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To Understand Exoplanet Habitability, We Need A Better Understanding Of Stellar Flaring
Without a better grasp of stellar flaring, our understanding of exoplanet habitability is at an impasse. Red dwarfs are the most numerous type of star in the galaxy, and they host many rocky exoplanets in their habitable zones. The problem is, they're known to flare so violently that it may negate their habitable zones. A group of researchers propose a new telescope designed solely to study stellar flaring.
I Am Artemis: Jacki Mahaffey
Listen to this audio excerpt from Jacki Mahaffey, Artemis II chief training officer:
0:00 / 0:00
Your browser does not support the audio element.When the Artemis II crew travels around the Moon aboard the Orion spacecraft, they will have spent countless hours training for their lunar mission, and Jacki Mahaffey will have played a role in preparing them for their journey.
As the Artemis II chief training officer at NASA’s Johnson Space Center in Houston, Mahaffey manages the planning, development, and implementation of the astronauts’ training and integrated simulations. Her job is to ensure that when the Artemis II crew travels around the Moon inside Orion, the astronauts and flight controllers are ready for every moment — expected and unexpected.
Training is all risk mitigation for the mission. By preparing the astronauts and flight controllers for what they might encounter, we enable mission success.Jacki Mahaffey
Artemis II Chief Training Officer
The Artemis II crew began their rigorous training in 2023, but the work of Mahaffey and her team started long before that. Years before the training began, her team gathered the experts on how to operate the different aspects of Orion, and what the crew will need to know to execute their mission.
“One of my favorite moments from that process was when we all got together in one room, and everyone brought a piece of paper for every single lesson or training event that they expected to do with the crew,” Mahaffey said. “And we laid the entire thing out to figure out what’s the most logical order to put all of this training in, to help build that big picture for the crew.”
Training for Artemis II began shortly after the crew was announced, with Mahaffey and her team introducing the astronauts to Orion’s systems and operational basics. Once the necessary simulators and mockups were ready, the crew transitioned into hands-on training to build familiarity with their spacecraft.
At Johnson, Mahaffey’s team utilizes a range of specialized facilities, including the Space Vehicle Mockup Facility, where astronauts rehearse living and working inside the Orion mockup; the Orion Mission Simulator, which replicates flight software and displays; and the Neutral Buoyancy Laboratory, where the crew practices water survival techniques for post-splashdown scenarios.
Jacki Mahaffey, Artemis II Chief Training Officer at NASA’s Johnson Space Center in Houston, stands in front of the Orion mockup in Johnson’s Space Vehicle Mockup Facility.NASA/Rad Sinyak
“We try to simulate as much as we can here on Earth,” said Mahaffey. “But we still have gravity, so we rely on the crew’s experience to imagine how they’ll use the space in microgravity”
Three of the four Artemis II astronauts have flown in space before, and Mahaffey sees their experience as a powerful asset. They bring insights that shape procedures and training plans, and they learn from each other’s unique problem-solving styles.
“They are teaching us back about how to have that crew perspective of working in space and the things that are going to matter most,” she said.
Mahaffey’s journey began with a love for engineering and a role as a flight controller in Johnson’s Mission Control Center. She found joy in training others and eventually transitioned into a full-time training role. Now, she leads a team of about 100 contributors, all working to prepare the crew for their historic mission.
“I didn’t start out wanting to be a trainer — I studied engineering because I loved physics and math,” she said. “But as the job shifted toward applying that engineering knowledge, communicating, and planning how to operate a spacecraft, the natural next step was teaching others.”
In our organization, once you’ve learned to fish, you teach someone else to fish.Jacki Mahaffey
Artemis II Chief Training Officer
For Mahaffey, Artemis is a bridge connecting her family’s legacy with the future of space exploration. Her grandfather worked on control systems for Apollo, and she sees her work as a continuation of that story, now with more advanced technology and new frontiers.
“We’re doing some of the same things Apollo did, but expanding on them,” she said. “We’re learning more about the Moon, our Earth’s history, and how we’ll get to Mars.”
Her role during Artemis II also includes serving as an Artemis capcom, short for capsule communicator, the position in mission control that directly communicates with the crew members. Mahaffey plans to work the entry shift for Artemis II — helping to guide the crew to splashdown and ensuring their safe recovery. The moment will be a culmination of her entire team’s hard work.
“I’ll feel good when the recovery forces report that the hatch is open,” Mahaffey said. “That moment will be incredible.”
The Artemis II crew’s Chief Training Officer Jacki Mahaffey smiles during post insertion and deorbit preparation training at Johnson’s Space Vehicle Mockup Facility in Houston, Texas. The crew practiced getting the Orion spacecraft configured once in orbit, how to make it habitable, and suited up in their entry pressure suits to prepare for their return from the Moon. Credit: NASA/Mark Sowa About the AuthorErika Peters Share Details Last Updated Jan 05, 2026 Related Terms Explore More 3 min read I Am Artemis: Jen Madsen and Trey Perryman Article 1 week ago 3 min read Get In, We’re Going Moonbound: Meet NASA’s Artemis Closeout Crew Article 2 weeks ago 4 min read Artemis II Flight Crew, Teams Conduct Demonstration Ahead of Launch Article 2 weeks ago Keep Exploring Discover More Topics From NASA
Missions
Humans in Space
Climate Change
Solar System
I Am Artemis: Jacki Mahaffey
Listen to this audio excerpt from Jacki Mahaffey, Artemis II chief training officer:
0:00 / 0:00
Your browser does not support the audio element.When the Artemis II crew travels around the Moon aboard the Orion spacecraft, they will have spent countless hours training for their lunar mission, and Jacki Mahaffey will have played a role in preparing them for their journey.
As the Artemis II chief training officer at NASA’s Johnson Space Center in Houston, Mahaffey manages the planning, development, and implementation of the astronauts’ training and integrated simulations. Her job is to ensure that when the Artemis II crew travels around the Moon inside Orion, the astronauts and flight controllers are ready for every moment — expected and unexpected.
Training is all risk mitigation for the mission. By preparing the astronauts and flight controllers for what they might encounter, we enable mission success.Jacki Mahaffey
Artemis II Chief Training Officer
The Artemis II crew began their rigorous training in 2023, but the work of Mahaffey and her team started long before that. Years before the training began, her team gathered the experts on how to operate the different aspects of Orion, and what the crew will need to know to execute their mission.
“One of my favorite moments from that process was when we all got together in one room, and everyone brought a piece of paper for every single lesson or training event that they expected to do with the crew,” Mahaffey said. “And we laid the entire thing out to figure out what’s the most logical order to put all of this training in, to help build that big picture for the crew.”
Training for Artemis II began shortly after the crew was announced, with Mahaffey and her team introducing the astronauts to Orion’s systems and operational basics. Once the necessary simulators and mockups were ready, the crew transitioned into hands-on training to build familiarity with their spacecraft.
At Johnson, Mahaffey’s team utilizes a range of specialized facilities, including the Space Vehicle Mockup Facility, where astronauts rehearse living and working inside the Orion mockup; the Orion Mission Simulator, which replicates flight software and displays; and the Neutral Buoyancy Laboratory, where the crew practices water survival techniques for post-splashdown scenarios.
Jacki Mahaffey, Artemis II Chief Training Officer at NASA’s Johnson Space Center in Houston, stands in front of the Orion mockup in Johnson’s Space Vehicle Mockup Facility.NASA/Rad Sinyak“We try to simulate as much as we can here on Earth,” said Mahaffey. “But we still have gravity, so we rely on the crew’s experience to imagine how they’ll use the space in microgravity”
Three of the four Artemis II astronauts have flown in space before, and Mahaffey sees their experience as a powerful asset. They bring insights that shape procedures and training plans, and they learn from each other’s unique problem-solving styles.
“They are teaching us back about how to have that crew perspective of working in space and the things that are going to matter most,” she said.
Mahaffey’s journey began with a love for engineering and a role as a flight controller in Johnson’s Mission Control Center. She found joy in training others and eventually transitioned into a full-time training role. Now, she leads a team of about 100 contributors, all working to prepare the crew for their historic mission.
“I didn’t start out wanting to be a trainer — I studied engineering because I loved physics and math,” she said. “But as the job shifted toward applying that engineering knowledge, communicating, and planning how to operate a spacecraft, the natural next step was teaching others.”
In our organization, once you’ve learned to fish, you teach someone else to fish.Jacki Mahaffey
Artemis II Chief Training Officer
For Mahaffey, Artemis is a bridge connecting her family’s legacy with the future of space exploration. Her grandfather worked on control systems for Apollo, and she sees her work as a continuation of that story, now with more advanced technology and new frontiers.
“We’re doing some of the same things Apollo did, but expanding on them,” she said. “We’re learning more about the Moon, our Earth’s history, and how we’ll get to Mars.”
Her role during Artemis II also includes serving as an Artemis capcom, short for capsule communicator, the position in mission control that directly communicates with the crew members. Mahaffey plans to work the entry shift for Artemis II — helping to guide the crew to splashdown and ensuring their safe recovery. The moment will be a culmination of her entire team’s hard work.
“I’ll feel good when the recovery forces report that the hatch is open,” Mahaffey said. “That moment will be incredible.”
The Artemis II crew’s Chief Training Officer Jacki Mahaffey smiles during post insertion and deorbit preparation training at Johnson’s Space Vehicle Mockup Facility in Houston, Texas. The crew practiced getting the Orion spacecraft configured once in orbit, how to make it habitable, and suited up in their entry pressure suits to prepare for their return from the Moon. Credit: NASA/Mark Sowa About the AuthorErika Peters Share Details Last Updated Jan 05, 2026 Related Terms Explore More 3 min read I Am Artemis: Jen Madsen and Trey Perryman Article 1 week ago 3 min read Get In, We’re Going Moonbound: Meet NASA’s Artemis Closeout Crew Article 2 weeks ago 4 min read Artemis II Flight Crew, Teams Conduct Demonstration Ahead of Launch Article 2 weeks ago Keep Exploring Discover More Topics From NASAMissions
Humans in Space
Climate Change
Solar System
U.S. Axes Number of Recommended Childhood Vaccines in Blow to Public Health
The U.S. Centers for Disease Control and Prevention is reducing the recommended number of vaccines for children to those that protect against 11 diseases instead of the protections against 17 illnesses that it recommended previously
NASA to Cover US Spacewalks 94, 95 at International Space Station
NASA astronauts will conduct two spacewalks Thursday, Jan. 8, and Thursday, Jan. 15, outside the International Space Station, and the agency will provide comprehensive coverage.
The first spacewalk is scheduled to begin at 8 a.m. EST on Jan. 8 and last about six hours and 30 minutes. NASA will provide live coverage beginning at 6:30 a.m. on NASA+, Amazon Prime, and the agency’s YouTube channel. Learn how to stream NASA content through a variety of online platforms, including social media.
During U.S. spacewalk 94, NASA astronauts Mike Fincke and Zena Cardman will exit the station’s Quest airlock to prepare the 2A power channel for future installation of International Space Station Roll-Out Solar Arrays. Once installed, the array will provide additional power for the orbital laboratory, including critical support of its safe and controlled deorbit.
Fincke will serve as spacewalk crew member 1 and will wear a suit with red stripes, while Cardman will serve as spacewalk crew member 2 and will wear an unmarked suit. This spacewalk will be Cardman’s first and Fincke’s 10th, tying him for the most spacewalks by a NASA astronaut.
The second spacewalk is scheduled to begin at 7:10 a.m. on Jan. 15 and last about 6 hours and 30 minutes. NASA will provide live coverage beginning at 5:40 a.m. on NASA+, Amazon Prime, and the agency’s YouTube channel.
During U.S. spacewalk 95, two NASA astronauts will replace a high-definition camera on camera port 3, install a new navigational aid for visiting spacecraft, called a planar reflector, on the Harmony module’s forward port, and relocate an early ammonia servicer jumper — a flexible hose assembly that connects parts of a fluid system — along with other jumpers on the station’s S6 and S4 truss.
NASA will announce which astronauts are scheduled for the second spacewalk after the Jan. 8 spacewalk.
The spacewalks will be the 278th and 279th in support of space station assembly, maintenance and upgrades. Also, they are the first two International Space Station spacewalks of 2026, and the first by Expedition 74.
Learn more about International Space Station research and operations at:
-end-
Josh Finch / Jimi Russell
Headquarters, Washington
202-358-1100
joshua.a.finch@nasa.gov / james.j.russell@nasa.gov
Sandra Jones
Johnson Space Center, Houston
281-483-5111
sandra.p.jones@nasa.gov
NASA to Cover US Spacewalks 94, 95 at International Space Station
NASA astronauts will conduct two spacewalks Thursday, Jan. 8, and Thursday, Jan. 15, outside the International Space Station, and the agency will provide comprehensive coverage.
The first spacewalk is scheduled to begin at 8 a.m. EST on Jan. 8 and last about six hours and 30 minutes. NASA will provide live coverage beginning at 6:30 a.m. on NASA+, Amazon Prime, and the agency’s YouTube channel. Learn how to stream NASA content through a variety of online platforms, including social media.
During U.S. spacewalk 94, NASA astronauts Mike Fincke and Zena Cardman will exit the station’s Quest airlock to prepare the 2A power channel for future installation of International Space Station Roll-Out Solar Arrays. Once installed, the array will provide additional power for the orbital laboratory, including critical support of its safe and controlled deorbit.
Fincke will serve as spacewalk crew member 1 and will wear a suit with red stripes, while Cardman will serve as spacewalk crew member 2 and will wear an unmarked suit. This spacewalk will be Cardman’s first and Fincke’s 10th, tying him for the most spacewalks by a NASA astronaut.
The second spacewalk is scheduled to begin at 7:10 a.m. on Jan. 15 and last about 6 hours and 30 minutes. NASA will provide live coverage beginning at 5:40 a.m. on NASA+, Amazon Prime, and the agency’s YouTube channel.
During U.S. spacewalk 95, two NASA astronauts will replace a high-definition camera on camera port 3, install a new navigational aid for visiting spacecraft, called a planar reflector, on the Harmony module’s forward port, and relocate an early ammonia servicer jumper — a flexible hose assembly that connects parts of a fluid system — along with other jumpers on the station’s S6 and S4 truss.
NASA will announce which astronauts are scheduled for the second spacewalk after the Jan. 8 spacewalk.
The spacewalks will be the 278th and 279th in support of space station assembly, maintenance and upgrades. Also, they are the first two International Space Station spacewalks of 2026, and the first by Expedition 74.
Learn more about International Space Station research and operations at:
-end-
Josh Finch / Jimi Russell
Headquarters, Washington
202-358-1100
joshua.a.finch@nasa.gov / james.j.russell@nasa.gov
Sandra Jones
Johnson Space Center, Houston
281-483-5111
sandra.p.jones@nasa.gov
Stunningly Hot Galaxy Cluster Puts New Spin on How These Cosmic Behemoths Evolved
Scientists detected gas at least five times hotter than previous theories had predicted inside a galaxy cluster from the early universe
Northern Greenland ice dome melted before and could melt again
Northern Greenland ice dome melted before and could melt again
NASA’s Hubble Examines Cloud-9, First of New Type of Object
- Hubble Home
- Overview
- Impact & Benefits
- Science
- Observatory
- Team
- Multimedia
- News
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NASA, ESA, VLA, Gagandeep Anand (STScI), Alejandro Benitez-Llambay (University of Milano-Bicocca); Image Processing: Joseph DePasquale (STScI)
A team using NASA’s Hubble Space Telescope has uncovered a new type of astronomical object — a starless, gas-rich, dark-matter cloud considered a “relic” or remnant of early galaxy formation. Nicknamed “Cloud-9,” this is the first confirmed detection of such an object in the universe — a finding that furthers the understanding of galaxy formation, the early universe, and the nature of dark matter itself.
“This is a tale of a failed galaxy,” said the program’s principal investigator, Alejandro Benitez-Llambay of the Milano-Bicocca University in Milan, Italy. “In science, we usually learn more from the failures than from the successes. In this case, seeing no stars is what proves the theory right. It tells us that we have found in the local universe a primordial building block of a galaxy that hasn’t formed.”
The results, published in The Astrophysical Journal Letters, were presented at a press conference Monday at the 247th meeting of the American Astronomical Society in Phoenix.
“This cloud is a window into the dark universe,” said team member Andrew Fox of the Association of Universities for Research in Astronomy/Space Telescope Science Institute (AURA/STScI) for the European Space Agency. “We know from theory that most of the mass in the universe is expected to be dark matter, but it’s difficult to detect this dark material because it doesn’t emit light. Cloud-9 gives us a rare look at a dark-matter-dominated cloud.”
This image shows the location of Cloud-9, which is 14 million light-years from Earth. The diffuse magenta is radio data from the ground-based Very Large Array (VLA) showing the presence of the cloud. The dashed circle marks the peak of radio emission, which is where researchers focused their search for stars. Follow-up observations by the Hubble Space Telescope’s Advanced Camera for Surveys found no stars within the cloud. The few objects that appear within its boundaries are background galaxies. Before the Hubble observations, scientists could argue that Cloud-9 is a faint dwarf galaxy whose stars could not be seen with ground-based telescopes due to the lack of sensitivity. Hubble’s Advanced Camera for Surveys shows that, in reality, the failed galaxy contains no stars. Science: NASA, ESA, VLA, Gagandeep Anand (STScI), Alejandro Benitez-Llambay (University of Milano-Bicocca); Image Processing: Joseph DePasquale (STScI)
The object is called a Reionization-Limited H I Cloud, or “RELHIC.” The term “H I” refers to neutral hydrogen, and “RELHIC” describes a natal hydrogen cloud from the universe’s early days, a fossil leftover that has not formed stars. For years, scientists have looked for evidence of such a theoretical phantom object. It wasn’t until they turned Hubble toward the cloud, confirming that it is indeed starless, that they found support for the theory.
“Before we used Hubble, you could argue that this is a faint dwarf galaxy that we could not see with ground-based telescopes. They just didn’t go deep enough in sensitivity to uncover stars,” said lead author Gagandeep Anand of STScI. “But with Hubble’s Advanced Camera for Surveys, we’re able to nail down that there’s nothing there.”
The discovery of this relic cloud was a surprise. “Among our galactic neighbors, there might be a few abandoned houses out there,” said STScI’s Rachael Beaton, who is also on the research team.
Astronomers think RELHICs are dark matter clouds that couldn’t accumulate enough gas to form stars. They represent a window into the early stages of galaxy formation. Cloud-9 suggests the existence of many other small, dark matter-dominated structures in the universe — other failed galaxies. This discovery provides new insights into the dark components of the universe that are difficult to study through traditional observations, which focus on bright objects like stars and galaxies.
Scientists have studied hydrogen clouds near the Milky Way for many years, but these clouds tend to be much bigger and more irregular than Cloud-9. Compared with other observed hydrogen clouds, Cloud-9 is smaller, more compact, and highly spherical, making it look very different from the others.
The core of this object is composed of neutral hydrogen and is about 4,900 light-years in diameter. Researchers measured the hydrogen gas in Cloud-9 by the radio waves it emits, measuring it to be approximately one million times the mass of the Sun. Assuming that the gas pressure is balancing the dark matter cloud’s gravity, which appears to be the case, researchers calculated Cloud-9’s dark matter must be about five billion solar masses.
Cloud-9 is an example of structures and mysteries that don’t involve stars. Just looking at stars doesn’t give the full picture. Studying the gas and dark matter helps provide a more complete understanding of what’s going on in these systems that would otherwise be unknown.
Observationally, identifying these failed galaxies is challenging because nearby objects outshine them. Such systems are also vulnerable to environmental effects like ram-pressure stripping, which can remove gas as the cloud moves through intergalactic space. These factors further reduce their expected numbers.
The starless relic was discovered three years ago as part of a radio survey by the Five-hundred-meter Aperture Spherical Telescope (FAST) in Guizhou, China, a finding later confirmed by the Green Bank Telescope and the Very Large Array facilities in the United States. But only with Hubble could researchers definitively determine that the failed galaxy contains no stars.
Cloud-9 was simply named sequentially, having been the ninth gas cloud identified on the outskirts of a nearby spiral galaxy, Messier 94 (M94). The cloud is close to M94 and appears to have a physical association with the galaxy. High-resolution radio data shows slight gas distortions, possibly indicating interaction between the cloud and galaxy.
The cloud may eventually form a galaxy in the future, provided it grows more massive — although how that would occur is under speculation. If it were much bigger, say, more than 5 billion times the mass of our Sun, it would have collapsed, formed stars, and become a galaxy that would be no different than any other galaxy we see. If it were much smaller than that, the gas could have been dispersed and ionized and there wouldn’t be much left. But it’s in a sweet spot where it could remain as a RELHIC.
The lack of stars in this object provides a unique window into the intrinsic properties of dark matter clouds. The rarity of such objects and the potential for future surveys is expected to enhance the discovery of more of these “failed galaxies” or “relics,” resulting in insights into the early universe and the physics of dark matter.
The Hubble Space Telescope has been operating for more than 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 Cloud 9, Starless Gas CloudMagenta is radio data from the ground-based Very Large Array (VLA) showing the presence of Cloud-9. The dashed circle marks the area where researchers focused their search for stars. Hubble found no stars within Cloud-9. The few objects within its boundaries are background galaxies.
Cloud 9, Starless Gas Cloud Compass Image
This is an annotated composite image of Cloud-9, a Reionization-Limited H I Cloud (RELHIC), as captured by the Hubble Space Telescope’s ACS (Advanced Camera for Surveys) and the ground-based Very Large Array (VLA) radio telescope.
Cloud 9, Starless Gas Cloud Video
This annotated video shows the location of Cloud-9 on the sky. As the video zooms into this gas-rich, dark-matter cloud, it becomes evident that there are no stars within it. Only background galaxies appear behind Cloud-9, which has survived since the universe’s early days….
Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov
Ann Jenkins, Christine Pulliam
Space Telescope Science Institute
Baltimore, Maryland
- Science Paper: “The First RELHIC? Cloud-9 is a Starless Gas Cloud” by G. Anand et al., PDF (15.34 MB)
- Release on ESA/Hubble 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.
Hubble Science Highlights
Hubble Images
Hubble News
NASA’s Hubble Examines Cloud-9, First of New Type of Object
- Hubble Home
- Overview
- Impact & Benefits
- Science
- Observatory
- Team
- Multimedia
- News
- More
NASA, ESA, VLA, Gagandeep Anand (STScI), Alejandro Benitez-Llambay (University of Milano-Bicocca); Image Processing: Joseph DePasquale (STScI)
A team using NASA’s Hubble Space Telescope has uncovered a new type of astronomical object — a starless, gas-rich, dark-matter cloud considered a “relic” or remnant of early galaxy formation. Nicknamed “Cloud-9,” this is the first confirmed detection of such an object in the universe — a finding that furthers the understanding of galaxy formation, the early universe, and the nature of dark matter itself.
“This is a tale of a failed galaxy,” said the program’s principal investigator, Alejandro Benitez-Llambay of the Milano-Bicocca University in Milan, Italy. “In science, we usually learn more from the failures than from the successes. In this case, seeing no stars is what proves the theory right. It tells us that we have found in the local universe a primordial building block of a galaxy that hasn’t formed.”
The results, published in The Astrophysical Journal Letters, were presented at a press conference Monday at the 247th meeting of the American Astronomical Society in Phoenix.
“This cloud is a window into the dark universe,” said team member Andrew Fox of the Association of Universities for Research in Astronomy/Space Telescope Science Institute (AURA/STScI) for the European Space Agency. “We know from theory that most of the mass in the universe is expected to be dark matter, but it’s difficult to detect this dark material because it doesn’t emit light. Cloud-9 gives us a rare look at a dark-matter-dominated cloud.”
This image shows the location of Cloud-9, which is 14 million light-years from Earth. The diffuse magenta is radio data from the ground-based Very Large Array (VLA) showing the presence of the cloud. The dashed circle marks the peak of radio emission, which is where researchers focused their search for stars. Follow-up observations by the Hubble Space Telescope’s Advanced Camera for Surveys found no stars within the cloud. The few objects that appear within its boundaries are background galaxies. Before the Hubble observations, scientists could argue that Cloud-9 is a faint dwarf galaxy whose stars could not be seen with ground-based telescopes due to the lack of sensitivity. Hubble’s Advanced Camera for Surveys shows that, in reality, the failed galaxy contains no stars. Science: NASA, ESA, VLA, Gagandeep Anand (STScI), Alejandro Benitez-Llambay (University of Milano-Bicocca); Image Processing: Joseph DePasquale (STScI)The object is called a Reionization-Limited H I Cloud, or “RELHIC.” The term “H I” refers to neutral hydrogen, and “RELHIC” describes a natal hydrogen cloud from the universe’s early days, a fossil leftover that has not formed stars. For years, scientists have looked for evidence of such a theoretical phantom object. It wasn’t until they turned Hubble toward the cloud, confirming that it is indeed starless, that they found support for the theory.
“Before we used Hubble, you could argue that this is a faint dwarf galaxy that we could not see with ground-based telescopes. They just didn’t go deep enough in sensitivity to uncover stars,” said lead author Gagandeep Anand of STScI. “But with Hubble’s Advanced Camera for Surveys, we’re able to nail down that there’s nothing there.”
The discovery of this relic cloud was a surprise. “Among our galactic neighbors, there might be a few abandoned houses out there,” said STScI’s Rachael Beaton, who is also on the research team.
Astronomers think RELHICs are dark matter clouds that couldn’t accumulate enough gas to form stars. They represent a window into the early stages of galaxy formation. Cloud-9 suggests the existence of many other small, dark matter-dominated structures in the universe — other failed galaxies. This discovery provides new insights into the dark components of the universe that are difficult to study through traditional observations, which focus on bright objects like stars and galaxies.
Scientists have studied hydrogen clouds near the Milky Way for many years, but these clouds tend to be much bigger and more irregular than Cloud-9. Compared with other observed hydrogen clouds, Cloud-9 is smaller, more compact, and highly spherical, making it look very different from the others.
The core of this object is composed of neutral hydrogen and is about 4,900 light-years in diameter. Researchers measured the hydrogen gas in Cloud-9 by the radio waves it emits, measuring it to be approximately one million times the mass of the Sun. Assuming that the gas pressure is balancing the dark matter cloud’s gravity, which appears to be the case, researchers calculated Cloud-9’s dark matter must be about five billion solar masses.
Cloud-9 is an example of structures and mysteries that don’t involve stars. Just looking at stars doesn’t give the full picture. Studying the gas and dark matter helps provide a more complete understanding of what’s going on in these systems that would otherwise be unknown.
Observationally, identifying these failed galaxies is challenging because nearby objects outshine them. Such systems are also vulnerable to environmental effects like ram-pressure stripping, which can remove gas as the cloud moves through intergalactic space. These factors further reduce their expected numbers.
The starless relic was discovered three years ago as part of a radio survey by the Five-hundred-meter Aperture Spherical Telescope (FAST) in Guizhou, China, a finding later confirmed by the Green Bank Telescope and the Very Large Array facilities in the United States. But only with Hubble could researchers definitively determine that the failed galaxy contains no stars.
Cloud-9 was simply named sequentially, having been the ninth gas cloud identified on the outskirts of a nearby spiral galaxy, Messier 94 (M94). The cloud is close to M94 and appears to have a physical association with the galaxy. High-resolution radio data shows slight gas distortions, possibly indicating interaction between the cloud and galaxy.
The cloud may eventually form a galaxy in the future, provided it grows more massive — although how that would occur is under speculation. If it were much bigger, say, more than 5 billion times the mass of our Sun, it would have collapsed, formed stars, and become a galaxy that would be no different than any other galaxy we see. If it were much smaller than that, the gas could have been dispersed and ionized and there wouldn’t be much left. But it’s in a sweet spot where it could remain as a RELHIC.
The lack of stars in this object provides a unique window into the intrinsic properties of dark matter clouds. The rarity of such objects and the potential for future surveys is expected to enhance the discovery of more of these “failed galaxies” or “relics,” resulting in insights into the early universe and the physics of dark matter.
The Hubble Space Telescope has been operating for more than 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 Cloud 9, Starless Gas CloudMagenta is radio data from the ground-based Very Large Array (VLA) showing the presence of Cloud-9. The dashed circle marks the area where researchers focused their search for stars. Hubble found no stars within Cloud-9. The few objects within its boundaries are background galaxies.
Cloud 9, Starless Gas Cloud Compass Image
This is an annotated composite image of Cloud-9, a Reionization-Limited H I Cloud (RELHIC), as captured by the Hubble Space Telescope’s ACS (Advanced Camera for Surveys) and the ground-based Very Large Array (VLA) radio telescope.
Cloud 9, Starless Gas Cloud Video
This annotated video shows the location of Cloud-9 on the sky. As the video zooms into this gas-rich, dark-matter cloud, it becomes evident that there are no stars within it. Only background galaxies appear behind Cloud-9, which has survived since the universe’s early days….
Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov
Ann Jenkins, Christine Pulliam
Space Telescope Science Institute
Baltimore, Maryland
- Science Paper: “The First RELHIC? Cloud-9 is a Starless Gas Cloud” by G. Anand et al., PDF (15.34 MB)
- Release on ESA/Hubble 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.
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Cloud-9: a new celestial object found by Hubble
A team using the NASA/ESA Hubble Space Telescope has uncovered a new type of astronomical object – a starless, gas-rich, dark-matter cloud that is considered a 'relic' or remnant of early galaxy formation. Nicknamed 'Cloud-9,' this is the first confirmed detection of such an object in the Universe.
Ultramassive Black Holes and Their Galaxies: A Matter of Scale
There is a strong relation between the size of a galaxy's black hole and the motion of stars in the galaxy's core, known as the M-sigma relation. It turns out this relation doesn't work well for galaxies with ultramassive black holes.
5 Tips to Craft a Standout NASA Internship Application
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater) Four NASA interns pose in front of the NASA Pavilion at the EAA AirVenture Oshkosh, an annual airshow in Oshkosh, Wisconsin.NASA
A NASA internship provides a stellar opportunity to launch your future as part of America’s aerospace workforce. NASA interns take on meaningful work and contribute to exciting agency projects with the guidance of a supportive mentor. The agency’s internship program regularly ranks as the nation’s most prestigious and competition is steep: in fiscal year 2025, NASA’s Office of STEM Engagement received about 250,000 internship applications for its roughly 1,800 internship opportunities.
To give you the best shot at a NASA internship, we’ve compiled a list of tips mentors say can make an application stand out from the crowd. It is NASA’s mentors who create internship project descriptions, review applications, and take the lead in choosing candidates to work on their specific internship projects. Here’s what they had to say:
1. Your personal statement is your chance to make a lasting impression.Mentors pay close attention to personal statements to identify the best candidate for their project and team. A powerful personal statement shares personal background, experience, and goals, and how they relate to the needs of the project.
NASA mentors are looking for interns who will enjoy the work and fit in with the team culture. Beyond your academic background, grades, and interests, this is your chance to share your curiosity, enthusiasm, passion, or resilience. Show us who you are and what you can do!
2. Show off your academic achievements.Mentors love to see what academic expertise and hands-on experience you can bring to the internship project. Your transcripts, grade point average, coursework, research, academic projects, awards, and accomplishments are valuable highlights in your application.
3. Tell us about your extracurriculars, too!Who are you outside the classroom?
Mentors like to see well-rounded candidates whose interests take them beyond their chosen academic and career path. Include any extracurricular activities you participate in, such as a club or team at school or an organization in your community. Whether you’re involved in a local rocketry club, a school athletic team, or a musical ensemble, these pursuits may demonstrate academic skills or soft skills such as collaboration. Shared hobbies can also be a great point of personal connection with a future mentor.
4. Include as many of your skills as possible.Share the valuable skills that you can bring to an internship project. These could be technical skills, such as experience with specific tools or computer programming languages, and non-technical skills, which may include communications skills or leadership experience. Mentors search for skills that meet their project requirements and, match with the role, but also for unique skills that might be an added asset.
5. Give yourself a chance.Don’t count yourself out before you get started! If you have a passion for spaceflight or aviation, it’s worth applying for a NASA internship – even if you’re not a math, science, engineering, or technology major. That’s because NASA achieves its exploration goals with the support of a nationwide team with a wide variety of skills: communicators, creatives, business specialists, legal experts, and so many more. Take a look at NASA’s internship opportunities and you’ll find projects in a wide range of fields.
Yes, competition is fierce. But someone is going to land that internship – and that person could be you!
Learn MoreCheck eligibility requirements, see current deadlines, and launch your internship journey at https://intern.nasa.gov.
5 Tips to Craft a Standout NASA Internship Application
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater) Four NASA interns pose in front of the NASA Pavilion at the EAA AirVenture Oshkosh, an annual airshow in Oshkosh, Wisconsin.NASAA NASA internship provides a stellar opportunity to launch your future as part of America’s aerospace workforce. NASA interns take on meaningful work and contribute to exciting agency projects with the guidance of a supportive mentor. The agency’s internship program regularly ranks as the nation’s most prestigious and competition is steep: in fiscal year 2025, NASA’s Office of STEM Engagement received about 250,000 internship applications for its roughly 1,800 internship opportunities.
To give you the best shot at a NASA internship, we’ve compiled a list of tips mentors say can make an application stand out from the crowd. It is NASA’s mentors who create internship project descriptions, review applications, and take the lead in choosing candidates to work on their specific internship projects. Here’s what they had to say:
1. Your personal statement is your chance to make a lasting impression.Mentors pay close attention to personal statements to identify the best candidate for their project and team. A powerful personal statement shares personal background, experience, and goals, and how they relate to the needs of the project.
NASA mentors are looking for interns who will enjoy the work and fit in with the team culture. Beyond your academic background, grades, and interests, this is your chance to share your curiosity, enthusiasm, passion, or resilience. Show us who you are and what you can do!
2. Show off your academic achievements.Mentors love to see what academic expertise and hands-on experience you can bring to the internship project. Your resume, transcripts, grade point average, coursework, research, academic projects, awards, and accomplishments are valuable highlights in your application.
3. Tell us about your extracurriculars, too!Who are you outside the classroom?
Mentors like to see well-rounded candidates whose interests take them beyond their chosen academic and career path. Include any extracurricular activities you participate in, such as a club or team at school or an organization in your community. Whether you’re involved in a local rocketry club, a school athletic team, or a musical ensemble, these pursuits may demonstrate academic skills or soft skills such as collaboration. Shared hobbies can also be a great point of personal connection with a future mentor.
4. Include as many of your skills as possible.Share the valuable skills that you can bring to an internship project. These could be technical skills, such as experience with specific tools or computer programming languages, and non-technical skills, which may include communications skills or leadership experience. Mentors search for skills that meet their project requirements and, match with the role, but also for unique skills that might be an added asset.
5. Give yourself a chance.Don’t count yourself out before you get started! If you have a passion for spaceflight or aviation, it’s worth applying for a NASA internship – even if you’re not a math, science, engineering, or technology major. That’s because NASA achieves its exploration goals with the support of a nationwide team with a wide variety of skills: communicators, creatives, business specialists, legal experts, and so many more. Take a look at NASA’s internship opportunities and you’ll find projects in a wide range of fields.
Yes, competition is fierce. But someone is going to land that internship – and that person could be you!
Learn More- Check eligibility requirements, see current deadlines, and launch your internship journey at https://intern.nasa.gov.
- Click here to find NASA resume tips.
Scientific Balloon Begins Antarctic Ascent
Scientific Balloon Begins Antarctic Ascent
A scientific balloon starts its ascent into the air as it prepares to launch carrying NASA’s Payload for Ultrahigh Energy Observations (PUEO) mission. The mission lifted off from Antarctica at 5:56 a.m. NZST, Saturday, Dec. 20 (11:56 a.m., Friday, Dec. 19 in U.S. Eastern Time).
The PUEO mission is designed to detect radio signals created when highly energetic particles called neutrinos from space hit the ice. The PUEO payload will collect data that give us insight into events like the creation of black holes and neutron star mergers. Alongside the PUEO mission are two other balloons carrying calibration equipment sending test signals to help scientists make sure the payload equipment is working correctly when it tries to detect real signals from space.
Track the balloons in realtime.
Image credit: NASA/Scott Battaion
Longest-Ever Look at Stormy Region on the Sun Offers New Clues to Space Weather
Scientists observed an active region on the sun for a record 94 days, marking a “milestone in solar physics”
Press conference with ESA astronaut Sophie Adenot
Media representatives joined French ESA astronaut Sophie Adenot, on Monday 5 January, for a hybrid press conference to learn more about her first mission to space.
This event, held at the European Astronaut Centre (EAC) in Germany, was the final media event in Europe ahead of her launch to the International Space Station.
Sophie selected the name ‘εpsilon’ for her first mission, currently planned no earlier than 15 February, reflecting the power of small, yet impactful contributions, and how many parts come together to make a whole.
During εpsilon, Sophie will conduct a wide range of tasks on the International Space Station, including European-led scientific experiments, medical research, supporting Earth observation and contributing to operations and maintenance on the Station.