Jump to content

Hubble Studies a Potential Galactic Merger


Recommended Posts

  • Publishers
Posted

3 min read

Hubble Studies a Potential Galactic Merger

A dwarf irregular galaxy. It appears as a cloud of bluish gas, filled with point-like stars that spread beyond the edge of the gas. A few glowing red clouds sit near its center. Many other objects are visible around it: distant galaxies in the background, four-pointed stars in the foreground, and star clusters that are part of the galaxy appear as bright spots surrounded by more tiny stars.
This NASA/ESA Hubble Space Telescope image captures the dwarf irregular galaxy NGC 5238.
ESA/Hubble & NASA, F. Annibali

This NASA/ESA Hubble Space Telescope image features the dwarf irregular galaxy NGC 5238, located 14.5 million light-years from Earth in the constellation Canes Venatici. Its unexciting, blob-like appearance seems to resemble an oversized star cluster more than a classic image of a galaxy. Its lackluster appearance belies its complicated structure, which is the subject of a great deal of research. As the image reveals, Hubble is able to pick out the galaxy’s countless stars, as well as its associated globular clusters — glowing, bright spots both inside and around the galaxy swarmed by even more stars.

Astronomers theorize that NGC 5238 may have had a close encounter with another galaxy as recently as a billion years ago. NGC 5238’s distorted shape provides evidence for this interaction. As the two galaxies interacted, their gravity caused distortions in the distribution of stars in each galaxy. There’s no nearby galaxy which could have caused this disturbance, so astronomers think NGC 5238 devoured a smaller satellite galaxy. Astronomers look for traces of the consumed galaxy by closely examining the population of stars in NGC 5238, a task made for Hubble’s excellent resolution. One tell-tale sign of the smaller galaxy would be groups of stars with different properties from most of NGC 5238’s other stars, indicating they were originally formed in a separate galaxy. Another sign would be a burst of star formation that occurred abruptly at around the same time the two galaxies merged. The Hubble data used to create this image will help astronomers determine NGC 5238’s history.

Despite their small size and unremarkable appearance, it’s not unusual for dwarf galaxies like NGC 5238 to drive our understanding of galaxy formation and evolution. One main theory of galaxy evolution is that galaxies formed ‘bottom-up’ in a hierarchical fashion: star clusters and small galaxies were the first to form out of gas and dark matter. Over time, gravity gradually assembled these smaller objects into galaxy clusters and superclusters, which explains the shape of the largest structures we see in the universe today. A dwarf irregular galaxy like NGC 5238 merging with a smaller companion is just the type of event that might have started the process of galaxy assembly in the early universe. Hubble’s observations of tiny NGC 5238 may help test some of our most fundamental ideas of how the universe evolves!

Explore More

Media Contact:

Claire Andreoli
NASA’s Goddard Space Flight CenterGreenbelt, MD
claire.andreoli@nasa.gov

View the full article

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Topics

    • 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 News Hubble News Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Posters Hubble on the NASA App Glossary More 35th Anniversary Online Activities 2 min read
      Hubble Studies a Nearby Galaxy’s Star Formation
      This NASA/ESA Hubble Space Telescope image features the picturesque spiral galaxy NGC 4941. ESA/Hubble & NASA, D. Thilker This NASA/ESA Hubble Space Telescope image features the picturesque spiral galaxy NGC 4941, which lies about 67 million light-years from Earth in the constellation Virgo (The Maiden). Because this galaxy is nearby, cosmically speaking, Hubble’s keen instruments are able to pick out exquisite details such as individual star clusters and filamentary clouds of gas and dust.
      The data used to construct this image were collected as part of an observing program that investigates the star formation and stellar feedback cycle in nearby galaxies. As stars form in dense, cold clumps of gas, they begin to influence their surroundings. Stars heat and stir up the gas clouds in which they form through winds, starlight, and — eventually, for massive stars — by exploding as supernovae. These processes are collectively called stellar feedback, and they influence the rate at which a galaxy can form new stars.
      As it turns out, stars aren’t the only entities providing feedback in NGC 4941. At the heart of this galaxy lies an active galactic nucleus: a supermassive black hole feasting on gas. As the black hole amasses gas from its surroundings, the gas swirls into a superheated disk that glows brightly at wavelengths across the electromagnetic spectrum. Similar to stars — but on a much, much larger scale — active galactic nuclei shape their surroundings through winds, radiation, and powerful jets, altering not only star formation but also the evolution of the galaxy as a whole.
      Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
      Claire Andreoli (claire.andreoli@nasa.gov)
      NASA’s Goddard Space Flight Center, Greenbelt, MD
      Share








      Details
      Last Updated Apr 04, 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 Night Sky Challenge



      Hubble’s Galaxies



      35 Years of Hubble Images


      View the full article
    • By NASA
      Explore HubbleHubble Home OverviewAbout Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & BenefitsHubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts ScienceHubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky ObservatoryHubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb TeamHubble Team Career Aspirations Hubble Astronauts NewsHubble News Social Media Media Resources MultimediaMultimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Posters Hubble on the NASA App Glossary More35th Anniversary Online Activities 3 Min Read Hubble Spots Stellar Sculptors in Nearby Galaxy
      This dazzling NASA/ESA Hubble Space Telescope image features the young star cluster NGC 346. Credits: ESA/Hubble & NASA, A. Nota, P. Massey, E. Sabbi, C. Murray, M. Zamani (ESA/Hubble) As part of ESA/Hubble’s 35th anniversary celebrations, ESA is sharing a new image series revisiting stunning, previously released Hubble targets with the addition of the latest Hubble data and new processing techniques.
      This new image showcases the dazzling young star cluster NGC 346. Although both the James Webb Space Telescope and Hubble have released images of NGC 346 previously, this image includes new data and is the first to combine Hubble observations made at infrared, optical, and ultraviolet wavelengths into an intricately detailed view of this vibrant star-forming factory.
      This dazzling NASA/ESA Hubble Space Telescope image features the young star cluster NGC 346. ESA/Hubble & NASA, A. Nota, P. Massey, E. Sabbi, C. Murray, M. Zamani (ESA/Hubble) NGC 346 is in the Small Magellanic Cloud, a satellite galaxy of the Milky Way that lies 200,000 light-years away in the constellation Tucana. The Small Magellanic Cloud is less rich in elements heavier than helium — what astronomers call metals — than the Milky Way. This makes conditions in the galaxy similar to what existed in the early universe.
      NGC 346 is home to more than 2,500 newborn stars. The cluster’s most massive stars, which are many times more massive than our Sun, blaze with an intense blue light in this image. The glowing pink nebula and snakelike dark clouds are sculpted by the luminous stars in the cluster.
      Hubble’s exquisite sensitivity and resolution were instrumental in uncovering the secrets of NGC 346’s star formation. Using two sets of observations taken 11 years apart, researchers traced the motions of NGC 346’s stars, revealing them to be spiraling in toward the center of the cluster. This spiraling motion arises from a stream of gas from outside of the cluster that fuels star formation in the center of the turbulent cloud.
      The inhabitants of this cluster are stellar sculptors, carving out a bubble within the nebula. NGC 346’s hot, massive stars produce intense radiation and fierce stellar winds that pummel the billowing gas of their birthplace, dispersing the surrounding nebula.
      The nebula, named N66, is the brightest example of an H II (pronounced ‘H-two’) region in the Small Magellanic Cloud. H II regions are set aglow by ultraviolet light from hot, young stars like those in NGC 346. The presence of this nebula indicates the young age of the star cluster, as an H II region shines only as long as the stars that power it — a mere few million years for the massive stars pictured here.
      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.
      Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Explore Hubble NGC 346 Images and Science
      Download the image above

      NASA’s Hubble Finds Spiraling Stars, Providing Window into Early Universe

      Young Stars Sculpt Gas with Powerful Outflows in the Small Magellanic Cloud

      Hubble’s Black and White View

      Infant Stars in the Small Magellanic Cloud

      Hubble Captures Unique Ultraviolet View of a Spectacular Star Cluster

      Share
      Details
      Last Updated Apr 04, 2025 EditorAndrea GianopoulosLocationNASA Goddard Space Flight Center Contact Media
      Claire Andreoli
      NASA’s Goddard Space Flight Center
      Greenbelt, Maryland
      claire.andreoli@nasa.gov


      Bethany Downer
      ESA/Hubble Chief Science Communications Officer
      bethany.downer@esahubble.org


      Related Terms
      Hubble Space Telescope Astrophysics Astrophysics Division Goddard Space Flight Center Nebulae Stars The Universe Related Links
      ESA/Hubble’s 35th anniversary celebrations Release on ESA’s website 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.
      Exploring the Birth of Stars
      Hubble’s 35th Anniversary
      Hubble News
      View the full article
    • By European Space Agency
      Image: This new image from the NASA/ESA Hubble Space Telescope showcases NGC 346, a dazzling young star cluster in the Small Magellanic Cloud. The Small Magellanic Cloud is a satellite galaxy of the Milky Way, located 210 000 light-years away in the constellation Tucana. The Small Magellanic Cloud is less rich in elements heavier than helium — what astronomers call metals — than the Milky Way. This makes conditions in the galaxy similar to what existed in the early Universe.
      Although several images of NGC 346 have been released previously, this view includes new data and is the first to combine Hubble observations made at infrared, optical, and ultraviolet wavelengths into an intricately detailed view of this vibrant star-forming factory.
      NGC 346 is home to more than 2500 newborn stars. The cluster’s most massive stars, which are many times more massive than our Sun, blaze with an intense blue light in this image. The glowing pink nebula and snakelike dark clouds are the remnant of the birthplace of the stars in the cluster.
      The inhabitants of this cluster are stellar sculptors, carving out a bubble from the nebula. NGC 346’s hot, massive stars produce intense radiation and fierce stellar winds that pummel the billowing gas of their birthplace and begin to disperse the surrounding nebula.
      The nebula, named N66, is the brightest example of an H II (pronounced ‘H-two’) region in the Small Magellanic Cloud. H II regions are set aglow by ultraviolet light from hot young stars like those in NGC 346. The presence of the brilliant nebula indicates the young age of the star cluster, as an H II region shines only as long as the stars that power it — a mere few million years for the massive stars pictured here.
      [Image description: A star cluster within a nebula. The background is filled with thin, pale blue clouds. Parts are thicker and pinker in colour. The cluster is made up of bright blue stars that illuminate the nebula around them. Large arcs of dense dust curve around, before and behind the clustered stars, pressed together by the stars’ radiation. Behind the clouds of the nebula can be seen large numbers of orange stars.]
      View the full article
    • 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 News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Posters Hubble on the NASA App Glossary More 35th Anniversary Online Activities 5 Min Read 20-Year Hubble Study of Uranus Yields New Atmospheric Insights
      The image columns show the change of Uranus for the four years that STIS observed Uranus across a 20-year period. Over that span of time, the researchers watched the seasons of Uranus as the south polar region darkened going into winter shadow while the north polar region brightened as northern summer approaches. Credits:
      NASA, ESA, Erich Karkoschka (LPL) The ice-giant planet Uranus, which travels around the Sun tipped on its side, is a weird and mysterious world. Now, in an unprecedented study spanning two decades, researchers using NASA’s Hubble Space Telescope have uncovered new insights into the planet’s atmospheric composition and dynamics. This was possible only because of Hubble’s sharp resolution, spectral capabilities, and longevity. 
      The team’s results will help astronomers to better understand how the atmosphere of Uranus works and responds to changing sunlight. These long-term observations provide valuable data for understanding the atmospheric dynamics of this distant ice giant, which can serve as a proxy for studying exoplanets of similar size and composition.
      When Voyager 2 flew past Uranus in 1986, it provided a close-up snapshot of the sideways planet. What it saw resembled a bland, blue-green billiard ball. By comparison, Hubble chronicled a 20-year story of seasonal changes from 2002 to 2022. Over that period, a team led by Erich Karkoschka of the University of Arizona, and Larry Sromovsky and Pat Fry from the University of Wisconsin used the same Hubble instrument, STIS (the Space Telescope Imaging Spectrograph), to paint an accurate picture of the atmospheric structure of Uranus. 
      Uranus’ atmosphere is mostly hydrogen and helium, with a small amount of methane and traces of water and ammonia. The methane gives Uranus its cyan color by absorbing the red wavelengths of sunlight.
      The Hubble team observed Uranus four times in the 20-year period: in 2002, 2012, 2015, and 2022. They found that, unlike conditions on the gas giants Saturn and Jupiter, methane is not uniformly distributed across Uranus. Instead, it is strongly depleted near the poles. This depletion remained relatively constant over the two decades. However, the aerosol and haze structure changed dramatically, brightening significantly in the northern polar region as the planet approaches its northern summer solstice in 2030.
      The image columns show the change of Uranus for the four years that STIS observed Uranus across a 20-year period. Over that span of time, the researchers watched the seasons of Uranus as the south polar region darkened going into winter shadow while the north polar region brightened as northern summer approaches. NASA, ESA, Erich Karkoschka (LPL) Uranus takes a little over 84 Earth years to complete a single orbit of the Sun. So, over two decades, the Hubble team has only seen mostly northern spring as the Sun moves from shining directly over Uranus’ equator toward shining almost directly over its north pole in 2030. Hubble observations suggest complex atmospheric circulation patterns on Uranus during this period. The data that are most sensitive to the methane distribution indicate a downwelling in the polar regions and upwelling in other regions. 
      The team analyzed their results in several ways. The image columns show the change of Uranus for the four years that STIS observed Uranus across a 20-year period. Over that span of time, the researchers watched the seasons of Uranus as the south polar region (left) darkened going into winter shadow while the north polar region (right) brightened as it began to come into a more direct view as northern summer approaches.
      The top row, in visible light, shows how the color of Uranus appears to the human eye as seen through even an amateur telescope. 
      In the second row, the false-color image of the planet is assembled from visible and near-infrared light observations. The color and brightness correspond to the amounts of methane and aerosols. Both of these quantities could not be distinguished before Hubble’s STIS was first aimed at Uranus in 2002. Generally, green areas indicate less methane than blue areas, and red areas show no methane. The red areas are at the limb, where the stratosphere of Uranus is almost completely devoid of methane. 
      The two bottom rows show the latitude structure of aerosols and methane inferred from 1,000 different wavelengths (colors) from visible to near infrared. In the third row, bright areas indicate cloudier conditions, while the dark areas represent clearer conditions. In the fourth row, bright areas indicate depleted methane, while dark areas show the full amount of methane. 
      At middle and low latitudes, aerosols and methane depletion have their own latitudinal structure that mostly did not change much over the two decades of observation.  However, in the polar regions, aerosols and methane depletion behave very differently. 
      In the third row, the aerosols near the north pole display a dramatic increase, showing up as very dark during early northern spring, turning very bright in recent years. Aerosols also seem to disappear at the left limb as the solar radiation disappeared. This is evidence that solar radiation changes the aerosol haze in the atmosphere of Uranus. On the other hand, methane depletion seems to stay quite high in both polar regions throughout the observing period. 
      Astronomers will continue to observe Uranus as the planet approaches northern summer.
      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.
      Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Related Images & Videos
      20 Years of Uranus Observations





      Share








      Details
      Last Updated Mar 31, 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
      Ann Jenkins
      Space Telescope Science Institute, Baltimore, Maryland
      Ray Villard
      Space Telescope Science Institute, Baltimore, Maryland

      Related Terms
      Hubble Space Telescope Astrophysics Division Goddard Space Flight Center Planetary Environments & Atmospheres Planetary Science Planets The Solar System Uranus
      View the full article
    • 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 News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Posters Hubble on the NASA App Glossary More 35th Anniversary Online Activities 2 min read
      Hubble Spots a Chance Alignment
      This NASA/ESA Hubble image features the spiral galaxy NGC 5530. ESA/Hubble & NASA, D. Thilker The subject of today’s NASA/ESA Hubble Space Telescope image is the stunning spiral galaxy NGC 5530. This galaxy is situated 40 million light-years away in the constellation Lupus, the Wolf, and classified as a ‘flocculent’ spiral, meaning its spiral arms are patchy and indistinct.
      While some galaxies have extraordinarily bright centers that host a feasting supermassive black hole, the bright source near the center of NGC 5530 is not an active black hole but a star within our own galaxy, only 10,000 light-years from Earth. This chance alignment gives the appearance that the star is at the dense heart of NGC 5530.
      If you pointed a backyard telescope at NGC 5530 on the evening of September 13, 2007, you would have seen another bright point of light adorning the galaxy. That night, Australian amateur astronomer Robert Evans discovered a supernova, named SN 2007IT, by comparing NGC 5530’s appearance through the telescope to a reference photo of the galaxy. While it’s remarkable to discover even one supernova using this painstaking method, Evans has in fact discovered more than 40 supernovae this way! This particular discovery was truly serendipitous: it’s likely that the light from the supernova completed its 40-million-year journey to Earth just days before Evans spotted the explosion.
      Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Share








      Details
      Last Updated Mar 28, 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



      Hubble’s 35th Anniversary



      Hubble’s Night Sky Challenge


      View the full article
  • Check out these Videos

×
×
  • Create New...