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    • By NASA
      NASA/CXC/SAO/D. Bogensberger et al; Image Processing: NASA/CXC/SAO/N. Wolk; Even matter ejected by black holes can run into objects in the dark. Using NASA’s Chandra X-ray Observatory, astronomers have found an unusual mark from a giant black hole’s powerful jet striking an unidentified object in its path.
      The discovery was made in a galaxy called Centaurus A (Cen A), located about 12 million light-years from Earth. Astronomers have long studied Cen A because it has a supermassive black hole in its center sending out spectacular jets that stretch out across the entire galaxy. The black hole launches this jet of high-energy particles not from inside the black hole, but from intense gravitational and magnetic fields around it.
      The image shows low-energy X-rays seen by Chandra represented in pink, medium-energy X-rays in purple, and the highest-energy X-rays in blue.
      In this latest study, researchers determined that the jet is — at least in certain spots — moving at close to the speed of light. Using the deepest X-ray image ever made of Cen A, they also found a patch of V-shaped emission connected to a bright source of X-rays, something that had not been seen before in this galaxy.
      Called C4, this source is located close to the path of the jet from the supermassive black hole and is highlighted in the inset. The arms of the “V” are at least about 700 light-years long. For context, the nearest star to Earth is about 4 light-years away.
      Source C4 in the Centaurus A galaxy.NASA/CXC/SAO/D. Bogensberger et al; Image Processing: NASA/CXC/SAO/N. Wolk; While the researchers have ideas about what is happening, the identity of the object being blasted is a mystery because it is too distant for its details to be seen, even in images from the current most powerful telescopes.
      The incognito object being rammed may be a massive star, either by itself or with a companion star. The X-rays from C4 could be caused by the collision between the particles in the jet and the gas in a wind blowing away from the star. This collision can generate turbulence, causing a rise in the density of the gas in the jet. This, in turn, ignites the X-ray emission seen with Chandra.
      The shape of the “V,” however, is not completely understood. The stream of X-rays trailing behind the source in the bottom arm of the “V” is roughly parallel to the jet, matching the picture of turbulence causing enhanced X-ray emission behind an obstacle in the path of the jet. The other arm of the “V” is harder to explain because it has a large angle to the jet, and astronomers are unsure what could explain that.
      This is not the first time astronomers have seen a black hole jet running into other objects in Cen A. There are several other examples where a jet appears to be striking objects — possibly massive stars or gas clouds. However, C4 stands out from these by having the V-shape in X-rays, while other obstacles in the jet’s path produce elliptical blobs in the X-ray image. Chandra is the only X-ray observatory capable of seeing this feature. Astronomers are trying to determine why C4 has this different post-contact appearance, but it could be related to the type of object that the jet is striking or how directly the jet is striking it.
      A paper describing these results appears in a recent issue of The Astrophysical Journal. The authors of the study are David Bogensberger (University of Michigan), Jon M. Miller (University of Michigan), Richard Mushotsky (University of Maryland), Niel Brandt (Penn State University), Elias Kammoun (University of Toulouse, France), Abderahmen Zogbhi (University of Maryland), and Ehud Behar (Israel Institute of Technology).
      NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
      Read more from NASA’s Chandra X-ray Observatory.
      Learn more about the Chandra X-ray Observatory and its mission here:
      https://www.nasa.gov/chandra
      https://chandra.si.edu
      Visual Description
      This release features a series of images focusing on a collision between a jet of matter blasting out of a distant black hole, and a mysterious, incognito object.
      At the center of the primary image is a bright white dot, encircled by a hazy purple blue ring tinged with neon blue. This is the black hole at the heart of the galaxy called Centaurus A. Shooting out of the black hole is a stream of ejected matter. This stream, or jet, shoots in two opposite directions. It shoots toward us, widening as it reaches our upper left, and away from us, growing thinner and more faint as it recedes toward the lower right. In the primary image, the jet resembles a trail of hot pink smoke. Other pockets of granular, hot pink gas can be found throughout the image. Here, pink represents low energy X-rays observed by Chandra, purple represents medium energy X-rays, and blue represents high energy X-rays.
      Near our lower right, where the jet is at its thinnest, is a distinct pink “V”, its arms opening toward our lower right. This mark is understood to be the result of the jet striking an unidentified object that lay in its path. A labeled version of the image highlights this region, and names the point of the V-shape, the incognito object, C4. A wide view version of the image is composited with optical data.
      At the distance of Cen A, the arms of the V-shape appear rather small. In fact, each arm is at least 700 light-years long. The jet itself is 30,000 light-years long. For context, the nearest star to the Sun is about 4 light-years away.
      News Media Contact
      Megan Watzke
      Chandra X-ray Center
      Cambridge, Mass.
      617-496-7998
      mwatzke@cfa.harvard.edu
      Lane Figueroa
      Marshall Space Flight Center, Huntsville, Alabama
      256-544-0034
      lane.e.figueroa@nasa.gov
      View the full article
    • By NASA
      This artist’s concept shows interstellar object 1I/2017 U1 (‘Oumuamua) after its discovery in 2017. While itself not a dark comet, ‘Oumuamua’s motion through the solar system has helped researchers better understand the nature of the 14 dark comets discovered so far.European Southern Observatory / M. Kornmesser These celestial objects look like asteroids but act like comets now come in two flavors.
      The first dark comet — a celestial object that looks like an asteroid but moves through space like a comet — was reported less than two years ago. Soon after, another six were found. In a new paper, researchers announce the discovery of seven more, doubling the number of known dark comets, and find that they fall into two distinct populations: larger ones that reside in the outer solar system and smaller ones in the inner solar system, with various other traits that set them apart.
      The findings were published on Monday, Dec. 9, in the Proceedings of the National Academy of Sciences.
      Scientists got their first inkling that dark comets exist when they noted in a March 2016 study that the trajectory of “asteroid” 2003 RM had moved ever so slightly from its expected orbit. That deviation couldn’t be explained by the typical accelerations of asteroids, like the small acceleration known as the Yarkovsky effect.
      “When you see that kind of perturbation on a celestial object, it usually means it’s a comet, with volatile material outgassing from its surface giving it a little thrust,” said study coauthor Davide Farnocchia of NASA’s Jet Propulsion Laboratory in Southern California. “But try as we might, we couldn’t find any signs of a comet’s tail. It looked like any other asteroid — just a pinpoint of light. So, for a short while, we had this one weird celestial object that we couldn’t fully figure out.”
      Weird Celestial Objects
      Farnocchia and the astronomical community didn’t have to wait long for another piece of the puzzle. The next year, in 2017, a NASA-sponsored telescope discovered history’s first documented celestial object that originated outside our solar system. Not only did 1I/2017 U1 (‘Oumuamua) appear as a single point of light, like an asteroid, its trajectory changed as if it were outgassing volatile material from its surface, like a comet.
      “‘Oumuamua was surprising in several ways,” said Farnocchia. “The fact that the first object we discovered from interstellar space exhibited similar behaviors to 2003 RM made 2003 RM even more intriguing.”
      By 2023, researchers had identified seven solar system objects that looked like asteroids but acted like comets. That was enough for the astronomical community to bestow upon them their own celestial object category: “dark comets.” Now, with the finding of seven more of these objects, researchers could start on a new set of questions.
      “We had a big enough number of dark comets that we could begin asking if there was anything that would differentiate them,” said Darryl Seligman, a postdoctoral fellow in the department of Physics at Michigan State University, East Lansing, and lead author of the new paper. “By analyzing the reflectivity,” or albedo, “and the orbits, we found that our solar system contains two different types of dark comets.”
      Two Kinds of Dark Comets
      The study’s authors found that one kind, which they call outer dark comets, have similar characteristics to Jupiter-family comets: They have highly eccentric (or elliptical) orbits and are on the larger side (hundreds of meters or more across).
      The second group, inner dark comets, reside in the inner solar system (which includes Mercury, Venus, Earth, and Mars), travel in nearly circular orbits, and are on the smaller side (tens of meters or less).
      Like so many astronomical discoveries, Seligman and Farnocchia’s research not only expands on our knowledge of dark comets, but it also raises several additional questions: Where did dark comets originate? What causes their anomalous acceleration? Could they contain ice?
      “Dark comets are a new potential source for having delivered the materials to Earth that were necessary for the development of life,” said Seligman. “The more we can learn about them, the better we can understand their role in our planet’s origin.”
      For more information about asteroids and comets, visit:
      https://www.jpl.nasa.gov/topics/asteroids/
      Small Body Research at JPL NASA Learns More About Interstellar Visitor 'Oumuamua Lesson: Comet on a Stick News Media Contacts
      Ian J. O’Neill
      Jet Propulsion Laboratory, Pasadena, Calif.
      818-354-2649
      ian.j.oneill@jpl.nasa.gov
      Karen Fox / Molly Wasser
      NASA Headquarters, Washington
      202-358-1600
      karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
      Bethany Mauger
      Michigan State University, East Lansing
      maugerbe@msu.edu
      2024-168
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      Last Updated Dec 09, 2024 Related Terms
      Comets Asteroids The Solar System Explore More
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    • By USH
      A strange image has been circulating across social media in Thailand, showing a large, dark pillar-like structure mysteriously appearing in the sky over Ubon Ratchathani. According to the photographer, the picture was taken on Sunday, October 20, 2024, while they were trying to capture the "beautiful, colorful sky.

      This peculiar sighting isn't entirely unprecedented. Similar strange phenomena have been reported before. On October 7, 2015, a mysterious "floating city" with skyscrapers appeared in the clouds over Foshan, Guangdong province in China. Again, on March 18, 2016, ghostly buildings were seen above the sea along the port of Dalian, in Liaoning Province, China, lingering in the sky for several minutes. 

      Most recently, on September 11, 2020, an eerie image resembling the Hogwarts School from Harry Potter was spotted hovering over modern buildings in Jinan, Shandong Province. On July 14, 2022, a bizarre occurrence was also witnessed by residents in Haikou, Hainan, where a mysterious floating city appeared in the sky. 

      Scientists suggest that these events are most likely optical illusions, with mirages being the leading theory. Mirages occur when light rays bend, causing distant objects or parts of the sky to appear displaced. One specific type, known as a Fata Morgana, can create towering, distorted images of distant objects, contributing to these surreal sights. 

      Although the sightings between 2015 and 2022 were witnessed by many, the photographer in Thailand later realized that the mysterious pillar hadn't been visible to the naked eye at the time. This discovery has led some to speculate that the phenomenon might have been caused by a Project Blue Beam test, holographic technology, or even a temporary vortex connected to a parallel universe.
       





      View the full article
    • By NASA
      AMS-02 mounted on the outside of the space station.NASA Visible matter in the form of stars and planets adds up to about five percent of the total known mass of the Universe. The rest is either dark matter, antimatter, or dark energy. The exact nature of these substances is unknown, but the International Space Station’s Alpha-Magnetic Spectrometer or AMS-02 is helping to solve the mystery.
      AMS-02 collects data on charged particles from cosmic ray events, which helps scientists understand the origin of those rays and could ultimately reveal whether dark matter and antimatter exist.
      To date, the instrument has collected data on about 573 events per second on average – just over 18 billion per year. This high volume of data enables highly precise statistical analyses, and multiple groups of researchers independently process the raw data to ensure accurate results.
      Learn more about astrophysics research on the space station.
      This view shows the core of AMS-02, a massive magnet that bends particles from space to reveal whether their charge is positive or negative.NASA AMS-02 is the hexagonal shape visible on one of the space station’s trusses, just to the right of the center.NASA Keep Exploring Discover More Topics
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    • By NASA
      2 min read
      Hubble Reaches a Lonely Light in the Dark
      NASA, ESA, C. Gallart (Instituto de Astrofisica de Canarias), A. del Pino Molina (Centro de Estudios de Fisica del Cosmos de Aragon), and R. van der Marel (Space Telescope Science Institute); Image Processing: Gladys Kober (NASA/Catholic University of America) A splatter of stars glows faintly at almost 3 million light-years away in this new image from NASA’s Hubble Space Telescope. Known as the Tucana Dwarf for lying in the constellation Tucana, this dwarf galaxy contains a loose bundle of aging stars at the far edge of the Local Group, an aggregation of galaxies including our Milky Way, bound together by gravity. The Tucana Dwarf was discovered in 1990 by R.J. Lavery, the same year Hubble launched.
      What makes the Tucana Dwarf distinct from other dwarf galaxies comes in two parts: its classification, and its isolation. As a dwarf spheroidal galaxy, it is much smaller and less luminous than most other dwarf galaxies. Dust is sparse and the stellar population skews towards the older range, giving them a dimmer look. Additionally, the Tucana Dwarf lies about 3.6 million light-years from the Local Group’s center of mass, far from the Milky Way and other galaxies. It is only one of two dwarf spheroidal galaxies in the Local Group to be this remote, making astronomers theorize that a close encounter with a larger galactic neighbor called Andromeda slingshotted it into the distance about 11 billion years ago.
      Having such pristine properties enables scientists to use the Tucana Dwarf as a cosmic fossil. Dwarf galaxies could be the early ingredients for larger galaxies, and with older stars residing in such an isolated environment, analyzing them can help trace galaxy formation back to the dawn of time. For that reason, Hubble reached far across the Local Group using the capabilities of the Advanced Camera for Surveys and Wide Field and Planetary Camera 2 to meet this distant, lonely galaxy. Examining its structure, composition, and star formation history sheds light on the epoch of reionization, when the first stars and galaxies arose from the dark billions of years ago.

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      Claire Andreoli
      NASA’s Goddard Space Flight Center, Greenbelt, MD
      claire.andreoli@nasa.gov
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      Last Updated Aug 23, 2024 Editor Michelle Belleville Location NASA Goddard Space Flight Center Related Terms
      Astrophysics Galaxies Goddard Space Flight Center Hubble Space Telescope Stars Keep Exploring Discover More Topics From NASA
      Hubble Space Telescope


      Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.


      Hubble Science



      Hubble’s Galaxies



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