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By NASA
ESA/Hubble & NASA, M. J. Koss, A. J. Barth The light that the NASA/ESA Hubble Space Telescope collected to create this image reached the telescope after a journey of 250 million years. Its source was the spiral galaxy UGC 11397, which resides in the constellation Lyra (The Lyre). At first glance, UGC 11397 appears to be an average spiral galaxy: it sports two graceful spiral arms that are illuminated by stars and defined by dark, clumpy clouds of dust.
What sets UGC 11397 apart from a typical spiral lies at its center, where a supermassive black hole containing 174 million times the mass of our Sun grows. As a black hole ensnares gas, dust, and even entire stars from its vicinity, this doomed matter heats up and puts on a fantastic cosmic light show.
Material trapped by the black hole emits light from gamma rays to radio waves, and can brighten and fade without warning. But in some galaxies, including UGC 11397, thick clouds of dust hide much of this energetic activity from view in optical light. Despite this, UGC 11397’s actively growing black hole was revealed through its bright X-ray emission — high-energy light that can pierce the surrounding dust. This led astronomers to classify it as a Type 2 Seyfert galaxy, a category used for active galaxies whose central regions are hidden from view in visible light by a donut-shaped cloud of dust and gas.
Using Hubble, researchers will study hundreds of galaxies that, like UGC 11397, harbor a supermassive black hole that is gaining mass. The Hubble observations will help researchers weigh nearby supermassive black holes, understand how black holes grew early in the universe’s history, and even study how stars form in the extreme environment found at the very center of a galaxy.
Text credit: ESA
Image credit: ESA/Hubble & NASA, M. J. Koss, A. J. Barth
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By NASA
2 min read
Hubble Captures an Active Galactic Center
This Hubble image shows the spiral galaxy UGC 11397. ESA/Hubble & NASA, M. J. Koss, A. J. Barth The light that the NASA/ESA Hubble Space Telescope collected to create this image reached the telescope after a journey of 250 million years. Its source was the spiral galaxy UGC 11397, which resides in the constellation Lyra (The Lyre). At first glance, UGC 11397 appears to be an average spiral galaxy: it sports two graceful spiral arms that are illuminated by stars and defined by dark, clumpy clouds of dust.
What sets UGC 11397 apart from a typical spiral lies at its center, where a supermassive black hole containing 174 million times the mass of our Sun grows. As a black hole ensnares gas, dust, and even entire stars from its vicinity, this doomed matter heats up and puts on a fantastic cosmic light show.
Material trapped by the black hole emits light from gamma rays to radio waves, and can brighten and fade without warning. But in some galaxies, including UGC 11397, thick clouds of dust hide much of this energetic activity from view in optical light. Despite this, UGC 11397’s actively growing black hole was revealed through its bright X-ray emission — high-energy light that can pierce the surrounding dust. This led astronomers to classify it as a Type 2 Seyfert galaxy, a category used for active galaxies whose central regions are hidden from view in visible light by a donut-shaped cloud of dust and gas.
Using Hubble, researchers will study hundreds of galaxies that, like UGC 11397, harbor a supermassive black hole that is gaining mass. The Hubble observations will help researchers weigh nearby supermassive black holes, understand how black holes grew early in the universe’s history, and even study how stars form in the extreme environment found at the very center of a galaxy.
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Claire Andreoli (claire.andreoli@nasa.gov)
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Last Updated Jun 27, 2025 Related Terms
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By NASA
6 Min Read NASA’s Chandra Shares a New View of Our Galactic Neighbor
The Andromeda galaxy, also known as Messier 31 (M31), is the closest spiral galaxy to the Milky Way at a distance of about 2.5 million light-years. Astronomers use Andromeda to understand the structure and evolution of our own spiral, which is much harder to do since Earth is embedded inside the Milky Way.
The galaxy M31 has played an important role in many aspects of astrophysics, but particularly in the discovery of dark matter. In the 1960s, astronomer Vera Rubin and her colleagues studied M31 and determined that there was some unseen matter in the galaxy that was affecting how the galaxy and its spiral arms rotated. This unknown material was named “dark matter.” Its nature remains one of the biggest open questions in astrophysics today, one which NASA’s upcoming Nancy Grace Roman Space Telescope is designed to help answer.
X-ray: NASA/CXO/UMass/Z. Li & Q.D. Wang, ESA/XMM-Newton; Infrared: NASA/JPL-Caltech/WISE, Spitzer, NASA/JPL-Caltech/K. Gordon (U. Az), ESA/Herschel, ESA/Planck, NASA/IRAS, NASA/COBE; Radio: NSF/GBT/WSRT/IRAM/C. Clark (STScI); Ultraviolet: NASA/JPL-Caltech/GALEX; Optical: Andromeda, Unexpected © Marcel Drechsler, Xavier Strottner, Yann Sainty & J. Sahner, T. Kottary. Composite image processing: L. Frattare, K. Arcand, J.Major This new composite image contains data of M31 taken by some of the world’s most powerful telescopes in different kinds of light. This image includes X-rays from NASA’s Chandra X-ray Observatory and ESA’s (European Space Agency’s) XMM-Newton (represented in red, green, and blue); ultraviolet data from NASA’s retired GALEX (blue); optical data from astrophotographers using ground based telescopes (Jakob Sahner and Tarun Kottary); infrared data from NASA’s retired Spitzer Space Telescope, the Infrared Astronomy Satellite, COBE, Planck, and Herschel (red, orange, and purple); and radio data from the Westerbork Synthesis Radio Telescope (red-orange).
The Andromeda Galaxy (M31) in Different Types of Light.X-ray: NASA/CXO/UMass/Z. Li & Q.D. Wang, ESA/XMM-Newton; Infrared: NASA/JPL-Caltech/WISE, Spitzer, NASA/JPL-Caltech/K. Gordon (U. Az), ESA/Herschel, ESA/Planck, NASA/IRAS, NASA/COBE; Radio: NSF/GBT/WSRT/IRAM/C. Clark (STScI); Ultraviolet: NASA/JPL-Caltech/GALEX; Optical: Andromeda, Unexpected © Marcel Drechsler, Xavier Strottner, Yann Sainty & J. Sahner, T. Kottary. Composite image processing: L. Frattare, K. Arcand, J.Major Each type of light reveals new information about this close galactic relative to the Milky Way. For example, Chandra’s X-rays reveal the high-energy radiation around the supermassive black hole at the center of M31 as well as many other smaller compact and dense objects strewn across the galaxy. A recent paper about Chandra observations of M31 discusses the amount of X-rays produced by the supermassive black hole in the center of the galaxy over the last 15 years. One flare was observed in 2013, which appears to represent an amplification of the typical X-rays seen from the black hole.
These multi-wavelength datasets are also being released as a sonification, which includes the same wavelengths of data in the new composite. In the sonification, the layer from each telescope has been separated out and rotated so that they stack on top of each other horizontally, beginning with X-rays at the top and then moving through ultraviolet, optical, infrared, and radio at the bottom. As the scan moves from left to right in the sonification, each type of light is mapped to a different range of notes, from lower-energy radio waves up through the high energy of X-rays. Meanwhile, the brightness of each source controls volume, and the vertical location dictates the pitch.
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In this sonification of M31, the layers from each telescope has been separated out and rotated so that they stack on top of each other horizontally beginning with X-rays at the top and then moving through ultraviolet, optical, infrared, and radio at the bottom. As the scan moves from left to right in the sonification, each type of light is mapped to a different range of notes ranging from lower-energy radio waves up through the high-energy of X-rays. Meanwhile, the brightness of each source controls volume and the vertical location dictates the pitch.NASA/CXC/SAO/K.Arcand, SYSTEM Sounds (M. Russo, A. Santaguida This new image of M31 is released in tribute to the groundbreaking legacy of Dr. Vera Rubin, whose observations transformed our understanding of the universe. Rubin’s meticulous measurements of Andromeda’s rotation curve provided some of the earliest and most convincing evidence that galaxies are embedded in massive halos of invisible material — what we now call dark matter. Her work challenged long-held assumptions and catalyzed a new era of research into the composition and dynamics of the cosmos. In recognition of her profound scientific contributions, the United States Mint has recently released a quarter in 2025 featuring Rubin as part of its American Women Quarters Program — making her the first astronomer honored in the series.
NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
Read more from NASA’s Chandra X-ray Observatory Learn more about the Chandra X-ray Observatory and its mission here:
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Visual Description
This release features several images and a sonification video examining the Andromeda galaxy, our closest spiral galaxy neighbor. This collection helps astronomers understand the evolution of the Milky Way, our own spiral galaxy, and provides a fascinating insight into astronomical data gathering and presentation.
Like all spiral galaxies viewed at this distance and angle, Andromeda appears relatively flat. Its spiraling arms circle around a bright core, creating a disk shape, like a large dinner plate. In most of the images in this collection, Andromeda’s flat surface is tilted to face our upper left.
This collection features data from some of the world’s most powerful telescopes, each capturing light in a different spectrum. In each single-spectrum image, Andromeda has a similar shape and orientation, but the colors and details are dramatically different.
In radio waves, the spiraling arms appear red and orange, like a burning, loosely coiled rope. The center appears black, with no core discernible. In infrared light, the outer arms are similarly fiery. Here, a white spiraling ring encircles a blue center with a small golden core. The optical image is hazy and grey, with spiraling arms like faded smoke rings. Here, the blackness of space is dotted with specks of light, and a small bright dot glows at the core of the galaxy. In ultraviolet light the spiraling arms are icy blue and white, with a hazy white ball at the core. No spiral arms are present in the X-ray image, making the bright golden core and nearby stars clear and easy to study.
In this release, the single-spectrum images are presented side by side for easy comparison. They are also combined into a composite image. In the composite, Andromeda’s spiraling arms are the color of red wine near the outer edges, and lavender near the center. The core is large and bright, surrounded by a cluster of bright blue and green specks. Other small flecks in a variety of colors dot the galaxy, and the blackness of space surrounding it.
This release also features a thirty second video, which sonifies the collected data. In the video, the single-spectrum images are stacked vertically, one atop the other. As the video plays, an activation line sweeps across the stacked images from left to right. Musical notes ring out when the line encounters light. The lower the wavelength energy, the lower the pitches of the notes. The brighter the source, the louder the volume.
News Media Contact
Megan Watzke
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Lane Figueroa
Marshall Space Flight Center, Huntsville, Alabama
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Last Updated Jun 25, 2025 EditorLee MohonContactLane Figueroa Related Terms
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By NASA
Explore Hubble Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts Multimedia Images Videos Sonifications Podcasts e-Books Online Activities 3D Hubble Models Lithographs Fact Sheets Posters Hubble on the NASA App Glossary News Hubble News Social Media Media Resources More 35th Anniversary Online Activities 2 min read
Hubble Captures Starry Spectacle
This NASA/ESA Hubble Space Telescope image features the barred spiral galaxy NGC 685. ESA/Hubble & NASA, J. Lee, F. Belfiore A galaxy ablaze with young stars is the subject of this NASA/ESA Hubble Space Telescope image. Named NGC 685, this galaxy is situated about 64 million light-years away in the constellation Eridanus (the River). NGC 685 is a barred spiral because its feathery spiral arms sprout from the ends of a bar of stars at the galaxy’s center. The Milky Way is also a barred spiral, but our galaxy is a little less than twice the size of NGC 685.
Astronomers used Hubble to study NGC 685 for two observing programs, both focused on star formation. It’s no surprise that NGC 685 was part of these programs: numerous patches of young, blue stars highlight the galaxy’s spiral arms. Also visible are pink gas clouds, called H II (pronounced ‘H-two’) regions, that glow for a short time when particularly hot and massive stars are born. An especially eye-catching H II region peeks out at the bottom edge of the image. Despite the dozens of star-forming regions evident in this image, NGC 685 converts an amount of gas equivalent to less than half the mass of the Sun into stars each year.
The Hubble data collected for the two observing programs will allow astronomers to catalogue 50,000 H II regions and 100,000 star clusters in nearby galaxies. By combining Hubble’s sensitive visible and ultraviolet observations with infrared data from the NASA/ESA/CSA James Webb Space Telescope and radio data from the Atacama Large Millimeter/submillimeter Array, researchers can peer into the depths of dusty stellar nurseries and illuminate the stars forming there.
Text Credit: ESA/Hubble
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Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
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Last Updated Jun 05, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Hubble Space Telescope Astrophysics Astrophysics Division Galaxies Goddard Space Flight Center Spiral Galaxies The Universe Keep Exploring Discover More Topics From Hubble
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Hubble’s Galaxies
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By NASA
Explore Hubble Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts Multimedia Images Videos Sonifications Podcasts e-Books Online Activities 3D Hubble Models Lithographs Fact Sheets Posters Hubble on the NASA App Glossary News Hubble News Social Media Media Resources More 35th Anniversary Online Activities 5 Min Read Apocalypse When? Hubble Casts Doubt on Certainty of Galactic Collision
This NASA Hubble Space Telescope image of NGC 520 offers one example of possible encounter scenarios between our Milky Way and the Andromeda galaxy. NGC 520 is the product of a collision between two disk galaxies that started 300 million years ago. Credits:
NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and B. Whitmore (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 NASA’s 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 as inevitable as, in the words of Benjamin Franklin, “death and taxes.”
But now a new study using data from Hubble and the European Space Agency’s (ESA) Gaia space telescope says “not so fast.” 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.
These galaxy images illustrate three possible encounter scenarios between our Milky Way and the neighboring Andromeda galaxy. Top left: Galaxies M81 and M82. Top right: NGC 6786, a pair of interacting galaxies. Bottom: NGC 520, two merging galaxies. Science: NASA, ESA, STScI, DSS, Till Sawala (University of Helsinki); Image Processing: Joseph DePasquale (STScI) 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.
100,000 Crash-Dummy Simulations
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.
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Explore More
Hubble Provides Bird’s-Eye View of Andromeda Galaxy’s Ecosystem (2025)
Hubble Shows Milky Way is Destined for Head-on Collision with Andromeda Galaxy (2012)
Galaxy Details and Mergers
Hubble Traces Hidden History of Andromeda Galaxy (2025)
Hubble’s High-Definition Panoramic View of the Andromeda Galaxy (2015)
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Milky Way and Andromeda Encounters
This selection of images of external galaxies illustrates three encounter scenarios between our Milky Way and the neighboring Andromeda galaxy. Top left: Galaxies M81 and M82. Top right: NGC 6786, a pair of interacting galaxies. Bottom: NGC 520, two merging galaxies.
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Last Updated Jun 02, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center
Contact Media Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov
Ray Villard
Space Telescope Science Institute
Baltimore, Maryland
Related Terms
Hubble Space Telescope Andromeda Galaxy Astrophysics Astrophysics Division Galaxies Goddard Space Flight Center Interacting Galaxies The Milky Way The Universe
Keep Exploring Discover More Topics From Hubble
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