A speed camera for the universe

The stars (or rather galaxies) of the show.
A montage of eight time-delay gravitational lens systems. There’s an entire galaxy at the center of each image, and the bright points in rings around them are gravitationally lensed images of quasars behind the galaxy. These images are false-color and are composites of data from different telescopes and instruments.
Image Credit: ©2025 TDCOSMO Collaboration et al.
(CC BY-ND 4.0)

There is an important and unresolved tension in cosmology regarding the rate at which the universe is expanding, and resolving this could reveal new physics. Astronomers constantly seek new ways to measure this expansion in case there may be unknown errors in data from conventional markers such as supernovae. Recently, researchers including those from the University of Tokyo measured the expansion of the universe using novel techniques and new data from the latest telescopes. Their method exploits the way light from extremely distant objects takes multiple pathways to get to us. Differences in these pathways help improve models on what happens at the largest cosmological scales, including expansion.

Helium leak on the exoplanet WASP-107b

Artist's view of WASP-107b. The planet’s low density and the intense irradiation from its star allow helium to escape the planet and form an asymmetric extended and diffuse envelope around it.
Image Credit: © University of Geneva/NCCR PlanetS/Thibaut Roger

An international team including UNIGE observed with the JWST huge clouds of helium escaping from the exoplanet Wasp-107b. 

An international team, including astronomers from the University of Geneva (UNIGE) and the National Centre of Competence in Research PlanetS, has observed giant clouds of helium escaping from the exoplanet WASP-107b. Obtained with the James Webb Space Telescope, these observations were modeled using tools developed at UNIGE. Their analysis, published in the journal Nature Astronomy, provides valuable clues for understanding this atmospheric escape phenomenon, which influences the evolution of exoplanets and shapes some of their characteristics. 

Sometimes a planet’s atmosphere escapes into space. This is the case for Earth, which irreversibly loses a little over 3 kg of matter (mainly hydrogen) every second. This process, called ‘‘atmospheric escape’’, is of particular interest to astronomers for the study of exoplanets located very close to their star, which, heated to extreme temperatures, are precisely subject to this phenomenon. It plays a major role in their evolution. 

Stars defy the black hole: research in Cologne shows stable orbits around Sagittarius A*

Image Credit: NASA

New observations made with the ERIS instrument at the Very Large Telescope facility disprove from the assumption that the supermassive black hole at the center of the Milky Way devours nearby dust objects. 

An international research team led by PD Dr Florian Peißker at the University of Cologne has used the new observation instrument ERIS (Enhanced Resolution Imager and Spectrograph) at the Very Large Telescope (VLT) facility in Chile to show that several so-called ‘dusty objects’ follow stable orbits around the supermassive black hole Sagittarius A* at the center of our galaxy. Earlier studies had surmised that some of these objects could be swallowed up by the black hole. New data refutes this assumption. The findings have been published under the title ‘ABCD’ in the journal Astronomy & Astrophysics. 

The study focused on four of these unusual celestial bodies, which have been the subject of much discussion in recent years. In particular, G2 was long regarded as a pure dust and gas cloud. It was thought to have been initially elongated by the gravitational pull of Sagittarius A*, a process known as 'spaghettification', before being destroyed. However, the specific observations made with ERIS, which captures radiation in the near-infrared range, show that G2 follows a stable orbit. This is an indication that there is a star inside the dust cloud. These results confirm that the center of the Milky Way is not only destructive but can also be surprisingly stable. 

A sparkling ‘Diamond Ring’ in space: Astronomers in Cologne unravel the mystery of a cosmic ring

Stars Brewing in Cygnus X
Image Credit: NASA/JPL-Caltech/Harvard-Smithsonian CfA

The structure of gas and dust resembles a glowing diamond ring. Computer simulations and observations made on board the 'flying observatory' SOFIA are now able to explain the special shape. 

An international team led by researchers from the University of Cologne has solved the mystery of an extraordinary phenomenon known as the ‘Diamond Ring’ in the star-forming region Cygnus X, a huge, ring-shaped structure made of gas and dust that resembles a glowing diamond ring. In similar structures, the formations are not flat but spherical in shape. How this special shape came about was previously unknown. The results have been published under the title ‘The Diamond Ring in Cygnus X: an advanced stage of an expanding bubble of ionized carbon’ in the journal Astronomy & Astrophysics. 

The ring has a diameter of around 20 light years and shines strongly infrared light. It is the relic of a former cosmic bubble that was once formed by the radiation and winds of a massive star. In contrast to other similar objects, the ‘Diamond Ring’ does not have a rapidly expanding spherical shell, but only a slowly expanding ring. 

Astronomers discover a superheated star factory in the early universe

Glowing deep red from the distant past: galaxy Y1 shines thanks to dust grains heated by newly-formed stars (circled in this image from the James Webb telescope).
Image Credit: NASA, ESA, CSA, STScI, J. Diego (Instituto de Física de Cantabria, Spain), J. D’Silva (U. Western Australia), A. Koekemoer (STScI), J. Summers & R. Windhorst (ASU), and H. Yan (U. Missouri)

Astronomers have uncovered a previously unknown, extreme kind of star factory by taking the temperature of a distant galaxy using the ALMA telescope. The galaxy is glowing intensely in superheated cosmic dust while forming stars 180 times faster than our own Milky Way. The discovery indicates how galaxies could have grown quickly when the universe was very young, solving a long-standing puzzle for astronomers.  

The first generations of stars formed under conditions very different from anywhere we can see in the nearby universe today. Astronomers are studying these differences using powerful telescopes that can detect galaxies so far away their light has travelled towards us for billions of years.   

Astronomy: In-Depth Description

James Webb Space Telescope view of IRAS 04302+2247, a planet-forming disc located about 525 light-years away in a dark cloud within the Taurus star-forming region.
Image Credit: ESA/Webb, NASA & CSA, M. Villenave et al.

Astronomy is the natural science dedicated to the study of all celestial objects and phenomena originating beyond Earth's atmosphere. Its primary goals are to understand the physical and chemical properties of these objects, their origins and evolution, and the fundamental laws governing the universe as a whole.

McGill-led team maps ‘weather’ on a nearby brown dwarf in unprecedented detail

Study reveals patchy clouds and shifting atmospheric layers on a free-floating planetary-mass object just 20 light-years away, offering potential insights into planet and star formation
Image Credit: Anastasiia Nahurna.

Researchers at McGill University and collaborating institutions have mapped the atmospheric features of a planetary-mass brown dwarf, a type of space object that is neither a star nor a planet, existing in a category in-between. This particular brown dwarf’s mass, however, is just at the threshold between being a Jupiter-like planet and a brown dwarf. It has thus also been called a free-floating, or rogue, planet, not bound to a star. Using the James Webb Space Telescope (JWST), the team captured subtle changes in light from SIMP 0136, revealing complex, evolving weather patterns across its surface.

“Despite the fact that right now we cannot directly image habitable planets around other stars, we can develop methods of learning about the meteorology and atmospheric composition on very similar worlds,” said Roman Akhmetshyn, a McGill MSc student in physics and the study's lead author.

New study revises our picture of the most common planets in the galaxy

A new study finds that many “mini-Neptunes”—perhaps the most common planets in the galaxy—are under so much pressure from their heavy atmospheres that the surface is likely compressed solid. Illustration Credit: NASA/JPL-Caltech/R. Hurt (IPAC)

As telescopes have become more powerful, it’s turned out our solar system is not the only game in town: There are millions of other planets out there in the galaxy. 

But we’re still teasing out clues about what they are actually like. 

One of the puzzles is a kind of planet that appears to be one of the most common types in the universe. Known as “mini-Neptunes” because they run a little smaller than Neptune in our solar system, these planets are made of some mix of rock and metal, with thick atmospheres mostly made of hydrogen, helium, and perhaps water. Strangely, despite their abundance elsewhere, they have no analogue in our own solar system, making the population something of an enigma. 

But a new study published Nov. 5, led by Prof. Eliza Kempton with the University of Chicago, adds a new wrinkle to our best picture yet of these distant worlds.

X-Ray Study Reveals New Details About Betelgeuse’s Elusive Companion Star

Betelbuddy, the companion star to Betelgeuse. This image is a color composite made from exposures from the Digitized Sky Survey 2.
Image Credit: ESO/Digitized Sky Survey 2. Acknowledgment: Davide De Martin

Astronomers have long suspected that Betelgeuse — the bright red star blazing in Orion's shoulder — wasn't alone. Now, thanks to a fleeting cosmic window and swift action by Carnegie Mellon University researchers, the true nature of its elusive companion has been illuminated.

In a race against time, the CMU researchers secured director’s discretionary time on both NASA’s Chandra X-ray Observatory and the Hubble Space Telescope to investigate the long-predicted — but never detected — companion star to Betelgeuse. The timing was critical: Around Dec. 6, the companion, nicknamed “Betelbuddy,” reached its maximum separation from the massive red supergiant just before it would disappear behind it for two more years.

“It turns out that there had never been a good observation where Betelbuddy wasn't behind Betelgeuse,” said Anna O’Grady, a McWilliams Postdoctoral Fellow at Carnegie Mellon’s McWilliams Center for Cosmology and Astrophysics. “This represents the deepest X-ray observations of Betelgeuse to date.”

Moon-forming disc around massive planet

An artistic rendering of a dust and gas disc encircling the young exoplanet, CT Cha b, 625 light-years from Earth. Spectroscopic data from the NASA/ESA/CSA James Webb Space Telescope suggest the disc contains the raw materials for moon formation. The planet appears at lower right, while its host star and surrounding protoplanetary disc are visible in the background. 
Image Credit: NASA, ESA, CSA, STScI, G. Cugno (University of Zürich, NCCR PlanetS), S. Grant (Carnegie Institution for Science), J, Olmsted (STScI), L. Hustak (STScI)

The NASA/ESA/CSA James Webb Space Telescope has provided the first direct measurements of the chemical and physical properties of a potential moon-forming disc encircling a large exoplanet. The carbon-rich disc surrounding the world called CT Cha B, which is located 625 light years away from Earth, is a possible construction yard for moons, although no moons are detected in the Webb data.

Our Solar System contains eight major planets, and more than 400 known moons orbiting six of these planets. Where did they all come from? There are multiple formation mechanisms. The case for large moons, like the four Galilean satellites around Jupiter, is that they condensed out of a dust and gas disc encircling the planet when it formed. But that would have happened over 4 billion years ago, and there is scant forensic evidence today.

UP-led astronomy research team explores formation of giant radio galaxies

An artistic representation of a what a giant cosmic jet the size of the distance between the Milky Way and Andromeda could look like
Illustration Credit: Courtesy of University of Pretoria

Enabled by supercomputing, University of Pretoria (UP) researchers have led an international team of astronomers that has provided deeper insight into the entire life cycle (birth, growth and death) of giant radio galaxies, which resemble “cosmic fountains” – jets of superheated gas that are ejected into near-empty space from their spinning supermassive black holes.

The findings of this breakthrough study were published in the journal Astronomy & Astrophysics, and challenge known theoretical models by explaining how extragalactic cosmic fountains grows to cover such colossal distances, raising new questions about the mechanisms behind these vast cosmic structures.

The research team – which was led by astrophysicist Dr Gourab Giri, who holds a postdoctoral fellowship from the South African Radio Astronomy Observatory at UP –  consisted of Associate Professor Kshitij Thorat and Extraordinary Professor Roger Deane of UP’s Faculty of Natural and Agricultural Sciences; Prof Joydeep Bagchi of Christ University in India; Prof DJ Sailkia of the Inter-University Centre for Astronomy and Astrophysics, also in India; and Dr Jacinta Delhaize of the University of Cape Town (UCT).

This study tackles a key question in modern astrophysics: how these structures, which are larger than galaxies and are made up of black hole jets, interact over cosmological timescales with their very thin, gaseous surroundings. 

SwRI models pluto-charon formation scenario that mimics earth-moon system

Using advanced models, SwRI led new research that indicates that the formation of Pluto and Charon may parallel that of the Earth-Moon system. In the resulting 'kiss-and-captureâ regime, Pluto and Charon collide and stick together in the shape of a snowman. They rotate as one body until Pluto pushes Charon out into a stable orbit.
Image Credit: Courtesy of SwRI/Adeene Denton/Robert Melikyan

A NASA postdoctoral researcher at Southwest Research Institute has used advanced models that indicate that the formation of Pluto and Charon may parallel that of the Earth-Moon system. Both systems include a moon that is a large fraction of the size of the main body, unlike other moons in the solar system. The scenario also could support Pluto’s active geology and possible subsurface ocean, despite its location at the frozen edge of the solar system.

“We think the Earth-Moon system initiated when a Mars-sized object hit the Earth and led to the formation of our large Moon sometime later,” said Dr. Adeene Denton, who led the research, published in Nature Geoscience. “In comparison, Mars has two tiny moons that look like potatoes, while the moons of the giant planets make up a small fraction of their total systems.”

Scientists Have Detailed the Nature of the Darkest Gamma-ray Burst in the Universe

Objects like GRB 150309A tend to be located deep within galaxies.
Photo Credit: Graham Holtshausen

An international group of scientists has presented the results of a detailed spectral analysis of the instantaneous and residual X-ray emission (afterglow) from the intense two-episode dark gamma-ray burst GRB 150309A. The researchers' task was to determine the nature of the instantaneous emission and the composition of the jet ejected in the burst. In addition, based on optical and X-ray spectral analysis of the energy distribution, the researchers performed modeling of the parent galaxy of GRB 150309A to study the surrounding interstellar medium in which this outburst occurred. The results of the analysis are presented in a paper published in the journal Astronomy and Astrophysics.

A bright flash GRB 150309A lasting about 52 seconds was detected on March 9, 2015, by the Gamma-ray Burst Observatory of the Fermi Gamma-ray Space Telescope, a space observatory in low Earth orbit. The event consisted of two bursts: about 200 seconds after the first, more powerful burst, an episode of faint and quiet emission followed.

Despite the strong gamma-ray emission, optical observations with the BOOTES (Burst Observer and Optical Transient Exploration System) and GTC (Gran Telescopio Canarias) telescopes were inconclusive: only the parent galaxy of the outburst signal was detected at optical wavelengths. The X-ray afterglow of GRB 150309A was detected about 5.2 hours after the outburst by the CIRCE instrument installed on the GTC at the Spanish La Palma Observatory.

The optical inaccessibility under intense gamma-ray emission and the intense red X-ray afterglow detected in the near-infrared with CIRCE led scientists to suggest that GRB 150309A belongs to a subclass of dark bursts.

Scientists release new insight about Southern Ring Nebula

The Southern Ring Nebula, or NGC 3132, was one of the first objects observed by the James Webb Space Telescope.
Image Credit: NASA/ESA/CSA/STScI  

Planetary nebulae have been studied for centuries, but astronomers are getting new looks and a better understanding of the structures and compositions of these gaseous remnants of dying stars thanks to the ability to study objects at multiple wavelengths and dimensions.

The Southern Ring Nebula, or NGC 3132, is one such object. Rochester Institute of Technology Chester F. Carlson Center for Imaging Science and School of Physics and Astronomy Professor Joel Kastner and his team used Submillimeter Array (SMA) mapping to take a closer look at the nebula, which was one of the first cosmic objects observed by the James Webb Space Telescope soon after its deployment in 2022. The researchers found that most of the molecular gas in the nebula actually lies in an enormous, expanding ring, and further, that the nebula has a second, nearly perpendicular, expanding ring. The research findings were recently published in The Astrophysical Journal. Kastner is the founding director of RIT’s Laboratory for Multiwavelength Astrophysics.

Inspired by the JWST infrared images, which dramatically reveal how hydrogen gas in molecular form threads through the Southern Ring, Kastner and the team used SMA radio-wavelength mapping to measure both the distribution on the sky and the precise velocities of carbon monoxide gas in the nebula. The measurements establish which regions of the Southern Ring Nebula are moving toward and away from us, revealing the two rings. The team’s new SMA results support previous findings that the nebula’s present form is the result of interactions between the dying star and one or possibly two companion stars.

Astronomers discover 49 new galaxies in under three hours

The MeerKAT radio telescope, located in South Africa, enabled this discovery of 49 brand new galaxies.
Photo Credit: South African Radio Astronomy Observatory (SARAO)

An international team of astronomers has discovered 49 new gas-rich galaxies using the MeerKAT radio telescope in South Africa.

Dr Marcin Glowacki, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR) in Western Australia, led the research, which aimed to study the star-forming gas in a single radio galaxy.  Although the team didn’t find any star-forming gas in the galaxy they were studying, Dr Glowacki instead discovered other galaxies while inspecting the data.

In total, the gas of 49 galaxies were detected. Dr Glowacki said this was a great example of how fantastic an instrument like MeerKAT is for finding the star-forming gas in galaxies.

The observations, which lasted less than three hours and were facilitated by IDIA (Inter-University Institute for Data Intensive Astronomy), made this discovery possible.

“I did not expect to find almost fifty new galaxies in such a short time,” Dr Glowacki said. “By implementing different techniques for finding galaxies, which are used for other MeerKAT surveys, we were able to detect all of these galaxies and reveal their gas content.”

The new galaxies have been informally nicknamed the 49ers, a reference to the 1849 California gold rush miners. Dr Glowacki views the 49 new galaxies as valuable as gold nuggets in our night sky. Many galaxies are near each other, forming galaxy groups, with several identified in one observation.

Rethinking galactic origins through heavy-element mapping challenges conventional theory

Galactic gas shows varying heavy element distribution: blue indicates scarcity, red indicates richness. Heavy elements are less abundant in gas than Galaxy.
Image Credit: T. Hayakawa/Y.Fukui, Nagoya University

A groundbreaking study of the origins of intermediate-velocity clouds (IVCs) challenges a 20-year-old theory and suggests a new era of deep-space research. Researchers at Nagoya University in Japan discovered that IVCs have much lower heavy elements than previously reported. Rather than the materials being constantly recycled like water in a fountain, their findings suggest that the particles that make the clouds originated outside our galaxy. The group published their findings in Monthly Notices of the Royal Astronomical Society. 

IVCs are a type of interstellar cloud characterized by their velocity. They are found at altitudes of thousands of light years away throughout the Milky Way. Gas clouds are important because they are sources of elements that enable star formation and the creation of planetary systems. 

In the conventional model, elements are released back into the interstellar medium when the stars die in events called supernovae. This material is then reincorporated into the gas clouds. According to this model, the heavy elements in IVCs are generated through nuclear fusion reactions and supernova explosions within our galaxy. 

Groundbreaking survey reveals secrets of planet birth around dozens of stars

This research brings together observations of more than 80 young stars that might have planets forming around them in spectacular discs. This small selection from the survey shows 10 discs from the three regions of our galaxy observed in the papers. V351 Ori and V1012 Ori are located in the most distant of the three regions, the gas-rich cloud of Orion, some 1600 light-years from Earth. DG Tau, T Tau, HP Tau, MWC758 and GM Aur are located in the Taurus region, while HD 97048, WW Cha and SZ Cha can be found in Chamaeleon I, all of which are about 600 light-years from Earth.  The images shown here were captured using the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument mounted on ESO’s Very Large Telescope (VLT). SPHERE’s state-of-the-art extreme adaptive optics system corrects for the turbulent effects of Earth’s atmosphere, yielding crisp images of the discs around stars. The stars themselves have been covered with a coronagraph — a circular mask that blocks their intense glare, revealing the faint discs around them.  The discs have been scaled to appear roughly the same size in this composition. 
Full Size Zoomable Image
Image Credit: ESO/C. Ginski, A. Garufi, P.-G. Valegård et al.

In a series of studies, a team of astronomers has shed new light on the fascinating and complex process of planet formation. The stunning images, captured using the European Southern Observatory's Very Large Telescope (ESO’s VLT) in Chile, represent one of the largest ever surveys of planet-forming discs. The research brings together observations of more than 80 young stars that might have planets forming around them, providing astronomers with a wealth of data and unique insights into how planets arise in different regions of our galaxy.

“This is really a shift in our field of study,” says Christian Ginski, a lecturer at the University of Galway, Ireland, and lead author of one of three new papers published today in Astronomy & Astrophysics. “We’ve gone from the intense study of individual star systems to this huge overview of entire star-forming regions.”

Metal scar found on cannibal star

This artist’s impression shows the magnetic white dwarf WD 0816-310, where astronomers have found a scar imprinted on its surface as a result of having ingested planetary debris.  When objects like planets or asteroids approach the white dwarf they get disrupted, forming a debris disc around the dead star. Some of this material can be devoured by the dwarf, leaving traces of certain chemical elements on its surface.   Using ESO’s Very Large Telescope, astronomers found that the signature of these chemical elements changed periodically as the star rotated, as did the magnetic field. This indicates that the magnetic fields funneled these elements onto the star, concentrating them at the magnetic poles and forming the scar seen here.
Illustration Credit: ESO/L. Calçada

When a star like our Sun reaches the end of its life, it can ingest the surrounding planets and asteroids that were born with it. Now, using the European Southern Observatory’s Very Large Telescope (ESO’s VLT) in Chile, researchers have found a unique signature of this process for the first time — a scar imprinted on the surface of a white dwarf star. The results are published today in The Astrophysical Journal Letters.

“It is well known that some white dwarfs — slowly cooling embers of stars like our Sun — are cannibalizing pieces of their planetary systems. Now we have discovered that the star’s magnetic field plays a key role in this process, resulting in a scar on the white dwarf’s surface,” says Stefano Bagnulo, an astronomer at Armagh Observatory and Planetarium in Northern Ireland, UK, and lead author of the study.

New moons of Uranus and Neptune announced

The discovery image of the new Uranian moon S/2023 U1 using the Magellan telescope on November 4, 2023.  Uranus is just off the field of view in the upper left, as seen by the increased scattered light.  S/2023 U1 is the faint point of light in the center of the image. (There is an arrow pointing to it in the lower version of the image). The trails are from background stars. 
Image Credit: Scott Sheppard.

The Solar System has some new lunar members—the first new moon of Uranus discovered in more than 20 years, and likely the smallest, as well as two new moons of Neptune, one of which is the faintest moon ever discovered by ground-based telescopes. The discoveries were announced today by the International Astronomical Union's Minor Planet Center.

“The three newly discovered moons are the faintest ever found around these two ice giant planets using ground-based telescopes,” explained Carnegie Science’s Scott S. Sheppard. “It took special image processing to reveal such faint objects.”

The new Uranian member brings the ice giant planet’s total moon count to 28. At only 8 kilometers, it is probably the smallest of Uranus’ moons. It takes 680 days to orbit the planet. Provisionally named S/2023 U1, the new moon will eventually be named after a character from a Shakespeare play, in keeping with the naming conventions for outer Uranian satellites.

Black hole fashions stellar beads on a string

The international team used a combination of X-ray, radio, and optical data to understand how this unusual chain of star clusters formed stellar jewellery 3.8 billion light-years from Earth.
Image Credit: X-ray: NASA/CXC/SAO/O. Omoruyi et al.; Optical: NASA/ESA/STScI/G. Tremblay et al.; Radio: ASTRON/LOFAR; Image Processing: NASA/CXC/SAO/N. Wolk

One of the most powerful eruptions from a black hole ever recorded has been discovered by an international team of astronomers.

The mega-explosion, which took place billions of years ago, may help explain the formation of a pattern of star clusters resembling beads on a string, according to the study.

This stellar jewelry is located in SDSS J1531, a massive galaxy cluster 3.8 billion light-years from Earth, containing hundreds of individual galaxies and a huge reservoir of hot gas and dark matter.

At the heart of SDSS J1531, two of the cluster’s largest galaxies are colliding with one another.

These colliding giants are surrounded by a set of 19 large clusters of stars, called superclusters, arranged in an ‘S’ formation that resembles a string of beads.

The team used a combination of X-ray, radio, and optical data to understand how this unusual chain of star clusters formed.