed paper here. The false color image to the right, reduced to post here, is just one slice of that dataset. We are looking down at Uranus’ pole, as the rotational tilt is so severe the planet rotates on its side as it orbits the Sun. The grey circles on the outside are the planet’s faint rings. The orange blobs I think are aurora that rotate around the pole at high latitudes, as shown in this video. The orange represents the upper atmosphere.
Led by Paola Tiranti of Northumbria University in the United Kingdom, the study mapped out the temperature and density of ions in the atmosphere extending up to 5,000 kilometres above Uranus’s cloud tops, a region called the ionosphere where the atmosphere becomes ionised and interacts strongly with the planet’s magnetic field. The measurements show that temperatures peak between 3,000 and 4,000 kilometres, while ion densities reach their maximum around 1,000 kilometres, revealing clear longitudinal variations linked to the complex geometry of the magnetic field.
…Webb’s data confirm that Uranus’s upper atmosphere is still cooling, extending a trend that began in the early 1990s. The team measured an average temperature of around 426 kelvins (about 150 degrees Celsius), lower than values recorded by ground-based telescopes or previous spacecraft.
Two bright auroral bands were detected near Uranus’s magnetic poles, together with a distinct depletion in emission and ion density in part of the region between two bands (a feature likely linked to transitions in magnetic field lines). Similar darkened regions have been seen at Jupiter, where the geometry of the magnetic field there controls how charged particles travel through the upper atmosphere.
There is great uncertainty in these conclusions, mostly because the observations are for such a short time. It is like trying to understand the Earth’s climate after looking at it for only one day.
