Jase1        Posted at 2023-04-29 17:40:44(53Wks ago) Report Permalink URL | ||
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|  NASA helicopter captures glorious view of Mars, with some surprises Look closely at the Martian desert. NASA's extraterrestrial helicopter, Ingenuity, flew 40 feet into the Martian air and snapped an astonishing landscape on another world. On its 51st flight, the experimental craft — with rotors reaching four feet long from tip to tip — rose atop a hill just beyond the rim of Belva crater. The recently released view is grandiose. It looks, dare one say, earthly. The rocky desert is in the foreground. Eroded, windswept hills roll through the horizon. The sky is bright. And scattered among the vista are some curious signs of human exploration.  Credit: NASA / JPL-Caltech Helicopter legs: On the right and left sides of Ingenuity's image you can spot the ends of two of the spacecraft's legs as it hovers in the air. Helicopter shadow: At center-right, just to the right of a small grey rock, you can see Ingenuity's small shadow on the ground. The Perseverance rover: Perhaps most conspicuous is NASA's Perseverance rover, which landed with Ingenuity in February 2021 with a primary goal of seeking out potential evidence of past microbial life on Mars — if any ever existed, that is. The car-sized, six-wheeled rover is near the top left. Rover tracks: You can also spot the large robot's trail. From Perseverance, follow two horizontal lines running to the right across the image. The wheels are metallic, so they're truly noisy as they rumble over Mars' rocky terrain. Trash!: When the rover and its landing gear plummeted through the Martian atmosphere before a series of challenging landing maneuvers, debris such as wires and insulation were scattered throughout the desert. Just below the rover you can spot what NASA calls a "small piece of debris."  Credit: NASA / JPL-Caltech All of Ingenuity's grand aerial views are an unexpected gift. Mission planners hoped they could get five flights out of the little chopper. Now it's exceeded 50, with many more planned. The experimental Mars explorer is currently flying over more challenging terrain, a region rife with "dunes, boulders, and rocks, and surrounded by hills that could have us for lunch," Josh Anderson, NASA's Ingenuity operations lead, explained a couple weeks ago. Stay tuned as Ingenuity and Perseverance explore deeper into Mars' Jezero Crater, a land that is arid desert today, but once teemed with flowing water and muddy deltas. | |
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| BeowulfPosted at 2023-04-30 09:42:47(53Wks ago) Report Permalink URL | ||
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|  This Picture of the Week shows the young stellar object 244-440 in the Orion Nebula observed with ESO’s Very Large Telescope (VLT) –– the sharpest image ever taken of this object. That wiggly magenta structure is a jet of matter launched close to the star, but why does it have that shape?  Very young stars are often surrounded by discs of material falling towards the star. Some of this material can be expelled into powerful jets perpendicularly to the disc. The S-shaped jet of 244-440 suggests that what lurks at the center of this object isn’t one but two stars orbiting each other. This orbital motion periodically changes the orientation of the jet, similar to a water sprinkler. Another possibility is that the strong radiation from the other stars in the Orion cloud could be altering the shape of the jet. These observations, presented in a new paper led by Andrew Kirwan at Maynooth University in Ireland, were taken with the Multi Unit Spectroscopic Explorer (MUSE) instrument at ESO’s VLT in Chile. Red, green and blue colours show the distribution of iron, nitrogen and oxygen respectively. But this is just a small fraction of all the data gathered by MUSE, which actually takes thousands of images at different colours or wavelengths simultaneously. This allows astronomers to study not only the distribution of many different chemical elements but also how they move. Moreover, MUSE is installed at the VLT’s Unit Telescope 4, which is equipped with an advanced adaptive optics facility that corrects atmospheric turbulence, delivering images sharper than Hubble’s. These new observations will therefore allow astronomers to study with unprecedented detail how stars are born in massive clouds like Orion. Credit: ESO/Kirwan et al. & Beowulf  | |
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| Jase1Posted at 2023-05-01 14:25:56(52Wks ago) Report Permalink URL | ||
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|  Deimos, the smaller of Mars’s two moons, may be more like its planet than we realize. New, high-resolution views of the tiny moon were recently captured by a United Arab Emirates spacecraft named Hope. Part of the Emirates Mars Mission (EMM), Hope used its onboard instruments to capture never-before-seen views of the space rock. Mars has two oddly-shaped moons — Phobos and Deimos, which are just 17 miles and 9 miles in diameter, respectively. Their quirky dimensions, diminutive size, and proximity to the asteroid belt have led scientists to believe that both of these rocky bodies were likely captured asteroids. But thanks to new images beamed back by the Hope orbiter, a new theory is emerging. “We’re getting the highest resolution [images] ever,” says Hessa Al Matroushi, the mission’s science lead. The images, which were shared at the European Geoscience Union meeting on April 24, help to strengthen the notion that Deimos formed at the same time as Mars. Following its launch in 2020, the Hope Mars orbiter arrived at the red planet in 2021 and has spent its time studying the Martian atmosphere. Now that its primary science mission is complete, the spacecraft has enough fuel reserves to start a secondary mission: observe Deimos in detail. Hope completed its first flyby of the tiny moon on March 10, whizzing by just 60 miles above Deimos’s surface. The only other spacecraft to get that close was NASA’s Viking 2 orbiter in 1977, but it carried more rudimentary cameras and scientific instruments. During its initial flyby, Hope trained all three of its instruments onto Deimos, studying the moon in different wavelengths to try and determine its composition. Preliminary analysis shows that Deimos is more similar to Mars than to carbon-rich asteroids. “It looks like Mars more than it looks like an asteroid,” says Al Matroushi, expressing how ecstatic she and her team were when they first saw the images come through. “Mars was in the background and that was just mind-blowing,” she said. Scientists are not quite sure yet how Deimos formed, but they are convinced that it is more like Mars than an asteroid, and quite different from Mars’ other moon, Phobos. Al Matroushi said that the team did not find an abundance of carbon and organics as they would if Deimos had asteroid origins. “If there were carbon or organics, we would see spikes in wavelengths,” she said. “But the data was very flat.” Just like our moon, Deimos is tidally locked to Mars, which means that observations of the moon from the planet’s surface or any spacecraft in low Mars orbit would always see the same side of Deimos. Fortunately for science, Hope has a very elongated orbit that extends to 40,000 kilometers above the planet, which enables the Hope spacecraft to observe and image Deimos’ far side. These observations will allow the team to analyze differences between the near and far sides of Deimos to expand on what we know about the moon and Mars. Al Matroushi says that Hope’s observations of Deimos will continue through 2024, alongside additional Mars observations. “We didn’t want to get just a one-time observation of Deimos,” she said. “We knew we wanted more.” | |
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| BeowulfPosted at 2023-05-01 17:47:09(52Wks ago) Report Permalink URL | ||
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|  Some of the most dramatic events in the Universe occur when certain stars die — and explode catastrophically in the process. Such explosions, known as supernovae, mainly occur in a couple of ways: either a massive star depletes its fuel at the end of its life, become dynamically unstable and unable to support its bulk, collapses inwards, and then violently explodes; or a white dwarf in an orbiting stellar couple syphons more mass off its companion than it is able to support, igniting runaway nuclear fusion in its core and beginning the supernova process. Both types result in an intensely bright object in the sky that can rival the light of a whole galaxy. In the last 20 years the galaxy NGC 5468, visible in this image, has hosted a number of observed supernovae of both the aforementioned types: SN 1999cp, SN 2002cr, SN2002ed, SN2005P, and SN2018dfg. Despite being just over 130 million light-years away, the orientation of the galaxy with respect to us makes it easier to spot these new ‘stars’ as they appear; we see NGC 5468 face on, meaning we can see the galaxy’s loose, open spiral pattern in beautiful detail in images such as this one from the NASA/ESA Hubble Space Telescope. Credit: ESA/Hubble & NASA, A. Riess et al. & Beowulf | |
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| SoupPosted at 2023-05-02 00:00:46(52Wks ago) Report Permalink URL | ||
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| Webb finds water vapor, but is it from a rocky planet or its star? by NASA  This artist concept represents the rocky exoplanet GJ 486 b, which orbits a red dwarf star that is only 26 light-years away in the constellation Virgo. By observing GJ 486 b transit in front of its star, astronomers sought signs of an atmosphere. They detected hints of water vapor. However, they caution that while this might be a sign of a planetary atmosphere, the water could be on the star itself—specifically, in cool starspots—and not from the planet at all. GJ 486 b is about 30% larger than the Earth and weighs three times as much. It orbits its star closely in just under 1.5 days. Credit: ILLUSTRATION: NASA, ESA, CSA, Joseph Olmsted (STScI) GJ 486 b is about 30% larger than the Earth and three times as massive, which means it is a rocky world with stronger gravity than Earth. It orbits a red dwarf star in just under 1.5 Earth days. It is too close to its star to be within the habitable zone, with a surface temperature of about 800 degrees Fahrenheit. And yet, Webb observations show hints of water vapor. The water vapor could be from an atmosphere enveloping the planet, in which case it would need to be continually replenished due to losses from stellar irradiation. But an equally likely possibility is that the water vapor is actually from the outer layer of the planet's cool host star. Additional Webb observations will help answer the question: Can a rocky planet maintain, or reestablish, an atmosphere in the harsh environment near a red dwarf star? The most common stars in the universe are red dwarf stars, which means that rocky exoplanets are most likely to be found orbiting such a star. Red dwarf stars are cool, so a planet has to hug it in a tight orbit to stay warm enough to potentially host liquid water (meaning it lies in the habitable zone). Such stars are also active, particularly when they are young, releasing ultraviolet and X-ray radiation that could destroy planetary atmospheres. As a result, one important open question in astronomy is whether a rocky planet could maintain, or reestablish, an atmosphere in such a harsh environment. To help answer that question, astronomers used NASA's James Webb Space Telescope to study a rocky exoplanet known as GJ 486 b. It is too close to its star to be within the habitable zone, with a surface temperature of about 800 degrees Fahrenheit (430 degrees Celsius). And yet, their observations using Webb's Near-Infrared Spectrograph (NIRSpec) show hints of water vapor. If the water vapor is associated with the planet, that would indicate that it has an atmosphere despite its scorching temperature and close proximity to its star. Water vapor has been seen on gaseous exoplanets before, but to date no atmosphere has been definitively detected around a rocky exoplanet. However, the team cautions that the water vapor could be on the star itself—specifically, in cool starspots—and not from the planet at all. "We see a signal and it's almost certainly due to water. But we can't tell yet if that water is part of the planet's atmosphere, meaning the planet has an atmosphere, or if we're just seeing a water signature coming from the star," said Sarah Moran of the University of Arizona in Tucson, lead author of the study. "Water vapor in an atmosphere on a hot rocky planet would represent a major breakthrough for exoplanet science. But we must be careful and make sure that the star is not the culprit," added Kevin Stevenson of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, principal investigator on the program. GJ 486 b is about 30% larger than the Earth and three times as massive, which means it is a rocky world with stronger gravity than Earth. It orbits a red dwarf star in just under 1.5 Earth days. It is expected to be tidally locked, with a permanent day side and a permanent night side.  This graphic shows the transmission spectrum obtained by Webb observations of rocky exoplanet GJ 486 b. The science team’s analysis shows hints of water vapor; however, computer models show that the signal could be from a water-rich planetary atmosphere (indicated by the blue line) or from starspots from the red dwarf host star (indicated by the yellow line). The two models diverge noticeably at shorter infrared wavelengths, indicating that additional observations with other Webb instruments will be needed to constrain the source of the water signal. The background illustration of a planet is an artist concept. Webb has not taken an image of the planet.. Credit: ILLUSTRATION: NASA, ESA, CSA, Joseph Olmsted (STScI). SCIENCE: Sarah E. Moran (University of Arizona), Kevin B. Stevenson (APL), Ryan MacDonald (University of Michigan), Jacob A. Lustig-Yaeger (APL) GJ 486 b transits its star, crossing in front of the star from our point of view. If it has an atmosphere, then when it transits starlight would filter through those gasses, imprinting fingerprints in the light that allow astronomers to decode its composition through a technique called transmission spectroscopy. The team observed two transits, each lasting about an hour. They then used three different methods to analyze the resulting data. The results from all three are consistent in that they show a mostly flat spectrum with an intriguing rise at the shortest infrared wavelengths. The team ran computer models considering a number of different molecules, and concluded that the most likely source of the signal was water vapor. While the water vapor could potentially indicate the presence of an atmosphere on GJ 486 b, an equally plausible explanation is water vapor from the star. Surprisingly, even in our own Sun, water vapor can sometimes exist in sunspots because these spots are very cool compared to the surrounding surface of the star. GJ 486 b's host star is much cooler than the Sun, so even more water vapor would concentrate within its starspots. As a result, it could create a signal that mimics a planetary atmosphere. "We didn't observe evidence of the planet crossing any starspots during the transits. But that doesn't mean that there aren't spots elsewhere on the star. And that's exactly the physical scenario that would imprint this water signal into the data and could wind up looking like a planetary atmosphere," explained Ryan MacDonald of the University of Michigan in Ann Arbor, one of the study's co-authors. A water vapor atmosphere would be expected to gradually erode due to stellar heating and irradiation. As a result, if an atmosphere is present, it would likely have to be constantly replenished by volcanoes ejecting steam from the planet's interior. If the water is indeed in the planet's atmosphere, additional observations are needed to narrow down how much water is present. Future Webb observations may shed more light on this system. An upcoming Webb program will use the Mid-Infrared Instrument (MIRI) to observe the planet's day side. If the planet has no atmosphere, or only a thin atmosphere, then the hottest part of the day side is expected to be directly under the star. However, if the hottest point is shifted, that would indicate an atmosphere that can circulate heat. Ultimately, observations at shorter infrared wavelengths by another Webb instrument, the Near-Infrared Imager and Slitless Spectrograph (NIRISS), will be needed to differentiate between the planetary atmosphere and starspot scenarios. "It's joining multiple instruments together that will really pin down whether or not this planet has an atmosphere," said Stevenson. The study is accepted for publication in The Astrophysical Journal Letters. | |
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| SoupPosted at 2023-05-02 02:47:12(52Wks ago) Report Permalink URL | ||
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| The far side of the Milky Way Astronomers achieve record measurement for an improved picture of our home galaxy Astronomers from the Max Planck Institute for Radio Astronomy in Bonn, Germany, and the Harvard-Smithsonian Center for Astrophysics, using the Very Long Baseline Array, have directly measured a distance of more than 66,000 light-years to a star-forming region. This region, known as G007.47+00.05, is on the opposite side of our Milky Way Galaxy from the Sun. The researchers' achievement reaches deep into the Milky Way’s terra incognita and nearly doubles the previous record for distance measurement within our Galaxy.  Glimpse of the Milky Way: this artist's view shows the location of the Sun and the star forming region G007.47+00.05 at the opposite side of the galaxy, in the Scutum-Centaurus spiral arm. © Bill Saxton, NRAO/AUI/NSF; Robert Hurt, NASA. Distance measurements are crucial for an understanding of the structure of the Milky Way. Most of our Galaxy's material, consisting principally of stars, gas, and dust, lies within a flattened disk, in which our Solar System is embedded. Because we cannot see our Galaxy face-on, its structure, including the shape of its spiral arms, can only be mapped by measuring distances to objects elsewhere in the Galaxy. The astronomers used a technique called trigonometric parallax, first applied by Friedrich Wilhelm Bessel in 1838 to measure the distance to the star 61 Cygni in the constellation of the Swan. This technique measures the apparent shift in the sky position of a celestial object as seen from opposite sides of the Earth's orbit around the Sun. This effect can be demonstrated by holding a finger in front of one's nose and alternately closing each eye -- the finger appears to jump from side to side. Measuring the angle of an object's apparent shift in position this way allows astronomers to use simple trigonometry to directly calculate the distance to that object. The smaller the measured angle, the greater the distance is. In the framework of the Bar and Spiral Structure Legacy (BeSSeL) Survey, it is now possible to measure parallaxes a thousand times more accurate than Friedrich Bessel. The Very Long Baseline Array (VLBA), a continent-wide radio telescope system, with ten dish antennas distributed across North America, Hawaii, and the Caribbean, can measure the minuscule angles associated with great distances. In this case, the measurement was roughly equal to the angular size of a baseball on the Moon. "Using the VLBA, we now can accurately map the whole extent of our Galaxy," says Alberto Sanna, of the Max Planck Institute for Radio Astronomy in Germany (MPIfR). The new VLBA observations, made in 2014 and 2015, measured a distance of more than 66,000 light-years to the star-forming region G007.47+00.05 on the opposite side of the Milky Way from the Sun, well past the Galaxy's center in a distance of 27,000 light-years. The previous record for a parallax measurement was about 36,000 light-years.  Highly complex observations: The calculation of distances is principally simple, but requires highly accurate measurements of the angle of apparent shifts in an object's position - only the VLBA has the capability to deliver such measurements. © Bill Saxton, NRAO/AUI/NSF; Robert Hurt, NASA. "Most of the stars and gas in our Galaxy are within this newly-measured distance from the Sun. With the VLBA, we now have the capability to measure enough distances to accurately trace the Galaxy's spiral arms and learn their true shapes," Sanna explains. The VLBA observations measured the distance to a region where new stars are being formed. Such regions include areas where molecules of water and methanol act as natural amplifiers of radio signals -- masers, the radio-wave equivalent of lasers for light waves. This effect makes the radio signals bright and readily observable with radio telescopes. The Milky Way has hundreds of such star-forming regions that include masers. "So we have plenty of 'mileposts' to use for our mapping project. But this one is special: Looking all the way through the Milky Way, past its center, way out into the other side", says the MPIfR's Karl Menten. The astronomers' goal is to finally reveal what our own Galaxy looks like if we could leave it, travel outward perhaps a million light-years, and view it face-on, rather than along the plane of its disk. This task will require many more observations and much painstaking work, but, the scientists say, the tools for the job now are in hand. How long will it take? "Within the next 10 years, we should have a fairly complete picture," predicts Mark Reid of the Harvard-Smithsonian Center for Astrophysics. | |
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| BeowulfPosted at 2023-05-02 17:55:35(52Wks ago) Report Permalink URL | ||
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|  This Hubble Picture of the Week shows the spiral galaxy Messier 98, which is located about 45 million light-years away in the constellation of Coma Berenices (Berenice's Hair). It was discovered in 1781 by the French astronomer Pierre Méchain, a colleague of Charles Messier, and is one of the faintest objects in Messier’s astronomical catalogue. Messier 98 is estimated to contain about a trillion of stars, and is full of cosmic dust — visible here as a web of red-brown stretching across the frame — and hydrogen gas. This abundance of star-forming material means that Messier 98 is producing stellar newborns at a high rate; the galaxy shows the characteristic signs of stars springing to life throughout its bright centre and whirling arms. This image of Messier 98 was taken in 1995 with the Wide Field and Planetary Camera 2, an instrument that was installed on the NASA/ESA Hubble Space Telescope from 1993 till 2009. These observations were taken in infrared and visible light as part of a study of galaxy cores within the Virgo Cluster, and feature a portion of the galaxy near the centre. Credit: ESA/Hubble & NASA, V. Rubin et al. & Beowulf | |
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| SoupPosted at 2023-05-03 00:05:39(52Wks ago) Report Permalink URL | ||
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| NASA animation sizes up the universe's biggest black holes by Francis Reddy, NASA  This frame from NASA’s new animation compares the sizes of three supermassive black holes in relation to planetary orbits in our solar system. At top left, unlabeled, is the black hole at the center of the Circinus galaxy. Below it lies the giant black hole in galaxy M32. And at right is the more massive black hole at the heart of our own Milky Way galaxy. Credit: NASA's Goddard Space Flight Center Conceptual Image Lab A new NASA animation highlights the "super" in supermassive black holes. These monsters lurk in the centers of most big galaxies, including our own Milky Way, and contain between 100,000 and tens of billions of times more mass than our sun. "Direct measurements, many made with the help of the Hubble Space Telescope, confirm the presence of more than 100 supermassive black holes," said Jeremy Schnittman, a theorist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "How do they get so big? When galaxies collide, their central black holes eventually may merge together too." In 2019 and 2022, a planet-spanning network of radio observatories called the Event Horizon Telescope produced, respectively, the first images of the giant black holes at the centers of M87 and the Milky Way. They revealed a bright ring of hot orbiting gas surrounding a circular zone of darkness. Any light crossing the event horizon—the black hole's point of no return—becomes trapped forever, and any light passing close to it is redirected by the black hole's intense gravity. Together, these effects produce a "shadow" about twice the size of the black hole's actual event horizon. All monster black holes are not equal. Watch this video to see how they compare to each other and to our solar system. The black holes shown, which range from 100,000 to more than 60 billion times our Sun’s mass, are scaled according to the sizes of their shadows – a circular zone about twice the size of their event horizons. Only one of these colossal objects resides in our own galaxy, and it lies 26,000 light-years away. Smaller black holes are shown in bluish colors because their gas is expected to be hotter than that orbiting larger ones. Scientists think all of these objects shine most intensely in ultraviolet light. Credit: NASA's Goddard Space Flight Center Conceptual Image Lab The new NASA animation shows 10 supersized black holes that occupy center stage in their host galaxies, including the Milky Way and M87, scaled by the sizes of their shadows. Starting near the sun, the camera steadily pulls back to compare ever-larger black holes to different structures in our solar system. First up is 1601+3113, a dwarf galaxy hosting a black hole packed with the mass of 100,000 suns. The matter is so compressed that even the black hole's shadow is smaller than our sun. The black hole at the heart of our own galaxy, called Sagittarius A* (pronounced ay-star), boasts the weight of 4.3 million suns based on long-term tracking of stars in orbit around it. Its shadow diameter spans about half that of Mercury's orbit in our solar system.  Our galaxy’s supersized black hole, Sagittarius A*, as seen by the Event Horizon Telescope. It contains the equivalent mass of 4.3 million Suns and lies about 26,000 light-years away. Credit: EHT Collaboration The animation shows two monster black holes in the galaxy known as NGC 7727. Located about 1,600 light-years apart, one weighs 6 million solar masses and the other more than 150 million suns. Astronomers say the pair will merge within the next 250 million years. "Since 2015, gravitational wave observatories on Earth have detected the mergers of black holes with a few dozen solar masses thanks to the tiny ripples in space-time these events produce," said Goddard astrophysicist Ira Thorpe. "Mergers of supermassive black holes will produce waves of much lower frequencies which can be detected using a space-based observatory millions of times larger than its Earth-based counterparts."  The two bright knots at the center of galaxy NGC 7727 each represent a dense group of stars surrounding a supermassive black hole. Only 1,600 light-years separate the pair. Astronomers expect them to merge within the next 250 million years. Credit: ESO/Voggel et al. That's why NASA is collaborating with ESA (European Space Agency) to develop their LISA mission, the Laser Interferometer Space Antenna, expected to launch sometime in the next decade. LISA will consist of a constellation of three spacecraft in a triangle that shoot laser beams back and forth over millions of miles to precisely measure their separations. This will enable the detection of passing gravitational waves from merging black holes with masses up to a few hundred million suns. Astronomers are exploring other detection techniques to tackle even bigger mergers. At the animation's larger scale lies M87's black hole, now with a updated mass of 5.4 billion suns. Its shadow is so big that even a beam of light—traveling at 670 million mph (1 billion kph)—would take about two and a half days to cross it.  Light from the supermassive black hole known as TON 618 (circled) takes more than 10 billion years to reach us. Credit: SDSS The movie ends with TON 618, one of a handful of extremely distant and massive black holes for which astronomers have direct measurements. This behemoth contains more than 60 billion solar masses, and it boasts a shadow so large that a beam of light would take weeks to traverse it. | |
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| Jase1Posted at 2023-05-03 08:48:58(52Wks ago) Report Permalink URL | ||
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| Is there another massive celestial body out there that we still can’t see with even our most advanced telescopes? BY DARREN ORF MAY 2, 2023  Black holes, arguably the strangest objects in the known universe, are notoriously difficult to detect. Scientists from Johns Hopkins University theorize that objects, such as a hypothetical topological soliton, may seem like a black hole at a distance but would actually act much differently up close. Because this massive celestial object with no event horizon would allow light to escape, solitons could effectively act more like stars than true black holes. It’s hard to not be enamored with the gravitational mechanics of a black hole. Past a black hole’s event horizon, absolutely crushing gravity plays havoc on our understanding of physics and produces mind-boggling theoretical concepts such as “singularity” and more grotesque ideas like “spaghettification.” Because these amazing celestial objects are, by their nature, extremely difficult to detect (they essentially gobble light, after all), some scientists wonder if there could be similar massive, black hole-like objects that our advanced telescopes simply can’t detect— or even know to look for in the first place. Scientists at Johns Hopkins University constructed mathematical models that supported the possibility of the existence of these objects, known as topological solitons. From afar, these objects would resemble a Black Hole (thus making them frustratingly elusive to our prying eyes). But up close, they would actually scramble and emit a faint amount of light—something that’s impossible in a true black hole, where gravity is too immense for light to escape. The team’s results were published in the journal Physical Review D. "Light is strongly bent, but instead of being absorbed like it would in a black hole, it scatters in funky motions until at one point it comes back to you in a chaotic manner," Pierre Heidmann, a Johns Hopkins physicist and lead on the study, said in a press release. Heidmann previously published studies fine-tuning the inner workings of these hypothetical celestial bodies in 2021. "You don't see a dark spot. You see a lot of blur, which means light is orbiting like crazy around this weird object." With the detection of gravitational waves in 2015, which effectively confirmed the existence of black holes, Heidmann’s team decided to hunt for objects that could produce similar waves but acted differently than your usual, run-of-the-mill black hole. The resulting topological soliton is a purely hypothetical entity, but one that adheres to both string theory and Albert Einstein’s general theory of relativity. The researchers’ simulations successfully recreated what a topological soliton would look like if placed in front of a camera lens. "These are the first simulations of astrophysically relevant string theory objects, since we can actually characterize the differences between a topological soliton and a black hole as if an observer was seeing them in the sky," Heidmann says. These topological solitons join a long list of hypothetical space objects, including gravastars, boson stars, dark-energy stars, and even entire dark galaxies. These mathematically possible objects play an important role in helping scientists and astrophysicists consider what all could be out there other than just the familiar suns, galaxies, and yes, even black holes. "How would you tell when you don't have a black hole? We don't have a good way to test that," says co-author and Johns Hopkins physicist Ibrahima Bah. "Studying hypothetical objects like topological solitons will help us figure that out as well." The universe is a stranger place than we think—even if we can’t see it with our naked eyes. | |
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| Jase1Posted at 2023-05-03 17:08:13(52Wks ago) Report Permalink URL | ||
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| What a Mess. A Black Hole's Stellar Meal is Brighter and Longer Lasting Than Ever Seen Before by Brian Koberlein  It’s a tale as old as time. A cataclysmic event occurs in the universe and releases a tremendous amount of energy in a short period of time. The event then fades into the darkness and the cosmos returns to normal. These short-lived cosmic events are known as transients and include things such as supernovae and gamma-ray bursts. Transients are quite common, but some of them can challenge explanations. Take for example the transient known as ZTF20abrbeie, nicknamed Scary Barbie. Scary Barbie was first observed in 2020 and was later observed over a range of wavelengths. It’s an unusual transient for two reasons. The first is that it has lasted much longer than typical transients. A fast radio burst can last for seconds. The afterglow of a supernova can be observed for a month, but Scary Barbie has lasted for more than 800 days and continues to be visible. The second is how terrifyingly energetic it is. A supernova can outshine a galaxy, but Scary Barbie is a thousand times more energetic than the brightest supernovae. It’s hard to imagine the scale of this transient. According to a study being published in The Astrophysical Journal Letters there’s really only one phenomenon that could explain Scary Barbie: A star being consumed by a black hole.[^1] Black holes don’t swallow stars whole. They first rip the star apart in what is known as a tidal disruption event (TDE). The superheated material of the star is captured by the black hole. Based on observations of ZTF20abrbeie, it was likely a TDE involving a 14 solar mass star and a supermassive black hole more massive than 100 million Suns.  One of the strange things about this transient is that it doesn’t seem to be associated with a particular galaxy. That’s unusual since supermassive black holes tend to lurk in galactic centers. But then again, this transient is so unusual it wasn’t immediately recognized. The team only discovered it through an AI software package they developed known as the Recommender Engine For Intelligent Transient Tracking (REFITT). REFITT combs through observational data looking for transients to study. It came across Scary Barbie in public data from Palomar Observatory’s Zwicky Transient Facility. Once they discovered it, the team then gathered data from other observatories. This work is a great example of how public data and AI data mining can lead to unexpected discoveries. Only by making data publically accessible and developing tools to filter through this information are these discoveries possible. Science works best when everyone can participate, as this latest study shows. Who knows what other amazing things are lurking in public data just waiting to be discovered? | |
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| BeowulfPosted at 2023-05-03 17:35:42(52Wks ago) Report Permalink URL | ||
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|  At a distance of just 160 000 light-years, the Large Magellanic Cloud (LMC) is one of the Milky Way’s closest companions. It is also home to one of the largest and most intense regions of active star formation known to exist anywhere in our galactic neighbourhood — the Tarantula Nebula. This NASA/ESA Hubble Space Telescope image shows both the spindly, spidery filaments of gas that inspired the region’s name, and the intriguing structure of stacked “bubbles” that forms the so-called Honeycomb Nebula (to the lower left). The Honeycomb Nebula was found serendipitously by astronomers using ESO’s New Technology Telescope to image the nearby SN1987A, the closest observed supernova to Earth for over 400 years. The nebula’s strange bubble-like shape has baffled astronomers since its discovery in the early 1990s. Various theories have been proposed to explain its unique structure, some more exotic than others. In 2010, a group of astronomers studied the nebula and, using advanced data analysis and computer modelling, came to the conclusion that its unique appearance is likely due to the combined effect of two supernovae — a more recent explosion has pierced the expanding shell of material created by an older explosion. The nebula’s especially striking appearance is suspected to be due to a fortuitous viewing angle; the honeycomb effect of the circular shells may not be visible from another viewpoint. Credit: ESA/Hubble & NASA & Beowulf Acknowledgements: Judy Schmidt (Geckzilla) | |
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| harkPosted at 2023-05-03 22:39:44(52Wks ago) Report Permalink URL | ||
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| The Moon has been a subject of awe and fascination for millennia, with its shape-shifting powers and enigmatic dark side. And though it’s the one celestial body on which man has taken (small) steps, we still have big leaps to go in understanding its potential and uncovering its secrets. However, one hidden feature of the Moon has been unearthed by scientists and it’s very, very big, and very, very heavy. Buried beneath its South Pole-Aitken basin – one of the largest preserved craters in the Solar System – is a structure which weighs at least 2.18 billion kilogrammes and measures more than 300km (186 miles) in depth and 2,000km (1,243 miles) in length. The researchers who made the discovery, all based in the US, posited that the “anomaly” could be made out of metal from the core of an asteroid or oxides from the crystallisation of a magma ocean. "One of the explanations of this extra mass is that the metal from the asteroid that formed this crater is still embedded in the Moon's mantle,” lead author Peter B. James, from Houston’s Baylor University, said in a statement shared with IFLScience. Illustrating just how gigantic this thing is, he went on: "Imagine taking a pile of metal five times larger than the Big Island of Hawaii and burying it underground. That's roughly how much unexpected mass we detected.” The groundbreaking finding was made thanks to NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission, which measures changes in the Moon’s gravitational field.  | |
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| SoupPosted at 2023-05-04 00:56:17(52Wks ago) Report Permalink URL | ||
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| The ultra-fast space winds that shape the evolution of galaxies by Università di Bologna  Luminosity (upper panel) and rest-frame 4–10 keV counts (lower panel) plotted against redshift for the objects in the SUBWAYS sample and the comparison samples (T10; C21), as labeled. In the lower panel we also mark the sources of the 3XMM sample, used to select the SUBWAYS targets, with small empty circles. Credit: Astronomy & Astrophysics (2022). DOI: 10.1051/0004-6361/202245036 They are called UFOs, but aliens have nothing to do with them. They are the ultra-fast outflows: space winds that emerge from the surroundings of supermassive black holes and blow at speeds close to that of light. An international research team has explored this still little-understood phenomenon, hunting for these gas emissions, which are crucial to understanding the mechanisms regulating the behavior of supermassive black holes in their active phase. The research project is called SUBWAYS (SUper massive Black hole Winds in the x-rAYS) and the first results have been published in two papers in Astronomy & Astrophysics. The first of these, led by scholars from the University of Bologna and INAF, is mainly based on data obtained from ESA's XMM-Newton space telescope. The scholars analyzed 22 active galactic nuclei (AGN), i.e., the regions surrounding supermassive black holes at the center of galaxies and emitting enormous amounts of radiations across the entire electromagnetic spectrum when black holes are in the active phase. The investigation showed that in about 30% of the active galactic nuclei analyzed, there are space winds traveling at speeds between 10% and 30% of the speed of light. "These results allow us to establish with greater certainty that a significant proportion of active galactic nuclei hosts ultra-fast winds called UFOs, ultra-fast outflows," explains Marcella Brusa, professor at the University of Bologna and INAF associate, as well as coordinator of the entire SUBWAYS project. "And we were able to confirm that the intensity of these gas flows is sufficient to significantly change the ecosystem of their galaxies." Between a supermassive black hole and the galaxy that surrounds it, there is in fact a close relationship that reciprocally influences their formation and evolution. The mechanisms driving this reciprocal relationship are still poorly understood, but among the key ingredients may be the ultra-fast winds emitted by active galactic nuclei.  Artistic view of multiphase AGN-driven winds highlighting the different phases and scales that are involved in the outflow. The wind propagates from the central engine (< 1 pc; a), through the surrounding ISM (1 pc–1 kpc; b), out to the boundaries of the host galaxy (> 10 kpc; c). SUBWAYS will investigate the outflow in its launching phase, when the gas is highly ionized, and the presence of fast moving material can be revealed in X-rays. (figure adapted from Cicone et al. 2018, Nat. As. 2, 176). Credit: University of Bologna These powerful emissions arise when part of the gas in the accretion disk is ejected outwards, thus transferring some of the matter and energy produced to interstellar space, a mechanism that has important implications for regulating the process of star formation. In order to detect UFOs, spectra emitted in the X-ray band are analyzed, looking for absorptions produced by the presence of highly ionized materials such as iron. This phenomenon is due to the extreme temperatures—up to tens of millions of degrees—generated in the vicinity of supermassive black holes. With this in mind, SUBWAYS scientists managed to obtain 1.6 million seconds of observation time (more than eighteen days) with the ESA XMM-Newton X-ray Space Telescope. They thus explored 17 active galactic nuclei in the relatively nearby universe (between about 1.5 and 5 billion light years away), to which they added data from another 5 AGN already collected in previous observations. "These observations have allowed us to obtain new independent evidence of the existence of highly ionized matter that is ejected from the innermost regions of active galactic nuclei at speeds close to that of light," says Gabriele Matzeu, researcher at the University of Bologna, INAF associate and first author of the paper presenting the results on UFOs statistics. "These outcomes have allowed us to learn more about these ultrafast winds and to better understand their role in shaping the evolution process of galaxies." The result of the research work was published in Astronomy & Astrophysics in the article 'Supermassive Black Hole Winds in X-rays: SUBWAYS. I. Ultra-fast outflows in quasars beyond the local Universe.' Astronomy & Astrophysics also published the companion paper 'Supermassive Black Hole Winds in X-rays: SUBWAYS. II. HST UV spectroscopy of winds at intermediate redshifts,' led by Missagh Mehdipour (Space Telescope Science Institute, Baltimore, U.S.), which presents a study of lower-velocity and lower-ionization gas flows visible in the ultraviolet band thanks to the HST satellite. | |
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| BeowulfPosted at 2023-05-04 04:58:38(52Wks ago) Report Permalink URL | ||
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|  This captivating new image shows the Crab Nebula in bright neon colours. The unusual image was produced by combining data from telescopes spanning nearly the entire electromagnetic spectrum, from radio waves to X-rays. The Karl G. Jansky Very Large Array (VLA) provided information about the nebula gathered in the radio regime (coloured in red). NASA’s Spitzer Space Telescope took images in the infrared (yellow). The NASA/ESA Hubble Space Telescope provided the images made in optical wavelengths (coloured in green). ESA’s XMM-Newton telescope observed the Crab Nebula in the ultraviolet (blue) and NASA’s Chandra X-ray Observatory provided the data for X-ray radiation (purple). The Crab Nebula, located 6500 light-years from Earth in the constellation of Taurus (The Bull), is the result of a supernova explosion which was observed by Chinese and other astronomers in 1054. At its centre is a pulsar: a super-dense neutron star, spinning once every 33 milliseconds, shooting out rotating lighthouse-like beams of radio waves and visible light. Surrounding the pulsar lies a mix of material; some of it was originally expelled from the star before it went supernova, and the rest was ejected during the explosion itself. Fast-moving winds of particles fly off from the neutron star, energising the dust and gas around it. These different layers and intricacies of the nebula can be observed in all of the different wavelengths of light. Credit: NASA, ESA, G. Dubner (IAFE, CONICET-University of Buenos Aires) et al.; A. Loll et al.; T. Temim et al.; F. Seward et al.; VLA/NRAO/AUI/NSF; Chandra/CXC; Spitzer/JPL-Caltech; XMM-Newton/ESA; and Hubble/STScI & Beowulf | |
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| Jase1Posted at 2023-05-04 10:31:01(52Wks ago) Report Permalink URL | ||
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| Literally. BY JACKIE APPEL MAY 3, 2023  NASA recently took the temperature of an Earth “cousin” exoplanet. A small rocky planet in the famous TRAPPIST-1 system, it turned out to be about 450°F. This temperature tells scientists that the planet—TRAPPIST-1b—most likely doesn’t have an atmosphere. One of the most exciting jobs entrusted to the James Webb Space Telescope is the finding and observation of exoplanets. And it’s up to the task. The first planet the telescope spotted around another star was one of the hardest kinds to find. It’s just getting started. But it’s not just finding new planets—the JWST is finding additional data on known planets too. And recently it turned its giant, mirrored eye on the TRAPPIST-1 system to analyze the exoplanet orbiting closest to that star. TRAPPIST-1 is a big deal in exoplanet astronomy, particularly in the search for life on other worlds. There are currently eight programs in JWST’s first year of operation dedicated to the TRAPPIST-1 alone. The system consists of one star and a string of at least seven Earth “cousins,”, three of which NASA believes are in the star’s “goldilocks zone.” The goldilocks zone is the region where astronomers believe a planet could have liquid water, which gives it the best chances of hosting extraterrestrial life. The planet JWST most recently analyzed, though, isn’t one of those potentially habitable ones. The telescope took a look at the innermost planet in the system—TRAPPIST-1b—partially because we want any and all data we can get on this fascinating system, and partially because it was the easiest of the seven exoplanets to see. Over the course of its examination, JWST successfully took the temperature of a rocky exoplanet for the first time ever. Lacking a thermometer anywhere in the vicinity, the team behind the telescope had to get creative. Their desired temperature would come in the form of the infrared radiation TRAPPIST-1b was giving off, something infrared-expert JWST is perfectly suited to collect. The team waited until the planet was just about to pass behind its star, a moment during which most of its day side was briefly facing towards us and it would be shining the brightest. This gave the researchers the amount of infrared radiation given off by both the star and the planet combined. They then allowed the planet to pass fully behind the star and took an infrared reading again for just the star. The radiation from the star was subtracted out from the combined radiation of the star and the planet, leaving behind just the radiation from the planet. It turns out, TRAPPIST-1b is hot—around 450°F. And that temperature is enough to have scientists pretty sure that the planet doesn’t have an atmosphere at all. The research team compared the recorded temperature to their models, and found it was almost perfectly consistent with the expected temperature of a body made of rock without an atmosphere. They published the paper detailing this discovery late last month. The researchers still want to confirm their finding with further observations, but the data they have already tells a compelling story. It’s all about circulation. If the planet had an atmosphere with which to circulate the heat from its star, it would be about 50°F cooler than it is. And if it had a carbon dioxide atmosphere, it would be even cooler. Being able to look at planets in the TRAPPIST-1 system in this kind of detail is like being in a candy store for exoplanet scientists. There was one target that I dreamed of having,” Pierre-Olivier Lagage—astrophysicist and one of the authors on this paper, who has been working on the development of JWST for over two decades—said in a press release. “And it was this one. This is the first time we can detect the emission from a rocky, temperate planet. It’s a really important step in the story of discovering exoplanets.” | |
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| Jase1Posted at 2023-05-04 20:17:42(52Wks ago) Report Permalink URL | ||
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| Only took over a century. BY JACKIE APPEL MAY 3, 2023  Researchers have confirmed what lies at the core of Mars. Using seismic data from NASA’s InSight lander, the team was able to determine things like composition, state, and density of the core. The core is fully liquid, unlike our own, and made mostly of iron-alloy. We now know for sure what lies at the core of the Red Planet. Researchers were recently able to finally confirm the makeup of Mars’s core using seismic waves that traveled through the planet. Thanks to NASA’s InSight lander, we can now be certain that Mars has a completely liquid core made predominantly of iron-alloy, with uncommonly high amounts of sulfur and oxygen. “In 1906, scientists first discovered the Earth’s core by observing how seismic waves from earthquakes were affected by traveling through it,” said Vedran Lekic, geologist and one of the authors of the paper detailing these results, said in a press release. “More than a hundred years later, we’re applying our knowledge of seismic waves to Mars. With InSight, we’re finally discovering what’s at the center of Mars and what makes Mars so similar yet distinct from Earth.” In order to ascertain this information, the team tracked the aftermath of two literally world-shaking events through Mars—one was a marsquake (the Martian equivalent of an earthquake) and the other was the shock from a large impact. The seismic waves from theses events travel at different speeds depending on what they hit along the way, so those traveling through the core will move at different rates than those that miss the core altogether. When researchers compare the waves that passed through the core to those that only passed through the mantle, they are able to read the signatures carried by the waves and sleuth out the core’s makeup—reading off everything from what state the matter is in and how dense it is, to what substances comprise the innermost region. The “uncommonly high amounts of sulfur and oxygen” seem to be the star of this particular core-centric show. Apparently, the core of Mars is almost one-fifth lighter elements like those (as opposed to heavy elements like iron), a much higher percentage than what makes up our own core. It should be said here that researchers were pretty sure of these results already. The data from InSight largely confirms what models of Mars’s core have been saying for some time, rather than challenging any kind of long-held hypothesis. But that’s not to say the results aren’t exciting. Confirming models means we were correct, and that we can now move forward with probing our Martian-core-related questions without having to go back to the drawing board. Many of those questions revolve around formation, as the difference between Mars’s core and our own points to substantial variation in how the two planets formed. Understanding those formation processes is critical to scientists who want to understand why Mars and Earth are so different, or how planetary systems like our Solar System form in the first place. “This was a huge effort, involving state-of-the-art seismological techniques which have been honed on Earth, in conjunction with new results from mineral physicists and the insights from team members who simulate how planetary interiors change over time,” Jessica Irving, a researcher and first author on the study, said in a press release. “But the work paid off, and we now know much more about what’s happening inside the Martian core.” | |
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| Jase1Posted at 2023-05-05 09:03:44(52Wks ago) Report Permalink URL | ||
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|  Saturn Is Sucking Up Its Rings By Victor Tangermann | May 4, 2023 | 11:43 AM Rings of Power Saturn's innermost rings are steadily disappearing as they're being sucked up into the planet's upper atmosphere — and scientists are still trying to figure out why, Space.com reports, using the mighty James Webb Space Telescope. The planet's icy rings are collapsing into the planet as icy rain, succumbing to its intense gravity. But there's a lot we still don't know about the cosmic vacuuming act. For instance, we have no idea how old the rings are — and it's even possible they're relatively young: some scientists believe Saturn's rings are a mere 100 million years old, meaning that they weren't in the picture while dinosaurs were still roaming the Earth. Quick Death Plenty of questions remain, with researchers trying to figure out how long these rings will exist and if they could ever come back. "We’re still trying to figure out exactly how fast they are eroding," said James O’Donoghue, a JAXA researcher who is hoping to track the rings' demise using the Keck telescope in Hawaii and James Webb, in a statement. "Currently, research suggests the rings will only be part of Saturn for another few hundred million years." "This may sound like a long time, but in the history of the universe this is a relatively quick death," he added. "We could be very lucky to be around at a time when the rings exist." To find a more precise answer, O'Donoghue and his team are hoping to make long-term observations to monitor how the trend fluctuates over time. In and Out The team suspects the changing Sun's radiation during Saturn's 29.5-year orbit may be influencing how much icy material falls toward the planet's upper atmosphere. "We suspect that when the rings are edge-on with the sun, the ring rain will slow down," O'Donoghue told Space.com. "And that when they are tilted to face the sun, the ring rain influx will increase." It's a fascinating conundrum that has puzzled astronomers for years. "I think it would be fascinating if the life time of the rings was only 100 million years or so and that their age was billions of years," O'Donoghue told Space.com. "Since it means we evolved just in time to see them before they vanished." | |
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| Jase1Posted at 2023-05-05 15:42:54(52Wks ago) Report Permalink URL | ||
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|  The International Space Station passes the sun in a gorgeous portrait by photographer Andrew McCarthy. The photo took 12 hours, three telescopes, and thousands of smaller images to create. Can you spot the space station in this portrait of an increasingly active sun? The sun is incomprehensibly massive, turbulent, and violent. It erupts high-energy radiation into space, some of which slams into the International Space Station rocketing around Earth. The ISS circles our planet 16 times a day. With the right telescope, from the right location, you can see it passing overhead. And for just a few precious milliseconds, the astronaut-staffed space laboratory will occasionally zip across the face of the sun. Photographer Andrew McCarthy recently captured that split moment in a stunning portrait that took 12 hours to compose, three telescopes to capture, and two blown-out tires along the way. It may look like a single photo, but it's actually a mosaic of thousands of images. So, can you spot the space station in this portrait?  Here's a hint: The space station is next to a sunspot — a region of the solar surface that appears dark because it's colder than the surrounding area. "It almost gets lost in the sunspot," McCarthy told Insider. It looks like the station is on the surface of the sun, but that's just because it's so far from us: 250 miles above Earth. Still don't see it? Let's zoom in a bit.  It's right here:  The space station is just an unassuming silhouette against the sun's roiling plasma.As the sun grows more active, that ultra-hot material has been shooting into space more frequently, sometimes toward Earth, in eruptions called solar flares or coronal mass ejections. In March, solar eruptions caused the Northern Lights, aka the aurora borealis, to make an unprecedented appearance as far south as Phoenix, Arizona. But they can also knock out power grids, black out radio signals, push satellites out of orbit, confuse GPS, and even damage technology on the space station. McCarthy didn't experience any tech issues from solar eruptions, but he did have his own problems capturing this image. It required a balance of perfect timing, precise physics, and a lot of persistence. Stranded in the desert in pursuit of the space station The space station passes between Earth and the sun frequently, but to get a good photo McCarthy needed it to be directly overhead. "Otherwise the space station's lower on the horizon and smaller," he said. He noted the dates and exact times when it would pass overhead in the Arizona desert about two hours from his home. At the first opportunity, he loaded hundreds of pounds of equipment into his car and drove out to the precise spot he had calculated. He set up his telescopes. The skies were clear. He was poised to snag the photo. At the moment of the space station's transit — less than half a second as it crossed the sun — a rogue cloud bumbled past and blocked the view. McCarthy tried again another day. On the drive out, his tire exploded. Another attempt to snag the space station and the sun had failed. But he wasn't deterred. The space station zips across the sun like a fast-moving needle in a haystack  It was 100 degrees that day, McCarthy said. He pulled over and set up his equipment on the side of the road. The telescopes' field of view was small in order to get lots of detail, so he had to take hundreds of little snapshots of each portion of the solar surface. He would stack and stitch them together into a mosaic for the final picture. "Under the bright sun I'm looking at this laptop screen and just trying to figure out, on a fairly featureless sun, where I'm supposed to point my telescope," McCarthy said. He used the sunspots as a visual cue, knowing the space station would pass in front of them. them. "I'd plotted my position on Earth based on where the [International Space Station] would transit that particular sunspot," he said. "So long as I could get that sunspot in my field of view, I would also get the ISS." In the background, McCarthy wanted to capture the fiery drama of the sun's chromosphere, the thin layer of plasma between its visible surface (the photosphere) and the outermost layer of its atmosphere (the corona). In this layer, the sun's plasma reaches broiling temperatures upwards of 10,000 degrees Fahrenheit — so hot that its hydrogen emits a reddish light, according to NASA. That's the chromosphere light McCarthy wanted to capture. In chromosphere images, the sun looks like "a hairy ball" because of all the plasma movement, McCarthy said. But the space station shows up in visible light. That's why McCarthy needed three telescopes. One captured the "hydrogen alpha" emissions of the chromosphere. The other two captured optical light to resolve the space station, since its shadowy silhouette stood out against the uniform light of the sun's outer atmosphere. His telescopes snapped about 230 images per second. "If I wasn't shooting at a very fast rate, I would've actually completely missed it," McCarthy said. But he snagged dozens of raw photosphere images of the space station, like the one below, so he could stack them to get the clearest possible snapshot of the big satellite.  Meanwhile, the hydrogen alpha telescope captured tens of thousands of close-up images across the sun's surface, to stitch together like a quilt. As McCarthy drove back from the desert, another tire blew out. This time, when he got home he replaced all three old tires. "Thankfully it didn't happen on the way there," he said. "At least I got the shot this time." Though it's fun to search for the space station in this image, McCarthy doesn't like how much it blends in. "From a composition standpoint, I think I can do better as an artist in how I framed that final shot. So I'm going to go after another one and I think it'll be even better," McCarthy said. | |
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| BeowulfPosted at 2023-05-05 17:56:22(52Wks ago) Report Permalink URL | ||
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|  IC 342 is a challenging cosmic target. Although it is bright, the galaxy sits near the equator of the Milky Way’s galactic disc, where the sky is thick with glowing cosmic gas, bright stars, and dark, obscuring dust. In order for astronomers to see the intricate spiral structure of IC 342, they must gaze through a large amount of material contained within our own galaxy — no mean feat! As a result IC 342 is relatively difficult to spot and image, giving rise to its intriguing nickname: the “Hidden Galaxy”. Located very close (in astronomical terms!) to the Milky Way, this sweeping spiral galaxy would be among the brightest in the sky were it not for its dust-obscured location. The galaxy is very active, as indicated by the range of colours visible in this NASA/ESA Hubble Space Telescope image, depicting the very central region of the galaxy. A beautiful mixture of hot, blue star-forming regions, redder, cooler regions of gas, and dark lanes of opaque dust can be seen, all swirling together around a bright core. In 2003, astronomers confirmed this core to be a specific type of central region known as an HII nucleus — a name that indicates the presence of ionised hydrogen — that is likely to be creating many hot new stars. Credit: ESA/Hubble & NASA & Beowulf | |
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| Jase1Posted at 2023-05-06 08:39:59(52Wks ago) Report Permalink URL | ||
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|  See the terrifying scale of a supermassive black hole in NASA visualization by Georgina Torbet This week is black hole week, and NASA is celebrating by sharing some stunning visualizations of black holes, including a frankly disturbing visualization to help you picture just how large a supermassive black hole is. Supermassive black holes are found at the center of galaxies (including our own) and generally speaking, the bigger the galaxy, the bigger the black hole. While a typical black hole weighs up to around 10 times the mass of the sun, supermassive black holes can weigt millions or even billions of times the mass of the sun. These objects are incredibly dense, though, and it’s hard to picture just how big such an object would be. That’s the point of this video comparison, which shows the size of different types of black holes in comparison to our solar system, scaled according to their shadows. Learning about black holes is challenging because their tremendous gravity means that they absorb light that comes too close to them — however, they often have disks of dust and gas swirling around them that rubs together and gets hot, making them visible to telescopes. Astronomers can’t directly see the black holes themselves, but they can see this warm matter, which is how the Event Horizon Telescope project has been able to capture famous images of black holes.  This is the first image of Sagittarius A* (or Sgr A* for short), the supermassive black hole at the center of our galaxy. It’s the first direct visual evidence of the presence of this black hole. It was captured by the Event Horizon Telescope (EHT), an array that links together eight existing radio observatories across the planet to form a single “Earth-sized” virtual telescope. The telescope is named after the “event horizon”, the boundary of the black hole beyond which no light can escape. EHT Collaboration Supermassive black holes are particularly interesting to study because we are still learning about their relationship to the galaxies which they inhabit, and about how they grow so large. “Direct measurements, many made with the help of the Hubble Space Telescope, confirm the presence of more than 100 supermassive black holes,” said Jeremy Schnittman, a theorist at NASA’s Goddard Space Flight Center, in a statement. “How do they get so big? When galaxies collide, their central black holes eventually may merge together too.” This merging process would be epic, producing such great force that gravitational waves would be detectable from Earth. But to tune into these waves, we’ll need a new instrument like the upcoming Laser Interferometer Space Antenna mission, a collaboration between NASA and the European Space Agency that will use three spacecraft that shoot lasers toward each other and which will be able to detect these gravitational waves. “Since 2015, gravitational wave observatories on Earth have detected the mergers of black holes with a few dozen solar masses thanks to the tiny ripples in space-time these events produce,” said Goddard astrophysicist Ira Thorpe. “Mergers of supermassive black holes will produce waves of much lower frequencies which can be detected using a space-based observatory millions of times larger than its Earth-based counterparts.” | |
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| BeowulfPosted at 2023-05-06 09:47:55(52Wks ago) Report Permalink URL | ||
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|  Sparkling at the centre of this beautiful NASA/ESA Hubble Space Telescope image is a Wolf–Rayet star known as WR 31a, located about 30 000 light-years away in the constellation of Carina (The Keel). The distinctive blue bubble appearing to encircle WR 31a, and its uncatalogued stellar sidekick, is a Wolf–Rayet nebula — an interstellar cloud of dust, hydrogen, helium and other gases. Created when speedy stellar winds interact with the outer layers of hydrogen ejected by Wolf–Rayet stars, these nebulae are frequently ring-shaped or spherical. The bubble — estimated to have formed around 20 000 years ago — is expanding at a rate of around 220 000 kilometres per hour! Unfortunately, the lifecycle of a Wolf–Rayet star is only a few hundred thousand years — the blink of an eye in cosmic terms. Despite beginning life with a mass at least 20 times that of the Sun, Wolf–Rayet stars typically lose half their mass in less than 100 000 years. And WR 31a is no exception to this case. It will, therefore, eventually end its life as a spectacular supernova, and the stellar material expelled from its explosion will later nourish a new generation of stars and planets. Credit: ESA/Hubble & NASA & Beowulf Acknowledgement: Judy Schmidt | |
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| Jase1Posted at 2023-05-06 18:49:39(52Wks ago) Report Permalink URL | ||
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|  NASA, ESA, CSA, O. Jones (UK ATC), G. De Marchi (ESTEC), and M. Meixner (USRA). Image processing: A. Pagan (STScI), N. Habel (USRA), L. Lenkic (USRA) and L. Chu (NASA/Ames) The ingredients for planet formation have turned up in part of a nearby galaxy where it was thought planets might not emerge. The discovery, reported on April 24 in Nature Astronomy and made using NASA’s hugely powerful James Webb Space Telescope (JWST), suggests that planet formation may be more common throughout the Universe than previously thought. “I’ve waited a long time to be able to do these observations,” says Olivia Jones, an astrophysicist at the UK Astronomy Technology Centre in Edinburgh and the lead author of the study. “It’s not been possible to do them before.” The findings follow a flood of discoveries enabled by JWST, which launched in December 2021 and beamed back its first science images last July. Researchers looked at NGC 346, a highly active star-forming region in a galaxy near the Milky Way called the Small Magellanic Cloud (SMC). They chose this place because it has a very low concentration of metals — which astronomers define as any element heavier than hydrogen and helium. That makes it resemble the conditions during the ‘cosmic noon’, a period approximately ten billion years ago when stars formed in a flurry in nearly all the galaxies of the Universe. Furthermore, NGC 346 is much bigger than other star-forming regions nearby, allowing astronomers to see more clearly how stars interact with each other and how they take shape. Seeking low-mass stars The researchers were mainly interested in studying low-mass stars because they are much more common in the Universe than high-mass stars. The Sun is a low-mass star, so understanding star formation in NGC 346 could also help explain the birth of the Solar System. But it had been challenging to study the birth of low-mass stars because they emit a lot of dust as they form, which hides their light. The best way to see through the dust is by capturing infrared light, something JWST’s predecessor, the Hubble Space Telescope, wasn’t built to do. “With Webb, you can see these stars right at that moment of being born,” says Jones. Dust, however, is also crucial to detecting planet formation. The dust released by a star when it’s born can collect into a disk that eventually turns into planets. It wasn’t known whether enough dust could survive for planets to form in NGC 346, because the low-metal conditions make such disks susceptible to fast evaporation by light. Impossible planets The researchers used filters on JWST’s camera to find combinations of infrared wavelengths that allowed them to identify stars at various stages of their lives. They found enough dust, collecting in signature ways, to indicate planet formation was possible. Spotting the ingredients for planets in NGC 346 broadens understanding of where planets can exist, says Stefanie Milam, deputy project scientist for JWST planetary science at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s giving us a lot more area to start searching for planet formation and star formation beyond what we had originally presumed.” Researchers understand how, once rocky planets begin to take shape in low-metal galaxies, they can collect more dust, says Jones. But how enough dust survives to foster planet formation in the first place is still a mystery, she says. What’s next? It’s too soon to say whether the existence of more planets increases the probability that there is life elsewhere in the Universe, says Jones. But she wants to look at NGC 346 more closely for signs of certain substances, including water and carbon dioxide. Jones plans to use JWST to conduct follow-up observations in around six months, targeting the potential planetary systems reported in the latest study. Further in the future, investigating whether other unexpected galaxies can nurture planet formation will help to build a better picture of how the process works, says Milam. “I think the discovery space is just infinite,” Milam says. “Hands down, we’re ready for the next generation of astrophysics.” | |
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| Jase1Posted at 2023-05-07 09:52:14(52Wks ago) Report Permalink URL | ||
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|  NASA: Four Uranus moons may have oceans that are miles deep By Eric Ralls - 05-05-2023 A re-examination of data from the Voyager spacecraft, coupled with advanced computer modeling, has led to a groundbreaking discovery by NASA scientists. They now believe that four of Uranus' largest moons - Ariel, Umbriel, Titania, and Oberon - likely contain an ocean layer sandwiched between their cores and icy crusts (see image here). This new research is the first to delve into the evolution of the interior makeup and structure of all five major moons of Uranus, including Miranda, and suggests that four of these moons may harbor oceans that could be tens of miles deep. Uranus boasts at least 27 moons in total, with the four largest ranging in size from Ariel, which measures 720 miles (1,160 kilometers) across, to Titania, which spans 980 miles (1,580 kilometers) in diameter. Scientists have long speculated that Titania, due to its larger size, would be more likely to retain internal heat generated by radioactive decay. The other moons were previously thought to be too small to retain enough heat to prevent an internal ocean from freezing, particularly given that heating caused by the gravitational pull of Uranus is only a minor heat source. Studying Uranus from afar before launching a mission The 2023 Planetary Science and Astrobiology Decadal Survey conducted by the National Academies prioritized the exploration of Uranus. In anticipation of a potential mission, planetary scientists are concentrating their efforts on studying the ice giant and its mysterious system. The recent study, published in the Journal of Geophysical Research, not only provides insight into how a future mission might explore the moons of Uranus, but also has broader implications for understanding other celestial bodies, according to lead author Julie Castillo-Rogez of NASA's Jet Propulsion Laboratory in Southern California. “When it comes to small bodies - dwarf planets and moons - planetary scientists previously have found evidence of oceans in several unlikely places, including the dwarf planets Ceres and Pluto, and Saturn’s moon Mimas," said Castillo-Rogez. “So there are mechanisms at play that we don’t fully understand. This paper investigates what those could be and how they are relevant to the many bodies in the solar system that could be rich in water but have limited internal heat.” To conduct their research, the scientists revisited data from the 1980s Voyager 2 flybys of Uranus and combined it with findings from ground-based observations. They then developed computer models that incorporated additional discoveries from NASA's Galileo, Cassini, Dawn, and New Horizons missions, each of which unveiled ocean worlds. These models also included insights into the chemistry and geology of Saturn's moon Enceladus, Pluto and its moon Charon, and Ceres - all icy bodies similar in size to the moons of Uranus. How the study was done The research team made use of advanced computer modeling to analyze the porosity of their surfaces. They discovered that the moons' surfaces are likely insulated enough to retain the internal heat necessary for hosting an ocean. Moreover, they identified a potential heat source within the moons' rocky mantles, which release hot liquid and could help maintain a warm environment for an ocean—particularly in Titania and Oberon, where the oceans may even be warm enough to potentially support habitability. By investigating the composition of the oceans, scientists can also gain insights into the materials that may be present on the moons' icy surfaces, depending on whether substances from the subsurface were pushed up through geological activity. What the researchers learned Observations from telescopes have revealed evidence that at least one of the moons, Ariel, has material that flowed onto its surface, possibly from icy volcanoes, relatively recently. Miranda, the innermost and fifth largest moon, also exhibits surface features that appear to be of recent origin, suggesting it may have held enough heat to maintain an ocean at some point. However, recent thermal modeling indicates that Miranda is unlikely to have hosted water for long, as it loses heat too rapidly and is probably frozen now. Castillo-Rogez explained that internal heat isn't the only factor contributing to a moon's subsurface ocean. The study's key finding reveals that chlorides, along with ammonia, are likely abundant in the oceans of Uranus' largest moons. Ammonia is known to act as an antifreeze, and the modeling also suggests that salts present in the water would provide an additional antifreeze source, helping to maintain the moons' internal oceans. Many questions left unanswered Despite these groundbreaking discoveries, many questions about Uranus' large moons remain. Castillo-Rogez acknowledges the need for further research: “We need to develop new models for different assumptions on the origin of the moons in order to guide planning for future observations.” Unraveling the mysteries of these moons will help scientists and engineers select the most suitable instruments for studying them. For instance, knowing that ammonia and chlorides may be present would mean that spectrometers, which identify compounds by their reflected light, would need to use a wavelength range covering both types of compounds. Furthermore, this knowledge can aid in designing instruments capable of probing the deep interior for liquid. Generally, searching for electrical currents contributing to a moon's magnetic field is the best way to detect a deep ocean, as demonstrated by the Galileo mission scientists at Jupiter's moon Europa. However, the cold water in the interior oceans of moons like Ariel and Umbriel could hinder the oceans' ability to carry these electrical currents, presenting a new challenge for scientists working to uncover what lies beneath the surface of these enigmatic celestial bodies. The integration of this wealth of data has allowed scientists to deepen our understanding of the moons of Uranus and the potential for water-rich bodies throughout our solar system. More about Uranus Uranus is the seventh planet from the Sun and the third largest in our solar system, with a diameter of about 31,518 miles (50,724 kilometers). It is an ice giant, like Neptune, and consists primarily of hydrogen and helium along with various ices such as water, ammonia, and methane. It has a unique pale blue-green color due to the presence of methane in its atmosphere, which absorbs red light and reflects the blue-green hues. Uranus also has a distinct feature: its axis is tilted at an extreme angle of 98 degrees relative to its orbit, causing the planet to essentially rotate on its side. Uranus has a ring system composed of 13 faint rings that are predominantly made up of dust and small chunks of rock. It also has a complex system of at least 27 known moons, named after characters from the works of William Shakespeare and Alexander Pope. The five largest moons are Miranda, Ariel, Umbriel, Titania, and Oberon, each displaying distinct geological features and characteristics. Miranda The innermost and smallest of the five main moons, Miranda has a diameter of about 290 miles (466 kilometers) and features a bizarre landscape with giant canyons, ridges, and icy cliffs. Some theories suggest that the moon might have experienced a massive impact or tectonic activity in the past. Ariel With a diameter of approximately 720 miles (1,160 kilometers), Ariel is the fourth largest moon of Uranus. It has a relatively smooth surface with some large impact craters and a network of fault valleys and ridges, indicating signs of past geological activity. Umbriel Umbriel is the third largest moon, with a diameter of around 727 miles (1,169 kilometers). It has a dark and heavily cratered surface, indicating that it has been relatively inactive geologically. Titania The largest moon of Uranus, Titania has a diameter of approximately 980 miles (1,580 kilometers). Its surface features deep canyons, vast plains, and large impact craters, suggesting a mix of geological processes. Oberon With a diameter of about 945 miles (1,520 kilometers), Oberon is the second largest moon of Uranus. It has a heavily cratered surface with some large impact basins and mountainous terrain. Recent studies have revealed that four of these major moons—Ariel, Umbriel, Titania, and Oberon—likely contain subsurface oceans between their cores and icy crusts. This discovery has sparked interest in understanding their potential habitability and the mechanisms that allow them to maintain liquid water beneath their surfaces. While there is still much to learn about Uranus and its moons, these celestial bodies provide a fascinating glimpse into the diverse range of planetary systems and environments that exist within our solar system. | |
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| Jase1Posted at 2023-05-07 17:14:35(52Wks ago) Report Permalink URL | ||
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| Strange worlds, here we come. BY JACKIE APPEL MAY 5, 2023  Astronomers have invented a new method for searching out and spotting exoplanets. It combines two previous methods—astrometry and direct imaging—to narrow down targets before confirming the presence of a planet. Researchers hope this will allow the search for other worlds to become more efficient and effective. Exoplanets are undeniably fascinating. Other world around other stars that could hold the answers to all kinds of large-scale space questions—including, potentially, whether or not we are alone in the universe. Since finding the first exoplanets in 1992, researchers have spotted over 5000 of these extraterrestrial worlds, and they have their sights set on finding many, many more. But just because we’ve found so many so far doesn’t mean it’s been easy. It has taken a lot of work to distill effective methods for spotting these cosmically tiny bodies. And researchers believe they have found one of the most effective methods yet—one that actually combines two methods together. Generally, exoplanets are found through one of five methods. There’s the transit method, which allows researchers to spot planets when they block light by orbiting in front of their host star. There’s the radial velocity method, where you can spot planets by measuring the gravitational effect they have on their stars. There’s gravitational microlensing, where a second star acts as a telescope and causes a flash of light if an exoplanet is present. There’s astrometry, where scientists look for how an exoplanet causes a host star to move in relation to other stars. And there’s direct imaging, where you just… see an exoplanet directly. Usually, all of those methods are used on their own. They’ve been successful, but they often involve casting a very wide net and seeing what gets trapped. But recently, astronomers were able to combine astrometry and direct imaging together and find an exoplanet. They used astrometry to narrow down what stars might be good candidates to search for exoplanets, and then direct imaged those stars to see if the planets were in fact present. This seems like an obvious thing to do—narrow down the hunt and then be able to target potential exoplanet sites more efficiently. But it requires two huge sets of data—one of set of astronomy data and another corresponding set of direct imaging data. Getting access to that kind of data is tricky when everyone wants to use the telescopes all the time for every project. So, the team started with what they already had. They went through over 25 years of astrometric data that had already been gathered by the ESA’s Gaia and Hipparcos missions. Once they had used that data to identify their targets, they reserved time on the Subaru Telescope (located on top of Maunakea in Hawai’i) to follow up with direct imaging. And so far, it has worked in at least one instance. The team discovered the existance of HIP99770b, a hot Jupiter-like planet orbiting around the star HIP99770. HIP99770 would usually be quite difficult to find exoplanets around, as it’s twice the size of our Sun, and stars that massive often block out a lot of what’s around them. In the future, the team hopes that they can use their technique to find even more exoplanets even more efficiently. Especially considering that this approach, when it works, does eventually provide direct imaging data. Direct imaging data is critical for analyzing the temperatures, characteristics, and atmospheres of far-off worlds. Combining new techniques with new tech like the James Webb Space Telescope and the upcoming Nancy Grace Roman Telescope—who knows how many new and exciting worlds we’ll find. | |
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| BeowulfPosted at 2023-05-07 17:51:06(52Wks ago) Report Permalink URL | ||
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|  This NASA/ESA Hubble Space Telescope image shows the planetary nebula NGC 2452, located in the southern constellation of Puppis. The blue haze across the frame is what remains of a star like our Sun after it has depleted all its fuel. When this happens, the core of the star becomes unstable and releases huge numbers of incredibly energetic particles that blow the star's atmosphere away into space. At the centre of this blue cloud lies what remains of the nebula's progenitor star. This cool, dim, and extremely dense star is actually a pulsating white dwarf, meaning that its brightness varies over time as gravity causes waves that pulse throughout the small star's body. NGC 2452 was discovered by Sir John Herschel in 1847. He initially defined it as "an object whose nature I cannot make out. It is certainly not a star, nor a close double star [...] I should call it an oblong planetary nebula". To early observers like Herschel with their smaller telescopes, planetary nebulae resembled gaseous planets, and so were named accordingly. The name has stuck, although modern telescopes like Hubble have made it clear that these objects are not planets at all, but the outer layers of dying stars being thrown off into space. A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestants Luca Limatola and Budeanu Cosmin Mirel. Credit: ESA/Hubble & NASA & Beowulf Acknowledgements: Luca Limatola, Budeanu Cosmin Mirel | |
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