Tag: science

The shoreline of Pluto’s frozen nitrogen sea

11:10 am

The shoreline of Pluto's frozen nitrogen sea
Click for full resolution. For original
images go here and here.

Cool image time! In my continuing exploration of the New Horizons’ image archive, I keep finding things that I do not remember ever seeing before. The two New Horizon pictures used to create the panorama to the right (here and here) were taken by the spacecraft only thirteen minutes before its closest approach to Pluto at 7,800 miles on July 14, 2015. It shows the Al-Idrisi mountains — thought to be made up of frozen ice as hard as granite — and the frozen nitrogen sea that pushes against those mountains and squeezes them into their jumbled shape. For scale, the image is estimated to be fifty miles wide.

In December 2015 the science team released a small section of one of two images, focused specifically at that nitrogen sea shoreline, noting:

Great blocks of Pluto’s water-ice crust appear jammed together in the informally named al-Idrisi mountains. Some mountain sides appear coated in dark material, while other sides are bright.

The team however did not release this wider panorama produced by both images, which I think gives a better perspective of what we are looking at.

I posted an even wider shot of this shoreline on January 29, 2026. If you look closely at that picture, you can spot the features to the right, but much smaller seen from a greater distance.

For the larger context, below is a wide shot of Pluto indicating the part of the planet where this image is located.
» Read more

4 comments

The weird landscape of Mars’ death valley

11:19 am

Taffy terrain
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on October 28, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The science team labels this “bands near mesa,” an apt description. What we are looking at is a geological feature unique to Mars, but also unique to only one particular place on Mars, the planet’s death valley, the place in Hellas Basin with the lowest relative elevation of any spot on Mars.

The feature is called taffy terrain. According to a 2014 paper, the scientists posit that this material must be some sort of “a viscous fluid,” naturally flowing downward into “localized depressions.” Those localized depressions however happen to also be at the very basement of Mars.

Note how in some spots the bands appear to have been stripped off, exposing small hollows in which dust has become trapped over time to form ripple dunes.
» Read more

1 comment

Webb tracks Uranus’ atmosphere over 15 hours

9:27 am

Uranus and its atmosphere
Click for original image.

Using the Webb Space Telescope, astronomers on January 19, 2025 were able to observe Uranus for fifteen straight hours, tracking the atmosphere’s temperature and structure more completely than ever before.

You can read the peer-reviewed paper here. The false color image to the right, reduced to post here, is just one slice of that dataset. We are looking down at Uranus’ pole, as the rotational tilt is so severe the planet rotates on its side as it orbits the Sun. The grey circles on the outside are the planet’s faint rings. The orange blobs I think are aurora that rotate around the pole at high latitudes, as shown in this video. The orange represents the upper atmosphere.

Led by Paola Tiranti of Northumbria University in the United Kingdom, the study mapped out the temperature and density of ions in the atmosphere extending up to 5,000 kilometres above Uranus’s cloud tops, a region called the ionosphere where the atmosphere becomes ionised and interacts strongly with the planet’s magnetic field. The measurements show that temperatures peak between 3,000 and 4,000 kilometres, while ion densities reach their maximum around 1,000 kilometres, revealing clear longitudinal variations linked to the complex geometry of the magnetic field.

…Webb’s data confirm that Uranus’s upper atmosphere is still cooling, extending a trend that began in the early 1990s. The team measured an average temperature of around 426 kelvins (about 150 degrees Celsius), lower than values recorded by ground-based telescopes or previous spacecraft.

Two bright auroral bands were detected near Uranus’s magnetic poles, together with a distinct depletion in emission and ion density in part of the region between two bands (a feature likely linked to transitions in magnetic field lines). Similar darkened regions have been seen at Jupiter, where the geometry of the magnetic field there controls how charged particles travel through the upper atmosphere.

There is great uncertainty in these conclusions, mostly because the observations are for such a short time. It is like trying to understand the Earth’s climate after looking at it for only one day.

0 comments

Saturn’s moon Enceladus, as seen during Cassini’s last close fly-by

1:22 pm

Enceladus as seen during Cassini's last close fly-by
Click for original.

Cool image time! On December 19, 2015 the Saturn orbiter Cassini made its last close fly-by of the moon Enceladus, known best for the many geysers detected on its surface venting water and other carbon-based materials.

The picture to the right, reduced and enhanced to post here, shows that the entire face of this
Saturn’s moon Enceladus, as seen during that fly-by. The moon itself is only about 310 miles across.

Its icy surface is evident, as are the many fractures, some meandering almost like rivers. Interestingly, for some reason there are a lot more craters in the lower hemisphere, while the upper hemisphere is more completely covered with fractures.

The black outline indicates the approximate area captured by the two close-up images below.
» Read more

0 comments

Webb imaged a star before it went supernova

11:14 am

Webb detection of a supernova progenitor
Click for original image.

One of the biggest challenges facing astronomers for more than four centuries has been the detection of a star prior to its going supernova. Until very recently, no such detection had ever happened, and so astronomers could only guess at the kind of stars or binary systems that might result in these gigantic stellar explosions.

In recent years the improvement in telescopes, both in orbit and on the ground, has produced some successes, whereby the progenitor star was imaged in archival imagery and found after the explosion. The sample however has been small, and the data limited to only a few wavelengths.

Now, the Webb Space Telescope has made its first detection of a supernova progenitor, in the infrared. That image is to the right, showing the star prior to the June 2025 supernova explosion.

By carefully aligning Hubble and Webb images taken of NGC 1637, the team was able to identify the progenitor star in images taken by Webb’s MIRI (Mid-Infrared Instrument) and NIRCam (Near-Infrared Camera) in 2024. They found that the star appeared surprisingly red – an indication that it was surrounded by dust that blocked shorter, bluer wavelengths of light. “It’s the reddest, most dusty red supergiant that we’ve seen explode as a supernova,” said graduate student and co-author Aswin Suresh of Northwestern University.

This excess of dust could help explain a long-standing problem in astronomy that could be described as the case of the missing red supergiants. Astronomers expect the most massive stars that explode as supernovas to also be the brightest and most luminous. So, they should be easy to identify in pre-supernova images. However, that hasn’t been the case.

One potential explanation is that the most massive aging stars are also the dustiest. If they’re surrounded by large quantities of dust, their light could be dimmed to the point of undetectability. The Webb observations of supernova 2025pht support that hypothesis.

You can read the peer-reviewed paper here [pdf].

1 comment

First visual detection of another star’s heliosphere

9:38 am

A baby star's heliosphere
Click for full image.

Using both the Hubble Space Telescope and the Chandra X-ray Observatory, astronomers have made the first visual detection of another star’s heliosphere, in both X-rays and in the infrared.

The image to the right, cropped to post here.

Astronomers have nicknamed the HD 61005 star system the “Moth” because it is surrounded by large amounts of dust patterned similarly to the shape of a moth’s wings when viewed through infrared telescopes. The wings are formed from material left behind after the formation of the star, similar to the Kuiper Belt in our own solar system. Observations of these wings with NASA’s Hubble Space Telescope showed that the interstellar matter surrounding HD 61005 is about a thousand times denser than that around the Sun.

The wings are the points to the left and right. The star’s young heliosphere, which they dub an “astrosphere,” is the purple glow above and below. From the caption:

In this composite image of HD 61005 in the inset, X-rays from Chandra (purple and white) have been combined with infrared data from Hubble (blue and white). Chandra reveals a bright source of X-rays in the center of the image, which is the star itself surrounded by the star’s astrosphere. The wing-like structure sweeping away from the star in the infrared image is dusty material that remained behind after the formation of the star. These wings have been swept backwards as they fly through space.

As this star and its solar system are very young, what we have is a very dusty accretion disk interacting with a very temperamental baby star.

0 comments

Pluto’s splotched surface

12:30 pm

Pluto's splotched surface
For original images go here and here.

Cool image time! The panorama above was created using two photographs (found here and here) taken by New Horizons during its close fly-by of Pluto on July 14, 2015. It looks at Pluto’s western limb, well lit by the Sun, from a distance of approximately 60,000 miles.

I pulled these images from the New Horizons’ archive specifically because I don’t remember ever seeing them publicly released by the science team. More important, they show a surface far more alien than other more well-known New Horizon pictures. Are those round splotches impact craters or some alien type of volcanic caldera? Note also the vertical cracks that appear to divide this terrain near the center.

It would be a serious mistake to make any conclusions. In the emptiness of the outer solar system, the impact rates are going to be far less than in the inner solar system, so assuming impacts is dangerous. Pluto meanwhile has an alien surface of frozen nitrogen seas often filled with floating mountains of frozen water ice. For it to also produce weird volcanic eruptions of nitrogen, sublimating away like bubbling tomato sauce when it is simmering, is quite possible.

2 comments

The dimmest galaxy yet found

9:57 am

The dimmest galaxy yet found
Click for original image.

The uncertainty of science: Using ground-based and orbiting telescopes, astronomers think they have identified what might be the dimmest galaxy yet discovered, revealed almost entirely not from its stars but from the four globular clusters that reside within or near it.

The image to the right, cropped and sharpened to post here, shows that galaxy, dubbed CDG-2, along with those four globular clusters. From the press release:

To confirm one of the dark galaxy candidates, astronomers employed a trio of observatories: the NASA/ESA Hubble Space Telescope, ESA’s Euclid space observatory, and the ground-based NAOJ Subaru Telescope in Hawaii. Hubble’s high-resolution imaging revealed a close collection of four globular clusters in the Perseus galaxy cluster, 300 million light-years away. Follow-up studies using Hubble, Euclid, and Subaru data then revealed a faint, diffuse glow surrounding the star clusters – strong evidence of an underlying galaxy.

“This is the first galaxy detected solely through its globular cluster population,” said David. “Under conservative assumptions, the four clusters represent the entire globular cluster population of CDG-2.”

Preliminary analysis suggests CDG-2 has the luminosity of roughly 1 million Sun-like stars, with the globular clusters accounting for 16% of its visible content.

The scientists next claim that 99% of the galaxy’s mass is made up of dark matter, a material no one has yet detected except for the gravitational influence its invisible mass imposes on visible objects. It appears the astronomers don’t believe the mass that has been detected is sufficient to hold this galaxy together, and thus they need dark matter to explain its existence.

I simply wonder if the distances involved simply make the matter hard to see.

No matter. This is a cool discovery, because it tells us there is much out there hidden in the darkness we will always find difficult if not impossible to detect.

3 comments

UAE extends mission of its Al-Amal Mars orbiter

8:57 am

Deimos with Mars in the background
Al-Amal’s 2023 image of Deimos, the first good
picture of the moon ever taken. Click for full movie.

The United Arab Emirates (UAE) yesterday announced it is extending the mission of its Al-Amal Mars orbiter (“Hope” in English) to 2028, significantly beyond its initial planned mission of two years.

Launched in July 2020, the Hope Probe successfully entered Mars orbit in February 2021 after a seven-month interplanetary journey, marking a historic achievement as the first Arab nation to reach the Red Planet. Originally designed as a two-year mission to observe and study Mars’ atmosphere, the probe has far exceeded expectations. Since reaching Mars, it has gathered around 10 terabytes of scientific data, shared through more than a dozen datasets with research institutions worldwide.

The probe itself was mostly built by American engineers and organizations, as part of a deal to train UAE students. Once in operation around Mars, the UAE and those students took over almost all operations. It orbits Mars in a very wide orbit, allowing it to study global weather and atmosphere conditions, such as dust storms.

6 comments

Pluto’s floating mountains of frozen ice

10:18 am

Pluto's floating mountains
Click for original image.

Cool image time! The picture to the right, rotated, cropped, and sharpened to post here, was taken by New Horizons on July 14, 2015 when it made its close fly-by of Pluto.

The picture looks at the part of Pluto that was close to sunset. Hence the mountain’s long dramatic shadow. The raw image webpage provides little information, including a scale of 0.0 meters, which means nothing. My guess is that these mountains could be several hundred to several thousand feet high based on data from other New Horizon mountain images, but that is a pure guess.

What we think we know is that these mountains are likely made of ice, which at Pluto’s eternally cold environment is as hard as granite. We also think we know that they float on a layer of frozen nitrogen, but because that nitrogen can sublimate into gas when Pluto’s climate warms as its orbit brings it closer to the Sun, the foundation of these mountains is quite unstable. They can roll and drift about, even if they are the size of the Appalachian mountains in the eastern U.S.

I continue to delve into the New Horizons’ archive, and have discovered a trove of quite amazing pictures that hadn’t been featured by the science team during the fly-by. Pluto really is an alien place. Stay tuned, there is more to come!

2 comments

A sinuous Martian ridge of uncertain origin

10:06 am

A sinuous ridge of uncertain origin
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on July 21, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It was posted today by the camera team as a captioned image, with the caption as follows:

The sinuous ridge is approximately 10 meters wide and several kilometers long. The floor surrounding this ridge has been eroding laterally, forming pits and circular features suggestive of removal (sublimation) of subsurface ice. However, landforms such as channels or moraines that might suggest the presence of water or ice are lacking, so the ridge itself does not appear to have formed by fluvial or glacial processes.

Perhaps this curious feature is an exhumed dike formed from magma emanating from Alba Mons in subsurface fractures.

Alba Mons is a gigantic shield volcano to the west.
» Read more

1 comment

Engineers have shut down the Gehrels-Swift space telescope in a last attempt to save it

8:07 am

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

In order to delay the moment the orbit of the Gehrels-Swift Observatory decays — to increase the chance a rescue mission can get there in time — engineers have now stopped almost all scientific observations temporarily.

On Feb. 11, NASA’s Neil Gehrels Swift Observatory temporarily suspended most science operations in an effort to reduce atmospheric drag and slow the spacecraft’s orbital decay. Halting these activities will enable controllers to keep the spacecraft in an orientation that minimizes drag effects, extending its time in orbit in anticipation of a reboost mission.

“Normally, Swift quickly turns to view its targets — especially the fleeting, almost daily explosions called gamma-ray bursts — with multiple telescopes,” said principal investigator S. Bradley Cenko at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Swift’s Burst Alert Telescope will continue to detect gamma-ray bursts, but the spacecraft will no longer slew to observe targets with its other telescopes.”

…To maximize the orbit boost’s chances of success, Swift’s average altitude needs to be above about 185 miles. As of early February, Swift’s average altitude had fallen below about 250 miles.

NASA has awarded the orbital repair startup Katalyst the contract to rescue Gehrels-Swift, but the company has a very challenging mission. It got the contract only a few months ago, in September 2025, and is refitting its planned satellite rescue demo mission to save the space telescope instead. The graphic to the right shows how its rescue robot will approach and grab Gehrels-Swift to raise its orbit, but it must be noted that the telescope has no planned grapple points, and Katalyst’s robot has never done this before.

Moreover, the robot will be launched using the last Pegasus rocket in Northrop Grumman’s warehouse, with a launch scheduled now for sometime this summer. That means Katalyst has had to go from contract award to launch in less than a year, a pace that up until now has been unheard of in the space business. If successful however Katalyst will once again demonstrate the benefits of the capitalism model, whereby NASA buys the product from the private sector rather than building it itself. Left to NASA, this rescue mission would never happen.

And even if Katalyst’s rescue fails, that the company could get it built and launched in such a short time still proves the value of the capitalism model. Freedom and capitalism and competition at least made the attempt possible.

1 comment
1 … 8 9 10 11 12 … 729