Members Can Post Anonymously On This Site
-
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 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 Studies Small but Mighty Galaxy
This NASA/ESA Hubble Space Telescope features the nearby galaxy NGC 4449. ESA/Hubble & NASA, E. Sabbi, D. Calzetti, A. Aloisi This portrait from the NASA/ESA Hubble Space Telescope puts the nearby galaxy NGC 4449 in the spotlight. The galaxy is situated just 12.5 million light-years away in the constellation Canes Venatici (the Hunting Dogs). It is a member of the M94 galaxy group, which is near the Local Group of galaxies that the Milky Way is part of.
NGC 4449 is a dwarf galaxy, which means that it is far smaller and contains fewer stars than the Milky Way. But don’t let its small size fool you — NGC 4449 packs a punch when it comes to making stars! This galaxy is currently forming new stars at a much faster rate than expected for its size, which makes it a starburst galaxy. Most starburst galaxies churn out stars mainly in their centers, but NGC 4449 is alight with brilliant young stars throughout. Researchers believe that this global burst of star formation came about because of NGC 4449’s interactions with its galactic neighbors. Because NGC 4449 is so close, it provides an excellent opportunity for Hubble to study how interactions between galaxies can influence the formation of new stars.
Hubble released an image of NGC 4449 in 2007. This new version incorporates several additional wavelengths of light that Hubble collected for multiple observing programs. These programs encompass an incredible range of science, from a deep dive into NGC 4449’s star-formation history to the mapping of the brightest, hottest, and most massive stars in more than two dozen nearby galaxies.
The NASA/ESA/CSA James Webb Space Telescope has also observed NGC 4449, revealing in intricate detail the galaxy’s tendrils of dusty gas, glowing from the intense starlight radiated by the flourishing young stars.
Text Credit: ESA/Hubble
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 Jun 20, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Hubble Space Telescope Astrophysics Astrophysics Division Galaxies Goddard Space Flight Center Irregular 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
Galaxy Details and Mergers
Hubble’s Night Sky Challenge
View the full article
-
By NASA
This NASA/ESA Hubble Space Telescope image features the barred spiral galaxy IC 758.ESA/Hubble & NASA, C. Kilpatrick This serene spiral galaxy hides a cataclysmic past. The galaxy IC 758, shown in this NASA/ESA Hubble Space Telescope image, is situated 60 million light-years away in the constellation Ursa Major.
Hubble captured this image in 2023. IC 758 appears peaceful, with its soft blue spiral arms curving gently around its hazy barred center. However, in 1999, astronomers spotted a powerful explosion in this galaxy. The supernova SN 1999bg marked the dramatic end of a star far more massive than the Sun.
Researchers do not know exactly how massive this star was before it exploded, but will use these Hubble observations to measure the masses of stars in SN 1999bg’s neighborhood. These measurements will help them estimate the mass of the star that went supernova. The Hubble data may also reveal whether SN 1999bg’s progenitor star had a companion, which would provide additional clues about the star’s life and death.
A supernova represents more than just the demise of a single star — it’s also a powerful force that can shape its neighborhood. When a massive star collapses, triggering a supernova, its outer layers rebound off its shrunken core. The explosion stirs the interstellar soup of gas and dust out of which new stars form. This interstellar shakeup can scatter and heat nearby gas clouds, preventing new stars from forming, or it can compress them, creating a burst of new star formation. The cast-off layers enrich the interstellar medium, from which new stars form, with heavy elements manufactured in the core of the supernova.
Text Credit: ESA/Hubble
Image Credit: ESA/Hubble & NASA, C. Kilpatrick
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 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 Studies a Spiral’s Supernova Scene
This NASA/ESA Hubble Space Telescope image features the barred spiral galaxy IC 758. ESA/Hubble & NASA, C. Kilpatrick This serene spiral galaxy hides a cataclysmic past. The galaxy IC 758, shown in this NASA/ESA Hubble Space Telescope image, is situated 60 million light-years away in the constellation Ursa Major.
Hubble captured this image in 2023. IC 758 appears peaceful, with its soft blue spiral arms curving gently around its hazy barred center. However, in 1999, astronomers spotted a powerful explosion in this galaxy. The supernova SN 1999bg marked the dramatic end of a star far more massive than the Sun.
Researchers do not know exactly how massive this star was before it exploded, but will use these Hubble observations to measure the masses of stars in SN 1999bg’s neighborhood. These measurements will help them estimate the mass of the star that went supernova. The Hubble data may also reveal whether SN 1999bg’s progenitor star had a companion, which would provide additional clues about the star’s life and death.
A supernova represents more than just the demise of a single star — it’s also a powerful force that can shape its neighborhood. When a massive star collapses, triggering a supernova, its outer layers rebound off its shrunken core. The explosion stirs the interstellar soup of gas and dust out of which new stars form. This interstellar shakeup can scatter and heat nearby gas clouds, preventing new stars from forming, or it can compress them, creating a burst of new star formation. The cast-off layers enrich the interstellar medium, from which new stars form, with heavy elements manufactured in the core of the supernova.
Text Credit: ESA/Hubble
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 Jun 13, 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
Homing in on Cosmic Explosions
Hubble’s Night Sky Challenge
View the full article
-
By NASA
Explore Webb Webb News Latest News Latest Images Webb’s Blog Awards X (offsite – login reqd) Instagram (offsite – login reqd) Facebook (offsite- login reqd) Youtube (offsite) Overview About Who is James Webb? Fact Sheet Impacts+Benefits FAQ Science Overview and Goals Early Universe Galaxies Over Time Star Lifecycle Other Worlds Observatory Overview Launch Deployment Orbit Mirrors Sunshield Instrument: NIRCam Instrument: MIRI Instrument: NIRSpec Instrument: FGS/NIRISS Optical Telescope Element Backplane Spacecraft Bus Instrument Module Multimedia About Webb Images Images Videos What is Webb Observing? 3d Webb in 3d Solar System Podcasts Webb Image Sonifications Webb’s First Images Team International Team People Of Webb More For the Media For Scientists For Educators For Fun/Learning 5 Min Read NASA’s Webb ‘UNCOVERs’ Galaxy Population Driving Cosmic Renovation
White diamonds show the locations of 20 of the 83 young, low-mass, starburst galaxies found in infrared images of the giant galaxy cluster Abell 2744. Full image and description shown below. Credits:
NASA/ESA/CSA/Bezanson et al. 2024 and Wold et al. 2025 Astronomers using data from NASA’s James Webb Space Telescope have identified dozens of small galaxies that played a starring role in a cosmic makeover that transformed the early universe into the one we know today.
“When it comes to producing ultraviolet light, these small galaxies punch well above their weight,” said Isak Wold, an assistant research scientist at Catholic University of America in Washington and NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Our analysis of these tiny but mighty galaxies is 10 times more sensitive than previous studies, and shows they existed in sufficient numbers and packed enough ultraviolet power to drive this cosmic renovation.”
Wold discussed his findings Wednesday at the 246th meeting of the American Astronomical Society in Anchorage, Alaska. The study took advantage of existing imaging collected by Webb’s NIRCam (Near-Infrared Camera) instrument, as well as new observations made with its NIRSpec (Near-Infrared Spectrograph) instrument.
Image A: Webb search finds dozens of tiny, young star-forming galaxies
Symbols mark the locations of young, low-mass galaxies bursting with new stars when the universe was about 800 million years old. Using a filter sensitive to such galaxies, NASA’s James Webb Space Telescope imaged them with the help of a natural gravitational lens created by the massive galaxy cluster Abell 2744. In all, 83 young galaxies were found, but only the 20 shown here (white diamonds) were selected for deeper study. The inset zooms into one of the galaxies.
Download high-resolution images from NASA’s Scientific Visualization Studio NASA/ESA/CSA/Bezanson et al. 2024 and Wold et al. 2025 The tiny galaxies were discovered by Wold and his Goddard colleagues, Sangeeta Malhotra and James Rhoads, by sifting through Webb images captured as part of the UNCOVER (Ultradeep NIRSpec and NIRCam ObserVations before the Epoch of Reionization) observing program, led by Rachel Bezanson at the University of Pittsburgh in Pennsylvania.
The project mapped a giant galaxy cluster known as Abell 2744, nicknamed Pandora’s cluster, located about 4 billion light-years away in the southern constellation Sculptor. The cluster’s mass forms a gravitational lens that magnifies distant sources, adding to Webb’s already considerable reach.
Image B: Galaxy cluster helps reveal young, low-mass galaxies bursting with stars
White diamonds show the locations of 20 of the 83 young, low-mass, starburst galaxies found in infrared images of the giant galaxy cluster Abell 2744. This composite incorporates images taken through three NIRCam filters (F200W as blue, F410M as green, and F444W as red). The F410M filter is highly sensitive to light emitted by doubly ionized oxygen — oxygen atoms that have been stripped of two electrons — at a time when reionization was well underway. Emitted as green light, the glow was stretched into the infrared as it traversed the expanding universe over billions of years. The cluster’s mass acts as a natural magnifying glass, allowing astronomers to see these tiny galaxies as they were when the universe was about 800 million years old. NASA/ESA/CSA/Bezanson et al. 2024 and Wold et al. 2025 For much of its first billion years, the universe was immersed in a fog of neutral hydrogen gas. Today, this gas is ionized — stripped of its electrons. Astronomers, who refer to this transformation as reionization, have long wondered which types of objects were most responsible: big galaxies, small galaxies, or supermassive black holes in active galaxies. As one of its main goals, NASA’s Webb was specifically designed to address key questions about this major transition in the history of the universe.
Recent studies have shown that small galaxies undergoing vigorous star formation could have played an outsized role. Such galaxies are rare today, making up only about 1% of those around us. But they were abundant when the universe was about 800 million years old, an epoch astronomers refer to as redshift 7, when reionization was well underway.
The team searched for small galaxies of the right cosmic age that showed signs of extreme star formation, called starbursts, in NIRCam images of the cluster.
“Low-mass galaxies gather less neutral hydrogen gas around them, which makes it easier for ionizing ultraviolet light to escape,” Rhoads said. “Likewise, starburst episodes not only produce plentiful ultraviolet light — they also carve channels into a galaxy’s interstellar matter that helps this light break out.”
Image C: A deeper look into small, young, star-forming galaxies during reionization
At left is an enlarged infrared view of galaxy cluster Abell 2744 with three young, star-forming galaxies highlighted by green diamonds. The center column shows close-ups of each galaxy, along with their designations, the amount of magnification provided by the cluster’s gravitational lens, their redshifts (shown as z — all correspond to a cosmic age of about 790 million years), and their estimated mass of stars. At right, measurements from NASA’s James Webb Space Telescope’s NIRSpec instrument confirm that the galaxies produce strong emission in the light of doubly ionized oxygen (green bars), indicating vigorous star formation is taking place. NASA/ESA/CSA/Bezanson et al. 2024 and Wold et al. 2025 The astronomers looked for strong sources of a specific wavelength of light that signifies the presence of high-energy processes: a green line emitted by oxygen atoms that have lost two electrons. Originally emitted as visible light in the early cosmos, the green glow from doubly ionized oxygen was stretched into the infrared as it traversed the expanding universe and eventually reached Webb’s instruments.
This technique revealed 83 small starburst galaxies as they appear when the universe was 800 million years old, or about 6% of its current age of 13.8 billion years. The team selected 20 of these for deeper inspection using NIRSpec.
“These galaxies are so small that, to build the equivalent stellar mass of our own Milky Way galaxy, you’d need from 2,000 to 200,000 of them,” Malhotra said. “But we are able to detect them because of our novel sample selection technique combined with gravitational lensing.”
Image D: Tiny but mighty galaxy helped clear cosmic fog
One of the most interesting galaxies of the study, dubbed 41028 (the green oval at center), has an estimated stellar mass of just 2 million Suns — comparable to the masses of the largest star clusters in our own Milky Way galaxy. NASA/ESA/CSA/Bezanson et al. 2024 and Wold et al. 2025 Similar types of galaxies in the present-day universe, such as green peas, release about 25% of their ionizing ultraviolet light into surrounding space. If the low-mass starburst galaxies explored by Wold and his team release a similar amount, they can account for all of the ultraviolet light needed to convert the universe’s neutral hydrogen to its ionized form.
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
To learn more about Webb, visit:
https://science.nasa.gov/webb
By Francis Reddy
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Downloads
Click any image above to open a larger version.
Download high-resolution images from NASA’s Scientific Visualization Studio.
Media Contacts
Laura Betz – laura.e.betz@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Related Information
Article: Types of Galaxies
Video: Different types of galaxies
More Webb News
More Webb Images
Webb Science Themes
Webb Mission Page
Related For Kids
What is the Webb Telescope?
SpacePlace for Kids
En Español
Ciencia de la NASA
NASA en español
Space Place para niños
Keep Exploring Related Topics
James Webb Space Telescope
Webb is the premier observatory of the next decade, serving thousands of astronomers worldwide. It studies every phase in the…
Galaxies
Galaxies Stories
Universe
Share
Details
Last Updated Jun 11, 2025 Editor Marty McCoy Contact Laura Betz laura.e.betz@nasa.gov Related Terms
James Webb Space Telescope (JWST) Astrophysics Galaxies Goddard Space Flight Center Science & Research The Universe View the full article
-
By NASA
A new online portal by NASA and the Alaska Satellite Facility maps satellite radar meas-urements across North America, enabling users to track land movement since 2016 caused by earthquakes, landslides, volcanoes, and other phenomena.USGS An online tool maps measurements and enables non-experts to understand earthquakes, subsidence, landslides, and other types of land motion.
NASA is collaborating with the Alaska Satellite Facility in Fairbanks to create a powerful web-based tool that will show the movement of land across North America down to less than an inch. The online portal and its underlying dataset unlock a trove of satellite radar measurements that can help anyone identify where and by how much the land beneath their feet may be moving — whether from earthquakes, volcanoes, landslides, or the extraction of underground natural resources such as groundwater.
Spearheaded by NASA’s Observational Products for End-Users from Remote Sensing Analysis (OPERA) project at the agency’s Jet Propulsion Laboratory in Southern California, the effort equips users with information that would otherwise take years of training to produce. The project builds on measurements from spaceborne synthetic aperture radars, or SARs, to generate high-resolution data on how Earth’s surface is moving.
The OPERA portal shows how land is sinking in Freshkills Park, which is being built on the site of a former landfill on Staten Island, New York. Landfills tend to sink over time as waste decomposes and settles. The blue dot marks the spot where the portal is showing movement in the graph.Alaska Satellite Facility Formally called the North America Surface Displacement Product Suite, the new dataset comes ready to use with measurements dating to 2016, and the portal allows users to view those measurements at a local, state, and regional scales in a few seconds. For someone not using the dataset or website, it could take days or longer to do a similar analysis.
“You can zoom in to your country, your state, your city block, and look at how the land there is moving over time,” said David Bekaert, the OPERA project manager and a JPL radar scientist. “You can see that by a simple mouse click.”
The portal currently includes measurements for millions of pixels across the U.S. Southwest, northern Mexico, and the New York metropolitan region, each representing a 200-foot-by-200-foot (60-meter-by-60-meter) area on the ground. By the end of 2025, OPERA will add data to cover the rest of the United States, Central America, and Canada within 120 miles (200 kilometers) of the U.S. border. When a user clicks on a pixel, the system pulls measurements from hundreds of files to create a graph visualizing the land surface’s cumulative movement over time.
Land is rising at the Colorado River’s outlet to the Gulf of California, as indicated in this screenshot from the OPERA portal. The uplift is due to the sediment from the river building up over time. The graph shows that the land at the blue dot has risen about 8 inches (20 centimeters) since 2016.Alaska Satellite Facility “The OPERA project automated the end-to-end SAR data processing system such that users and decision-makers can focus on discovering where the land surface may be moving in their areas of interest,” said Gerald Bawden, program scientist responsible for OPERA at NASA Headquarters in Washington. “This will provide a significant advancement in identifying and understanding potential threats to the end users, while providing cost and time savings for agencies.”
For example, water-management bureaus and state geological surveys will be able to directly use the OPERA products without needing to make big investments in data storage, software engineering expertise, and computing muscle.
How It Works
To create the displacement product, the OPERA team continuously draws data from the ESA (European Space Agency) Sentinel-1 radar satellites, the first of which launched in 2014. Data from NISAR, the NASA-ISRO (Indian Space Research Organisation) Synthetic Aperture Radar mission, will be added to the mix after that spacecraft launches later this year.
The OPERA portal shows that land near Willcox, Arizona, subsided about 8 inches (20 centimeters) since between 2016 and 2021, in large part due to groundwater pumping. The region is part of an area being managed by state water officials.Alaska Satellite Facility Satellite-borne radars work by emitting microwave pulses at Earth’s surface. The signals scatter when they hit land and water surfaces, buildings, and other objects. Raw data consists of the strength and time delay of the signals that echo back to the sensor.
To understand how land in a given area is moving, OPERA algorithms automate steps in an otherwise painstaking process. Without OPERA, a researcher would first download hundreds or thousands of data files, each representing a pass of the radar over the point of interest, then make sure the data aligned geographically over time and had precise coordinates.
Then they would use a computationally intensive technique called radar interferometry to gauge how much the land moved, if at all, and in which direction — towards the satellite, which would indicate the land rose, or away from the satellite, which would mean it sank.
“The OPERA project has helped bring that capability to the masses, making it more accessible to state and federal agencies, and also users wondering, ‘What’s going on around my house?’” said Franz Meyer, chief scientist of the Alaska Satellite Facility, a part of the University of Alaska Fairbanks Geophysical Institute.
Monitoring Groundwater
Sinking land is a top priority to the Arizona Department of Water Resources. From the 1950s through the 1980s, it was the main form of ground movement officials saw, as groundwater pumping increased alongside growth in the state’s population and agricultural industry. In 1980, the state enacted the Groundwater Management Act, which reduced its reliance on groundwater in highly populated areas and included requirements to monitor its use.
The department began to measure this sinking, called subsidence, with radar data from various satellites in the early 2000s, using a combination of SAR, GPS-based monitoring, and traditional surveying to inform groundwater-management decisions.
Now, the OPERA dataset and portal will help the agency share subsidence information with officials and community members, said Brian Conway, the department’s principal hydrogeologist and supervisor of its geophysics unit. They won’t replace the SAR analysis he performs, but they will offer points of comparison for his calculations. Because the dataset and portal will cover the entire state, they also could identify areas not yet known to be subsiding.
“It’s a great tool to say, ‘Let’s look at those areas more intensely with our own SAR processing,’” Conway said.
The displacement product is part of a series of data products OPERA has released since 2023. The project began in 2020 with a multidisciplinary team of scientists at JPL working to address satellite data needs across different federal agencies. Through the Satellite Needs Working Group, those agencies submitted their requests, and the OPERA team worked to improve access to information to aid a range of efforts such as disaster response, deforestation tracking, and wildfire monitoring.
NASA-Led Project Tracking Changes to Water, Ecosystems, Land Surface News Media Contacts
Andrew Wang / Jane J. Lee
Jet Propulsion Laboratory, Pasadena, Calif.
626-379-6874 / 818-354-0307
andrew.wang@jpl.nasa.gov / jane.j.lee@jpl.nasa.gov
2025-076
Share
Details
Last Updated Jun 06, 2025 Related Terms
Earth Science Earth Science Division Earthquakes Jet Propulsion Laboratory Natural Disasters Volcanoes Explore More
4 min read NASA Mars Orbiter Captures Volcano Peeking Above Morning Cloud Tops
Article 9 mins ago 8 min read ICESat-2 Applications Team Hosts Satellite Bathymetry Workshop
Introduction On September 15, 2018, the NASA Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) mission…
Article 1 day ago 5 min read Jack Kaye Retires After a Storied Career at NASA
Jack Kaye [NASA HQ—Associate Director for Research, Earth Science Division (ESD)] has decided to retire…
Article 1 day ago Keep Exploring Discover More Topics From NASA
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
-
Check out these Videos
Recommended Posts
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.