Gemini North Discovers Long-Predicted Stellar Companion of Betelgeuse?
Gemini North telescope in Hawai‘i reveals never-before-seen companion to Betelgeuse, solving millennia-old mystery
Gemini North Discovers Long-Predicted Stellar Companion of Betelgeuse. Using the NASA-NSF-funded ‘Alopeke instrument on the Gemini North telescope, one half of the International Gemini Observatory, partly funded by the U.S. National Science Foundation (NSF) and operated by NSF NOIRLab, astronomers have discovered a companion star in an incredibly tight orbit around Betelgeuse. This discovery answers the millennia-old question of why this famous star experiences a roughly six-year-long periodic change in its brightness, and provides insight into the physical mechanisms behind other variable red supergiants. The companion star appears blue here because, based on the team’s analysis, it is likely an A- or B-type star, both of which are blue-white due to their high temperatures. ‘Alopeke is funded by the NASA-NSF Exoplanet Observational Research Program (NN-EXPLORE). Credit: International Gemini Observatory/NOIRLab/NSF/AURA Image Processing: M. Zamani (NSF NOIRLab)
Please notice that, according to the published studies, Betelgeuse’s companion might not be a star.
Astronomers have discovered a companion star in an incredibly tight orbit around Betelgeuse using the NASA and U.S. National Science Foundation-funded ‘Alopeke instrument on Gemini North, one half of the International Gemini Observatory, partly funded by the NSF and operated by NSF NOIRLab. This discovery answers the longstanding mystery of the star’s varying brightness and provides insight into the physical mechanisms behind other variable red supergiants.
Photo of the constellation Orion with annotations from IAU and Sky & Telescope. Credit: E. Slawik/NOIRLab/NSF/AURA/M. Zamani
Betelgeuse is one of the brightest stars in the night sky, and the closest red supergiant to Earth. It has an enormous volume, spanning a radius around 700 times that of the Sun. Despite only being ten million years old, which is considered young by astronomy standards, it’s late in its life. Located in the shoulder of the constellation Orion, people have observed Betelgeuse with the naked eye for millennia, noticing that the star changes in brightness over time. Astronomers established that Betelgeuse has a main period of variability of around 400 days and a more extended secondary period of around six years.
Betelgeuse is one of the brightest stars in the night sky, and the closest red supergiant to Earth. Credit: IAU and Sky & Telescope
In 2019 and 2020, there was a steep decrease in Betelgeuse’s brightness — an event referred to as the ‘Great Dimming.’ The event led some to believe that a supernova death was quickly approaching, but scientists were able to determine the dimming was actually caused by a large cloud of dust ejected from Betelgeuse.
The Great Dimming mystery was solved, but the event sparked a renewed interest in studying Betelgeuse, which brought about new analyses of archival data on the star. One analysis led scientists to propose that the cause of Betelgeuse’s six-year variability is the presence of a companion star [1]. But when the Hubble Space Telescope and the Chandra X-Ray Observatory searched for this companion, no detections were made.
The companion star has now been detected for the first time by a team of astrophysicists led by Steve Howell, a senior research scientist at NASA Ames Research Center. They observed Betelgeuse using a speckle imager called ‘Alopeke. ‘Alopeke, which means ‘fox’ in Hawaiian, is funded by the NASA–NSF Exoplanet Observational Research Program (NN-EXPLORE) and is mounted on the Gemini North telescope, one half of the International Gemini Observatory, funded in part by the U.S. National Science Foundation and operated by NSF NOIRLab.
Speckle imaging is an astronomical imaging technique that uses very short exposure times to freeze out the distortions in images caused by Earth’s atmosphere. This technique enables high resolution, which, when combined with the light collecting power of Gemini North’s 8.1-meter mirror, allowed for Betelgeuse’s faint companion to be directly detected.
Analysis of the companion star’s light allowed Howell and his team to determine the companion star’s characteristics. They found that it is six magnitudes fainter than Betelgeuse in the optical wavelength range, it has an estimated mass of around 1.5 times that of the Sun, and it appears to be an A- or B-type pre-main-sequence star — a hot, young, blue-white star that has not yet initiated hydrogen burning in its core.
Gemini North Discovers Long-Predicted Stellar Companion of Betelgeuse. Using the NASA-NSF-funded ‘Alopeke instrument on the Gemini North telescope, one half of the International Gemini Observatory, partly funded by the U.S. National Science Foundation (NSF) and operated by NSF NOIRLab, astronomers have discovered a companion star in an incredibly tight orbit around Betelgeuse. This discovery answers the millennia-old question of why this famous star experiences a roughly six-year-long periodic change in its brightness, and provides insight into the physical mechanisms behind other variable red supergiants. The companion star appears blue here because, based on the team’s analysis, it is likely an A- or B-type star, both of which are blue-white due to their high temperatures. ‘Alopeke is funded by the NASA-NSF Exoplanet Observational Research Program (NN-EXPLORE). Credit: International Gemini Observatory/NOIRLab/NSF/AURA Image Processing: M. Zamani (NSF NOIRLab)
The companion is at a relatively close distance away from the surface of Betelgeuse — about four times the distance between the Earth and the Sun. This discovery is the first time a close-in stellar companion has been detected orbiting a supergiant star. Even more impressive — the companion orbits well within Betelgeuse’s outer extended atmosphere, proving the incredible resolving abilities of ‘Alopeke.
“Gemini North’s ability to obtain high angular resolutions and sharp contrasts allowed the companion of Betelgeuse to be directly detected,” says Howell. Furthermore, he explains that ‘Alopeke did what no other telescope has done before: “Papers that predicted Betelgeuse’s companion believed that no one would likely ever be able to image it.”
This discovery provides a clearer picture of this red supergiant’s life and future death. Betelgeuse and its companion star were likely born at the same time. However, the companion star will have a shortened lifespan as strong tidal forces will cause it to spiral into Betelgeuse and meet its demise, which scientists estimate will occur within the next 10,000 years.
Photo of the constellation Orion produced by NOIRLab in collaboration with Eckhard Slawik, a German astrophotographer. Credit: E. Slawik/NOIRLab/NSF/AURA/M. Zamani
The discovery also helps to explain why similar red supergiant stars might undergo periodic changes in their brightness on the scale of many years. Howell shares his hope for further studies in this area:
“This detection was at the very extremes of what can be accomplished with Gemini in terms of high-angular resolution imaging, and it worked. This now opens the door for other observational pursuits of a similar nature.”
Martin Still, NSF program director for the International Gemini Observatory adds: “The speckle capabilities provided by the International Gemini Observatory continue to be a spectacular tool, open to all astronomers for a wide range of astronomy applications. Delivering the solution to the Betelgeuse problem that has stood for hundreds of years will stand as an evocative highlight achievement.”
Gemini North Discovers Long-Predicted Stellar Companion of Betelgeuse. Using the NASA-NSF-funded ‘Alopeke instrument on the Gemini North telescope, one half of the International Gemini Observatory, partly funded by the U.S. National Science Foundation (NSF) and operated by NSF NOIRLab, astronomers have discovered a companion star in an incredibly tight orbit around Betelgeuse. This discovery answers the millennia-old question of why this famous star experiences a roughly six-year-long periodic change in its brightness, and provides insight into the physical mechanisms behind other variable red supergiants. The companion star appears blue here because, based on the team’s analysis, it is likely an A- or B-type star, both of which are blue-white due to their high temperatures. ‘Alopeke is funded by the NASA-NSF Exoplanet Observational Research Program (NN-EXPLORE). Credit: International Gemini Observatory/NOIRLab/NSF/AURA Image Processing: M. Zamani (NSF NOIRLab)
Another opportunity to study Betelgeuse’s stellar companion will occur in November 2027 when it returns to its furthest separation from Betelgeuse, and thus easiest to detect. Howell and his team look forward to observations of Betelgeuse before and during this event to better constrain the nature of the companion.
Breathtaking views of astronomical events are a never-ending source of great excitement for the staff at Gemini North, one half of the International Gemini Observatory, supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab. One such example is the lunar eclipse taking place in the distance on the right side of this image, captured in 2019. It is seemingly encased in the dark blue band above the horizon. Lunar eclipses occur when Earth moves between the Sun and the Moon. The Moon, which is only visible by the sunlight reflected off it, is darkened by the Earth’s shadow. An eclipse like this one can be viewed from anywhere on Earth where the Moon is visible, though the extent of the eclipse depends on how aligned the Moon is to Earth’s shadow and one’s viewing location. In 2022, for example, the two lunar eclipses, both total eclipses, were visible from Gemini North in Hawai‘i. Credit: International Gemini Observatory/NOIRLab/NSF/AURA/J. Chu
Notes
[1] Two papers released in 2024 used decades of observations of Betelgeuse from many observers around the world to predict the orbit and location of the companion star (see DOI: 10.3847/1538-4357/ad93c8 and DOI: 10.3847/1538-4357/ad87f4).
More information
This research is presented in a paper titled “Probable Direct Imaging Discovery of the Stellar Companion to Betelgeuse” to appear in The Astrophysical Journal Letters on 24 July. DOI: 10.3847/2041-8213/adeaaf
The team is composed of Steve B. Howell (NASA Ames Research Center), David R. Ciardi (NASA Exoplanet Science Institute-Caltech/IPAC), Catherine A. Clark (NASA Exoplanet Science Institute-Caltech/IPAC), Douglas A. Hope (Georgia Tech Research Institute, Georgia State University), Colin Littlefield (NASA Ames Research Center, Bay Area Environmental Research Institute), Elise Furlan (NASA Exoplanet Science Institute-Caltech/IPAC).
NSF NOIRLab, the U.S. National Science Foundation center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), NSF Kitt Peak National Observatory (KPNO), NSF Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and NSF–DOE Vera C. Rubin Observatory (in cooperation with DOE’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona.
The scientific community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence of I’oligam Du’ag to the Tohono O’odham Nation, and Maunakea to the Kanaka Maoli (Native Hawaiians) community.
The NASA–NSF Exoplanet Observational Research Program (NN-EXPLORE) is a joint initiative to advance U.S. exoplanet science by providing the community with access to cutting-edge, ground-based observational facilities. Managed by NASA’s Exoplanet Exploration Program (ExEP), NN-EXPLORE supports and enhances the scientific return of space missions such as Kepler, TESS, HST, and JWST by enabling essential follow-up observations from the ground—creating strong synergies between space-based discoveries and ground-based characterization. ExEP is located at the Jet Propulsion Laboratory. More information at https://exoplanets.nasa.gov/exep/NNExplore/overview/.
Webb scratches beyond the surface of the Cat’s Paw Nebula (NGC 6334) for third anniversary
To mark its third year of highly productive science, astronomers used the NASA/ESA/CSA James Webb Space Telescope to scratch beyond the surface of the Cat’s Paw Nebula (NGC 6334), a massive, local star-forming region.
Webb’s NIRCam instrument was used to look at this particular area of the Cat’s Paw Nebula, which just scratches the surface of the telescope’s three years of groundbreaking science.
To celebrate the NASA/ESA/CSA James Webb Space Telescope’s third year of highly productive science, astronomers used the telescope to scratch beyond the surface of the Cat’s Paw Nebula (NGC 6334), a massive, local star-forming region. This area is of great interest to scientists, having been subject to previous study by NASA’s Hubble and retired Spitzer space telescopes, as they seek to understand the multiple steps required for a turbulent molecular cloud to transition to stars. With its near-infrared capabilities and sharp resolution, the telescope “clawed” back a portion of a singular “toe bean,” revealing a subset of mini toe bean-reminiscent structures composed of gas, dust, and young stars. Webb’s view reveals a chaotic scene still in development: Massive young stars are carving away at nearby gas and dust, while their bright starlight is producing a bright nebulous glow represented in blue. This is only a chapter in the region’s larger story. The disruptive young stars, with their relatively short lifespans and luminosity, will eventually quench the local star formation process. The Cat’s Paw Nebula is located approximately 4,000 light-years away in the constellation Scorpius. Credit: NASA, ESA, CSA, STScI
A star formation flex
The progression from a large molecular cloud to massive stars entails multiple steps, some of which are still not well understood by astronomers. Located approximately 4,000 light-years away in the constellation Scorpius, the Cat’s Paw Nebula offers scientists the opportunity to study the turbulent cloud-to-star process in great detail. Webb’s observation of the nebula in near-infrared light builds upon previous studies by the NASA/ESA Hubble and retired NASA Spitzer Space Telescope in visible- and infrared-light, respectively.
With its sharp resolution, Webb shows never-before-seen structural details and features: Massive young stars are carving away at nearby gas and dust, while their bright starlight is producing a bright nebulous glow represented in blue. It’s a temporary scene where the disruptive young stars, with their relatively short lifespans and luminosity, have a brief but important role in the region’s larger story. As a consequence of these massive stars’ lively behavior, the local star formation process will eventually come to a stop.
The opera house’s intricate structure
Start with the region at top centre, which is nicknamed the “Opera House” for its circular, tiered-like structure. The primary drivers for the area’s cloudy blue glow are most likely toward its bottom: either the light from the bright yellowish stars or from a nearby source still hidden behind the dense, dark brown dust.
Just below the orange-brown tiers of dust is a bright yellow star with diffraction spikes. While this massive star has carved away at its immediate surroundings, it has been unable to push the gas and dust away to greater distances, creating a compact shell of surrounding material.
Look closely to notice small patches, like the tuning fork-shaped area to the Opera House’s immediate left, that contain fewer stars. These seemingly vacant zones indicate the presence of dense foreground filaments of dust that are home to still-forming stars and block the light of stars in the background.
A spotlight on stars
Toward the image’s centre are small, fiery red clumps scattered amongst the brown dust. These glowing red sources mark regions where massive star formation is underway, albeit in an obscured manner.
Some massive blue-white stars, like the one in the lower left region, seem to be more sharply resolved than others. This is because any intervening material between the star and the telescope has been dissipated by stellar radiation.
Near the bottom of this region are small, dense filaments of dust. These tiny clumps of dust have managed to remain despite the intense radiation, suggesting that they are dense enough to form protostars. A small section of yellow at the right notes the location of a still-enshrouded massive star that has managed to shine through intervening material.
Across this entire scene are many small yellow stars with diffraction spikes. Bright blue-white stars are in the foreground of this Webb image, but some may be a part of the more expansive Cat’s Paw Nebula area.
One eye-catching aspect of this Webb image is the bright, red-orange oval at top right. Its low count of background stars implies it is a dense area just beginning its star-formation process. A couple of visible and still-veiled stars are scattered throughout this region, which are contributing to the illumination of the material in the middle. Some still-enveloped stars leave hints of their presence, like a bow shock at the bottom left, which indicates an energetic ejection of gas and dust from a bright source.
Another incredible year of science and images
Webb continued to return on its ambitious science goals over its third year of operations. Unexpected, bright hydrogen emission was found in the galaxy GZ-z13-1, a mere 330 million years after the Big Bang. Showcasing its coronagraph, Webb took direct images of exoplanets in the HR 8799 system which revealed how they likely formed. Then, astronomers discovered a potential new exoplanet in the debris disc around star TWA 7, the first such discovery made with Webb’s coronagraph — but surely not the last. Closer to home, astronomers were able to watch aurorae unfold over a period of just hours on Jupiter.
A remarkable view of a rare Einstein ring, a rich collection of galaxies that acts as a lens on the distant past, a protoplanetary disc sporting powerful stellar winds, and the Sombrero Galaxy seen in an entirely new light were just some of the images released over the past year through which Webb showed us a new view of the cosmos.
In a particular highlight from Webb, the first discovery of young brown dwarf stars outside our galaxy produced a truly breathtaking image of star cluster NGC 602, a vista of its many colours of ionised gas.
To celebrate the NASA/ESA/CSA James Webb Space Telescope’s third year of highly productive science, astronomers used the telescope to scratch beyond the surface of the Cat’s Paw Nebula (NGC 6334), a massive, local star-forming region. This area is of great interest to scientists, having been subject to previous study by NASA’s Hubble and retired Spitzer space telescopes, as they seek to understand the multiple steps required for a turbulent molecular cloud to transition to stars. With its near-infrared capabilities and sharp resolution, the telescope “clawed” back a portion of a singular “toe bean,” revealing a subset of mini toe bean-reminiscent structures composed of gas, dust, and young stars. Webb’s view reveals a chaotic scene still in development: Massive young stars are carving away at nearby gas and dust, while their bright starlight is producing a bright nebulous glow represented in blue. This is only a chapter in the region’s larger story. The disruptive young stars, with their relatively short lifespans and luminosity, will eventually quench the local star formation process. The Cat’s Paw Nebula is located approximately 4,000 light-years away in the constellation Scorpius. Credit: NASA, ESA, CSA, STScI
Webb captures evidence of a lightweight planet around TWA 7
Astronomers using the NASA/ESA/CSA James Webb Space Telescope have captured compelling evidence of a planet with a mass similar to Saturn orbiting the young nearby star TWA 7. If confirmed, this would represent Webb’s first direct image discovery of a planet, and the lightest planet ever seen with this technique.
The international team, led by Dr. Anne-Marie Lagrange, CNRS researcher at the Observatoire de Paris-PSL and Université Grenoble Alpes in France, detected a faint infrared source in the disc of debris surrounding TWA 7 using JWST’s Mid-Infrared Instrument (MIRI) and its coronagraph. The source is located about 1.5 arcseconds from the star on the sky which, at the distance of TWA7, is roughly fifty times the distance of the Earth to the Sun. This matches the expected position of a planet that would explain key features seen in the debris disc.
Using the coronagraph on Webb’s Mid-Infrared Instrument (MIRI) on 21 June 2024, the team carefully suppressed the bright glare of the host star to reveal faint nearby objects. This technique, called high-contrast imaging, enables astronomers to directly detect planets that would otherwise be lost in the overwhelming light from their host star. After subtracting residual starlight using advanced image processing, a faint infrared source was revealed near TWA 7, distinguishable from background galaxies or Solar System objects. The source is located in a gap in one of three dust rings that were discovered around TWA 7 by previous ground-based observations. Its brightness, colour, distance from the star, and position within the ring are consistent with theoretical predictions for a young, cold, Saturn-mass planet sculpting the surrounding debris disc.
“Our observations reveal a strong candidate for a planet shaping the structure of the TWA 7 debris disc, and its position is exactly where we expected to find a planet of this mass,”said Dr. Lagrange.
“This observatory enables us to capture images of planets with masses similar to those in the solar system, which represents an exciting step forward in our understanding of planetary systems, including our own,”
added co-author Mathilde Malin of Johns Hopkins University and the Space Telescope Science Institute in Baltimore.
Initial analysis suggests that the object — referred to as TWA 7b — could be a young, cold planet with a mass around 0.3 times that of Jupiter (~100 Earth masses) and a temperature near 320 Kelvin (roughly 47 degrees Celsius). Its location aligns with a gap in the disc, hinting at a dynamic interaction between the planet and its surroundings.
Debris discs filled with dust and rocky material are found around both young and older stars, although they are more easily detected around younger stars as they are brighter. They often feature visible rings or gaps, thought to be created by planets that have formed around the star, but such a planet has yet to be detected within a debris disc. Once verified, this discovery would mark the first time a planet has been directly associated with sculpting a debris disc and could offer the first observational hint of a trojan disc — a collection of dust trapped in the planet’s orbit.
TWA 7, also known as CE Antliae, is a young (~6.4 million years old) M-type star located about 111 light-years away in the TW Hydrae association. Its nearly face-on disc made it an ideal target for Webb’s high-sensitivity mid-infrared observations.
The findings highlight Webb’s ability to explore previously unseen, low-mass planets around nearby stars. Ongoing and future observations will aim to better constrain the properties of the candidate, verify its planetary status, and deepen our understanding of planet formation and disc evolution in young systems.This preliminary result showcases the exciting new frontier that JWST is opening for exoplanet discovery and characterisation.
These observations were taken as part of the Webb observing programme #3662. The results have been published today in Nature.
Astronomers using the NASA/ESA/CSA James Webb Space Telescope have captured compelling evidence of a planet with a mass similar to Saturn orbiting the young nearby star TWA 7. If confirmed, this would represent Webb’s first direct image discovery of a planet, and the lightest planet ever seen with this technique. Using the coronagraph on Webb’s Mid-Infrared Instrument (MIRI) on 21 June 2024, the team carefully suppressed the bright glare of the host star to reveal faint nearby objects. This technique, called high-contrast imaging, enables astronomers to directly detect planets that would otherwise be lost in the overwhelming light from their host star. After subtracting residual starlight using advanced image processing, a faint infrared source was revealed near TWA 7, distinguishable from background galaxies or Solar System objects. The source is located in a gap in one of three dust rings that were discovered around TWA 7 by previous ground-based observations. Its brightness, colour, distance from the star, and position within the ring are consistent with theoretical predictions for a young, cold, Saturn-mass planet sculpting the surrounding debris disc. Initial analysis suggests that the object — referred to as TWA 7b — could be a young, cold planet with a mass around 0.3 times that of Jupiter (~100 Earth masses) and a temperature near 320 Kelvin (roughly 47 degrees Celsius). In this image from MIRI, light from the star TWA 7 has been subtracted. The location of the star is marked with a circle and a star symbol at the centre of the image. This leaves light from the debris disc around the star, as well as other infrared sources, visible. The bright spot to the upper right of the star is the source identified as TWA 7b, within the debris disc. The more distant orange spot visible in the left of the image is an unrelated background star. Only a single MIRI band was used in this image (seen here in orange). The blue colour visible in the image results from an additional band taken by the SPHERE instrument of ESO’s Very Large Telescope (VLT), which showcases the location of the disc surrounding the host star and the exoplanet creating a gap within the disc that is revealed by MIRI. Credit: ESA/Webb, NASA, CSA, A.M. Lagrange, M. Zamani (ESA/Webb)
Hubble and a new study published in Nature Astronomy cast doubt on the certainty of a collision between the Milky Way and the Andromeda galaxy
Over a decade’s worth of NASA/ESA Hubble Space Telescope data was used to re-examine the long-held prediction that the Milky Way galaxy will collide with the Andromeda galaxy in about 4.5 billion years. The astronomers found that, based on the latest observational data from Hubble as well as the Gaia space telescope, there is only a 50-50 chance of the two galaxies colliding within the next 10 billion years. The study also found that the presence of the Large Magellanic Cloud can affect the trajectory of the Milky Way and make the collision less likely. The researchers emphasize that predicting the long-term future of galaxy interactions is highly uncertain, but the new findings challenge the previous consensus and suggest the fate of the Milky Way remains an open question.
Hubble and a new study published in Nature Astronomy cast doubt on the certainty of a collision between the Milky Way and the Andromeda galaxy. This selection of images of external galaxies illustrates three encounter scenarios between our Milky Way and the neighboring Andromeda galaxy. In the top left panel, a wide-field DSS image showing galaxies M81 and M82 serves as an example of the Milky Way and Andromeda passing each other at large distances. The top right panel shows NGC 6786, a pair of interacting galaxies displaying the telltale signs of tidal disturbances after a close encounter. The bottom panel shows NGC 520, a cosmic train wreck as two galaxies are actively merging together. Credit: NASA, ESA, STScI, Till Sawala (University of Helsinki), DSS, J. DePasquale (STScI)
As far back as 1912, astronomers realized that the Andromeda galaxy — then thought to be only a nebula — was headed our way. A century later, astronomers using the NASA/ESA Hubble Space Telescope were able to measure the sideways motion of Andromeda and found it was so negligible that an eventual head-on collision with the Milky Way seemed almost certain.
A smashup between our own galaxy and Andromeda would trigger a firestorm of star birth, supernovae, and maybe toss our Sun into a different orbit. Simulations had suggested it was inevitable.
However, a new study using data from Hubble and ESA’s Gaia suggests this may not necessarily be the case. Researchers combining observations from the two space observatories re-examined the long-held prediction of a Milky Way – Andromeda collision, and found it is far less inevitable than astronomers had previously suspected.
“We have the most comprehensive study of this problem today that actually folds in all the observational uncertainties,” said Till Sawala, astronomer at the University of Helsinki in Finland and lead author of the study, which appears today in the journal Nature Astronomy.
His team includes researchers at Durham University, United Kingdom; the University of Toulouse, France; and the University of Western Australia. They found that there is approximately a 50-50 chance of the two galaxies colliding within the next 10 billion years. They based this conclusion on computer simulations using the latest observational data.
Sawala emphasized that predicting the long-term future of galaxy interactions is highly uncertain, but the new findings challenge the previous consensus and suggest the fate of the Milky Way remains an open question.
“Even using the latest and most precise observational data available, the future of the Local Group of several dozen galaxies is uncertain. Intriguingly, we find an almost equal probability for the widely publicized merger scenario, or, conversely, an alternative one where the Milky Way and Andromeda survive unscathed,” said Sawala.
The collision of the two galaxies had seemed much more likely in 2012, when astronomers Roeland van der Marel and Tony Sohn of the Space Telescope Science Institute in Baltimore, Maryland published a detailed analysis of Hubble observations over a five-to-seven-year period, indicating a direct impact in no more than 5 billion years.
“It’s somewhat ironic that, despite the addition of more precise Hubble data taken in recent years, we are now less certain about the outcome of a potential collision. That’s because of the more complex analysis and because we consider a more complete system. But the only way to get to a new prediction about the eventual fate of the Milky Way will be with even better data,” said Sawala.
Astronomers considered 22 different variables that could affect the potential collision between our galaxy and our neighbor, and ran 100,000 simulations called Monte Carlo simulations stretching to 10 billion years into the future.
“Because there are so many variables that each have their errors, that accumulates to rather large uncertainty about the outcome, leading to the conclusion that the chance of a direct collision is only 50% within the next 10 billion years,” said Sawala.
“The Milky Way and Andromeda alone would remain in the same plane as they orbit each other, but this doesn’t mean they need to crash. They could still go past each other,” said Sawala.
Researchers also considered the effects of the orbits of Andromeda’s large satellite galaxy, M33, and a satellite galaxy of the Milky Way called the Large Magellanic Cloud (LMC).
“The extra mass of Andromeda’s satellite galaxy M33 pulls the Milky Way a little bit more towards it. However, we also show that the LMC pulls the Milky Way off the orbital plane and away from Andromeda. It doesn’t mean that the LMC will save us from that merger, but it makes it a bit less likely,” said Sawala.
In about half of the simulations, the two main galaxies fly past each other separated by around half a million light-years or less (five times the Milky Way’s diameter). They move outward but then come back and eventually merge in the far future. The gradual decay of the orbit is caused by a process called dynamical friction between the vast dark-matter halos that surround each galaxy at the beginning.
In most of the other cases, the galaxies don’t even come close enough for dynamical friction to work effectively. In this case, the two galaxies can continue their orbital waltz for a very long time.
The new result also still leaves a small chance of around 2% for a head-on collision between the galaxies in only 4 to 5 billion years. Considering that the warming Sun makes Earth uninhabitable in roughly 1 billion years, and the Sun itself will likely burn out in 5 billion years, a collision with Andromeda is the least of our cosmic worries.
Webb’s Titan forecast: partly cloudy with occasional methane showers
Astronomers see evidence of clouds bubbling up over Titan’s northern hemisphere.
A science team has combined data from the NASA/ESA/CSA James Webb Space Telescope and the Keck II telescope to see evidence of cloud convection on Saturn’s moon Titan in the northern hemisphere for the first time. Most of Titan’s lakes and seas are located in that hemisphere, and are likely replenished by an occasional rain of methane and ethane. Webb also has detected a key carbon-containing molecule that gives insight into the chemical processes in Titan’s complex atmosphere.
These infrared-light images of Titan were taken by the NASA/ESA/CSA James Webb Space Telescope on 11 July 2023. They show methane clouds appearing at different altitudes in Titan’s northern hemisphere. On the left side is a representative-colour image (1.4 microns is coloured blue, 1.5 microns is green, and 2.0 microns is red: filters F140M, F150W, and F200W, respectively). In the middle is a single-wavelength image taken by Webb at 2.12 microns. This wavelength is predominantly emitted from Titan’s lower troposphere. The rightmost image shows emission at 1.64 microns, which favours higher altitudes, in Titan’s upper troposphere and stratosphere (an atmospheric layer above the troposphere). Credit: NASA, ESA, CSA, STScI, Keck Observatory
Saturn’s moon Titan is an intriguing world cloaked in a yellowish, smoggy haze. Similar to Earth, the atmosphere is mostly nitrogen and has weather, including clouds and rain. Unlike Earth, whose weather is driven by evaporating and condensing water, frigid Titan has a methane (CH4) cycle. It evaporates from the surface and rises into the atmosphere, where it condenses to form methane clouds. Occasionally it falls as a chilly, oily rain onto a solid surface where water ice is hard as rocks.
“Titan is the only other place in our Solar System that has weather like Earth, in the sense that it has clouds and rainfall onto a surface,” explained lead author Conor Nixon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
The team observed Titan in November 2022 and July 2023 using both Webb and one of the twin ground-based W.M. Keck telescopes. Those observations not only showed clouds in the mid and high northern latitudes on Titan — the hemisphere where it is currently summer — but also showed those clouds apparently rising to higher altitudes over time. While previous studies have observed cloud convection at southern latitudes, this is the first time evidence for such convection has been seen in the north. This is significant because most of Titan’s lakes and seas are located in its northern hemisphere and evaporation from lakes is a major potential methane source.
On Earth the lowest layer of the atmosphere, or troposphere, extends up to an altitude of about 12 kilometers. However, on Titan, whose lower gravity allows the atmospheric layers to expand, the troposphere extends up to about 45 kilometers. Webb and Keck used different infrared filters to probe to different depths in Titan’s atmosphere, allowing astronomers to estimate the altitudes of the clouds. The science team observed clouds that appeared to move to higher altitudes over a period of days, although they were not able to directly see any precipitation occurring.
“Webb’s observations were taken at the end of Titan’s northern summer, which is a season that we were unable to observe with the Cassini-Huygens mission,” said Thomas Cornet of the European Space Agency, a co-author of the study. “Together with ground-based observations, Webb is giving us precious new insights into Titan’s atmosphere, that we hope to be able to investigate much closer-up in the future with a possible ESA mission to visit the Saturn system.”
Titan’s chemistry
Titan is an object of high astrobiological interest due to its complex organic (carbon-containing) chemistry, despite its frigid temperature of about -180 degrees Celsius. Organic molecules form the basis of all life on Earth, and studying them on a world like Titan may help scientists understand the processes that led to the origin of life on Earth.
The basic ingredient that drives much of Titan’s chemistry is methane. Methane in Titan’s atmosphere gets split apart by sunlight or energetic electrons from Saturn’s magnetosphere, and then recombines with other molecules to make substances like ethane (C2H6) along with more complex carbon-bearing molecules.
Webb’s data provided a key missing piece for our understanding of the chemical processes: a definitive detection of the methyl radical CH3. This molecule (called “radical” because it has a “free” electron that is not in a chemical bond) forms when methane is broken apart. Detecting this substance means that scientists can see chemistry in action on Titan for the first time, rather than just the starting ingredients and the end products.
“For the first time we can see the chemical cake while it’s rising in the oven, instead of just the starting ingredients of flour and sugar, and then the final, iced cake,” said co-author Stefanie Milam of the Goddard Space Flight Center.
The future of Titan’s atmosphere
This hydrocarbon chemistry has long-term implications for the future of Titan. When methane is broken apart in the upper atmosphere, some of it recombines to make other molecules that eventually end up on Titan’s surface in one chemical form or another, while some hydrogen escapes from the atmosphere. As a result, methane will be depleted over time, unless there is some source to replenish it.
A similar process occurred on Mars, where water molecules were broken up and the resulting hydrogen lost to space. The result was the dry, desert planet we see today.
“On Titan, methane is a consumable. It’s possible that it is being constantly resupplied and fizzing out of the crust and interior over billions of years. If not, eventually it will all be gone and Titan will become a mostly airless world of dust and dunes,” said Nixon.
This data was taken as part of Heidi Hammel’s Guaranteed Time Observations program to study the Solar System. The results were published in the journal Nature Astronomy.
These images of Titan were taken by the NASA/ESA/CSA James Webb Space Telescope on 11July 2023 (top row) and the ground-based W.M. Keck Observatories on 14 July 2023 (bottom row). They show methane clouds (denoted by the white arrows) appearing at different altitudes in Titan’s northern hemisphere. On the left side are representative-colour images from both telescopes. In the Webb image light at 1.4 microns is coloured blue, 1.5 microns is green, and 2.0 microns is red (filters F140M, F150W, and F200W, respectively). In the Keck image light at 2.13 microns is coloured blue, 2.12 microns is green, and 2.06 microns is red (H2 1-0, Kp, and He1b, respectively). In the middle column are single-wavelength images taken by Webb and Keck at 2.12 microns. This wavelength is sensitive to emission from Titan’s lower troposphere. The rightmost images show emission at 1.64 microns (Webb) and 2.17 microns (Keck), which favour higher altitudes, in Titan’s upper troposphere and stratosphere (an atmospheric layer above the troposphere). It demonstrates that the clouds are seen at higher altitudes on July 14 than earlier on July 11, indicative of upward motion. Credit: NASA, ESA, CSA, STScI, Keck Observatory
Bibliographic information:
Nixon, C.A., Bézard, B., Cornet, T. et al., The atmosphere of Titan in late northern summer from JWST and Keck observations, Nat Astron (2025), DOI: https://doi.org/10.1038/s41550-025-02537-3
The NASA/ESA/CSA James Webb Space Telescope has captured new details of the auroras on our Solar System’s largest planet. The dancing lights observed on Jupiter are hundreds of times brighter than those seen on Earth. With Webb’s advanced sensitivity, astronomers have studied the phenomena to better understand Jupiter’s magnetosphere.
The NASA/ESA/CSA James Webb Space Telescope has captured new details of the auroras on our Solar System’s largest planet. The dancing lights observed on Jupiter are hundreds of times brighter than those seen on Earth. These observations of Jupiter’s auroras were captured with Webb’s Near-InfraRed Camera (NIRCam) on 25 December 2023 (F335M filter). Scientists found that the emission from the trihydrogen ion, known as H3+, is far more variable than previously believed. H3+ is created by the impact of high energy electrons on molecular hydrogen. Because this emission shines brightly in the infrared, Webb’s instruments are well equipped to observe it. Credit: ESA/Webb, NASA, CSA, J. Nichols (University of Leicester), M. Zamani (ESA/Webb)
The auroras are created when high-energy particles enter a planet’s atmosphere near its magnetic poles and collide with atoms of gas. Not only are the auroras on Jupiter huge in size, they are also hundreds of times more energetic than auroras on Earth. Here, auroras are caused by solar storms — when charged particles rain down on the upper atmosphere, excite gases and cause them to glow colours of red, green and purple. Meanwhile, Jupiter has an additional source for its auroras; the strong magnetic field of the gas giant grabs charged particles from its surroundings. This includes not only the charged particles within the solar wind but also the particles thrown into space by its orbiting moon Io, known for its numerous and large volcanoes. Io’s volcanoes spew particles that, remarkably, escape the moon’s gravity and orbit Jupiter. A barrage of charged particles unleashed by the sun during solar storms also reaches the planet. Jupiter’s large and powerful magnetic field captures charged particles and accelerates them to tremendous speeds. These speedy particles slam into the planet’s atmosphere at high energies, which excites the gas and causes it to glow.
Now, Webb’s unique capabilities are providing new insights into the auroras on Jupiter. The telescope’s sensitivity allows astronomers to increase the shutter speed in order to capture fast-varying auroral features. New data was captured with Webb’s Near-InfraRed Camera (NIRCam) on Christmas Day 2023 by a team of scientists led by Jonathan Nichols from the University of Leicester in the United Kingdom.
“What a Christmas present it was – it just blew me away!” shared Nichols. “We wanted to see how quickly the auroras change, expecting it to fade in and out ponderously, perhaps over a quarter of an hour or so. Instead we observed the whole auroral region fizzing and popping with light, sometimes varying by the second.”
The NASA/ESA/CSA James Webb Space Telescope has captured new details of the auroras on our Solar System’s largest planet. The dancing lights observed on Jupiter are hundreds of times brighter than those seen on Earth. These observations of Jupiter’s auroras (shown on the left of the above image) were captured with Webb’s Near-InfraRed Camera (NIRCam) on 25 December 2023 (F335M filter). Scientists found that the emission from the trihydrogen ion, known as H3+, is far more variable than previously believed. H3+ is created by the impact of high energy electrons on molecular hydrogen. Because this emission shines brightly in the infrared, Webb’s instruments are well equipped to observe it. The image on the right shows the planet Jupiter to indicate the location of the observed auroras, which was originally published in 2023 (F164N, F212N, and F360M filters). Credit: NASA, ESA, CSA, STScI, Ricardo Hueso (UPV), Imke de Pater (UC Berkeley), Thierry Fouchet (Observatory of Paris), Leigh Fletcher (University of Leicester), Michael H. Wong (UC Berkeley), Joseph DePasquale (STScI), J. Nichols (University of Leicester), M. Zamani (ESA/Webb)
The team’s data found that the emission from the trihydrogen ion, known as H3+, is far more variable than previously believed. The observations will help develop scientists’ understanding of how Jupiter’s upper atmosphere is heated and cooled.
The team also uncovered some unexplained observations in their data.
“What made these observations even more special is that we also took pictures simultaneously in the ultraviolet with the NASA/ESA Hubble Space Telescope,” added Nichols. “Bizarrely, the brightest light observed by Webb had no real counterpart in Hubble’s pictures. This has left us scratching our heads. In order to cause the combination of brightness seen by both Webb and Hubble, we need to have an apparently impossible combination of high quantities of very low energy particles hitting the atmosphere – like a tempest of drizzle! We still don’t understand how this happens.”
The team now plans to study this discrepancy between the Hubble and Webb data and to explore the wider implications for Jupiter’s atmosphere and space environment. They also intend to follow up this research with more Webb observations, which they can compare with data from NASA’s Juno spacecraft to better explore the cause of the enigmatic bright emission. These insights may also support the European Space Agency’s Jupiter Icy Moons Explorer, Juice, which is en route to Jupiter to make detailed observations of the giant gas planet and its three large ocean-bearing moons – Ganymede, Callisto and Europa. Juice will take a look at Jupiter’s auroras with seven unique scientific instruments, including two imagers. These close-up measurements will help us understand how the planet’s magnetic field and atmosphere interact, as well as the effect that charged particles from Io and the other moons have on Jupiter’s atmosphere.
The NASA/ESA/CSA James Webb Space Telescope has captured new details of the auroras on our Solar System’s largest planet. The dancing lights observed on Jupiter are hundreds of times brighter than those seen on Earth. These observations of Jupiter’s auroras were captured with Webb’s Near-InfraRed Camera (NIRCam) on 25 December 2023 (F335M filter). Scientists found that the emission from the trihydrogen ion, known as H3+, is far more variable than previously believed. H3+ is created by the impact of high energy electrons on molecular hydrogen. Because this emission shines brightly in the infrared, Webb’s instruments are well equipped to observe it. The timestamps indicated in the lower right corner of each image indicates the time (UTC) when these observations were taken on 25 December 2023. Credit: ESA/Webb, NASA, CSA, J. Nichols(University of Leicester), M. Zamani (ESA/Webb)
These results were obtained from data using Webb’s Cycle 2 observing programme #4566 and Hubble’s observing programme #17471. The results were published today in Nature Communications.
In celebration of the NASA/ESA Hubble Space Telescope’s 35 years in Earth orbit, an assortment of compelling images have been released today that were recently taken by Hubble. This stretches from the planet Mars to dramatic images of stellar birth and death, to a magnificent neighbouring galaxy. After over three decades of perusing the restless universe, Hubble remains a household word as the most well-recognized telescope in scientific history.
Astronomers knew that placing a telescope above Earth’s blurry atmosphere would allow for them to behold the Universe like never before. Hubble’s view would be ten times sharper than conventional ground-based telescopes of the time. Its high sensitivity would uncover objects more than one-billionth the brightness of the faintest stars seen by the human eye. Unfiltered by Earth’s atmosphere, its broad wavelength coverage would stretch from ultraviolet to near-infrared light. Glorious celestial wonders would come into focus. Moreover, Hubble would be an audacious leap forward in human imagination, engineering prowess, and boundless curiosity.
Before Hubble, no generation ever had access to unimaginably vibrant views of space, stretching almost all the way back to almost the beginning of time. For most of history, the complexity and extent of the vast cosmos was left largely to human imagination. But Hubble entered the final sprint in the race to the edge of the visible Universe. In the early 1920s, the telescope’s namesake, astronomer Edwin Hubble, started this marathon with the discovery of galaxies outside of our Milky Way.
Hubble today is at the peak of its scientific return thanks to the dedication, perseverance and skills of engineers, scientists and mission operators. Astronaut shuttle crews gallantly chased and rendezvoused with Hubble on five servicing missions from 1993 to 2009. The astronauts, including ESA astronauts on two of the servicing missions, upgraded Hubble’s cameras, computers and other support systems.
By extending Hubble’s operational life the telescope has made nearly 1.7 million observations, looking at approximately 55,000 astronomical targets. Hubble discoveries have resulted in over 22,000 papers and over 1.3 million citations as of February 2025. All the data collected by Hubble is archived and currently adds up to over 400 terabytes. The demand for observing time remains very high with 6:1 oversubscriptions, making it one of the most in-demand observatories today.
Hubble’s long operational life has allowed astronomers to see astronomical changes spanning over three decades: seasonal variability on the planets in our solar system, black hole jets travelling at nearly the speed of light, stellar convulsions, asteroid collisions, expanding supernova bubbles, and much more.
A lasting legacy
Hubble’s legacy is the bridge between our past and future knowledge of a Universe that is unbelievably glorious, as well as rambunctious — with colliding galaxies, voracious black holes, and relentless stellar fireworks. Hubble, more than any other telescope, sees the Universe through the eyes of Einstein: microlensing, time-dilation, the cosmological constant, matter disappearing into a black hole, a source of gravitational waves.
Before 1990, powerful optical telescopes on Earth could see only halfway across the cosmos. Estimates for the age of the Universe disagreed by a big margin. Supermassive black holes were only suspected to be the powerhouses behind a rare zoo of energetic phenomena. Not a single planet had been seen around another star.
Among its long list of breakthroughs: Hubble’s deep fields unveiled myriad galaxies dating back to the early Universe; precisely measured the Universe’s expansion; found that supermassive black holes are common among galaxies; made the first measurement of the atmospheres of extrasolar planets; contributed to discovering dark energy, which is accelerating the Universe.
After three decades, Hubble remains a household word as the most well-recognized and celebrated scientific instrument in all of human history. Hubble’s discoveries and images have been nothing less than transformative for the public’s perception of the cosmos. Unlike any other telescope before it, Hubble has made astronomy very relevant, engaging, and accessible for people of all ages. Hubble became “the people’s telescope,” touching the minds as well as the emotions of hundreds of millions of humans around the globe.
A single Hubble snapshot can portray the Universe as awesome, mysterious, and beautiful—and at the same time chaotic, overwhelming, and foreboding. These pictures have become iconic, seminal, and timeless. They viscerally communicate the value of science: the awe and drive to seek understanding of our place in the cosmos. In commemoration NASA and ESA released images today of five astronomical targets that were selected for the celebration, ranging from planets to nebulae to galaxies.
The relentless pace of Hubble’s trailblazing discoveries kicked-started a new generation of space telescopes for the 21st century. The powerful James Webb Space Telescope may not have been built without Hubble revealing an “undiscovered country” of far-flung, seemingly countless galaxies. Hubble provided the first observational evidence that there was a lot for Webb to pursue in infrared wavelengths that reach even greater distances beyond Hubble’s gaze. Now, Hubble and Webb are often being used in complement to study everything from exoplanets to galaxy dynamics.
35th anniversary images
An assortment of compelling images have been released today that were recently taken by Hubble:
Mars: These are a combination of Hubble Space Telescope images of Mars taken from December 28th to 30th, 2024. At the midpoint of the observations, Mars was approximately 98 million kilometres from Earth. Thin water-ice clouds that are apparent in ultraviolet light give the Red Planet a frosty appearance. The icy northern polar cap was experiencing the start of Martian spring.
In celebration of the NASA/ESA Hubble Space Telescope’s 35 years in Earth orbit, an assortment of compelling images have been released today that were recently taken by Hubble:
Upper left: The planet Mars as seen in late December 2024. Thin water-ice clouds, revealed by Hubble’s unique ultraviolet capability, give the Red Planet a frosty appearance.
Upper right: Planetary nebula NGC 2899. This moth-like nebula is sculpted by the outflow of radiation and stellar winds from a dying star – a white dwarf – at the center.
Lower left: The Rosette Nebula. This is a small portion of the huge star-forming region. Dark clouds of hydrogen gas laced with dust are silhouetted across the image.
Lower right: The galaxy NGC 5335, which is a flocculent spiral galaxy with patchy streamers of star formation across its disc. A notable bar structure slices across the center of the galaxy.
Credit: NASA, ESA, STScI
This is a combination of Hubble Space Telescope images of Mars taken from December 28th to 30th, 2024. At the midpoint of the observations, Mars was approximately 98 million kilometres from Earth. Thin water-ice clouds that are apparent in ultraviolet light give the Red Planet a frosty appearance. The icy northern polar cap was experiencing the start of Martian spring.
In the left image, the bright orange Tharsis plateau is visible with its chain of dormant volcanoes. The largest volcano, Olympus Mons, pokes above the clouds at the 10 o’clock position near the northwest limb. At an elevation of 21 000 metres, it is 2.5 times the height of Mt. Everest above sea level. Valles Marineris, Mars’ roughly 4,000 kilometre-long canyon system, is a dark, linear, horizontal feature near center left.
In the right image, high-altitude evening clouds can be seen along the planet’s eastern limb. The 2,250-kilometre-wide Hellas basin, an ancient asteroid impact feature, appears far to the south. Most of the hemisphere is dominated by the classical “shark fin” feature, Syrtis Major.
Credit: NASA, ESA, STScI
This pair of NASA/ESA Hubble Space Telescope images of Mars taken on 28 December (top) and 29 December (bottom) 2024. Each image shows a different side of the planet, with the accompanying moon Phobos. Various features are identified in the images, including the polar ice caps and clouds, as well as multiple terrestrial features.
At the midpoint of the observations, Mars was approximately 98 million kilometres from Earth. Thin water-ice clouds that are apparent in ultraviolet light give the Red Planet a frosty appearance. The icy northern polar cap was experiencing the start of Martian spring.
In the top image, the bright orange Tharsis plateau is visible with its chain of dormant volcanoes. The largest volcano, Olympus Mons, pokes above the clouds at the 10 o’clock position near the northwest limb. At an elevation of over 21 000 meters, it is 2.5 times the height of Mt. Everest above sea level. Valles Marineris, Mars’ over 4,000-kilometre-long canyon system, is a dark, linear, horizontal feature near center left.
In the bottom image, high-altitude evening clouds can be seen along the planet’s eastern limb. The 2,250-kilometre-wide Hellas basin, an ancient asteroid impact feature, appears far to the south. Most of the hemisphere is dominated by the classical “shark fin” feature, Syrtis Major.
Credit: NASA, ESA, STScI
Planetary nebula NGC 2899: This object has a diagonal, bipolar, cylindrical outflow of gas. This is propelled by radiation and stellar winds from a nearly 22 000 degree Celsius white dwarf at the center. In fact, there may be two companion stars that are interacting and sculpting the nebula, which is pinched in the middle by a fragmented ring or torus – looking like a half-eaten donut. It has a forest of gaseous “pillars” that point back to the source of radiation and stellar winds. The colors are from glowing hydrogen and oxygen. The nebula lies approximately 4,500 light-years away in the southern constellation Vela.
This Hubble Space Telescope image captures the beauty of the moth-like planetary nebula NGC 2899. This object has a diagonal, bipolar, cylindrical outflow of gas. This is propelled by radiation and stellar winds from a nearly 22 000 degree Celsius white dwarf at the center. In fact, there may be two companion stars that are interacting and sculpting the nebula, which is pinched in the middle by a fragmented ring or torus – looking like a half-eaten donut. It has a forest of gaseous “pillars” that point back to the source of radiation and stellar winds. The colours are from glowing hydrogen and oxygen. The nebula lies approximately 4,500 light-years away in the southern constellation Vela.
Credit: NASA, ESA, STScI
This Hubble Space Telescope image captures the beauty of the moth-like planetary nebula NGC 2899. This object has a diagonal, bipolar, cylindrical outflow of gas. This is propelled by radiation and stellar winds from a nearly 22 000 degree Celsius white dwarf at the center. In fact, there may be two companion stars that are interacting and sculpting the nebula, which is pinched in the middle by a fragmented ring or torus – looking like a half-eaten donut. It has a forest of gaseous “pillars” that point back to the source of radiation and stellar winds. The colours are from glowing hydrogen and oxygen. The nebula lies approximately 4,500 light-years away in the southern constellation Vela.
Credit: NASA, ESA, STScI
Rosette Nebula: This is a Hubble Space Telescope photo of a small portion of the Rosette Nebula, a huge star-forming region spanning 100 light-years across and located 5,200 light-years away. Hubble zooms into a small portion of the nebula that is only 4 light-years across (the approximate distance between our Sun and the neighbouring Alpha Centauri star system.) Dark clouds of hydrogen gas laced with dust are silhouetted across the image. The clouds are being eroded and shaped by the seething radiation from the cluster of larger stars in the center of the nebula (NGC 2440). An embedded star seen at the tip of a dark cloud in the upper right portion of the image is launching jets of plasma that are crashing into the cold cloud around it. The resulting shock wave is causing a red glow. The colors come from the presence of hydrogen, oxygen, and nitrogen.
This is a Hubble Space Telescope photo of a small portion of the Rosette Nebula, a huge star-forming region spanning 100 light-years across and located 5,200 light-years away. Hubble zooms into a small portion of the nebula that is only 4 light-years across (the approximate distance between our Sun and the neighbouring Alpha Centauri star system.) Dark clouds of hydrogen gas laced with dust are silhouetted across the image. The clouds are being eroded and shaped by the seething radiation from the cluster of larger stars in the center of the nebula (NGC 2440). An embedded star seen at the tip of a dark cloud in the upper right portion of the image is launching jets of plasma that are crashing into the cold cloud around it. The resulting shock wave is causing a red glow. The colours come from the presence of hydrogen, oxygen, and nitrogen.
Credit: NASA, ESA, STScI
The Rosette Nebula is a vast star-forming region, 100 light-years across, that lies at one end of a giant molecular cloud the constellation Monoceros. The nebula is estimated to contain around 10,000 solar masses. The nebula is located about 5,000 light-years away from Earth. Intense radiation from the young stars inside a cluster in the nebula causes the gasses to glow. The background image is from the Digitized Sky Survey, while the inset is a small portion of the nebula as photographed by the Hubble Space Telescope. Dark clouds of hydrogen gas laced with dust are silhouetted across the image. The colours come from the presence of hydrogen, oxygen, and nitrogen.
Credit: NASA, ESA, STScI, DSS
This is a Hubble Space Telescope photo of a small portion of the Rosette Nebula, a huge star-forming region spanning 100 light-years across and located 5,200 light-years away. Hubble zooms into a small portion of the nebula that is only 4 light-years across (the approximate distance between our Sun and the neighbouring Alpha Centauri star system.) Dark clouds of hydrogen gas laced with dust are silhouetted across the image. The clouds are being eroded and shaped by the seething radiation from the cluster of larger stars in the center of the nebula (NGC 2440). An embedded star seen at the tip of a dark cloud in the upper right portion of the image is launching jets of plasma that are crashing into the cold cloud around it. The resulting shock wave is causing a red glow. The colours come from the presence of hydrogen, oxygen, and nitrogen.
Credit: NASA, ESA, STScI
Barred Spiral Galaxy NGC 5335: This object is categorized as a flocculent spiral galaxy with patchy streamers of star formation across its disk. There is a striking lack of well-defined spiral arms that are commonly found among galaxies, including our Milky Way. A notable bar structure slices across the center of the galaxy. The bar channels gas inwards toward the galactic center, fueling star formation. Such bars are dynamic in galaxies and may come and go over two-billion-year intervals. They appear in about 30 percent of observed galaxies, including our Milky Way.
The Hubble Space Telescope captured in exquisite detail a face-on view of a remarkable-looking galaxy. NGC 5335 is categorized as a flocculent spiral galaxy with patchy streamers of star formation across its disk. There is a striking lack of well-defined spiral arms that are commonly found among galaxies, including our Milky Way. A notable bar structure slices across the center of the galaxy. The bar channels gas inwards toward the galactic center, fueling star formation. Such bars are dynamic in galaxies and may come and go over two-billion-year intervals. They appear in about 30 percent of observed galaxies, including our Milky Way.
Credit: NASA, ESA, STScI
The Hubble Space Telescope captured in exquisite detail a face-on view of a remarkable-looking galaxy. NGC 5335 is categorized as a flocculent spiral galaxy with patchy streamers of star formation across its disk. There is a striking lack of well-defined spiral arms that are commonly found among galaxies, including our Milky Way. A notable bar structure slices across the center of the galaxy. The bar channels gas inwards toward the galactic center, fueling star formation. Such bars are dynamic in galaxies and may come and go over two-billion-year intervals. They appear in about 30 percent of observed galaxies, including our Milky Way.
Credit: NASA, ESA, STScI
Hubble’s science and discoveries in recent years
Even at the impressive age of 35, there has been no slowdown in the research and new discoveries made using Hubble — if anything, the opposite. Astronomers from Europe make intensive use of the telescope, with the share of observing time awarded to European-led programmes being consistently above the 15% guaranteed by ESA’s participation in the Hubble mission thanks to their many proposals with strong scientific merit. This has led directly to discoveries including evidence for an intermediate-mass black hole in Omega Centauri, a precursor to the earliest supermassive black holes, a bizarre explosion of extraordinarily bright light originating far from any host galaxy, hydrogen burning in white dwarf stars, and the absence of Population III stars as far back in time as Hubble can see. A particular highlight, and a demonstration of Hubble’s incredible capabilities, was the discovery in 2022 of Earendel. The most distant single star ever seen, Earendel is viewed 12.9 billion years into the past when the Universe was under a billion years old.
Benefitting from Hubble’s long operational life, the OPAL programme celebrated a decade studying the Solar System’s outer planets. Discoveries such as evidence for water vapour on Jupiter’s moons Europa and Ganymede, “spokes” in Saturn’s rings, the size of Jupiter’s Great Red Spot, and the colours of Uranus and Neptune are just some that have resulted. Smaller Solar System bodies got attention from Hubble as well — not least the asteroid Dimorphos, target of the DART asteroid redirection test. Hubble took images of Dimorphos before and after the impact alongside Webb, later producing a movie of the debris and spotting ejected boulders. A citizen science project also discovered thousands of asteroid trails in over two decades of archived Hubble snapshots.
Beyond the Solar System, Hubble proved its continued importance in the rapidly-growing field of research into exoplanets. It studied weather patterns in an exoplanet’s atmosphere, saw a new atmosphere being formed around a rocky exoplanet similar to Earth, and found a small exoplanet with water vapour in its atmosphere. Also completed in 2021 was a compilation of supernova host galaxies from 18 years of study, images that were used to measure the Hubble constant to its highest accuracy yet. This year too brought the culmination of the largest ever photomosaic of the Andromeda Galaxy, created from ten years of Hubble observations of our near neighbour.
More information
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 the 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.
Hubble spies a cosmic pillar in the Eagle Nebula, also known as Messier 16
In anticipation of the upcoming 35th anniversary of the NASA/ESA Hubble Space Telescope, ESA/Hubble is continuing the celebrations with a new view of the Eagle Nebula. This vast stellar nursery displays a towering spire of cosmic gas and dust that incorporates new data processing techniques developed since an image of this region was last released two decades ago.
Does this Hubble image of a sculpted pillar of gas and dust look to you like a curling party streamer, a plume of smoke from a blown-out candle, or an unusual balloon? Regardless of what you see when you gaze at this cosmic cloud, this new portrait is a cause for celebration.
As part of ESA/Hubble’s 35th anniversary celebrations, a new image series is being shared to revisit stunning Hubble targets that were previously released. New images of NGC 346 and the Sombrero Galaxy have already been published. Now, ESA/Hubble is revisiting the Eagle Nebula (originally published in 2005 as part of Hubble’s 15th anniversary celebrations) with new image processing techniques.
Unfurling along the length of the image is a pillar of cold gas and dust that is 9.5 light-years tall. As enormous as this dusty pillar is, it’s just one small piece of the greater Eagle Nebula, which is also called Messier 16. The name Messier 16 comes from the French astronomer Charles Messier, a comet hunter who compiled a catalogue of deep-sky objects that could be mistaken for comets.
The name Eagle Nebula was inspired by the nebula’s appearance. The edge of this shining nebula is shaped by dark clouds like this one, giving it the appearance of an eagle spreading its wings.
Not too far from the region pictured here are the famous Pillars of Creation, which Hubble has photographed multiple times, with images released in 1995 and 2015.
The heart of the nebula, which is located beyond the edge of this image, is home to a cluster of young stars. These stars have excavated an immense cavity in the centre of the nebula, shaping otherworldly pillars and globules of dusty gas. This particular feature extends like a pointing finger toward the centre of the nebula and the rich young star cluster embedded there.
The Eagle Nebula is one of many nebulae in the Milky Way that are known for their sculpted, dusty clouds. Nebulae take on these fantastic shapes when exposed to powerful radiation and winds from infant stars. Regions with denser gas are more able to withstand the onslaught of radiation and stellar winds from young stars, and these dense areas remain as dusty sculptures like the starry pillar shown here.
This image was developed using data from the Hubble observing programme #10393 (PI: K. Noll).
This towering structure of billowing gas and dark, obscuring dust might only be a small portion of the Eagle Nebula, but it is no less majestic in appearance for it. 9.5 light-years tall and 7000 light-years distant from Earth, this dusty sculpture is refreshed with the use of new processing techniques. The new Hubble image is part of ESA/Hubble’s 35th anniversary celebrations. The cosmic cloud shown here is made of cold hydrogen gas, like the rest of the Eagle Nebula. In such regions of space new stars are born among the collapsing clouds. Hot, energetic and formed in great numbers, the stars unleash an onslaught of ultraviolet light and stellar winds that sculpt the gas clouds around them. This produces fantastical shapes like the narrow pillar with blossoming head that we see here. The material in the pillar is thick and opaque to light; it is highlighted at its edges by the glow of more distant gas behind it. The blue colours of the background are dominated by emission from ionised oxygen; the red colours lower down, glowing hydrogen. Orange colours indicate starlight that has managed to break through the dust: bluer wavelengths are blocked more easily by dust, leaving the redder light to pass through. The stars responsible for carving this particular structure out of the stellar raw material lie just out of view, at the Eagle Nebula’s centre. As the pressure of their intense radiation batters and compresses the gas in this tower of clouds, it’s possible that further star formation is being ignited within. While the starry pillar has withstood these forces well so far, cutting an impressive shape against the background, eventually it will be totally eroded by the multitude of new stars that form in the Eagle Nebula. Credit: ESA/Hubble & NASA, K. Noll
Hubble provides a new view of a galactic favourite, Sombrero Galaxy, or Messier 104
In anticipation of the upcoming 35th anniversary of the NASA/ESA Hubble Space Telescope, ESA/Hubble is continuing the celebrations with a new image of the Sombrero Galaxy, also known as Messier 104. An eye-catching target for Hubble and a favourite of amateur astronomers, the enigmatic Sombrero Galaxy has features of both spiral and elliptical galaxies. This image incorporates new processing techniques that highlight the unique structure of this galaxy.
As part of ESA/Hubble’s 35th anniversary celebrations, a new image series is being shared to revisit stunning Hubble targets that were previously released. First, a new image of NGC 346 was published. Now, ESA/Hubble is revisiting a fan-favourite galaxy with new image processing techniques. The new image reveals finer detail in the galaxy’s disc, as well as more background stars and galaxies.
Several Hubble images of the Sombrero Galaxy have been released over the past two decades, including this well-known Hubble image from October 2003. In November 2024, the NASA/ESA/CSA James Webb Space Telescope also gave an entirely new perspective on this striking galaxy.
Located around 30 million light-years away in the constellation Virgo, the Sombrero Galaxy is instantly recognisable. Viewed nearly edge on, the galaxy’s softly luminous bulge and sharply outlined disc resemble the rounded crown and broad brim of the Mexican hat from which the galaxy gets its name.
Though the Sombrero Galaxy is packed with stars, it’s surprisingly not a hotbed of star formation. Less than one solar mass of gas is converted into stars within the knotted, dusty disc of the galaxy each year. Even the galaxy’s central supermassive black hole, which at 9 billion solar masses is more than 2000 times more massive than the Milky Way’s central black hole, is fairly calm.
The galaxy is too faint to be spotted with unaided vision, but it is readily viewable with a modest amateur telescope. Seen from Earth, the galaxy spans a distance equivalent to roughly one third of the diameter of the full Moon. The galaxy’s size on the sky is too large to fit within Hubble’s narrow field of view, so this image is actually a mosaic of several images stitched together.
One of the things that makes this galaxy especially notable is its viewing angle, which is inclined just six degrees off of the galaxy’s equator. From this vantage point, intricate clumps and strands of dust stand out against the brilliant white galactic nucleus and bulge, creating an effect not unlike Saturn and its rings — but on an epic galactic scale.
At the same time, this extreme angle makes it difficult to discern the structure of the Sombrero Galaxy. It’s not clear whether it’s a spiral galaxy, like our own Milky Way, or an elliptical galaxy. Curiously, the galaxy’s disc seems like a fairly typical disc for a spiral galaxy, and its spheroidal bulge and halo seem fairly typical for an elliptical galaxy — but the combination of the two components resembles neither a spiral nor an elliptical galaxy.
Researchers have used Hubble to investigate the Sombrero Galaxy, measuring the amount of metals (what astronomers call elements heavier than helium) in stars in the galaxy’s expansive halo. This type of measurement can illuminate a galaxy’s history, potentially revealing whether it has merged with other galaxies in the past. In the case of the Sombrero Galaxy, extremely metal-rich stars in the halo point to a possible merger with a massive galaxy several billion years ago. An ancient galactic clash, hinted at by Hubble’s sensitive measurements, could explain the Sombrero Galaxy’s distinctive appearance.
This image was developed using data from the Hubble observing programme #9714 (PI: K. Noll)
Located around 30 million light-years away in the constellation Virgo, the Sombrero Galaxy is instantly recognisable. Viewed nearly edge on, the galaxy’s softly luminous bulge and sharply outlined disc resemble the rounded crown and broad brim of the Mexican hat from which the galaxy gets its name. Though the Sombrero Galaxy is packed with stars, it’s surprisingly not a hotbed of star formation. Less than one solar mass of gas is converted into stars within the knotted, dusty disc of the galaxy each year. Even the galaxy’s central supermassive black hole, which at 9 billion solar masses is more than 2000 times more massive than the Milky Way’s central black hole, is fairly calm. The galaxy is too faint to be spotted with unaided vision, but it is readily viewable with a modest amateur telescope. Seen from Earth, the galaxy spans a distance equivalent to roughly one third of the diameter of the full Moon. The galaxy’s size on the sky is too large to fit within Hubble’s narrow field of view, so this image is actually a mosaic of several images stitched together. Credit: ESA/Hubble & NASA, K. Noll
Hubble investigates SGR 0501+4516 and the magnetar’s birthplace
Magnetars are ultra-dense stellar remnants with extremely strong magnetic fields. Researchers using the NASA/ESA Hubble Space Telescope have discovered that the magnetar SGR 0501+4516 was not born in a neighbouring supernova as previously thought. The birthplace of this object is now unknown, and SGR 0501+4516 is the likeliest candidate in our galaxy for a magnetar that was not born in a supernova. This discovery was made possible by Hubble’s sensitive instruments as well as precise benchmarks from ESA’s Gaia spacecraft.
In 2008, NASA’s Swift Observatory spotted brief, intense flashes of gamma rays from the outskirts of the Milky Way. The source, an object named SGR 0501+4516, is one of only about 30 known magnetars in the Milky Way.
A magnetar is a special type of neutron star. Neutron stars are some of the most extreme objects in the Universe. These stars typically pack more than the mass of the Sun into a sphere of neutrons about 20 kilometres across. Unsurprisingly, these exotic objects can display several extreme behaviours, such as X-ray and gamma-ray outbursts, intense magnetic fields and rapid rotation.
“Magnetars are neutron stars — the dead remnants of stars, composed entirely of neutrons. They’re so heavy and dense that the electrons and protons which make up atoms have been crushed together into neutrons. What makes magnetars unique is their extreme magnetic fields, billions of times stronger than the strongest magnets we have on Earth,”
said Ashley Chrimes, lead author of the discovery paper published today in the journal Astronomy & Astrophysics. Chrimes is a European Space Agency Research Fellow at the European Space Research and Technology Centre (ESTEC) in the Netherlands.
Most neutron stars are thought to be born in core-collapse supernovae. These spectacular cosmic explosions happen when stars far more massive than the Sun run out of fuel for nuclear fusion. The star’s outer layers fall inward and rebound off the collapsed core in an explosion that can briefly outshine an entire galaxy.
Because magnetars are themselves neutron stars, the natural explanation for their formation is that they too are born in supernovae. This appeared to be the case for SGR 0501+4516, which is located promisingly close to a supernova remnant called HB9. The separation between the magnetar and the center of the supernova remnant on the sky is just 80 arcminutes, or slightly wider than your pinky finger when viewed at the end of your outstretched arm.
But a decade-long study with Hubble cast doubt on the magnetar’s birthplace. After initial observations with ground-based telescopes shortly after SGR 0501+4516’s discovery, researchers leveraged Hubble’s exquisite sensitivity and steady pointing to spot the magnetar’s faint infrared glow in 2010, 2012 and 2020. Each of these images was aligned to a reference frame defined by observations from the European Space Agency’s Gaia spacecraft, which has crafted an extraordinarily precise three-dimensional map of nearly two billion stars in the Milky Way. This method revealed the subtle motion of the magnetar as it inched across the sky. This work therefore demonstrates that Hubble and ESA’s Gaia can reveal mysteries never seen before when joining forces.
“All of this movement we measure is smaller than a single pixel of a Hubble image,” said co-investigator Joe Lyman of the University of Warwick, United Kingdom. “Being able to robustly perform such measurements really is a testament to the long-term stability of Hubble.”
By tracking the magnetar’s position, the team was able to measure the object’s apparent motion across the sky. Both the speed and direction of SGR 0501+4516’s movement showed that the magnetar could not be associated with the nearby supernova remnant. Tracing the magnetar’s trajectory thousands of years into the past showed that there were no other supernova remnants or massive star clusters that it could be associated with.
If SGR 0501+4516 was not born in supernova remnant HB9, the magnetar must either be far older than its reported 20 000-year age, or it must have formed in another way. Magnetars may also be able to form through the merger of two lower-mass neutron stars or through a process called accretion-induced collapse. Accretion-induced collapse requires a binary star system containing a white dwarf: the crystallised core of a dead Sun-like star. If the white dwarf ensnares gas from its companion, it can grow too massive to support itself, leading to an explosion — or possibly the creation of a magnetar.
“Normally, this scenario leads to the ignition of nuclear reactions, and the white dwarf exploding, leaving nothing behind. But it has been theorised that under certain conditions, the white dwarf can instead collapse into a neutron star. We think this might be how SGR 0501 was born,” added Andrew Levan of Radboud University in the Netherlands and the University of Warwick in the United Kingdom.
SGR 0501+4516 is currently the best candidate for a magnetar in our galaxy that may have formed through a merger or accretion-induced collapse. Magnetars that form through accretion-induced collapse could provide an explanation for some of the mysterious cosmic signals called fast radio bursts, which are brief but powerful flashes of radio waves. In particular, this scenario may explain the origin of fast radio bursts that emerge from stellar populations too ancient to have recently birthed stars massive enough to explode as supernovae.
“Magnetar birth rates and formation scenarios are among the most pressing questions in high-energy astrophysics, with implications for many of the Universe’s most powerful transient events, such as gamma-ray bursts, superluminous supernovae, and fast radio bursts,” said Nanda Rea of the Institute of Space Sciences in Barcelona, Spain.
The research team has further Hubble observations planned to study the origins of other magnetars in the Milky Way, helping to understand how these extreme objects form.
This is an artist’s impression of a magnetar, which is a special type of neutron star. Neutron stars are some of the most extreme objects in the Universe. These stars typically pack more than the mass of the Sun into a sphere of neutrons about 20 kilometres across. Unsurprisingly, these exotic objects can display several extreme behaviours, such as X-ray and gamma-ray outbursts, intense magnetic fields and rapid rotation. Magnetars are a specific type of neutron star that are distinguished by their exceptionally strong magnetic fields (which are significantly stronger than those of typical neutron stars). Researchers using the NASA/ESA Hubble Space Telescope have discovered that the magnetar SGR 0501+4516 was not born in a neighbouring supernova as previously thought. The birthplace of this object is now unknown, and SGR 0501+4516 is the likeliest candidate in our galaxy for a magnetar that was not born in a supernova. It is one of only about 30 known magnetars in the Milky Way. Credit: ESA
Bibliographic information:
The infrared counterpart and proper motion of magnetar SGR 0501+4516, Astronomy & Astrophysics Volume 696, April 2025 A127, DOI: https://doi.org/10.1051/0004-6361/202453479
