Elliptical Galaxy NGC 7458

NGC 7458
Detail:  Low Res. (58 KB) / Mid. Res. (912 KB) / High Res. (9.4 MB)

NGC 7458 is a bright and well-defined elliptical galaxy located in the constellation Cetus. Elliptical galaxies are characterized by a strong concentration of light toward their centers that fades rapidly outward, and they lack the distinct structures seen in spiral galaxies. The overall reddish color of NGC 7458 indicates that it is composed predominantly of old stars. Elliptical galaxies in the present-day Universe are known to contain many very old stars, often more than 10 billion years old.

Distance from Earth: 240 million light-years
Instrument: Hyper Suprime-Cam (HSC)

Source: Subaru Telescope

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Where spiral arms and star formation meet

IC 486

A face-on view of the barred spiral galaxy IC 486, showing a bright, elongated central bar and softly curving, ring-like spiral arms with subtle blue star-forming regions and dark dust lanes, set against a black background dotted with distant galaxies and a few foreground stars.

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A luminous swirl set against the deep black of space, the barred spiral galaxy IC 486 glows with a soft, ethereal light in this new ESA/Hubble Picture of the Month image.

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

Hubble’s keen eye reveals subtle variations in colour across the galaxy. The pale, luminous centre is dominated by older stars, while faint bluish regions in the surrounding disc trace pockets of more recent star formation. Wisps of dust thread through the galaxy’s structure, gently obscuring light and tracing regions of increased molecular gas where new stars are likely to form.

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

The data used to make this image comes from two separate observing programmes — #17310 (PI: M. J. Koss) and #15444 (PI: A. J. Barth) — with similar aims: to survey nearby active galaxies like IC 486 and record detailed, high-quality images of their central black holes and the stars near the core of the galaxy. By combining Hubble’s sharp imaging with large comprehensive samples, these programmes are enabling detailed comparisons of how stars, gas, dust, and black holes interact in galaxy centres.

A key goal of this work is to understand how galaxies grow by linking their large-scale structures, such as bars and spiral arms, to activity in their nuclei. To achieve this, the research teams are leveraging both expert classifications and citizen science through Galaxy Zoo, with datasets that will ultimately be released to the public. In parallel, the same images are being used to test how well large language models and other machine learning techniques can reproduce or extend human classifications, offering a new way to scale galaxy morphology studies to the largest surveys that are currently being performed with the Euclid telescope.

Beyond IC 486 itself, the image is peppered with distant background galaxies and foreground stars. Some stars appear with characteristic diffraction spikes, while the more diffuse, reddish smudges are far more distant galaxies scattered across the cosmos.

Though it may appear calm and orderly, IC 486 is a dynamic system shaped by gravity and stellar evolution. Over millions of years, its structure will continue to evolve as stars are born, age, and fade, contributing to the ongoing story of galactic life in the Universe.

Source: ESA/Hubble/potm

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Links

• IC 486 (wide-field view)
• Image on ESA website
• Pan video: IC 486
• Pan video: IC 486 (wide-field view)

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NASA's IXPE and Chandra Take a New Look at an Old Supernova

RCW 86
Credit: X-ray: Chandra: NASA/CXC/SAO, XMM: ESA/XMM-NEWTON, IXPE:NASA/MSFC;
Optical: NSF/NOIRLab; Image Processing: NASA/CXC/SAO/J. Schmidt

JPEG (278.7 kb) - Large JPEG (4.2 MB) - Tiff (21.4 MB) - More Images

Tour: NASA's Chandra Rings in New Year With Champagne Cluster (Video)

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RCW 86 is approximately 8,000 light-years from Earth in the Southern constellation of Circinus, occupying a region of the sky slightly larger than the full moon. In the year 185 AD, Chinese astronomers recorded witnessing a “guest star” in this area of the night sky that remained visible for 8 months.

NASA’s IXPE observed the outer rim of the supernova remnant highlighted in purple at the lower right. When NASA’s Chandra X-ray Observatory targeted RCW 86, they discovered that a large “cavity” region around the system led the supernova to expand larger in a shorter amount of time than expected. The low-density cavity region could have led to RCW 86’s unique shape as well.

The full image puts IXPE’s data into context with legacy observations from two other X-ray telescopes: Chandra and the European Space Agency’s XMM-Newton. The yellow represents low-energy X-rays, while blue shows high-energy X-rays detected by Chandra and XMM-Newton. The starfield in the image comes from the National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory (NOIRlab).

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Source: NASA’s Chandra X-ray Observatory

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Visual Description:

This is an X-ray and optical image of supernova remnant RCW 86, which appears to be two slightly mismatched halves of a broken rough circle. The colors in the image are predominantly blue and gold with a spot of bright purple in the lower right corner. The texture of RCW 86 resembles that of nebulous and patchy fingers, and swirls of gas. This image combines data from four different telescopes to create a multi-wavelength view of the remains of an exploded star. X-ray images from NASA's Chandra X-ray Observatory and the ESA's XMM-Newton are combined to form the blue and gold colors in the image. The X-rays show the interstellar gas that has been heated to millions of degrees by the passage of the shock wave from the supernova. Additional X-ray data from NASA's IXPE are shown in purple, confined to a small circle in the lower right where IXPE observed. A faint starfield, a sprinkling of white stars across the image, from NSF's NOIRlab is also included.

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Fast Facts for RCW 86:

Credit: X-ray: Chandra: NASA/CXC/SAO, XMM: ESA/XMM-NEWTON, IXPE:NASA/MSFC; Optical: NSF/NOIRLab; Image Processing: NASA/CXC/SAO/J. Schmid

Release Date: March 25, 2026
Scale: Image is about 43.5 arcmin (101 light-years) across.
Category: Supernovas & Supernova Remnants
Coordinates (J2000): RA 14h 43m 20.6s | Dec -62° 29´ 52.8"
Constellation: Circinus
Observation Dates: 16 observations from Feb 2001–Jan 2021
Observation Time: 164 hours 10 minutes (6 days 20 hours 10 minutes)
Obs. ID: 1993, 2805, 4611, 7642, 10699, 13748, 14890, 15608-15611, 16952, 23597, 24330, 24331, 24931
Instrument: ACIS
Also Known As: G315.4-2.1
References: Silvestri, S. et al, 2026, ApJ, 988, 172.
Color Code: X-ray: (Chandra and XMM) blue and orange, (IXPE) purple; Optical: red, green, blue
Distance Estimate: About 8,000 light-years from Earth.

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An Impostor Explosion

An artist's impression of a collision between two neutron stars releasing gravitational and electromagnetic waves.
Credit: NASA's Goddard Space Flight Center/CI Lab

These images from the Hubble Space Telescope show the fading light of the kilonova associated with the gravitational wave event GW170817. Credit: NASA and ESA Acknowledgment: A. Levan (U. Warwick), N. Tanvir (U. Leicester), and A. Fruchter and O. Fox (STScI)

Over many centuries of observing the night sky, astronomers have found only a single visible afterglow of a collision between neutron stars. For a few days in the summer of 2025, it seemed like observers may have found another of these treasured but elusive prizes; unfortunately, the promising candidate turned out to be a supernova in disguise.

A Rare Prize

When two neutron stars (the ultra-dense remnants of massive stellar explosions) spiral together and collide, the cataclysm is energetic enough to release strong gravitational waves, forge heavy elements, and briefly glow across the electromagnetic spectrum. These events are called kilonovae, and they’re quite rare; while we may have detected a handful at high energies, there is only one event for which astronomers managed to record both gravitational waves and an optical transient.

That one kilonova, found back in 2017, taught astronomers much about how heavy elements are formed and left the scientific community hungry for more data. Since then, each time a gravitational wave detector like LIGO reports that it may have spotted a neutron star merger, telescopes across the world scramble to look in the probable region of the sky, hoping to find the short-lived electromagnetic counterpart.

Too Good to Be True

On 18 August 2025, the LIGO/Virgo/KAGRA collaboration sent out an alert that it may have detected a neutron star–neutron star merger. The odds that their signal was real weren’t great, and the researchers gave it just a 29% chance of being a genuine astrophysical signal. Still, given the potential payoff of finding the next kilonova, several telescopes quickly began searches for the optical counterpart. The gravitational wave signal suggested that the event likely came from a curved patch of sky delightfully referred to as the “northern banana,” and after trawling that region for a few nights, astronomers hauled in 47 new transients. Any one of these could have been the kilonova, and all of them received extensive follow-up observations.

A team led by James Gillanders (University of Oxford) recently summarized some of these follow-up observations carried out with the Pan-STARRS and ATLAS telescopes. In the initial exciting few days after the alert went out, one candidate transient stood out as the most promising. Named AT2025ulz, it was first spotted by the Zwicky Transient Facility and initially started fading rapidly and changing colors, just as models of kilonovae predict. For four days, it seemed like the world may have witnessed its second-ever kilonova. But then the telescopes began their fifth night of observations.

The light curve of SN2025ulz. Note that the source appeared to grow brighter again after about 5 days.
Credit: Gillanders et al. 2025

Supernova Unmasked

A scatter plot showing a rapidly fading, then reversing and spiking, light curve.

The light curve of AT2025ulz, after fading steadily in the preceding days, suddenly turned upwards; in other words, whatever was causing the transient got brighter. Models of kilonova evolution predict no such brightening, but Type IIb supernovae are known to follow just this behavior. AT2025ulz showed itself to be another run-of-the-mill stellar explosion, not the sought-after fireworks of two neutron stars slamming together.

Frustrating as this particular result may be, the effort was far from wasted. The team could use their non-detection of the true kilonova to place limits on its timing and peak magnitude, assuming it existed in the first place. And, as gravitational wave detectors grow more sensitive and alerts like this more common, hindsight will likely frame this scramble as a dress rehearsal for an ultimately successful kilonova recovery effort. Until then, astronomers will keep searching, and will keep their guard up against cosmic impostors.

By Ben Cassese

Citation

“Pan-STARRS Follow-Up of the Gravitational-Wave Event S250818k and the Light Curve of SN2025ulz,” J. H. Gillanders et al 2025 ApJL 995 L27. doi: 10.3847/2041-8213/ae2125

Source: American Astronomical Society - AAS-Nova

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Galactic warming: The ‘car engine-like’ effect heating our Milky Way

An artist’s impression of the Milky Way, with two of its satellite galaxies – the Large Magellanic Cloud and the Small Magellanic Cloud – in the bottom left. Credit: ESA/Gaia/DPAC, S. Payne-Wardenaar, L. McCallum et al (2025), Kevinmloch, F. Fraternali.

Licence type: Attribution (CC BY 4.0)

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Our Milky Way's halo of hot gas is warmer to the 'south' than the 'north' because of an internal combustion engine-like effect that is compressing the gas like a piston, a new study has found.

Computer simulations reveal that the Large Magellanic Cloud – a satellite galaxy below, or on the south side, of our own – attracts the Milky Way, causing gas in the southern half of the halo to compress and heat up.

This, a team of scientists led by the University of Groningen say, explains why the southern half of the halo is up to 12 per cent warmer than the northern part above the Milky Way's disc, a discrepancy which was measured in 2024 by the X-ray observatory eROSITA mounted on a German-Russian space telescope.

Their findings are published today in Monthly Notices of the Royal Astronomical Society.

Many galaxies, including our own, are surrounded by a vast sphere of thin and warm matter, also known as a halo of hot gas.

Scientists estimate that our Milky Way's gaseous halo has a mass of 100 billion solar masses, meaning there is more matter in the halo than in the galactic disc. The halo, which has a temperature of about 2 million degrees kelvin (a few hundred times hotter than the surface of the Sun), is the 'building material' of the much more compact and cooler disc of gas and stars – including the Sun – at the centre of it.

The Milky Way in the computer simulations is made of three 'components': the rotating disc with relatively cold gas, the much warmer gas around it and a large halo consisting of dark matter.

The so-called hydrodynamic simulation calculates movements of these three components caused by the gravitational attraction of the Magellanic Clouds, which are passing close by the Milky Way, over the course of about one billion years.

The results show that the Milky Way's cold disc is currently moving towards the satellite galaxies at about 40 kilometres per second because of the gravity of the Large Magellanic Cloud. In this process, the Milky Way compresses the gas at the bottom and the material heats up 13 to 20 per cent, according to the calculations.

The simulation also shows that the temperature difference between the northern and southern parts of the halo has arisen in the last 100 million years.

"We saw fairly quickly in the simulations that there was a warming effect," said Filippo Fraternali, professor of gas dynamics and the evolution of galaxies at the University of Groningen.

"It took a little longer before we realised what is going on here – namely the compression of gas like in the piston of an internal combustion engine, which then heats up to make the southern side of our Milky Way's halo warmer."

The simulations may also explain more asymmetries around the Milky Way, according to the researchers. For example, many more so-called high-velocity clouds are seen on the north side of the Milky Way than on the south side. These regions of gas – usually about 100 times cooler than the surrounding material – move around the galaxy at highly anomalous speeds.

"The lower pressure of the surrounding gas may make it easier for these clouds to form and survive there," Fraternali added.

Initially, the researchers were not looking for what they discovered. The simulations had already been published in 2019 as part of an attempt to find an explanation for gas moving around the Magellanic Clouds, among other things. At that time, the temperature difference had not yet been found.

"Typically, computer models are designed to explain certain observations. It is remarkable these simulations already contained the temperature asymmetry before it was found. It makes this result extra robust," Fraternali said.

Co-author Else Starkenburg, associate professor at the University of Groningen, added: "Our explanation for the temperature asymmetry measured by eROSITA is based on simple and well-understood physical processes as we also find them in, for example, combustion engines.

"That gives the result extra elegance."

Source: Royal Astronomical Society (RAS)/Research Highlights

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Media contacts:

Sam Tonkin
Royal Astronomical Society
Mob: +44 (0)7802 877 700
press@ras.ac.uk

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Science contacts:

Professor Filippo Fraternali
Kapteyn Institute, University of Groningen
fraternali@astro.rug.nl

Professor Else Starkenburg
Kapteyn Institute, University of Groningen
estarkenburg@astro.rug.nl

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Images & captions

Milky Way & the LMC

Caption: An artist’s impression of the Milky Way, with two of its satellite galaxies – the Large Magellanic Cloud and the Small Magellanic Cloud – in the bottom left.

Credit: ESA/Gaia/DPAC, S. Payne-Wardenaar, L. McCallum et al (2025), Kevinmloch, F. Fraternali.

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Further information

The paper ‘Temperature asymmetry in the Milky Way’s hot circumgalactic medium induced by the Magellanic Clouds’ by A. Oprea et al. has been published in Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/stag319.

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Notes for editors

About the Royal Astronomical Society

The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

The RAS organises scientific meetings, publishes international research journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

The RAS accepts papers for its journals based on the principle of successful peer review, following which experts on the Editorial Boards accept the papers for publication. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.

Keep up with the RAS on Instagram, Bluesky, LinkedIn, Facebook and YouTube.

Download the RAS Supermassive podcast

Submitted by Sam Tonkin on Thu, 26/03/2026 - 10:00

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The best places to look for alien life: Scientists identify 45 Earth-like worlds to explore for a 'Project Hail Mary'

A diagram depicting habitable zone boundaries across star type with rocky exoplanets from Bohl et al. (2026). The boundaries of the habitable zone shift based on star colour, since different wavelengths of light will heat a planet's atmosphere differently. Credit: Gillis Lowry / Pablo Carlos Budassi

Licence type: Attribution (CC BY 4.0)

If we're to find extraterrestrial life in the universe, astronomers have pinpointed the best places to look for it.

They have identified just under 50 rocky worlds most likely to be habitable out of the more than 6,000 exoplanets discovered so far.

Their research, published today in Monthly Notices of the Royal Astronomical Society, would be useful in a scenario portrayed in the newly-released Hollywood blockbuster Project Hail Mary, which sees Ryan Gosling's character having to travel to an exoplanet system in search of a way to save Earth.

On the way he encounters an alien lifeform named Rocky and the fictional extraterrestrial micro-organisms Astrophage and Taumoeba.

Professor Lisa Kaltenegger, director of the Carl Sagan Institute at Cornell University, and a team of undergraduate students used new data from the European Space Agency's Gaia mission and the NASA Exoplanet Archive to identify planets in the so-called habitable zone.

This is an area not too close to a host star that it’s too hot, and not too far away that it’s too cold. lt also means that, like Earth, a planet is much more likely to have water on its surface – which is a key ingredient for life.

The paper, titled 'Probing the limits of habitability: a catalogue of rocky exoplanets in the habitable zone', also shortlisted the worlds that receive the most similar energy from their star compared to what Earth gets from our Sun.

An artist’s impression of a planetary system around a slightly hotter star than our Sun. In prior research, Carl Sagan Institute scientists have theorised that organisms could evolve biofluorescence to protect themselves from a more intense star. Credit: Gillis Lowry

Licence type: Attribution (CC BY 4.0)

"As Project Hail Mary so beautifully illustrates, life might be much more versatile than we currently imagine, so figuring out which of the 6,000 known exoplanets would be most likely to host extraterrestrials such as Astrophage and Taumoeba – or Rocky – could prove critical, and not just to Ryan Gosling," Professor Kaltenegger said.

"Our paper reveals where you should travel to find life if we ever built a 'Hail Mary' spacecraft."

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 authors also hope the planets they have identified near the edges of the habitable zone will shed light on exactly where habitability ends and if scientists' theories about those limits are correct. While the idea of the habitable zone has been developed since the 1970s, new observations will be critical in establishing whether certain assumptions need adapting, Professor Kaltenegger said.

An artist's impression of a theoretical planet orbiting a redder star, which could cause microbes and plants on the planet's surface to reflect very different colours from Earth’s green forests. Credit: Gillis Lowry

Licence type: Attribution (CC BY 4.0)

In addition, exoplanets with unusual elliptical orbits around their star can trace the importance of a changing amount of heat hitting a world and help answer the question of whether a planet needs to stay in the habitable zone or can cross in and out of it and still remain habitable.

The transiting planets that can test the limit of habitability on the inner edge are K2-239 d, TOI-700e, K2-3d – as well as the planets Wolf 1061c and GJ 1061c, which make their stars wobble. Trappist-1g and Kepler-441b and GJ 102 can probe the outer edge of habitability where it gets extremely cold, the researchers say.

"While it's hard to say what makes something more likely to have life, identifying where to look is the first key step – so the goal of our project was to say 'here are the best targets for observation'," said Gillis Lowry, now a graduate student at San Francisco State University.

Fellow researcher Lucas Lawrence, now a graduate student at the University of Padua in Italy, said: "We wanted to create something that will enable other scientists to search effectively and we kept discovering new things about these worlds we wanted to investigate further."

Co-author Abigail Bohl, of Cornell University, added: "We know Earth is habitable, while Venus and Mars are not. We can use our Solar System as a reference to search for exoplanets that receive stellar energy between what Venus and Mars get.

"Observing these planets can help us understand when habitability is lost, how much energy is too much, and which planets remain habitable – or maybe never were.

"The same idea applies to eccentric planets: how much orbital eccentricity can a planet have while still holding onto its surface water and habitable conditions?

An artist’s impression of what the TRAPPIST-1 planetary system may look like showing (from left to right) TRAPPIST-1 a, b, c, d, e, f, g and h, based on available data about the planets' diameters, masses and distances from the host star. Of these, TRAPPIST-1 d, e, f and g are thought to be the most Earth-like planets. Credit: NASA/JPL-Caltech

Licence type: Attribution (CC BY 4.0)

"We identified planets at the inner and outer edges of the habitable zone, as well as those with the highest eccentricities, to test our understanding of what it takes for a planet to be and remain habitable. We also identified the targets that are most observable with the James Webb Space Telescope (JWST) and other telescopes."

The students also earmarked the best planets to observe with different techniques, to give scientists the best odds of finding signs of life if they exist on these worlds.

The list they've created will guide astronomers studying the night sky with JWST, the upcoming Nancy Grace Roman Space Telescope (set to launch in 2027), the Extremely Large Telescope (set to see first light in 2029), the Habitable Worlds Observatory (expected to launch in the 2040s) and the proposed Large Interferometer For Exoplanets (LIFE) project.

Observing these small exoplanets is the only way to confirm if they have atmospheres, and whether astronomers need to refine their ideas of what limits the habitable zone, Lowry said.

She added that she's already been using the list to take an early look at the 10 planets that receive very similar radiation to Earth, identifying two that are close enough to study with current or upcoming telescopes: TRAPPIST-1 e and TOI-715 b.

The TRAPPIST-1 planetary system is a main focus of observation with the JWST telescope, a programme led by Nikole Lewis, associate professor of astronomy at Cornell. Trappist-1 and TOI-715 b are both small red stars, making it easier to see the small, Earth-sized planets orbiting around them.

Source: Royal Astronomical Society (RAS)/Research Highlights

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Media contacts:

Sam Tonkin
Royal Astronomical Society
Mob: +44 (0)7802 877 700
press@ras.ac.uk

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Science contacts:

Professor Lisa Kaltenegger
Director of the Carl Sagan Institute at Cornell University
lk433@cornell.edu

Abigail Bohl
Cornell University
acb338@cornell.edu

Gillis Lowry
San Francisco State University
gel62@cornell.edu

Lucas Lawrence
University of Padua
lucaslawrence000@gmail.com

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Images & captions

Habitable zone planets diagram

Caption: A diagram depicting habitable zone boundaries across star type with rocky exoplanets from Bohl et al. (2026). The boundaries of the habitable zone shift based on star colour, since different wavelengths of light will heat a planet's atmosphere differently.

Credit: Gillis Lowry / Pablo Carlos Budassi

Earth-like exoplanet

Caption: An artist's impression of a planetary system around a slightly hotter star than our Sun. In prior research, Carl Sagan Institute scientists have theorised that organisms could evolve biofluorescence to protect themselves from a more intense star.

Credit: Gillis Lowry

Purple planet

Caption: An artist's impression of a theoretical planet orbiting a redder star, which could cause microbes and plants on the planet's surface to reflect very different colours from Earth's green forests.

Credit: Gillis Lowry

TRAPPIST-1 planetary system

Caption: An artist's impression of what the TRAPPIST-1 planetary system may look like showing (from left to right) TRAPPIST-1 a, b, c, d, e, f, g and h, based on available data about the planets' diameters, masses and distances from the host star. Of these, TRAPPIST-1 d, e, f and g are thought to be the most Earth-like planets.

Credit: NASA/JPL-Caltech

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Further information

The paper ‘Probing the limits of habitability: a catalogue of rocky exoplanets in the habitable zone’ by Bohl et al. has been published in Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/stag028

The full list of the 45 exoplanets identified in the paper:

GJ 1002 b - GJ 1002 c
GJ 1061 c - GJ 1061 d
GJ 251 c - GJ 273 b
GJ 3323 b
GJ 667 C c - GJ 667 C e - GJ 667 C f
GJ 682 b
K2-239 d
K2-288 B b
K2-3 d
K2-72 e
Kepler-1229 b
Kepler-1410 b
Kepler-1544 b
Kepler-1606 b
Kepler-1649 c
Kepler-1652 b
Kepler-186 f
Kepler-296 e - Kepler-296 f
Kepler-441 b
Kepler-442 b
Kepler-452 b
Kepler-62 e - Kepler-62 f
L 98-59 f
LHS 1140 b
LP 890-9 c
Proxima Centauri b
Ross 508 b
TOI-1266 d
TOI-700 d - TOI-700 e
TOI-715 b
TRAPPIST-1 d - TRAPPIST-1 e - TRAPPIST-1 f - TRAPPIST-1 g
Teegarden's Star c
v > Wolf 1061 c
Wolf 1069 b

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Notes for editors

About the Royal Astronomical Society

The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

The RAS organises scientific meetings, publishes international research and review journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.

Keep up with the RAS on Instagram, Bluesky, LinkedIn, Facebook and YouTube.

Download the RAS Supermassive podcast

Submitted by Sam Tonkin on Thu, 19/03/2026 - 10:18

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Radio Signals from the Edge of Extreme Stars

The illustration shows a pulsar (red sphere) and its strong magnetic field (yellow lines). As the stellar remnant rotates, narrow beams of radio waves (cones) sweep across the sky and become detectable as regular signals for observers on Earth. The beams originate close to the magnetic poles (yellow cones) but may also arise from a region farther out (blueish cone), as the new study suggests. The proportions and colours are not realistic and are for illustrative purposes only. © MPIfR

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To the point

• Astronomers analysed the radio and gamma-ray emission of nearly 200 extremely fast rotating pulsars.


• One-third of these millisecond pulsars show radio signals coming from two or more separate regions. Some of the isolated radio pulses line up perfectly with the emission of gamma-rays.


• The authors suggest that millisecond pulsars produce radio waves not just close to their surfaces, but also in a region far out, where magnetic fields sweep around at nearly the speed of light to keep up with the star’s rotation.

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A team of German and Australian astronomers found evidence that some of the fastest-spinning stars in the Universe broadcast radio waves from far beyond where scientists thought possible.

Pulsars are ultra-dense, rapidly spinning, and highly magnetised remnants of dead stars. They act like cosmic lighthouses, sending out regular pulses of radio waves and sometimes gamma rays in beams that sweep across the sky. A special class called millisecond pulsars spins hundreds of times per second and is among the most precise clocks in the Universe. For decades, astronomers believed that a pulsar’s radio signals are only produced close to the star’s surface, near its magnetic poles. The new study, published in the current issue of Monthly Notices of the Royal Astronomical Society, challenges that long-held idea.

An unexpected discovery

Michael Kramer from the Max Planck Institute for Radio Astronomy (MPIfR) in Germany and Simon Johnston from Australia’s national science agency, CSIRO, analysed radio observations of nearly 200 millisecond pulsars and compared them with gamma-ray data. The duo discovered something striking in this large data set: About one-third of millisecond pulsars show radio signals coming from two or more completely separate regions, with emission free gaps in between. In comparison, this behaviour occurs in only about 3% of slower rotating pulsars. Even more striking, many of these isolated radio pulses line up perfectly with gamma-ray flashes detected by NASA’s Fermi satellite — suggesting that both signals are produced in the same extreme region of space.

A surprising conclusion

To explain these patterns, the authors propose that millisecond pulsars produce radio waves in two very different places: one close to the star’s magnetic poles, as traditionally assumed, and another in a swirling “current sheet” just beyond the so-called light cylinder. Located farther out than the magnetic poles, the light cylinder marks the boundary where magnetic fields sweep around at nearly the speed of light to keep up with the star’s rotation. Depending on the observer's perspective on the pulsar, one sees radio emission from either near the surface, from far out, or from both regions. This gives rise to the unusual, broken-up radio profiles that puzzled astronomers for years. The “current sheet” of charged particles is already thought to be responsible for gamma-ray emission. The alignment of radio waves and gamma-rays can be explained through this shared place of origin.

The animation demonstrates the importance of perspective: Depending on the angle at which an observer sees the pulsar (red sphere), they will detect radio waves (cones) from near the magnetic poles, from a more distant region, or from both. This influences the appearance of the observed radio signals. Credit: Michael Kramer - Video

Exciting prospects and open questions

This discovery has several important consequences: More pulsars may be detectable than previously thought, because radio emission may not be limited to a narrow cone from close to the magnetic poles. Instead, it spreads over a wider range of directions. The finding also helps explain why astronomers often struggle to interpret the polarisation (orientation) of radio waves from millisecond pulsars. Furthermore, it suggests that nearly all gamma-ray millisecond pulsars also emit radio waves, even if those signals may be faint or difficult to detect. This raises new challenges for theory: Scientists now need to explain how stable radio pulses can be generated so far away from the star, in an extreme and turbulent environment.

“Millisecond pulsars are key tools for studying gravity, dense matter, and even gravitational waves. Understanding where their signals come from — and why they look the way they do — is essential for using them as precision instruments”, explains Michael Kramer. Co-author Simon Johnston adds: “This study shows that these tiny, fast-spinning stars are even more complex and surprising than we thought, broadcasting from both their surfaces and from the very edge of their magnetic reach.”

Source: Max Planck for Radio Astronomy/Press Releases

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Contacts:

Prof. Dr. Michael Kramer
Executive Director and Head of “Fundamental Physics in Radio Astronomy“ Research Dept.
Tel: +49 228 525-299
mkramer@mpifr-bonn.mpg.de
Max Planck Institute for Radio Astronomy, Bonn

Dr. Simon Johnston

Senior Principal Research Scientist, Australia Telescope National Facility
Contact via Rachel Rayner, CSIRO communications
Tel: +61 2 9372-4172 rachel.rayner@csiro.au
CSIRO, Australia’s national science agency

Dr. Nina Brinkmann
Press and Public Relations
Tel: +49 228 525-399
brinkmann@mpifr-bonn.mpg.de
Max Planck Institute for Radio Astronomy, Bonn

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Original publication

Michael Kramer and Simon Johnston
Radio emission from beyond the light cylinder in millisecond pulsars
Monthly Notices of the Royal Astronomical Society 547 (2026)

DOI

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Graphics

• pulsar 6.6 MB
• pulsar_annotated 2.46 MB

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'Space Archaeology' Reveals First Dynamic History of a Giant Spiral Galaxy

An artist's impression shows the giant spiral galaxy NGC 1365 as it collides and merges with a smaller companion galaxy, stirring up star formation and redistributing gas and heavy elements. Using a new "space archaeology" technique that reads the chemical fingerprints in the galaxy’s gas, astronomers have reconstructed how NGC 1365 grew over 12 billion years.Credit: Melissa Weiss/CfA. High resolution image

Six views of the spiral galaxy NGC 1365, as extracted from its spectro-photometric data cube, generated by the TYPHOON survey. On the far left is a broadband image of the galaxy balancing B (blue), V (visual) and R (red) continuum images to approximate what the human eye would see. The next image is a narrow-band image extracted from the TYPHOON data cube centered on the H alpha line of ionized hydrogen. Individual HII regions, powered by hot high-luminosity OB stars, are clearly seen outlining the two massive spiral arms. The next three images are slices centered on other diagnostic emission lines (Nitrogen, Sulfur, and a composite of all three diagnostic emission lines). The final panel shows the color-coded velocity field of NGC 1365. Credit: B. Madore, The Observatories, Carnegie Institution for Science. High resolution image

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For the first time, astronomers used galactic archaeology techniques to trace the chemical "fossil record" of a galaxy outside the Milky Way

Cambridge, MA (March 23, 2026) — A team of astronomers led by the Center for Astrophysics | Harvard and Smithsonian have for the first time used galactic archaeology, the study of detailed chemical fingerprints in deep space, to trace the history of a galaxy outside the Milky Way.

The study, published today in the journal Nature Astronomy, demonstrates a new way to reconstruct the evolution of distant galaxies, and opens up a new field of astronomy, called "extragalactic archaeology."

"This is the first time that a chemical archaeology method has been used with such fine detail outside our own galaxy," says Lisa Kewley, lead author, Harvard professor, and director of the Center for Astrophysics. "We want to understand how we got here. How did our own Milky Way form, and how did we end up breathing the oxygen that we're breathing right now?"

Using data from the TYPHOON survey on the Irénée du Pont telescope at the Las Campanas Observatory, the scientists examined the nearby spiral galaxy NGC 1365, whose wide disc shape is oriented so we can see it face-on from Earth. They achieved resolution sharp enough to separate and study individual star-forming clouds in the galaxy.

When they're young, hot stars shine brightly in the ultraviolet, and that intense light can excite nearby gases, Kewley explains. Each element, such as oxygen, in the gas then produces bright, narrow lines of light.

Astronomers know that the centers of galaxies usually have more heavy elements, including oxygen, while the outer parts have less. The oxygen pattern is shaped by several factors, including where and when stars formed and exploded as supernovae, how gas has flowed in or out of the galaxy, and past mergers with other galaxies.

By measuring how the oxygen patterns change across a galaxy and comparing with state-of-the-art galaxy simulations in the Illustris Project, the astronomers traced how the galaxy grew and merged with other galaxies over 12 billion years of cosmic time. The simulations track the motion of gas, star formation, black holes, and chemical evolution in galaxies from shortly after the Big Bang to the present day.

The astronomers searched through simulations of about 20,000 galaxies and found one that closely matched NGC 1365's observed properties, from which they inferred the galaxy's likely merger and growth history.

> The astronomers found that NGC 1365's central region formed early in the galaxy's history and developed a large amount of oxygen. The gas further out built up over 12 billion years through collisions with smaller dwarf galaxies. The gas in the outer spiral arms of the galaxy probably formed relatively late, over the last few billion years, and was also fed by gas and stars from merging dwarf galaxies.

"It's very exciting to see our simulations matched so closely by data from another galaxy," said Lars Hernquist, Mallinckrodt Professor of Astrophysics at Harvard and a CfA astronomer. "This study shows that the astronomical processes we model on computers are shaping galaxies like NGC 1365 over billions of years."

Overall, the study shows NGC 1365 began as a small galaxy and slowly grew into a giant spiral via multiple mergers with smaller dwarf galaxies.

The astronomers establish extragalactic archaeology as a powerful newapproach and tool that demonstrates that chemical fingerprints in a galaxy's gas can reveal its history, said Kewley.

"This study shows really well how you can produce observations to be directly aided by theory," she said. "I think it's also going to impact how we work together as theorists and observers, because this project was 50 percent theory and 50 percent observations, and you couldn't do one without the other. You need both to come to these conclusions."

By studying galaxies like NGC 1365, which bears similarities to the Milky Way, astronomers can gain insight into how typical or unusual our own galaxy may be and the different pathways galaxies can take to reach their current states.

"Do all spiral galaxies form in a similar way?" asked Kewley. "Are there differences between their formation? Where is their oxygen distributed now? Is our Milky Way different or unique in any way? Those are the questions we want to answer."

Source: Harvard-Smithsonian Center for Astrophysics (CfA)/News

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Original paper: DOI 10.1038/s41550-026-02808-7

The assembly history of NGC 1365 through chemical archaeology.Nature Astronomy. Lisa J. Kewley, Kathryn Grasha, Alex Garcia, Paul Torrey, Jeff Rich, S. Hemler, Qian-Hui Chen, Peixin Zhu, Mark Seibert, Lars Hernquist, Barry Madore.

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About the Center for Astrophysics | Harvard & Smithsonian

The Center for Astrophysics | Harvard & Smithsonian is a collaboration between Harvard and the Smithsonian designed to ask, and ultimately answer, humanity's greatest unresolved questions about the nature of the universe. The CfA is headquartered in Cambridge, MA, with research facilities across the U.S. and around the world.

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Authors include:

Lisa Kewley, Director and Scientist Center for Astrophysics | Harvard & Smithsonian; and Paine Professor of Astronomy at Harvard University

Kathryn Grasha, Research School for Astronomy & Astrophysics and ARC Centre of Excellence for All-Sky Astrophysics in 3 Dimensions (ASTRO 3D), Australian National University

Alex Garcia, Department of Astronomy, University of Florida and Department of Astronomy, University of Virginia; Paul Torrey, Department of Astronomy, Virginia Institute for Theoretical Astronomy, and The NSF-Simons AI Institute for Cosmic Origins, University of Virginia

Jeff Rich, The Observatories, Carnegie Institution for Science

Z. S. Hemler, Department of Astrophysical Sciences, Princeton University

Qian-Hui Chen, Research School for Astronomy & Astrophysics and ASTRO 3D, Australian National University

Peixin Zhu, Institute for Theory & Computation, Center for Astrophysics | Harvard & Smithsonian and Research School for Astronomy & Astrophysics, Australian National University

Mark Seibert, The Observatories, Carnegie Institution for Science

Lars Hernquist, Institute for Theory & Computation, Center for Astrophysics | Harvard & Smithsonian

Barry Madore, The Observatories, Carnegie Institution for Science

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Media Contact:

Christine Buckley
Director of Communications
Center for Astrophysics | Harvard & Smithsonian
Tel: 617-599-9628
christine.buckley@cfa.harvard.edu

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NASA’s Hubble Revisits Crab Nebula to Track 25 Years of Expansion

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Crab Nebula (2024 Hubble image)

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Crab Nebula (new image from 1999/2000 data)

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Crab Nebula (2024 Hubble image, annotated)

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Crab Nebula (new image from 1999/2000 data, annotated)

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Videos


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The Crab Nebula


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Pan Video: The Crab Nebula (2024 Hubble image)


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Pan Video: The Crab Nebula (new Hubble image from 1999/2000 data)

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Nearly a millennium ago, astronomers witnessed a brilliant new star blazing in the sky — a supernova so bright it was visible in daylight for weeks. Today, its expanding remnant, the Crab Nebula, continues to evolve 6,500 light-years away. First linked to historical records by Edwin Hubble, the nebula has since been studied in exquisite detail by the NASA/ESA Hubble Space Telescope, which has now revisited this ancient explosion to trace its ongoing expansion and transformation.

A quarter-century after its first observations of the full Crab Nebula, the Hubble Space Telescope has taken a fresh look at the supernova remnant. The Crab Nebula is the aftermath of SN 1054, located 6,500 light-years from Earth in the constellation Taurus.

The result is an unparalleled, detailed look at the aftermath of a supernova and how it has evolved over Hubble’s long lifetime. A paper detailing the new Hubble observation is published in The Astrophysical Journal.

The supernova remnant was discovered in the mid-18th century, and in the 1950s Edwin Hubble was among several astronomers who noted the close correlation between Chinese astronomical records of a supernova and the position of the Crab Nebula. The discovery that the heart of the Crab contained a pulsar — a rapidly rotating neutron star — that was powering the nebula’s expansion finally aligned modern observations and ancient records.

In its new image of the nebula, Hubble has captured extraordinary details of its filamentary structure, as well as the considerable outward movement of those filaments over 25 years, at a pace of 5.5 million kilometres per hour. Hubble is the only telescope with the combination of longevity and resolution capable of capturing these detailed changes.

For better comparison with the new image, Hubble’s 1999 image of the Crab was re-processed. The variation of colors in both of the Hubble images shows a combination of changes in local temperature and density of the gas as well as its chemical omposition.

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

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

According to the science team, the real value of Hubble’s Crab Nebula observations is still to come. The Hubble data can be paired with recent data from other telescopes that are observing the Crab in different wavelengths of light. The NASA/ESA/CSA James Webb Space Telescope released its infrared-light observations of the Crab Nebula in 2024. Comparison of the Hubble image with other contemporary multiwavelength observations will help scientists put together a more complete picture of the supernova’s continuing aftermath, centuries after astronomers first wondered at a new little star twinkling in the sky.

Source: ESA/Hubble/News

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More information

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

Image Credit: NASA, ESA, STScI, W. Blair (JHU). Image Processing: J. DePasquale (STScI)

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Links

• Release on NASA website
• Science paper

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Contacts

Bethany Downer
ESA/Hubble Chief Science Communications Officer
Email: Bethany.Downer@esahubble.org

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NASA’s Hubble Detects First-Ever Spin Reversal of Tiny Comet

Comet 41P (Artist's Concept)

This artist’s concept depicts comet 41P, a tiny Jupiter-family comet, as it approached the Sun and frozen gases began to sublimate and shoot material off into space. Credit Illustration: NASA, ESA, CSA, Ralf Crawford STScI).

Comet 41P Reversal Animation

This artist’s concept depicts comet 41P as it approached the Sun and frozen gases began to sublimate off the comet’s surface. This animation only depicts one jet, but this comet may have multiple streams of material ejecting into space. Credit Animation: NASA, ESA, CSA, Ralf Crawford (STScI). Video

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Astronomers using NASA’s Hubble Space Telescope have found evidence that the spinning of a small comet slowed and then reversed its direction of rotation, offering a dramatic example of how volatile activity can affect the spin and physical evolution of small bodies in the solar system. This is the first time researchers have observed evidence of a comet reversing its spin.

The object, comet 41P/Tuttle-Giacobini-Kresák, or 41P for short, likely originated in the Kuiper Belt, and was flung into its current trajectory by Jupiter’s gravity, now visiting the inner solar system every 5.4 years.

After its 2017 close passage around the Sun, scientists found that comet 41P experienced a dramatic slowdown in its rotation. Data from NASA’s Neil Gehrels Swift Observatory in May 2017 showed the object was spinning three times more slowly than it had in March 2017 when it was observed by the Discovery Channel Telescope at Lowell Observatory in Arizona.

A new analysis of follow-up Hubble observations has shown the spin of this comet took an even more unusual turn.

Hubble images from December 2017 detected the comet spinning much faster again, with a period of approximately 14 hours, compared to the 46 to 60 hours measured by Swift. The simplest explanation, researchers say, is that the comet continued slowing until it almost stopped, and was then forced to spin in the near-opposite direction by outgassing jets on its surface.

The science paper detailing this finding published Thursday in The Astronomical Journal.

Small, temperamental nucleus

Hubble also constrains the size of the comet’s nucleus, measuring it at around 0.6 miles across (about a kilometer), or about three times the height of the Eiffel Tower.

This is especially small for a comet, making it easy to torque, or twist.

As a comet approaches the Sun, heat causes frozen ices to sublimate, venting material into space.

“Jets of gas streaming off the surface can act like small thrusters,” said paper author David Jewitt of the University of California at Los Angeles. “If those jets are unevenly distributed, they can dramatically change how a comet, especially a small one, rotates.”

The comet was originally spinning in one direction, but gas jets pushing against that motion gradually slowed it down. Because the jets kept pushing, they ultimately caused the comet to start rotating in the opposite direction.

“It’s like pushing a merry-go-round,” said Jewitt. “If it’s turning in one direction, and then you push against that, you can slow it and reverse it.”

Evidence of rapid evolution

The study also shows that the comet’s overall activity has declined significantly since earlier returns. During its 2001 perihelion passage, 41P was unusually active for its size. By 2017, its gas production had decreased by roughly an order of magnitude.

This change suggests that the comet’s surface may be evolving quickly, possibly as near-surface volatile materials become depleted or covered by insulating dust layers.

Most changes in comet structure occur over centuries or longer. The rapid rotational shifts observed in comet 41P provide a rare opportunity to witness evolutionary processes unfolding on a human timescale.

Modeling based on the measured torques and mass loss rates suggest that continued rotational changes could eventually lead to structural instability for comet 41P. If a comet spins too rapidly, centrifugal forces can overcome its weak gravity and strength, potentially causing fragmentation or even disintegration.

“I expect this nucleus will very quickly self-destruct,” said Jewitt.

Yet, comet 41P has likely occupied its present orbit for roughly 1,500 years.

Archival find

Hubble has been collecting imaging and spectroscopic data from across the cosmos for over 35 years, and all of those observations are available in the Mikulski Archive for Space Telescopes, a central repository for data from more than a dozen astronomical missions, including Hubble.

Jewitt found these observations while browsing the archive, and realized they were yet-to-be analyzed.

By making NASA’s science data open to all, observations made years, or even decades ago, can be revisited to answer new scientific questions. In many cases, scientists continue to make discoveries not just with new observations, but by mining the archive built over decades of space exploration.

The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight ;Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.

Source: NASA's Hubble Space Telescope/News

Facebook: @NASAHubble - X (Twitter): @NASAHubble - Instagram: @NASAHubble

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Details:

Last Updated: Mar 26, 2026
Editor: Andrea Gianopoulos
Location: NASA Goddard Space Flight Center

Contact Media:

Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov

Hannah Braun, Ann Jenkins
Space Telescope Science Institute
Baltimore, Maryland

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NASA Webb, Hubble Share Most Comprehensive View of Saturn to Date

Saturn (Webb NIRCam and Hubble WFC3/UVIS)

Complementary views of Saturn from NASA’s James Webb Space Telescope and Hubble Space Telescope show a dynamic planet with atmospheric features, orbiting moons, and bright rings. Credit Image: NASA, ESA, CSA, STScI, Amy Simon (NASA-GSFC), Michael Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI)

Saturn (Webb NIRCam Image)

Captured Nov. 29, 2024 by NASA’s James Webb Space Telescope, this infrared view of Saturn shows its glowing icy rings and layered atmosphere. Several moons are visible, including Janus, Dione, and Enceladus. Credit Image: NASA, ESA, CSA, STScI, Amy Simon (NASA-GSFC), Michael Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI)

Saturn (WFC3/UVIS)

Captured Aug. 22, 2024 by NASA’s Hubble Space Telescope, this visible-light view of Saturn reveals the planet’s softly banded atmosphere and iconic rings. Several moons are also visible, labeled Janus, Mimas, and Epimetheus. Credit Image: NASA, ESA, CSA, STScI; Image Processing: Joseph DePasquale (STScI)

Saturn (Webb NIRCam Wide Image)

A wider view of Saturn from NASA’s James Webb Space Telescope shows six of Saturn’s larger moons, including the largest, Titan, at far left. Credit Image: NASA, ESA, STScI, Amy Simon (NASA-GSFC), Michael Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI)

Saturn (Webb NIRCam and Hubble WFC3/UVIS Compass Image)

These images of Saturn, captured by NASA’s James Webb and Hubble Spaces Telescopes, shows compass arrows, scale bar, and color key for reference. Credit Image: NASA, ESA, CSA, STScI; Image Processing: Joseph DePasquale (STScI)

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NASA’s James Webb Space Telescope and Hubble Space Telescope have teamed up to capture new views of Saturn, revealing the planet in strikingly different ways. Observing in complementary wavelengths of light, the two space observatories provide scientists with a richer, more layered understanding of the gas giant’s atmosphere.

Both sense sunlight reflected from Saturn’s banded clouds and hazes, but where Hubble reveals subtle color variations across the planet, Webb’s infrared view senses clouds and chemicals at many different depths in the atmosphere, from the deep clouds to the tenuous upper atmosphere.

Together, scientists can effectively ‘slice’ through Saturn’s atmosphere at multiple altitudes, like peeling back the layers of an onion. Each telescope tells a different part of Saturn’s story, and the observations together help researchers understand how Saturn’s atmosphere works as a connected three-dimensional system. Both complement previous observations done by NASA’s Cassini orbiter during its time studying the Saturnian system from 1997 to 2017.

The Hubble image seen here was captured as part of a more than a decade long monitoring program called OPAL (Outer Planet Atmospheres Legacy) in August 2024, while the Webb image was captured a few months later using Director’s Discretionary Time.

The newly released images highlight features from Saturn’s busy atmosphere.

In the Webb image, a long-lived jet stream known as the “ribbon wave” meanders across the northern mid-latitudes, influenced by otherwise undetectable atmospheric waves. Just below that, a small spot represents a lingering remnant from the “Great Springtime Storm” of 2010 to 2012. Several other storms dotting the southern hemisphere of Saturn are visible in Webb’s image, as well.

All these features are shaped by powerful winds and waves beneath the visible cloud deck, making Saturn a natural laboratory for studying fluid dynamics under extreme conditions.

Several of the pointed edges of Saturn’s iconic hexagon-shaped jet stream at its north pole, discovered by NASA’s Voyager spacecraft in 1981, are also faintly visible in both images. It remains one of the solar system’s most intriguing weather patterns. Its persistence over decades highlights the stability of certain large-scale atmospheric processes on giant planets. These are likely the last high-resolution looks we’ll see of the famous hexagon until the 2040’s, as the northern pole enters winter and will shift into darkness for 15 years.

In Webb’s infrared observations, Saturn’s poles appear distinctly grey-green, indicating light emitting at wavelengths around 4.3 microns. This distinct feature could come from a layer of high-altitude aerosols in Saturn’s atmosphere that scatters light differently at those latitudes. Another possible explanation is auroral activity, as charged molecules interacting with the planet’s magnetic field can produce glowing emissions near the poles.

NASA’s Hubble and Webb have already explored Saturn’s auroras, provided insights into Jupiter’s spectacular auroras also seen with Hubble, confirmed the auroras of Uranus glimpsed in 2011 by Hubble, and detected Neptune’s auroras for the first time with Webb.

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

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

Saturn’s orbit around the Sun, combined with the position of Earth in its annual orbit, determines our changing viewing angle of Saturn’s face and ring.

These 2024 observations, taken 14 weeks apart, show the planet moving from northern summer toward the 2025 equinox. As Saturn transitions into southern spring, and later southern summer in the 2030’s, Hubble and Webb will have progressively better views of that hemisphere.

Hubble’s observations of Saturn for decades have built a record of its evolving atmosphere. Programs like OPAL, with its annual monitoring, are allowing scientists to track storms, banding patterns, and seasonal shifts over time. Webb now adds powerful infrared capabilities to this ongoing record, extending what researchers can measure about Saturn’s atmospheric structure and dynamic processes.

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

Source: NASA's James Webb Space Telescope/Latest News

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Details:

Last Updated: Mar 26, 2026
Location: NASA Goddard Space Flight Center

Contact Media:

Laura Betz
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
laura.e.betz@nasa.gov

Hannah Braun
Space Telescope Science Institute
Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute
Baltimore, Maryland

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