Tag: exploration

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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Tantalizing Titania, Uranus’s largest moon

11:45 am

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

Titania as seen by Voyager-2
Click for original image.

This week’s tour of the five largest moons of Uranus continues today with a look at the highest resolution picture taken Uranus’s largest moon, Titania, when Voyager-2 did its fly-by of the solar system’s seventh planet on January 24, 1986. The image to the right, cropped and reduced to post here, was taken from about 229,000 miles, and can only resolve objects bigger than eight miles across. From the press release:

Titania is the largest satellite of Uranus, with a diameter of a little more than 1,000 miles. Abundant impact craters of many sizes pockmark the ancient surface. The most prominent features are fault valleys that stretch across Titania. They are up to 1,000 miles long and as much as 45 miles wide. In valleys seen at right-center, the sunward-facing walls are very bright. While this is due partly to the lighting angle, the brightness also indicates the presence of a lighter material, possibly young frost deposits. An impact crater more than 125 miles in diameter distinguishes the very bottom of the disk; the crater is cut by a younger fault valley more than 60 miles wide. An even larger impact crater, perhaps 180 miles across, is visible at top.

Two or three other images were taken by Voyager-2, but they don’t provide any significant additional information. All told the spacecraft was only able to see about 40% of Titania’s surface.

Subsequent research using a variety of orbiting telescopes have suggested there is water ice and carbon dioxide on the surface. This data also hints of the presence of a very very thin atmosphere. These results however are quite uncertain.

As with Uranus’s other moons Miranda, Ariel, and Umbriel that I highlighted earlier this week, the Voyager-2 data merely gives us a taste of what’s there. Forty years later we have learned almost nothing more about these distant worlds.

Tomorrow we look at Oberon. I will then follow-up the next day with a look at what we don’t know about Uranus and its moons.

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Scientists detect the five chemicals that make up DNA/RNA inside Ryugu samples

11:05 am

Ryugu's northern hemisphere
Ryugu as seen by Hayabusa-2 shortly before it grabbed
samples from the surface. Arrow indicates planned touchdown
site.

Scientists studying the samples brought back from the asteroid Ryugu by Japan’s probe Hayabusa-2 have found therein a full set of the five fundamental chemicals that make up either DNA or RNA: adenine, guanine, cytosine, thymine and uracil. From the paper’s [pdf] abstract:

Organic molecules delivered from extraterrestrial materials may have played a key role in supplying building blocks for life on Earth. Here we report all five canonical nucleobases—purines (adenine and guanine) and pyrimidines (cytosine, thymine and uracil)—in samples returned from the C-type asteroid (162173) Ryugu by JAXA’s Hayabusa2 mission and compare the results with data from similar extraterrestrial material.

Ryugu samples contain nearly equal amounts of purines and pyrimidines, whereas Murchison is enriched in purines and Bennu and Orgueil in pyrimidines. Samples from Ryugu, Bennu and Orgueil, which have a similar mineralogy and elemental composition, show purine-to-pyrimidine ratios negatively correlating with ammonia.

These observations indicate that the nucleobases in these samples may have formed via a shared pathway depending on the physicochemical environment of the respective parent bodies. The detection of diverse nucleobases in asteroid and meteorite materials demonstrates their widespread presence throughout the Solar System and reinforces the hypothesis that carbonaceous asteroids contributed to the prebiotic chemical inventory of early Earth.

In other words, the data from these samples suggests that the formation of life on Earth was greatly aided by the deposition of these carbon molecules from asteroids onto the Earth.

At the same time, some caution must be exercised. At present we only have samples from three asteroids, one of which (Orgueil) was obtained shortly after it crashed on Earth. It will take a much larger census of many in-space asteroids to confirm this hypothesis.

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Voyager-2’s only close-up image of Uranus’s moon Umbriel

12:38 pm

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

Umbriel as seen by Voyager-2
Click for source.

Today’s cool image continues our tour of the five largest moons of Uranus, as seen by Voyager-2 in 1986 during its close-up visit. The family portrait above, taken from more than three million miles away during Voyager-2’s approach, shows the relative sizes of those five moons as well as their location relative to Uranus, with Miranda in the closest orbit and Oberon the farthest. I have already posted close-ups from Miranda and Ariel. Today’s image moves us outward to Umbriel.

The image to the right is Voyager-2’s best picture. In fact, it is really Voyager-2’s only close-up image, and as you can see, it is not that close or sharp. I have not reduced it at all. This is how NASA released it. From the NASA press release:

The southern hemisphere of Umbriel displays heavy cratering in this Voyager 2 image, taken Jan. 24, 1986, from a distance of 346,000 miles. This frame, taken through the clear-filter of Voyager’s narrow-angle camera, is the most detailed image of Umbriel, with a resolution of about 6 miles.

Umbriel is the darkest of Uranus’ larger moons and the one that appears to have experienced the lowest level of geological activity. It has a diameter of about 750 miles and reflects only 16 percent of the light striking its surface; in the latter respect, Umbriel is similar to lunar highland areas. Umbriel is heavily cratered but lacks the numerous bright-ray craters seen on the other large Uranian satellites; this results in a relatively uniform surface albedo (reflectivity). The prominent crater on the terminator (upper right) is about 70 miles across and has a bright central peak.

The strangest feature in this image (at top) is a curious bright ring, the most reflective area seen on Umbriel. The ring is about 90 miles in diameter and lies near the satellite’s equator. The nature of the ring is not known, although it might be a frost deposit, perhaps associated with an impact crater. Spots against the black background are due to ‘noise’ in the data.

This lone picture of Umbriel by Voyager-2 illustrates even more starkly the very sparse data we have of Uranus and its moons. Voyager-2 is the only spacecraft to ever visit this planet, and it only did a quick fly-by, just long enough to give us this one dim snapshot view. It is forty years later, and no other missions have flown there, nor is any planned in the near future. There are proposals, but none are yet approved.

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Modeling says the Small Magellanic Cloud passed through the Large Magellanic Cloud 200 million years ago

11:18 am

Illustration of collision of Magellanic clouds
Click for original graphic.

According to new computer modeling, some astronomers now believe that a collision between the Small Magellanic Cloud (SMC) and the Large Magellanic Cloud (LMC) 200 million years ago best explains the chaotic movement of the stars in the former.

The SMC contains more mass in gas than in stars. Gas cools, contracts under gravity and settles into a rotating disk, the same process that shaped the spinning plane of our solar system. But when researchers, including those at University of Arizona, previously measured the motion of the SMC’s stars using the Hubble Space Telescope and the Gaia satellite of the European Space Agency, the SMC’s stars were not orbiting around the galaxy’s center the way stars in most galaxies do.

The possible reason, Rathore said, is a collision. A few hundred million years ago, the SMC crashed directly through the LMC’s disk. The LMC’s gravity disrupted the SMC’s internal structure and sent its stars into random, disordered motion. Also, the LMC’s gas applied a tremendous amount of pressure to the SMC’s gas and destroyed its gas rotation.

The graphic to the right illustrates that collision, based on the computer modeling. It appears the Small Magellanic Cloud’s passage through the Large Magellanic Cloud acted to shake the smaller cloud apart, spreading its stars and gas across a wider space.

You can read the paper here [pdf]. There is of course a great deal of uncertainty in these results, but they add weight to the general theory that galaxy formation is strongly impacted by such collisions. As the scientists note in the conclusion of their paper, “The SMC gives a front row view of group processes driving dramatic morphological and kinematic transformations.”

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The first Artemis lunar landings might not go to the Moon’s south pole

10:09 am

It appears from remarks recently by one NASA official, that while the south pole remains the agency’s main lunar base target, it is now looking into other landing options in order to make those first manned landing less risky and easier and quicker to achieve.

Amit Kshatriya, NASA Associate Administrator was very vague in his statement, but nonetheless this was what it appears he was saying:

We have opened up the, I would say, the performance specification for the early landing missions in as many ways as we can, in terms of different lunar orbits we want to take, or different other constraints … to make it as agile as possible, to recognize performance limitations in some of the machines we have and let our providers tell us, hey, if you took these constraints out of the way, how could we go faster? So we’re going to do that.

The agency’s administrator, Jared Isaacman, is also pushing to quickly begin sending a lot of unmanned landers to the south pole by next year. Thus, under this plan, we might actually find out first whether there really is water in those permanently shadowed craters, before committing our manned lunar base to this location.

This new approach makes a great deal of sense, especially since the data that has looked into those craters has been very inconclusive, some positive and some negative.

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Continuing our tour of Uranus’ five biggest moons: Ariel

12:17 pm

In preparing my cool image last week focused on the best Voyager-2 image of Uranus’ moon Miranda, I came to a realization that was somewhat startling. Voyager-2 is the only time a human spacecraft has gotten close to Uranus, and it was only close for a few days. Thus, the data and images it obtained of the gas giant and its moons is remarkable more sparse than I had ever realized.

You see, when these images were first released in 1986 they were exciting because they gave us that first look. Suddenly, a light was shined on something that had always been shrouded in darkness. It was a flood of data that needed processing.

It is now forty years later. No spacecraft has been there since, and thus we have gotten no more close-up information about Uranus or its moons. Data from Hubble and Webb has helped increase our knowledge of the planet itself, but of the moons nothing really new has been gleaned from this distance.

Uranus' five biggest moons

And so, to highlight how little we know, for the rest of this week I am going give my readers a tour of the few images Voyager-2 gave us of Uranus’ five biggest moons, the five that early astronomers had discovered prior to the space age and shown in the five pictures above, taken by Voyager-2 as it was approaching Uranus from a distance of about three million miles. They are, in order going from closest to farthest from Uranus, Miranda, Ariel, Umbriel, Titania and Oberon, with the images above designed to show their approximate relative sizes.

I already highlighted the strange, patchwork surface of Miranda last week, the smallest of these moons. Below is a mosaic made from the four highest resolution images of 720-mile-wide Ariel, the next out from Uranus, taken from a distance of about 80,000 miles.
» Read more

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Astronomers discover a super-Earth-sized exoplanet covered by a molten ocean of lava

9:53 am

Using the Webb Space Telescope astronomers think they have identified a super-Earth-sized exoplanet, dubbed L98-59d and orbiting a red dwarf star about 35 light years away, that is covered by a very deep molten ocean of lava.

Their results reveal that the mantle of L98-59d is likely molten silicate (similar to lava on Earth), with a global magma ocean extending thousands of kilometres beneath. This vast molten reservoir allows the planet to store extremely large amounts of sulphur deep inside its interior, over geologic timescales. The magma ocean also helps L98-59d to retain a thick hydrogen-rich atmosphere containing sulphur-bearing gases such as hydrogen sulphide (H2S). Normally, this would be lost to space over time, due to X-ray radiation produced by the host star.

You can read the peer-reviewed paper here [pdf]. This planet is part of a three-planet solar system, all of which transit the face of the star, allowing for excellent observations of their make-up. L98-59d is the outermost of the three.

This is the first molten exoplanet yet detected, though it is likely not the last. As new better telescopes come on-line both on Earth and especially in space, the ability to make more detailed observations of the thousands of exoplanets so far identified is certain to reveal many more strange objects, some of which will be probably far stranger than we can yet imagine.

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Terran Orbital wins contract to build cubesat to go to Apophis with ESA’s Ramses probe

9:08 am

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

The satellite company Terran Orbital, owned by Lockheed Martin, has won a contract from the European Space Agency (ESA) to build a cubesat to fly with its Ramses probe that will launch in 2028 and rendezvous with the potentially dangerous asteroid Apophis when it makes its very close fly-by of the Earth on April 13, 2029.

The CubeSat is named after Italian scientist Paolo Farinella and is backed by the Italian Space Agency. After successfully completing the Critical Design Review in January 2026, Tyvak International [a subsidiary of Terran Orbital] will begin the implementation phase, with launch currently planned for 2028.

…Operating aboard the RAMSES spacecraft, developed by OHB Italia, the Farinella CubeSat will be one of two spacecraft deployed to explore the asteroid’s subsurface using low-frequency radar. The satellite will also carry Horus, an optical instrument that acts as both a science imager and navigation camera, and Vista, a dust detector previously flown on the Milani CubeSat from ESA’s Hera mission.

Apophis is estimated to be about 1,200 feet across. When it does its fly-by in ’29 it will get within 20,000 miles of the Earth, dipping within the orbits used by geosynchronous satellites. It will then pass within 60,000 miles of the Moon. At its closest it will for a short time be visible to the naked eye.

Apophis’ orbit means that it has the potential in the next century or so to impact the Earth. This particular fly-by is significant because the Earth/Moon’s gravity will change the asteroid’s path in an unpredictable manner that could either increase or decrease that impact possibility on future fly-bys. And we won’t know until after the fly-by is complete.

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Miranda, the smallest of Uranus’ spherical moons

12:52 pm

Miranda as seen by Voyager-2
Click for original image.

Cool image time! The image to the right, reduced and sharpened to post here, was created from photographs taken on January 24, 1986 by Voyager-2 as it made its fly-by of the gas giant Uranus. From a later 1996 release:

Miranda, roughly 300 miles in diameter, exhibits varied geologic provinces, seen in this mosaic of clear-filter, narrow-angle images from Jan. 24, 1986. The images were obtained from distances of 18,730 to 25,030 miles; resolution ranges from 1,840 to 2,430 feet. These are among the highest-resolution pictures that Voyager has obtained of any of the new “worlds” it has encountered during its mission.

On Miranda, ridges and valleys of one province are cut off against the boundary of the next province. Probable compressional (pushed-together) folded ridges are seen in curvilinear patterns, as are many extensional (pulled-apart) faults. Some of these show very large scarps, or cliffs, ranging from 1,600 feet to 3 miles in height — that is, higher that the walls of the Grand Canyon on Earth.

This is really the only close look we have of this distant world. The other hemisphere remains a mystery, as it was in darkness when Voyager-2 zipped past. And though some of the individual shots that make up this mosiac are more detailed, they don’t provide that much more information.

Nonetheless, to my uneducated eye Miranda looks like a ball of thick molasses that some giant stirred a bit as gravity forced it to settle into its spherical shape. In this case the molasses is likely a mix of ice and other materials, not yet fully identified. The result is a tiny misshapen planet with some of the roughest topography known in the solar system, including one 12-mile high cliff face (the white streak at the image bottom) thought to be the highest in the solar system.

We don’t yet have a true understanding of the geological processes that formed this strange landscape, nor will we have until we have a lot more data, including a global map of the entire surface. And that won’t come until a spacecraft is sent there to look more closely. Right now no such mission is in the works. No NASA missions have been funded, though several have been proposed. And a Chinese mission was apparently canceled last year.

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China to begin construction of its Mars sample return spacecraft

8:13 am

China’s state-run press today announced it is about to begin construction of its Mars sample return spacecraft, Tianwen-3, set for launch in 2028.

Based on the announcement, that date seems very unlikely.

China’s mission to retrieve samples from Mars will advance to the flight model development phase within this year, Liu Jizhong, chief designer of the Tianwen-3 mission, said on Thursday. Building on the preliminary technical research and demonstrations, the mission has achieved breakthroughs in key technologies. The engineering team is now focused on developing prototypes, Liu, also a national legislator, told reporters.

The Mars sample return mission is scheduled for launch around 2028, with the goal of returning no less than 500 grams of Martian samples to Earth by around 2031. [emphasis mine]

They only have two years to get the spacecraft built, and it involves “an orbiter, a returner, a lander, an ascender, and a service module.” While China is basing this mission’s design on its successful Chang’e lunar sample return missions, returning samples from Mars is significantly more challenging. The ascent vehicle will have a much greater gravity to overcome, and doing a robotic rendezvous and docking in orbit around another planet millions of miles from Earth has never even been tried.

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Cubesat ultraviolet space telescope achieves first light

5:05 pm

Sparcs first light images
Click for original images.

A new low-cost cubesat-sized NASA ultraviolet space telescope, dubbed Sparcs, has achieved first light, successfully taking both near- and far-ultraviolet false-color images of a nearby star.

Those images are to the right, with the top the far-ultraviolet image and the bottom in the near ultraviolet. From the press release:

Roughly the size of a large cereal box, SPARCS will monitor flares and sunspot activity on low-mass stars — objects only 30% to 70% the mass of the Sun. These stars are among the most common in the Milky Way and host the majority of the galaxy’s roughly 50 billion habitable-zone terrestrial planets, which are rocky worlds close enough to their stars for temperatures that could allow liquid water and potentially support life.

The question astronomers will try to answer with this telescope is whether the solar activity on these stars is high enough to prevent life from forming in the star’s habitable zone. Because these stars are dim and small, the habitable zone is quite close to the star, which means solar activity has a higher impact on the planet. We don’t yet have sufficient data to determine the normal activity of such stars. Sparcs will provide a good first survey.

It will also demonstrate the viability of such small low-cost cubesats for this kind of research. If successful expect more such telescopes, some of which are likely to be private, like Blue Skies Space’s Mauve optical telescope already in orbit.

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A close-up of the dark side of Saturn’s moon Iapetus

11:55 am

Iapetus' equator ridge
Click for original image.

Cassini's first global close-up of Iapetus
Click for original image.

Today’s cool image is a double-header! The picture above, cropped to post here, was taken on September 10, 2007 during Cassini’s fly-by of Saturn’s moon Iapetus, taken from approximately 1,000 miles above the surface. It looks at the dark side of this two-toned planet (see yesterday’s cool image). As the moon’s rotation is tidally locked so that one side always faces Saturn, one hemisphere always leads while the other always trails. For some reason still unexplained, the leading hemisphere is covered with an almost pitch-black material, while the trailing hemisphere is bright and very white, its icy surface quite visible.

For context, to the right is a global image of that dark side taken during Cassini’s first fly-by of Iapetus on December 31, 2004. This picture highlights the long ridge that runs along the planet’s dark hemisphere’s equator that was the focus of the close-up image above. From the 2005 press release:

The most unique, and perhaps most remarkable feature discovered on Iapetus in Cassini images is a topographic ridge that coincides almost exactly with the geographic equator. The ridge is conspicuous in the picture as an approximately 12 miles band that extends from the western (left) side of the disc almost to the day/night boundary on the right. On the left horizon, the peak of the ridge reaches at least 8 miles above the surrounding terrain. Along the roughly 800-mile-length over which it can be traced in this picture, it remains almost exactly parallel to the equator within a couple of degrees. The physical origin of the ridge has yet to be explained. It is not yet clear whether the ridge is a mountain belt that has folded upward, or an extensional crack in the surface through which material from inside Iapetus erupted onto the surface and accumulated locally, forming the ridge.

Iapetus itself has a diameter of about 900 miles, so this ridge essentially crosses most of the dark hemisphere.

The 2007 press release did not provide enough information to pinpoint exactly where along that ridge the close-up is located, but no matter. Both images make very clear what we are looking at.

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Have astronomers spotted the collision of two exoplanets around a Sunlike star?

9:36 am

Changes in the infrared

Using data from a number of orbiting space telescopes, astronomers think they have detected the collision of two exoplanets, producing debris that for about 200 days variably blocked the light from the system’s star.

The images to the right come from figure 1 of their published paper [pdf], showing changes in the infrared as detected by the WISE space telescope. From the press release:

The star, named Gaia20ehk, was about 11,000 light-years from Earth near the constellation Pupis. It was a stable “main sequence” star, much like our sun, which meant that it should emit steady, predictable light. Yet this star began to flicker wildly. “The star’s light output was nice and flat, but starting in 2016 it had these three dips in brightness. And then, right around 2021, it went completely bonkers,” said Tzanidakis, a doctoral candidate in astronomy at the University of Washington. “I can’t emphasize enough that stars like our sun don’t do that. So when we saw this one, we were like ‘Hello, what’s going on here?’”

The cause of the flickering had nothing to do with the star itself: Huge quantities of rocks and dust — seemingly from out of nowhere — were passing in front of the distant star as the material orbited the system, patchily dimming the light that reached Earth. The likely source of all that debris was even more remarkable: a catastrophic collision between two planets.

…“The infrared light curve was the complete opposite of the visible light,” Tzanidakis said. “As the visible light began to flicker and dim, the infrared light spiked. Which could mean that the material blocking the star is hot — so hot that it’s glowing in the infrared.”

A cataclysmic collision between planets would certainly produce enough heat to explain the infrared energy. What’s more, the right kind of collision could also explain those initial dips in light.

The data suggests the collision occurred at an orbit comparable to that of the Earth’s, and took more than a half a year to largely dissipate.

All of this is a reasonable hypothesis based on the data available. Though there is a lot of uncertainty in this conclusion, the researchers considered other explanations, such as variability in the star itself, and found them less credible.

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Iapetus: Saturn’s ying-yang moon

11:55 am

Iapetus as seen by Cassini in 2007
Click for original image.

Cool image time! The image to the right, reduced and sharpened to post here, was taken on September 10, 2007 by the Saturn orbiter Cassini as it made its first close fly-by of the moon Iapetus, from a distance of about 45,000 miles.

Iapetus, about 912 miles in diameter, is one of the strangest objects in the solar system. As it orbits Saturn, its leading hemisphere is very dark, covered with almost pitch black material, while its trailing hemisphere is very bright. This picture captures a bit of both, with the dark leading hemisphere visible along the right edge.

In many places, the dark material–thought to be composed of nitrogen-bearing organic compounds called cyanides, hydrated minerals and other carbonaceous minerals–appears to coat equator-facing slopes and crater floors. The distribution of this material and variations in the color of the bright material across the trailing hemisphere will be crucial clues to understanding the origin of Iapetus’ peculiar bright-dark dual personality.

There are several theories to explain the planet’s strange ying-yang two-tone coloration. One suggests it is material thrown off by other Saturn moons that Iapetus sweeps up. Other theories suggest the planet’s orbit itself causes the two hemispheres to have different temperatures, allowing material to sublimate off the dark side and to the bright side.

No theory is presently accepted. Nor does any explain the data fully.

Tomorrow I’ll post a most intriguing close-up of Iapetus taken by Cassini during that 2007 fly-by.

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Interstellar comet 3I/Atlas is unusually enriched with windshield wiper fluid

10:45 am

New Hubble image of 3I/Atlas
Comet 3I/Atlas as seen by Hubble
in November 2025. Click for original.

While interstellar comet 3I/Atlas is remarkably like most comets from our own solar system, scientists have now found new evidence that it spalled off unusual amounts of methanol (CH3OH) — material normally used as windshield washer fluid, carburetor fluid, and cooking fuel — when it made its close fly-by of the Sun in the fall of 2025.

You can read the paper here [pdf] . The research also detected large amounts of prussic acid (HCN). As the comet made its closest pass to the Sun, the numbers increased. From the paper’s abstract:

The CH3OH production rate increased sharply from August through October, including an uptick near the inner edge of the H2 O sublimation zone at r H = 2 au. Compared to comets measured to date at radio wavelengths, the derived CH3 OH/HCN ratios in 3I/ATLAS of 124+30 −34 and 79−14 +11 on September 12 and 15, respectively, are among the most enriched values measured in any comet, surpassed only by anomalous solar system comet C/2016 R2 (PanSTARRS).

Though the numbers are high, they aren’t outside the range of what has been found in comets from our own solar system. Instead, this data suggests — as has all data so far — that Comet 3I/Atlas is a normal comet, but unique in its own way, as are all comets and in fact every object in space.

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A nearby red dwarf star has a solar system of four planets, one in the habitable zone

9:11 am

According to a new analysis of new data, astronomers now think the nearby red dwarf star GJ 887, only about 11 light years away, not only has a solar system of four planets, one of those planets is is a super-Earth orbiting the star in the habitable zone.

From the abstract:

With the Bayesian analysis, we confirmed a four-planet model, including the two previously known planets at periods of 9.2619 ± 0.0005 d and 21.784 ± 0.004 d, as well as two newly confirmed exoplanets: an Earth-mass planet, with a 4.42490 ± 0.00014 d period and a sub-meter-per-second amplitude, and a super-Earth with a 50.77 ± 0.05 d period located in the habitable zone (HZ). This super-Earth is the second closest planet in the HZ, after Proxima Cen b.

The super-Earth has a mass estimated to be anywhere from two to ten times that of Earth, so if any life could exist on it that life would have to be adapted for an extremely strong gravitational field. The star itself appears to be relatively benign for an M dwarf, having a “low level of magnetic activity”, though it does exhibit some flaring that could pose a threat to the development of life on the planet.

Unfortunately, this system is not aligned in a way to allow transits of these planets across the face of the star, so these conclusions are based on gravitational wobbles of the star analyzed by computer modeling. Lots of uncertainty. The scientists hope that direct observations of the planet by future space telescopes will reduce these uncertainties. At the moment, the proposed privately-funded Lazuli optical orbiting telescope has the best chance of doing this work, but it isn’t expected to launch before the end of the decade. It will have a 3.1 meter primary mirror, larger than Hubble’s 2.4 meter mirror.

It is a so far very slow news day in space.

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Pluto’s cratered glacial terrain

12:56 pm

Panorama of Pluto's eastern limb
Click for full resolution. For original images go here, here, here, and here.

Pluto in true color
Click for original image.

Cool image time! The panorama above, created from four New Horizons’ images that were cropped and enhanced to post here, was taken by New Horizons on July 14, 2015 (here, here, here, and here), about 30 minutes before its closest approach of 7,800 miles above Pluto.

I have searched the New Horizons’ press release archive, and as far as I can tell, this sequence of images and the terrain it shows was never highlighted publicly by the science team. For that reason, I am not sure exactly where to place it on the global true-color image of Pluto to the right, released by the science team shortly after that fly-by. I suspect the panorama covers a strip on the eastern limb of the globe, in the darker crater region to the east of Pluto’s giant frozen nitrogen sea. It is also possible this is actually covering the north pole regions, with the raw images as released oriented with north to the right.

Other than these guesses I cannot tell. If anyone has better information please provide it in the comments.

What the panorama does show us is cracked and pitted terrain, thought to be mostly made up of frozen ice mixed with dust and debris with some nitrogen and other materials thrown in. Though in many ways it resembles the Moon, that similarity is only very superficial. For example, the polygon shapes near the picture’s center suggest ice floes or glaciers, though there is no underground liquid ocean on which they could float.

This is a very alien world. And it is likely even more alien than the few pictures obtained during that New Horizons’ fly-by have suggested. After all, we only saw in high resolution one hemisphere. Who knows what’s really on the planet’s other side?

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Voyager to make “a multi-million-dollar strategic investment” in Max Space’s inflatable habitats

3:16 pm

Voyager-Max lunar habitat
Click for original image.

In an expansion of a partnership announced last month, Voyager Technologies — the lead company in the consortium building the Starlab space station — today announced it is now making “a multi-million-dollar strategic investment” in Max Space’s inflatable habitats, aiming at winning contracts both for NASA’s proposed Moon base as well as any other “future deep space missions.”

The actual dollar amount has not yet been released, but my sources say it is in “the low eight figures,” or more than $10 million but probably less than $25 million.

This partnership appears aimed not at NASA’s space station program nor enhancing Starlab. Instead, it is focused on providing NASA (and other commercial operations) inflatable habitats that can be launched and quickly established on the Moon and elsewhere, as shown by the artist’s rendering to the right. It appears Voyager will build the foundation, base, and airlock, while Max will provide the inflatable module above. From the press release:

This initiative directly supports NASA’s historical Artemis Program and aligns precisely with Administrator Isaacman’s announcement to be on the Moon to stay by 2028. Max Space delivers critical enabling infrastructure, maximizing livable volume, enhancing crew safety, and reducing the cost and complexity of surface deployment. It complements Voyager’s broader lunar roadmap, including cislunar mission management, surface logistics, propulsion, power systems, and future surface infrastructure, reinforcing a shared vision of the Moon as an operational domain, not a temporary destination.

In other words, the two companies are aiming to become major suppliers for NASA’s Artemis lunar base, and to do that by offering a way to get it quickly built and operational, at a reasonable cost.

I suspect it will be a few years before NASA issues any such contracts. It will first want to see both companies demonstrate success, both with Voyager’s Starlab and Max Space’s own demo station module scheduled for launch in ’27. Nonetheless, this announcement puts them on the map in the race to get those contracts, and begins to put some commercial reality to the American colonization of the solar system.

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Webb takes a look at a strange planetary nebula

9:49 am

Nebula PMR-1
Click for original image.

Cool image time! The two false-color pictures to the right, reduced to post here, were taken by two different infrared cameras on the Webb Space Telescope.

The object, PMR-1, is about 5,000 light years away and has apparently not been studied very much in the past. In 2013 astronomers used the Spitzer Space Telescope to get a first look in the infrared, at a much lower resolution. They also gave this object a nickname, the “Exposed Cranium” nebula. From the Webb press release:

The nebula appears to have distinct regions that capture different phases of its evolution — an outer shell of gas that was blown off first and consists mostly of hydrogen, and an inner cloud with more structure that contains a mix of different gases. Both Webb’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument) show a distinctive dark lane running vertically through the middle of the nebula that defines its brain-like look of left and right hemispheres. Webb’s resolution shows that this lane could be related to an outburst or outflow from the central star, which typically occurs as twin jets burst out in opposite directions. Evidence for this is particularly notable at the top of the nebula in Webb’s MIRI image, where it looks like the inner gas is being ejected outward.

While there is still much to be understood about this nebula, it’s clear that it is being created by a star near the end of its fuel-burning “life.” In their end stages, stars expel their outer layers. It’s a dynamic and fairly fast process, in cosmic terms. Webb has captured a moment in this star’s decline. What ultimately happens will depend on the mass of the star, which is yet to be determined. If it’s massive enough, it will explode in a supernova. A less massive Sun-like star will continue to shed layers until only its core remains as a dense white dwarf, which will cool off over eons.

The dark lane suggests we are looking at the star’s equator, with the two lobes on either side the material being flung out ward from the poles. It is also possible this is wrong, because the lobes on either side do not have a clear distinct jet-like appearance.

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Dart changed the orbit of the Didymos/Dimorphos binary asteroids around the Sun

2:54 pm

Dimorphos just after impact

When the Dart spacecraft impacted the asteroid Dimorphos in September 2022, it not only shortened Dimophos’ orbit around its companion asteroid Didymos by about 33 minutes while reshaping the asteroid, a new study has found that it also changed very slightly the orbit of both asteroids around the Sun.

The image to the right, annotated to post here, was taken by the Italian LICIACube spacecraft moments after the September 26, 2022 impact.

The research paper describing this research can be found here. From the press release:

The new study shows the impact ejected so much material from the binary system that it also changed the binary’s orbital period around the Sun by 0.15 seconds. “The change in the binary system’s orbital speed was about 11.7 microns per second, or 1.7 inches per hour,” said Rahil Makadia, the study’s lead author at the University of Illinois Urbana-Champaign. “Over time, such a small change in an asteroid’s motion can make the difference between a hazardous object hitting or missing our planet.”

To be precise, the orbital speed was slowed 1.7 inches per hour, which while tiny would mean its solar orbit is now slightly shortened.

The result proves that a similar impact could be used on some asteroids to deflect them from hitting the Earth, though we would need to know a lot about that asteroid prior to launching the mission to accurately predict the orbital change. Otherwise, any impact could be a dangerous crap shoot that could do more harm than good.

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Curiosity looks uphill at its upcoming travels

12:41 pm

Panorama looking up Mount Sharp
Click for original.

Overview map
Click for interactive map.

Cool image time! Since May 2025 Curiosity has been exploring in great detail the boxwork formations located on the lower slopes of Mount Sharp. It is now about to complete those investigations, with the Curiosity science team beginning their planning for moving onward and upward.

The panorama above, enhanced to post here, was taken on March 2, 2026 by the rover’s right navigation camera. It looks uphill along the valley that Curiosity is in toward the mountainous region the rover is targeting. Note that the peak of Mount Sharp is not visible, being more than 25 miles away beyond the horizon and about 15,000 feet higher up.

The blue dot on the overview map to the right mark Curiosity’s present position. The yellow lines indicate roughly the area this panorama covers. The red dotted line marks the rover’s approximate planned route, while the white dotted line indicates Curiosity’s actual travels.

Right now Curiosity is traveling through a geological layer the scientists have dubbed the sulfate unit. The lighter colored hills seen on the horizon have also been identified as sulfate, but believed to be much more pure. The geology there should be very different. Instead of rough and rocky it could be like traveling over soft porous sand. This however is merely a guess on my part, based on imagery of those light-colored hills.

The actual route through those hills however remains unknown. Either the science team has not yet released it, or is still trying to figure out the best way through.

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ESA loses contact with the coronagraph satellite of its duel-satellite Proba-3 mission

9:24 am

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

The European Space Agency (ESA) today announced that engineers have lost contact with the Coronagraph satellite of its duel-satellite Proba-3 mission, and are working now to recover contact.

During the weekend of 14–15 February 2026, an anomaly onboard Proba-3’s Coronagraph spacecraft triggered a chain reaction that led to the progressive loss of attitude (spacecraft orientation) and prevented the entry into safe mode.

Because the spacecraft’s solar panel was no longer facing the Sun, the onboard battery started to discharge quickly. This caused the spacecraft to enter survival mode, when minimum electronics are active and data transmission to the ground is interrupted.

The exact root cause of the anomaly is under investigation, and mission teams and operators have joined forces to attempt to re-establish contact with the spacecraft to recover the situation.

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. Based on this report, it does not look good that the spacecraft can be recovered.

At the same time, the mission has apparently achieved all of its initial goals, and was now on an extended mission.

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New Webb data says asteroid 2024 YR4 will miss the Moon in 2032

2:54 pm

Asteroid 2024 YR4 as seen by Webb in the mid-infrared
Asteroid 2024 YR4 as seen by Webb in the
mid-infrared in April 2025. Click for original image.

New Webb data collected in February has now eliminated any chance the potentially dangerous asteroid 2024 YR4 will hit either the Earth or the Moon when it makes its next close pass on December 22, 2032.

Using data from NASA’s James Webb Space Telescope observations collected on Feb. 18 and 26, experts from NASA’s Center for Near-Earth Object Studies at the agency’s Jet Propulsion Laboratory in Southern California have refined near-Earth asteroid 2024 YR4’s orbit and are ruling out a chance of lunar impact on Dec. 22, 2032. With the new data, 2024 YR4 is expected to pass by the lunar surface at a distance of 13,200 miles (21,200 km).

Earlier less precise data had suggested 2024 YR4 had a 4.3% chance of hitting the Moon in 2032. That chance is now zero. This result is actually disappointing, in that an impact of this asteroid, estimated to be about 200 feet in diameter, would have not only been spectacular, but would have been scientifically useful. We would have been able to observe it closely with many ground- and space-based telescopes, and garnered a lot of useful information about the asteroid, the Moon, and the very nature of impacts.

The impact would have also eliminated the chance this asteroid might hit the Earth in the future. 2024 YR4 orbits the Sun about every four years. Previous calculations suggested another potentially dangerous fly-by of Earth in 2047, but these numbers are unreliable because the orbit will be changed by the 2032 fly-by in ways that cannot be predicted as yet.

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The auroras of Jupiter and Ganymede

11:13 am

According to two different university press releases in the past month, new details have been discovered about the auroras found on Jupiter as well as its largest moon, Ganymede, caused by the interaction of Jupiter’s powerful magnetic field not only with Ganymede’s weak one but with the motion of all four Galilean moons as they orbit the gas giant.

The first study used data from Juno when it made a close fly-by of Ganymede in 2021. It not only showed how the aurora was caused by interaction between the magnetic fields of Jupiter and Ganymede, it found that Ganymede’s auroras were similar to those on Earth.

Similar structures, known as ‘beads’, have been observed in the auroras of Earth and Jupiter, where they are linked to sub-storms and dawn storms, large-scale rearrangements of the magnetosphere that release enormous amounts of energy and produce intense auroral activity,” explains Alessandro Moirano, post-doctoral researcher at LPAP.

Ganymede interacts with Jupiter’s space environment in a similar way to how Earth interacts with the solar wind; therefore, the discovery of auroral patches on Ganymede similar to those on Earth suggests that the fundamental physical process(es) could be generally induced in the coupling between any celestial body, its magnetosphere, and external forces.

The aurora's on Jupiter
The auroral footprints of Io and Europa
on Jupiter

The second study, released yesterday, used the Webb Space Telescope to a get a more detailed look at Jupiter’s auroras, caused as the four Galilean moons — Io, Europa, Ganymede, and Callisto — travel through Jupiter’s powerful magnetic field, causing energetic particles to following Jupiter’s magnetic field lines down to its poles, there creating the auroras.

Webb’s data found that the auroral footprints on Jupiter caused by each moon were different from Jupiter’s own aurora.

However, the footprints created by Io and Europa, did not have the characteristics expected from Jupiter’s main aurora, which contains a lot of hot material. Instead, in one snapshot, they discovered a cold spot within Io’s auroral footprint that registered temperatures much lower than expected, with extraordinarily high densities.

As the data was limited to a single 22-hour window, the results are very uncertain. More observations are planned, covering a longer time period, to see if this phenomenon can be captured again.

All of these results are very tantalizing, but to really get a handle on what is going on will require continuous observations over years, from many spacecraft devoted exclusively to Jupiter. And that isn’t going to happen for quite some time.

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The mysterious spokes in Saturn’s rings

11:59 am

A bent spoke in Saturn's rings
Click for original.

Cool image time! When Voyager-1 did its fly-by of Saturn in December 1980, its cameras captured something in the gas giant’s rings that no one had predicted or expected, spokes of brightness pointing outward along the surface of the rings at right angles to the planet. Even more puzzling, these spokes actually appeared to rotate around Saturn, always pointing away from it.

The picture to the right, cropped, reduced, and enhanced to post here, was taken on March 7, 2007 by the Saturn orbiter Cassini. It shows a close-up of one such spoke, though in this case it is bent. From the press release:

A bright spoke extends across the unilluminated side of Saturn’s B ring about the same distance as that from London to Cairo. The background ring material displays some azimuthal (i.e., left to right) asymmetry. The radial (outward from Saturn) direction is up in this view. A noticeable kink in the spoke occurs very close to the radius where ring particles orbit the planet at the speed of Saturn’s magnetic field. Such a connection is most intriguing to scientists studying these ghostly ring phenomena.

If gravity alone were affecting the spoke material, there would be no kink and the entire spoke would be angled toward right, like the bottom portion. That it bends to the left above the kink indicates that some other force, possibly related to the magnetic field, is acting on the spoke material. The shape might also indicate that the spoke did not form in a radial orientation, thus challenging scientists’ assumptions about these features.

In other words, the spokes exist because of multiple factors, some still unknown, that cause these streaks of brightness in the rings. For some reason, the millions of tiny ice particles that comprise the rings are brightened along these spokes, and it isn’t just gravity that is causing it.

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Charon’s surface, completely unlike Pluto

1:09 pm

Panorama of part of Charon's surface
Click for full resolution. For original images go here, here, and here.

Charon

Cool image time! The panorama above, created from three images taken by New Horizons as it began its July 14, 2015 fly-by of the Pluto-Charon double planet system (found here, here, and here), show in close-up one specific swath of Charon cutting across its equatorial regions.

The true color global image of Charon to the right shows the approximate area covered by the panorama above. For scale, Charon has a diameter of about 750 miles, about half that of Pluto. For clarity I have rotated the panorama so that it more closely aligns with the rectangle of global image.

One of the most remarkable discoveries made during New Horizons’ fly-by was how completely different Pluto and Charon appeared, despite their likely formation together at the same time and in the same location of the early solar system. While Pluto had frozen nitrogen seas and water ice mountains floating at the shores, Charon more resembled Mercury, cratered with many large ridges and canyons criss-crossing its service. Both planets appear to be icy, but somehow Charon appears to lack the large differentiated variety of materials seen on Pluto.

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Old and new optical space telescopes team up to view the Cat’s Eye

9:39 am

Cat's Eye Nebula as seen by both Hubble and Euclid
Click for original images.

Astronomers using both NASA’s long established Hubble Space Telescope and Europe’s new Euclid space telescope have produced new optical/infrared images of the Cat’s Eye planetary nebula.

Those images are to the right, cropped, reduced, and sharpened to post here. The Hubble image at bottom shows the complex structure of the nebula itself, located about 4,400 light years away and believed created by the inner orbital motions of a binary star system that act almost like the blades in a blender, mixing the material thrown off by one or both of the stars as they erupt in their latter stages of life.

In Euclid’s wide, near-infrared, and visible light view, the arcs and filaments of the nebula’s bright central region are situated within a halo of colorful fragments of gas zooming away from the star. This ring was ejected from the star at an earlier stage, before the main nebula at the center formed. The whole nebula stands out against a backdrop teeming with distant galaxies, demonstrating how local astrophysical beauty and the farthest reaches of the cosmos can be seen together with Euclid.

Euclid has a primary mirror 1.2 meters in diameter, about half that of Hubble. Though it can’t zoom in with the same resolution, its view is as sharp since it is in space above the atmosphere. It thus provides a wider view, which in this case helps provide a larger context to the detailed close-up view provided by Hubble.

In many ways Euclid is Hubble’s replacement, produced by the European Space Agency, as NASA and the American astronomy community has not been able to get together to build their own new optical orbiting telescope.

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