Tag: exploration

Tiny polygon ridges on Mars

9:19 am

Tiny polygon ridges on Mars
Click for original image.

Cool image time! The picture to the right, cropped and reduced slightly to post here, was taken on June 21, 2026 by the high resolution camera on the Mars rover Curiosity. It looks down to provide a close-up of the ground the rover is presently parked over, a surface covered with thousands of these tiny polygon ridges, all of which appear less than three inches across.

For a wider view and the overall context, see my post from June 24, 2026. While from a distance the ground at this point looked smoother than anything the rover has seen in more than five years since it entered the foothills of Mount Sharp, once it got close it discovered the ground was completely covered with these small polygons.

The picture to the right is part of a close-up mosaic of these polygons the science team is gathering using the high resolution camera.

The geology here is certainly puzzling. Polygon cracks are not unusual on both Earth and Mars, in places where the ground was once wet and then dried. In drying the material shrinks, producing polygon-configured cracks. On Earth those cracks often fill later with material that is more resistant, such as lava, which remains to form ridges when the surrounding dirt erodes away. Whether this was the process here on Mars however is not known. For one thing, why are these polygons so small? And why so uniform in size?

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Firefly buys the AI navigation technology used on its Blue Ghost lunar landing

8:45 am

Blue Ghost's shadow on the Moon, with the Earth in the background
Blue Ghost’s shadow on the Moon, with the Earth in the background,
after its 2025 touchdown.

Firefly has now acquired Space-ng, the company that makes the AI navigation technology and software that Firefly used on its successful Blue Ghost lunar landing in 2025.

Space-ng’s vision navigation software was utilized during Firefly’s historic Blue Ghost Mission 1 to determine position and attitude, detect hazardous lunar terrain, and autonomously redirect Blue Ghost in real-time, enabling a safe, precise touchdown within the Moon’s Mare Crisium.

…In addition to vision navigation software, Space-ng brings high-resolution spacecraft cameras and AI compute hardware to enable advanced space domain awareness, onboard optical navigation, rendezvous and proximity operations, and docking without requiring GPS or GNSS. Firefly plans to integrate Space-ng’s technologies across its fleet of lunar landers and orbital vehicles to support its growing mission manifest, including three additional lunar missions under NASA’s Commercial Lunar Payload Services initiative, another lunar mission supporting NASA MoonFall, and a space domain awareness mission for the Defense Innovation Unit.

Of all the recent attempts by commercial companies to land on the Moon, Firefly is the only one to have a complete success. While Space-ng’s technology worked perfectly to guide Blue Ghost to a safe touch down, the guidance technology used by Intuitive Machines (twice), Ispace (twice), Beresheet, and the first Vikram lander for India all failed close to landing. No wonder Firefly decided to buy it.

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Astronomers: We might be experiencing a shower of comets from the distant Oort cloud due to a close pass of another star 2.5 million years ago

1:18 pm

The uncertainty of science: Using computer models and the somewhat sparse data about the distant Oort cloud on the outer fringes of our solar system (from 2,000 to 200,000 astronomical units [au] away) and combining that with the data from the Gaia space telescope that mapped precisely the motions and distances of billions of Milky Way stars, astronomers now posit that the close pass of another star about 2.5 million years ago perturbed the Oort cloud and thus produced the shower of comets that humanity has been experiencing for the last few thousand years.

HD 7977 is a still nearby Sun-like star in the constellation Cassiopeia whose close passage was discovered by the Gaia mission. Approximately 2.5 million years ago, the orbits of the Sun and HD 7977 brought the two stars close together, but exactly how close is still an open question. Gaia data suggest they passed within 4000-25000 astronomical units of one another. Now, Kaib and Raymond have shown that the orbits of long-period comets suggest HD 7977 came within 6000-10000 AU of our Sun, setting off a major shower of new comets into the inner solar system.

You can read the preprint paper here [pdf].

These results are filled with many uncertainties of course. For one, the actual distance for HD 7977’s close pass is not well constrained. The margin of error is large, so that the star might have not done anything at all. Second, our map of the Oort cloud is very uncertain. In fact, it exists at this time only in theory, as it has never been directly observed. Astronomers hypothesize its existence based on the orbits of the long period comets that they have documented for the past few centuries, all coming from that distant region. So while it appears to exist, that existence remains unproven.

These uncertainties thus make the conclusions of this paper interesting but unconfirmed. Nonetheless, they are fascinating, because they are strongly suggestive, and hint at the impact of the galaxy and its stars on the evolution of our solar system itself. That impact is real, though tracing its history is difficult because of the vast time scales and distances. It appears the Gaia data and computers are giving us a first glimpse into that past history.

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Astronomers discover two exoplanets as dense as cotton candy

9:40 am

The observed transits of TOI-791 c.
The observed transits of TOI-791 c by different telescopes
during its 232 day orbit. Figure 9 from the paper.

Using a combination of ground- and space-based telescopes, astronomers have now discovered two exoplanets in the same solar system that have a deas dense as cotton candy.

You can read their paper here. From the NASA press release:

Data from NASA’s TESS (Transiting Exoplanet Survey Satellite) mission has revealed two new “super-puff” planets, giant worlds so light that their density is comparable to cotton candy. Scientists calculate that these Jupiter-sized planets—named TOI-791 b and TOI-791 c—are the “puffiest” worlds ever found.

The planets orbit a Sun-like star named TOI-791 that is approximately 1,113 light years away from Earth. The TESS mission first detected the planets by watching for repeated dips in TOI-791’s brightness, a telltale sign that a planet is transiting, or passing in front of, a star. Further study revealed two large planets with unusual features.

TOI-791 b is nearly the same size as Jupiter but contains just 3.0 percent of Jupiter’s mass. TOI-791 c is even larger than Jupiter but contains just 5.9 percent of Jupiter’s mass.

The data for determining both planet’s density came from follow-up observations using a telescope based in Antarctica. Both planets have long orbits, 139 and 232 days respectively, so these observations took place over a period of eight years, in order to capture multiple orbital transits.

One interesting tidbit: Though the data suggests both planets are spherical, this is not confirmed with certainty. Overall, the nature of such puffy planets is not really understood at this time.

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Smooth on Mars is apparently not so smooth

11:00 am

Panorama on June 17, 2026
Click for full resolution. For original images, go here and here.

Overview map
Click for interactive map.

Last week I noted how the terrain that stood ahead of Curiosity in its travels on Mount Sharp on Mars appeared to be the smoothest the rover had seen in years.

This week it turns out that upon closer inspection, smooth on Mars is not as smooth as it seems. The panorama above, created from two pictures taken by the rover’s left navigation camera on June 17, 2026 (here and here), provides a much closer view of that smooth ground, and revealed that it isn’t actually smooth at all, but covered with small polygons. The inset on the left shows the area in the white rectangle at full resolution, making the patterned nature of the ground very obvious. From today’s update by the science team:

From up close, the parking spot looks anything but smooth. … There are polygons, veins, lamination, and probably more, once we inspect the higher-resolution images taken today. “Higher-resolution” is the key for why we were in for such a surprise! The features are quite small, a few centimeters across, and therefore we could not see them in the orbital images or from a distance in our navigation and mast camera images. The camera resolution from a distance just isn’t enough to see them. But up close, the terrain revealed all its beauty!

The blue dot on the overview map to the right marks Curiosity’s present position, the white dotted line its actual travels, the red dotted line its planned route. The yellow lines indicate roughly the area covered by the panorama above. The rim of Gale Crater can dimly be seen through the dusty atmosphere 20 to 30 miles away.

Explaining the geological process that caused this patterned surface is beyond my pay grade. My first guess would be it is related to the past presence of water, in the form of liquid or ice, but no one should take that guess very seriously.

As I have said many times, Mars is strange, Mars is wonderful, but above all, Mars is alien.

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Scientists: Interstellar Comet 3I/Atlas is very old, as much as 12 billion years old

12:51 pm

Webb data
Click for original image.

Based on spectroscopic data obtained by the Webb Space Telescope in the past year as interstellar Comet 3I/Atlas zipped through our solar system, a team of scientists have now concluded that its make-up suggests it is extremely old, as much as 12 billion years old, which means it was formed in the very early universe not that long after the Big Bang.

You can read their paper here [pdf]. The graph to the right was published by NASA of the infrared spectroscopic data produced by the Webb Space Telescope that supports this conclusion. That data shows the comet was lacking in isotopes commonly found today, while enriched in isotopes expected only in the early universe. From the paper’s abstract:

[W]e report isotopic measurements of the interstellar comet 3I/ATLAS, which reveal an elemental composition unlike any Solar System body. The water in 3I/ATLAS is enriched in deuterium, at a level of D/H = (0.98 ± 0.06)%, which is more than an order of magnitude higher than in known comets, while its range of 12[Carbon]/13[Carbon] ratios (141–191 for CO2 and 123–172 for CO) exceeds typical values found in the Solar System, as well as nearby interstellar clouds and protoplanetary disks.

Such extreme isotopic signatures indicate formation at temperatures ≲ 30 K in a relatively metal-poor environment. When interpreted with respect to models for Galactic chemical evolution, the carbon isotopic composition implies that 3I/ATLAS may have accreted as long ago as 12 billion years, following a period of intense, early star formation. 3I/ATLAS thus represents a preserved fragment of an ancient planetary system.

As the scientists add in what I think is an understatement, “Its distant origin in space and time makes 3I/ATLAS a uniquely-valuable object studies tool for Galactic archaeology.”

That the comet is still remarkable similar in many other ways to comets in our solar system also tells us that the formation processes that form all solar systems are somewhat common. The solar system in which Comet 3I/Atlas formed was different from ours only that it formed when the universe was young, and thus somewhat different in make-up. Otherwise the processes were the same.

At the same time, Comet 3I/Atlas has given us a window into the early universe, and suggests future interstellar comets will do the same. And there will be future interstellar comets, because we are now developing the observational tools to see them as they routinely fly past on a regular basis.

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Scientists skeptical of dark energy fight back!

9:06 am

Will cosmologists every enter?
Will cosmologists ever enter?

The uncertainty of science: In apparent direct response to the June 11, 2026 press release by cosmologists claiming that their data is correct and that the universe’s expansion is accelerating in the early universe and thus dark energy must exist, a different team of scientists today issued their own press release and research paper stating that the evidence of that acceleration is faulty and based upon a false assumption about supernovae.

The original discovery of dark matter and the acceleration was based on the brightness of a certain type of supernova in the early universe, which also assumed that brightness was always the same for every explosion. The new research says otherwise.

The team analysed the supernovae from the Pantheon+ dataset, one of the most comprehensive catalogues of its kind, and incorporated a recently proposed correction that takes into account the age of the stars that eventually produce these supernova explosions. They also checked whether the inferred acceleration of the expansion rate is indeed the same in every direction, as is assumed in the standard cosmological model. “There is increasing evidence that the brightness of Type Ia supernovae depends on the age of the stars they come from,” said Professor Sarkar, a co-author of the study. “If this effect is not accounted for, it can lead to the erroneous conclusion that the expansion rate is accelerating.”

After applying the correction, the researchers found that the data no longer support a picture of a uniformly accelerating universe. Instead, their analysis suggests that cosmic expansion is overall slowing down rather than speeding up.

Their conclusion is blunt: “There is thus no evidence for isotropic accelerated expansion of the Universe, which can be ascribed to either a Cosmological Constant or more general dark energy.”

In other words, there is solid disagreement within the cosmological community about the existence of dark energy. Some believe it exists, based on the supernova data. Some do not, because the data depends on too many assumptions about those supernovae that further observations suggest are wrong.

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Astronomers discover an asymmetrical radio galaxy distorted wildly as it plows into the surrounding galactic medium

9:49 am

Distorted radio galaxy
Figure 1 from the paper. Click for original.

Using ground-based radio telescopes, astronomers have now discovered a very strange asymmetrical radio galaxy squashed into a gigantic arc almost two million light years across as the galaxy pushes its way into the surrounding material of an even more gigantic galactic cluster.

In RAD-BAARG [the name they have given the galaxy], the researchers say one of the jets appears to interact with a large bow shock-like structure formed as the host galaxy falls through the surrounding hot gas toward a nearby cluster of galaxies. Similar to the shockwave formed ahead of a supersonic aircraft, a galaxy moving faster than the speed of sound in the surrounding intracluster medium can compress the ambient gas and generate a large-scale shock front.

The radio-emitting plasma from RAD-BAARG appears to illuminate this otherwise extremely faint structure, making it visible in low-frequency radio images, according to the team. The western side of the source contains a narrow jet feeding a sector-shaped emission region and a giant arc-like feature extending over nearly 560 kiloparsecs (1.8 million light years).

On the opposite side, the jet develops a distorted S-shaped morphology followed by a faint offset tail extending to almost 600 kiloparsecs. The overall structure suggests strong interaction between the radio plasma and the surrounding large-scale environment.

You can read their published paper here. The images to the right are figure 1 from that paper. The top image is just the radio data. The bottom image shows the contours of that radio data over the optical view. The cross marks the location of object’s host galaxy, as seen in the optical.

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Katalyst’s Link rescue satellite goes airborne in advance of launch

9:26 am

Katalyst's proposed Swift rescue mission
Katalyst’s proposed Swift rescue mission.
Click for original image.

Katalyst’s Link rescue satellite — that will attempt to grab the Gehrels-Swift space telescope and raise its orbit — began its journey to its launch area over the south Pacific on June 18, 2026 when Northrop Grumman’s Pegasus rocket that will launch it was taken airborne by company’s Stargazer L-1011 airplane.

Stargazer, a modified L-1011 operated by Northrop Grumman, took off for Kwajalein Atoll, part of the Republic of the Marshall Islands in the South Pacific Ocean. Attached to the belly of the aircraft was one of the company’s Pegasus XL rockets with LINK inside.

…Stargazer will carry Pegasus and LINK to Kwajalein Atoll, part of the Republic of the Marshall Islands in the South Pacific Ocean with stopovers in California and Hawai’i.

Sometime later this month Stargazer will go to its launch area, climb to 40,000 feet, and release the Pegasus rocket, which will then ignite its engines to carry Link into orbit. Link will then attempt to rendezvous with Gehrels-Swift, using its robot arms to catch it (the telescope has no grapple attachment). If successful, it will then raise the telescope’s orbit so that it can resume observations for years to come.

The mission is daring in more ways than just described. Katalyst has never done this before. It is a startup that reconfigured its first demo mission into this rescue mission.

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Final results from Lucy’s 2025 fly-by of asteroid Donaldjohanson: A tumbling peanut!

8:00 am

Lucy's gravitational field
Click for movie.

The science team for the asteroid probe Lucy yesterday published their final results from the spacecraft’s fly-by of the main belt asteroid Donaldjohanson in April 2025, outlining their present hypothesis based on the data as to the asteroid’s origins and evolution that has left it today a tumbling peanut.

The image to the right comes from a short animation showing the asteroid’s computed tumbling. The colors indicate the strength of its gravitational field, depending on slope. “Higher values (warmer colors) indicate steeper terrain relative to the local gravitational pull.” From the conclusion of their published paper:

We propose the following scenario for the formation and evolution of DJ [Donaldjohanson]. The parent body of the Erigone family was ≈80 km in diameter and was destroyed by a ≈20-km impactor at ≈155 [million years ago]. DJ’s bilobed shape probably arose from the accretion of fragments from this break-up event. This left DJ with an initial spin period of ≪10 hours.

The YORP effect [the pressure of sunlight] then slowed DJ’s rotation and shifted its spin axis toward low obliquity. After 20 to 60 [million years], DJ’s spin period reached ≈10 hours, causing slopes in the neck region to fail. The resulting widespread mass movement toward both lobes produced the ridge and smoothed the neck region.

Sometime later (<40 [million years ago), craters smaller than 0.4 km were globally erased, possibly owing to seismic shaking by an impact. Localized mass wasting on the neck continued, degrading the morphology of many craters without altering the small crater SFD. From 80 to 120 [million years] after formation, DJ’s rotation entered its current NPA [non–principal axis] state, with a spin period of 100 to 200 hours.

A more prosaic way of describing “non–principal axis state” is to say the asteroid is tumbling.

Lucy is presently on its way to the Trojan asteroids that orbit with Jupiter 60 degrees fore and aft of the gas giant. It will fly past ten Trojans during its mission, with the first the asteroid Eurybates on Aug. 12, 2027.

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A “thermal anomaly” in young Martian lava

12:08 pm

A
Click for original image.

Cool image time! The picture to the right, cropped and reduced to post here, was taken on May 1, 2026 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The science team labels this picture “Thermal Anomaly in Young Lava Flows”. The anomaly, indicated by the arrow, is the distinctly blue floor of the unnamed small 300-foot-wide crater about a third of a mile east of that 30-foot-high mesa. According to MRO guidelines [pdf] for interpreting the colors the camera produces:

Frost and ice are also relatively blue, but bright, and often concentrated at the poles or on pole-facing slopes. Some bedrock is also relatively bright and blue, but not as much as frost or ice, and it has distinctive morphologies.

The guidelines say more, but based on this information it suggests the floor of that crater is unusually cold, able to hold frost and ice. The picture was taken during the Martian winter, so seeing frost inside this crater at this time is possible, though its location, deep inside the dry equatorial regions of Mars where no near surface ice is generally found, tells us that if this is frost, it is truly unusual, deserving the description of “an anomaly.”
» Read more

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Spotting dozens of Martian dust devils in one observation

10:50 am

Overview map

Dozens of active dust devils in one image
Click for source.

Using Europe’s Mars Express orbiter, scientists have found it is possible to identify multiple active dust devils at a time on the surface of Mars.

The circles on the image to the right shows dozens of such dust devils, at the outlet region of a valley on Mars dubbed Mamers Valles, located at the western end of the 2,000-mile-long mid-latitude strip I dub glacier country (as shown on the overview map above), because practically every image of this region shows glacial features. This location is where Mamer Valles drains into the northern lowland plains.

Mars Express is uniquely equipped to spot these mini whirlwinds. To form a single image using its High Resolution Stereo Camera – the instrument responsible for these new snapshots – the spacecraft combines sequential views from up to nine separate camera channels (which look at Mars in a different colour, from a different direction, or a mix of the two). If nothing changes on the martian surface while these are being taken, the multiple perspectives align – but if something is moving about, it stands out clearly from its surroundings.

In this new set of images, Mars Express captures not one but dozens of active dust devils.

The image to the right covers about a hundred miles from top to bottom. It is part of a long term project using Mars Express to map the dust devil activity on the entire Martian surface. Not surprisingly, dust devils do not occur everywhere in equal amounts. It appears they favor certain locations, with more generally found in the high latitudes of the cratered southern hemisphere.

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Tianwen-2 appears to be correctly approaching its target asteroid Kamo-oalewa

9:41 am

Though China has made no official update on the status of Tianwen-2, its first asteroid sample return mission, the spacecraft’s maneuvers that amateurs have been tracking suggest it is approaching its target asteroid Kamoʻoalewa as planned, with a rendezvous set for July.

Despite the lack of official updates, the observed maneuvers fit the approach sequence described in Tianwen-2’s mission design. According to a paper by Zhang Rongqiao and colleagues published in SCIENTIA SINICA Physica, Mechanica & Astronomica, the spacecraft’s approach to Kamo’oalewa follows a planned sequence of phases, including the June 7 rendezvous, concluding when the probe has closed to within 20 kilometers of the asteroid’s surface, marking the starting point for close-proximity science operations. This will include global mapping and surveying and sample site selection.

A mission engineer, delivering a presentation on behalf of Zhang He at the 35th Meeting of the NASA Small Bodies Assessment Group (SBAG) June 11, confirmed Tianwen-2 is scheduled to arrive at Kamo’oalewa in July, without providing details on current distance from the asteroid.

The mission is somewhat similar in concept to NASA’s OSIRIS-Rex and Japan’s Hayabusa-2 asteroid missions, both of which rendezvoused with an asteroid and grabbed samples to return to Earth. China however has posted little information about Tianwen-2, including few pictures. One can’t help wondering if this reticence is because the spacecraft’s design its stolen, and China doesn’t want to make this obvious. It is known that China hacked into the computer systems of JPL, NASA, and Japan’s space agency JAXA.

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Astronomers discover a third galaxy devoid of dark matter

12:22 pm

Galaxy DF9
Click for original image.

The uncertainty of science: Using the Keck telescope in Hawaii, astronomers have discovered a galaxy that apparently has no dark matter, the third such galaxy discovered.

The galaxy, dubbed DF9, is shown to the right. It is part of a region that includes the other two galaxies with no dark matter, suggesting all three were formed in linked circumstances.

The team used Keck Observatory’s Keck Cosmic Web Imager (KCWI) to measure the motions of stars inside DF9 by analyzing the light emitted across different wavelengths. Those measurements revealed that DF9 has a mass of only about 100 million Suns, consistent entirely with the galaxy’s visible matter. If the galaxy contained a typical amount of dark matter, astronomers would expect it to be about 100 times more massive.

Dark matter was invented by astronomers in the 1960s to explain the inexplicable fast rotation of stars in the outer fringes of every galaxy they looked at, much faster than accounted for by the visible mass of each galaxy. That fast rotation suggested there was a lot more matter there that could not be seen, as much as one quarter of all mass according to some models. This unseen matter was then labeled “dark matter”, though even three-quarters of a century later it still remains undetected directly.

That these galaxies have no dark matter poses a difficult problem. At present the scientists are trying to come up with scenarios for creating these galaxies without it, but I suspect they will be hard-pressed to come up with any theory that convinces anyone.

I can’t help wondering if the problem isn’t the fast rotation of the stars, but the observations themselves. Maybe there is something we are missing or are unable to detect, because of the vast distances and faint nature of the light. Either way, dark matter, there or not, remains one of the big fundamental mysteries of cosmology.

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Curiosity sees smooth ground for the first time in years

11:01 am

June 12, 2026 Curiosity panorama
Click for full resolution version. Click here, here, and here for original images.

Overview mapd
Click for interactive map.

Cool image time! The panorama above was created from three pictures taken on June 12, 2026 by the left navigation camera on the Mars rover Curiosity (see here, here, and here). It shows the immediate ground uphill in front of the rover, which appears to be the smoothest ground that Curiosity has seen in about five years, since it entered the foothills at the base of Mount Sharp in 2021.

Since then the terrain has been routinely boulder strewn. In one case, the ground was so rocky and rough that the science team had to back off from their original plans and find a different route.

The panorama above shows something wholly different, a patch of relatively smooth ground with only a scattering of sharp rocks protruding periodically from below. This ground is likely the rover’s first taste of what the science team calls the “yardang unit”, the light colored hills in the lower right of the overview map to the right. For years that team has looked at those hills, wondering what it would be like to drive Curiosity on them. Their geology suggests a much softer terrain, sand shaped into dunes (yardangs) by the wind. The unknown was always whether the ground was structurally strong enough for the rover to traverse it.

It looks like they are about to get their first clue. Based on the panorama above, the ground appears very promising.

On the overview map, the blue dot marks Curiosity’s present position, with the red-dotted line is planned route and white-dotted line its actual travels. The yellow lines indicate approximately the area covered by the panorama.

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A galaxy as seen by Hubble and Webb

9:23 am

A galaxy seen by Hubble and Webb
Click for original image.

Cool image time. The picture to the right, cropped and reduced to post here, was taken on March 20, 2026 in a coordinated observations by both the Hubble and Webb space telescopes.

This March 20, 2026, image of Messier 64, or the Black Eye Galaxy, is a composite view from NASA’s Hubble Space Telescope and James Webb Space Telescope. It shows Messier 64 captured at near- and mid-infrared wavelengths by Webb, while Hubble’s image shows the galaxy in ultraviolet, visible, and near-infrared light.

Messier 64 is characterized by its bizarre internal motion. The gas in the outer regions of this spiral galaxy is rotating in the opposite direction from the gas and stars in its inner regions. This strange behavior may be the result of a merger between M64 and a satellite galaxy over a billion years ago.

The red in this image is dust, as the galaxy gets its nickname from the dark streak that wraps around its nucleus on its left side. In optical that streak is dark. Here Webb’s infrared view sees it in false color red.

READERS: It appears that it is a very slow news day today. Other than SpaceX’s IPO, which is on-going and too soon to post any reports, I can so far find nothing much of great significance on which to report.

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Parker makes 28th close fly-by of the Sun

12:48 pm

The overall flight plan for Parker
The overall flight plan for Parker. The green indicates
this most recent close approaches.

The Parker Solar Probe this past week successfully completed its 28th close fly-by of the Sun, zipping past its surface at a distance of only 3.8 million miles.

During this solar encounter, which started June 3 and ends Saturday, June 13, Parker’s four scientific instrument packages gathered data from inside the Sun’s atmosphere, or corona. Parker will begin returning detailed spacecraft telemetry on June 14, with science data transmission set to run from Wednesday, June 17 to Tuesday, June 30.

…Parker also equaled its record-setting speed of 430,000 mph — a mark that, like Parker’s distance to the Sun, was set during a close approach on Dec. 24, 2024, and matched during five flybys since, most recently on March 11. Parker will continue matching these speed and distance records during future flybys.

Engineers estimate the spacecraft’s heat shield experiences temperatures exceeding 1,700 degrees Fahrenheit with each close pass.

With each pass the spacecraft dives deep into the Sun’s corona and gathers data about it unobtainable from a distance. It is also gathering that data over time, as it first arrived in 2018, when the Sun was at its solar minimum with little sunspot activity. Since then it has ramped up to maximum and is presently thought to be on its way back down to minimum (though this still remains uncertain). Parker’s ability to gather data cross this timeline is invaluable for gaining a better understanding of the Sun’s behavior.

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Evidence of supernova remnant near the center of the Milky Way?

10:21 am

Supernova remnant near the Milky Way's center
Click for original image.

Using two X-ray space telescopes, astronomers now think they have detected evidence of a supernova remnant very close to the center of the Milky Way.

You can read their paper here [pdf]. The image to the right is a composite of optical (the stars), radio (the red nebula), and Chanda’s X-ray data (the blue nebula). From the press release:

The evidence for the new supernova remnant, located about 26,000 light-years from Earth, comes from X-ray data from Chandra and XMM-Newton. The X-ray data reveals a “blob” of X-ray emission [indicated by blue] that may come from the remains of a massive star that self-destructed as a supernova, buried within the larger cloud of expanding gas.

The location of this suspected supernova remnant in the image is [that blue region]. It is in bubble of gas [the surrounding larger and smaller red objects] that has had electrons stripped away from hydrogen — called an “H II region” — surrounding a massive, young star. If this is indeed a supernova remnant, then it is expanding at about two million miles per hour and is at least about 1,700 years old.

,..The long filaments seen in the radio image are caused by energetic particles travelling along magnetic fields that are mostly directed perpendicular to the plane of the galaxy.

According to the paper, this supernova remnant is found on the western edge of a vast energized gas cloud called the Central Molecular Zone (CMZ), 1,600 to 1,900 light years across, that spans the Milky Way’s center. The features seen in the image above are part of a feature on the CMZ’s western edge called Sagittarius C, which apparently has not been studied as much as other parts of the CMZ.

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A look back at a significant moment in human history: the first picture of the Moon’s far side

12:14 pm

The first picture ever taken of the Moon's far side, by Luna-3
Click for original image.

Today’s cool image is being posted not because of its beauty or high resolution, but because it was a significant first that shined a light on a mystery that had baffled all humanity since the first time a human being in Africa looked up and observed the Moon.

The picture to the right, reduced slightly and smoothed to remove some camera artifacts, was the first picture ever taken of the hidden far side of the Moon, captured by the Soviet Union’s Luna-3 probe on October 7, 1959, one day after it had passed less than 3,900 miles above the surface. As it moved away, it looked back, and took this picture from a distance of about 40,000 miles.

The picture ain’t what we are used to nowadays from space, but you need to put yourself back in time to truly appreciate it. For literally the entire history of humanity, this view had been hidden. Dreamers, philosophers, scientists, and ordinary people would look at the near side of the Moon almost nightly, but no one knew what was on the other side. Whole religious myths grew up about this unknown. Some science fiction writers of the 19th century fantasized there was air and water there and thus housed an alien civilization, purposely positioned so we couldn’t see it.

Suddenly, with this picture, that side was no longer hidden. This one Luna-3 picture showed humanity that the Moon’s far side was not much different than the near side, though much more cratered with fewer dark mare regions. It had no air or water. Nor were there alien civilizations.

But that age-old mystery was now solved. For those living in the 1950s, it was something of a revelation to see this picture. For those who came after, it is important to try to imagine the significance of that revelation. Suddenly, the mysteries of the universe were no longer unsolvable. Suddenly, we had the ability to solve them.

This picture, like all new knowledge, also brought with it new mysteries, based not on a hidden view but on real data and real questions. Now the goal was understand that data in order to solve the history of the Moon’s geology and how it fit into the formation of the Earth and the entire solar system. That endeavor is still on-going, with its solution not yet entirely in sight.

One last point: Though this picture is woefully inadequate compared to modern planetary images, it also carries a remarkable amount of good information that has since been confirmed by other spacecraft. To get an idea, compare it with a similar global view produced using Lunar Reconnaissance Orbiter (LRO)’s full dataset. The features match quite well, and a close look at the Luna 3 picture reveals many details not immediately evident that match well with the LRO image. The Russian engineers who made this happen should be rememberd and honored for their achievement.

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New Webb data suggests little red dots are supermassive black holes embedded in gas cloud

11:02 am

Little Red Dot GLIMPSE-17775
Little Red Dot GLIMPSE-17775

Using spectroscopic infrared data obtained by the Webb Space Telescope, astronomers now posit that the mysterious little red dots found by Webb in the very early universe are supermassive black holes embedded in a dense cloud of ionized gas.

The scientists focused Webb on the little red dot dubbed GLIMPSE-17775, shown to the right in a false color image produced by Webb’s near infrared camera. You can read their paper here [pdf].

The spectroscopic data collected by Webb contains multiple lines of evidence that support the interpretation that little red dot GLIMPSE-17775 is a black hole star: a rapidly accreting, or growing, black hole enveloped in a dense gas cocoon, which is reprocessing the light emitted from near the black hole and producing the features seen in the spectrum.

Among the 40-plus lines that the team detected in GLIMPSE-17775’s spectrum were various independent indicators that all align with the BH* scenario [the name the scientists use for this model]. For example, the team found that many of the spectral lines, such as hydrogen, oxygen, and helium, do not fit a simple model of a rotating gas cloud. Instead, the best fit model includes a broadening effect known as electron scattering, a telltale sign that a dense, layered gas cocoon is enshrouding this source.

The strength and ratios of certain lines to each other, most notably the 16 iron lines that compose what the team has dubbed an “iron forest” and certain oxygen lines, require a high-energy source to produce them, like a rapidly accreting black hole. Additionally, astronomers noted the fluorescence and absorption of helium in the spectrum, both of which individually suggest that there is a dense medium enveloping a powerful source.

The researchers claim this theory will work to explain all the other little red dots that Webb has detected in the early universe. They also claim it explains how the dots could be there so soon after the Big Bang, as they don’t have to be as supermassive as first believed. If very large, there wasn’t time for them to coalesce following the Big Bang. This model suggests instead that they can be much smaller black holes, thus allowing time for their formation without contradicting present Big Bang cosmology.

There is of course a lot of uncertainty here. For example, GLIMPSE-17775’s data is microlensed, which distorts it. While scientists think they understand the distortions fully, their inability to see this object and the foreground object doing the microlensing from multiple perspectives requires them to make many assumptions that cannot be proven, and could very well be wrong.

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