Jump to content

A Puzzle of Galactic Evolution is Solved – Massive Gas Clouds Seed the Galaxy with the Stuff of Stars


Recommended Posts

Posted
low_STSCI-H-p-9946a-k1340x520.png

Massive clouds of gas, discovered long ago but only recently identified as being within the margins of the Milky Way, play a key role in the galaxy's ability to churn out new stars by raining gas onto the plane of the galaxy. Researchers have chipped away at a three-decade-old mystery about the nature and role of those massive gas clouds, called high-velocity clouds. In the process, they've discovered a mechanism by which the galaxy is seeded with the stuff of stars and solved a long-standing question of galactic evolution.

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
      2 min read
      Space Cloud Watch Needs Your Photos of Night-Shining Clouds 
      Noctilucent Clouds observed from Bozeman, MT on 16 July 2009 at 4:29 MDT. The Space Cloud Watch project needs more photos like this one to diagnose changes in our atmosphere! Photo credit: Dr. Joseph A Shaw Noctilucent or night-shining clouds are rare, high-altitude clouds that glow with a blue silvery hue at dusk or dawn when the sun shines on them from below the horizon. These ice clouds typically occur near the north and south poles but are increasingly being reported at mid- and low latitudes. Observing them helps scientists better understand how human activities may affect our atmosphere.
      Now, the Space Cloud Watch project is asking you to report your own observations of noctilucent clouds and upload your own photographs. Combined with satellite data and model simulations, your data can help us figure out why these noctilucent clouds are suddenly appearing at mid-low latitudes, where temperatures are usually too warm for them to form.
       “I find these clouds fascinating and can’t wait to see the amazing pictures,” said project lead Dr. Chihoko Cullens from the University of Colorado, Boulder Laboratory for Atmospheric and Space Physics. 
      Did you see or photograph any night-shining clouds? Upload them here. Later, the science team will transfer them to a site on the Zooniverse platform where you or other volunteers can help examine them and identify wave structures in the cloud images.
      If you love clouds, NASA has more citizen science projects for you. Try Cloudspotting on Mars, Cloudspotting on Mars: Shapes, or GLOBE Observer Clouds!
      Share








      Details
      Last Updated May 15, 2025 Related Terms
      Citizen Science Heliophysics Explore More
      4 min read Eclipses, Auroras, and the Spark of Becoming: NASA Inspires Future Scientists


      Article


      20 hours ago
      6 min read What NASA Is Learning from the Biggest Geomagnetic Storm in 20 Years


      Article


      6 days ago
      2 min read Amateur Radio Scientists Shine at the 2025 HamSCI Workshop


      Article


      2 weeks ago
      View the full article
    • By NASA
      Credit: NASA NASA has selected Rocket Lab USA Inc. of Long Beach, California, to launch the agency’s Aspera mission, a SmallSat to study galaxy formation and evolution, providing new insights into how the universe works.
      The selection is part of NASA’s Venture-Class Acquisition of Dedicated and Rideshare (VADR) launch services contract. This contract allows the agency to make fixed-price indefinite-delivery/indefinite-quantity launch service task order awards during VADR’s five-year ordering period, with a maximum total contract value of $300 million.
      Through the observation of ultraviolet light, Aspera will examine hot gas in the space between galaxies, called the intergalactic medium. The mission will study the inflow and outflow of gas from galaxies, a process thought to contribute to star formation.
      Aspera is part of NASA’s Pioneers Program in the Astrophysics Division at NASA Headquarters in Washington, which funds compelling astrophysics science at a lower cost using small hardware and modest payloads. The principal investigator for Aspera is Carlos Vargas at the University of Arizona in Tucson. NASA’s Launch Services Program, based at the agency’s Kennedy Space Center in Florida, manages the VADR contract.
      To learn more about NASA’s Aspera mission and the Pioneers Program, visit:
      https://go.nasa.gov/42U1Wkn
      -end-
      Joshua Finch / Tiernan Doyle
      Headquarters, Washington
      202-358-1600
      joshua.a.finch@nasa.gov / tiernan.doyle@nasa.gov
      Patti Bielling
      Kennedy Space Center, Florida
      321-501-7575
      patricia.a.bielling@nasa.gov
      Share
      Details
      Last Updated May 14, 2025 LocationNASA Headquarters Related Terms
      Space Operations Mission Directorate Kennedy Space Center Launch Services Office Launch Services Program NASA Headquarters 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 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 Pinpoints Young Stars in Spiral Galaxy
      This NASA/ESA Hubble Space Telescope image features the spiral galaxy NGC 1317. ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team In this image, the NASA/ESA Hubble Space Telescope peers into the spiral galaxy NGC 1317 in the constellation Fornax, located more than 50 million light-years from Earth. Visible in this galaxy image is a bright blue ring that hosts hot, young stars. NGC 1317 is one of a pair, but its rowdy larger neighbor, NGC 1316, lies outside Hubble’s field of view. Despite the absence of its neighboring galaxy, this image finds NGC 1317 accompanied by two objects from very different parts of the universe. The bright point ringed with a crisscross pattern is a star from our own galaxy surrounded by diffraction spikes, whereas the redder elongated smudge is a distant galaxy lying far beyond NGC 1317.
      The data presented in this image are from a vast observing campaign of hundreds of observations from Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys. Combined with data from the ALMA array in the Atacama Desert, these observations help astronomers chart the connections between vast clouds of cold gas and the fiercely hot, young stars that form within them. ALMA’s unparalleled sensitivity at long wavelengths identified vast reservoirs of cold gas throughout the local universe, and Hubble’s sharp vision pinpointed clusters of young stars, as well as measuring their ages and masses.
      Often the most exciting astronomical discoveries require this kind of telescope teamwork, with cutting-edge facilities working together to provide astronomers with information across the electromagnetic spectrum. The same applies to Hubble’s observations that laid the groundwork for the NASA/ESA/CSA James Webb Space Telescope’s scientific observations.
      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 May 14, 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 Science Highlights



      Science Behind the Discoveries


      View the full article
    • By NASA
      The NASA Ames Science Directorate recognizes the outstanding contributions of (pictured left to right) Dennis Leveson-Gower and Laura Iraci. Their commitment to the NASA mission represents the entrepreneurial spirit, technical expertise, and collaborative disposition needed to explore this world and beyond.
      Space Biosciences Star: Dennis Leveson-Gower
      Dennis Leveson-Gower, Assistant Branch Chief of Bioengineering, has contributed to numerous projects and payloads within the Space Biosciences Division since 2012. He is recognized for exceptional leadership, operational excellence, and strategic collaboration that have advanced the Bioengineering Branch and strengthened partnerships with commercial spaceflight organizations.
      Earth Science Star: Laura Iraci
      Laura Iraci is a Senior Research Scientist in the Atmospheric Science Branch. She is recognized for her outstanding scientific leadership and her impactful role as a mentor. As head of the Trace Gas Group, Laura develops and deploys custom atmospheric sampling and remote sensing instrumentation for critical NASA suborbital and spaceflight missions, including major airborne science field campaigns. She is equally dedicated to mentoring early-career researchers, with many advancing into highly productive staff positions at NASA.

      View the full article
    • By NASA
      Explore Hubble Science Hubble Space Telescope NASA’s Hubble Pinpoints… 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   7 Min Read NASA’s Hubble Pinpoints Roaming Massive Black Hole
      This six-panel illustration of a tidal disruption event around a supermassive black hole shows the collision with a star followed by an explosion detected in X-ray as well as Hubble Space Telescope visible-light observations. Credits:
      Artwork: NASA, ESA, STScI, Ralf Crawford (STScI) Like a scene out of a sci-fi movie, astronomers using NASA telescopes have found “Space Jaws.”
      Lurking 600 million light-years away, within the inky black depths between stars, there is an invisible monster gulping down any wayward star that plummets toward it. The sneaky black hole betrayed its presence in a newly identified tidal disruption event (TDE) where a hapless star was ripped apart and swallowed in a spectacular burst of radiation. These disruption events are powerful probes of black hole physics, revealing the conditions necessary for launching jets and winds when a black hole is in the midst of consuming a star, and are seen as bright objects by telescopes.
      The new TDE, called AT2024tvd, allowed astronomers to pinpoint a wandering supermassive black hole using NASA’s Hubble Space Telescope, with similar supporting observations from NASA’s Chandra X-Ray Observatory and the NRAO Very Large Array telescope that also showed that the black hole is offset from the center of the galaxy.
      The paper will be published in an upcoming issue of The Astrophysical Journal Letters.
      This six-panel illustration of a tidal disruption event around a supermassive black hole shows the following: 1) A supermassive black hole is adrift inside a galaxy, its presence only detectable by gravitational lensing; 2) A wayward star gets swept up in the black hole’s intense gravitational pull; 3) The star is stretched or “spaghettified” by gravitational tidal effects; 4) The star’s remnants form a disk around the black hole; 5) There is a period of black hole accretion, pouring out radiation across the electromagnetic spectrum, from X-rays to radio wavelengths; and 6) The host galaxy, seen from afar, contains a bright flash of energy that is offset from the galaxy’s nucleus, where an even more massive black hole dwells. Artwork: NASA, ESA, STScI, Ralf Crawford (STScI) Surprisingly, this one million-solar-mass black hole doesn’t reside exactly in the center of the host galaxy, where supermassive black holes are typically found, and actively gobble up surrounding material. Out of approximately 100 TDE events recorded by optical sky surveys so far, this is the first time an offset TDE has been identified. The rest are associated with the central black holes of galaxies.
      In fact, at the center of the host galaxy there is a different supermassive black hole weighing 100 million times the mass of the Sun. Hubble’s optical precision shows the TDE was only 2,600 light-years from the more massive black hole at the galaxy’s center. That’s just one-tenth the distance between our Sun and the Milky Way’s central supermassive black hole.
      This bigger black hole spews out energy as it accretes infalling gas, and it is categorized as an active galactic nucleus. Strangely, the two supermassive black holes co-exist in the same galaxy, but are not gravitationally bound to each other as a binary pair. The smaller black hole may eventually spiral into the galaxy’s center to merge with the bigger black hole. But for now, it is too far separated to be gravitationally bound.
      A TDE happens when an infalling star is stretched or “spaghettified” by a black hole’s immense gravitational tidal forces. The shredded stellar remnants are pulled into a circular orbit around the black hole. This generates shocks and outflows with high temperatures that can be seen in ultraviolet and visible light.
      “AT2024tvd is the first offset TDE captured by optical sky surveys, and it opens up the entire possibility of uncovering this elusive population of wandering black holes with future sky surveys,” said lead study author Yuhan Yao of the University of California at Berkeley. “Right now, theorists haven’t given much attention to offset TDEs. “I think this discovery will motivate scientists to look for more examples of this type of event.”
      This is a Hubble Space Telescope image of distant galaxy that is host to the telltale signature of a roaming supermassive black hole. Science: NASA, ESA, STScI, Yuhan Yao (UC Berkeley); Image Processing: Joseph DePasquale (STScI) A Flash in the Night
      The star-snacking black hole gave itself away when several ground-based sky survey telescopes observed a flare as bright as a supernova. But unlike a supernova, astronomers know that this came from a black hole snacking on a star because the flare was very hot, and showed broad emission lines of hydrogen, helium, carbon, nitrogen, and silicon. The Zwicky Transient Facility at Caltech’s Palomar Observatory, with its 1.2-meter telescope that surveys the entire northern sky every two days, first observed the event.
      “Tidal disruption events hold great promise for illuminating the presence of massive black holes that we would otherwise not be able to detect,” said Ryan Chornock, associate adjunct professor at UC Berkeley and a member of the ZTF team. “Theorists have predicted that a population of massive black holes located away from the centers of galaxies must exist, but now we can use TDEs to find them.”
      The flare was seemingly offset from the center of a bright massive galaxy as cataloged by  Pan-STARRS (Panoramic Survey Telescope and Rapid Response System), the Sloan Digital Sky Survey, and the DESI Legacy Imaging Survey. To better determine that it was not at the galactic center, Yao’s team used NASA’s Chandra X-ray Observatory to confirm that X-rays from the flare site were also offset.
      It took the resolving power of Hubble to settle any uncertainties. Hubble’s sensitivity to ultraviolet light also allows it to pinpoint the location of the TDE, which is much bluer than the rest of the galaxy.
      This is a combined Hubble Space Telescope/Chandra X-Ray Observatory image of a distant galaxy that is host to the telltale signature of a roaming supermassive black hole. Both telescopes caught a tidal disruption event (TDE) caused by the black hole eating a star. Science: NASA, ESA, STScI, Yuhan Yao (UC Berkeley); Image Processing: Joseph DePasquale (STScI) Origin Unknown
      The black hole responsible for the TDE is prowling inside the bulge of the massive galaxy. The black hole only becomes apparent every few tens of thousands of years when it “burps” from capturing a star, and then it goes quiet again until its next meal comes along.
      How did the black hole get off-center? Previous theoretical studies have shown that black holes can be ejected out of the centers of galaxies because of three-body interactions, where the lowest-mass member gets kicked out. This may be the case here, given the stealthy black hole’s close proximity to the central black hole. “If the black hole went through a triple interaction with two other black holes in the galaxy’s core, it can still remain bound to the galaxy, orbiting around the central region,“ said Yao.
      An alternative explanation is that the black hole is the surviving remnant of a smaller galaxy that merged with the host galaxy more than 1 billion years ago. If that is the case, the black hole might eventually spiral in to merge with the central active black hole sometime in the very far future. So at present, astronomers don’t know if it’s coming or going.
      Erica Hammerstein, another UC Berkeley postdoctoral researcher, scrutinized the Hubble images as part of the study, but did not find any evidence of a past galaxy merger. But she explained, “There is already good evidence that galaxy mergers enhance TDE rates, but the presence of a second black hole in AT2024tvd’s host galaxy means that at some point in this galaxy’s past, a merger must have happened.”
      Specialized for different kinds of light, observatories like Hubble and Chandra work together to pinpoint and better understand fleeting events like these. Future telescopes that will also be optimized for capturing transient events like this one include the National Science Foundation’s Vera C. Rubin Observatory and NASA’s upcoming Nancy Grace Roman Space Telescope. They will provide more opportunities for follow-up Hubble observations to zero in on a transient’s exact location.
      Explore More:

      Monster Black Holes are Everywhere


      Hubble Focus: Black Holes – Into the Vortex e-Book


      Science Behind the Discoveries: Black Holes


      Hubble’s Universe Uncovered: Black Holes

      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.
      ZTF is a public-private partnership, with equal support from the ZTF Partnership and from the U.S. National Science Foundation.
      Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Related Images & Videos
      Six panel illustration of Black Hole TDE AT2024tvd
      This is a six-panel illustration of a tidal disruption event around a supermassive back hole.


      Black Hole TDE AT2024tvdu00a0
      This is a Hubble Space Telescope image of a distant galaxy that is host to the telltale signature of a roaming supermassive black hole.


      Black Hole TDE AT2024tvd (Hubble + Chandra)
      This is a combined Hubble Space Telescope/Chandra X-Ray Observatory image of a distant galaxy that is host to the telltale signature of a roaming supermassive black hole.


      Black Hole TDE AT2024tvd Compass Image
      This is a combined Hubble Space Telescope/Chandra X-Ray Observatory image of a distant galaxy that is host to the telltale signature of a roaming supermassive black hole.


      Black Hole Tidal Disruption Event
      This is a video animation of a tidal disruption event (TDE), an intense flash of radiation caused by the supermassive black hole eating a star. The video begins by zooming into a galaxy located 600 million light-years away.




      Share








      Details
      Last Updated May 08, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center
      Contact Media Claire Andreoli
      NASA’s Goddard Space Flight Center
      Greenbelt, Maryland
      claire.andreoli@nasa.gov
      Ray Villard
      Space Telescope Science Institute
      Baltimore, Maryland

      Related Terms
      Hubble Space Telescope Astrophysics Astrophysics Division Black Holes Chandra X-Ray Observatory Galaxies Goddard Space Flight Center
      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


      View the full article
  • Check out these Videos

×
×
  • Create New...