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    • By NASA
      NASA’s Dawn spacecraft captured this image of Vesta as it left the giant asteroid’s orbit in 2012. The framing camera was looking down at the north pole, which is in the middle of the image.NASA/JPL-Caltech/UCLA/MPS/DLR/IDA Known as flow formations, these channels could be etched on bodies that would seem inhospitable to liquid because they are exposed to the extreme vacuum conditions of space.
      Pocked with craters, the surfaces of many celestial bodies in our solar system provide clear evidence of a 4.6-billion-year battering by meteoroids and other space debris. But on some worlds, including the giant asteroid Vesta that NASA’s Dawn mission explored, the surfaces also contain deep channels, or gullies, whose origins are not fully understood.
      A prime hypothesis holds that they formed from dry debris flows driven by geophysical processes, such as meteoroid impacts, and changes in temperature due to Sun exposure. A recent NASA-funded study, however, provides some evidence that impacts on Vesta may have triggered a less-obvious geologic process: sudden and brief flows of water that carved gullies and deposited fans of sediment. By using lab equipment to mimic conditions on Vesta, the study, which appeared in Planetary Science Journal, detailed for the first time what the liquid could be made of and how long it would flow before freezing.
      Although the existence of frozen brine deposits on Vesta is unconfirmed, scientists have previously hypothesized that meteoroid impacts could have exposed and melted ice that lay under the surface of worlds like Vesta. In that scenario, flows resulting from this process could have etched gullies and other surface features that resemble those on Earth.
      To explore potential explanations for deep channels, or gullies, seen on Vesta, scientists used JPL’s Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE, to simulate conditions on the giant asteroid that would occur after meteoroids strike the surface.NASA/JPL-Caltech But how could airless worlds — celestial bodies without atmospheres and exposed to the intense vacuum of space — host liquids on the surface long enough for them to flow? Such a process would run contrary to the understanding that liquids quickly destabilize in a vacuum, changing to a gas when the pressure drops.
      “Not only do impacts trigger a flow of liquid on the surface, the liquids are active long enough to create specific surface features,” said project leader and planetary scientist Jennifer Scully of NASA’s Jet Propulsion Laboratory in Southern California, where the experiments were conducted. “But for how long? Most liquids become unstable quickly on these airless bodies, where the vacuum of space is unyielding.”
      The critical component turns out to be sodium chloride — table salt. The experiments found that in conditions like those on Vesta, pure water froze almost instantly, while briny liquids stayed fluid for at least an hour. “That’s long enough to form the flow-associated features identified on Vesta, which were estimated to require up to a half-hour,” said lead author Michael J. Poston of the Southwest Research Institute in San Antonio.
      Launched in 2007, the Dawn spacecraft traveled to the main asteroid belt between Mars and Jupiter to orbit Vesta for 14 months and Ceres for almost four years. Before ending in 2018, the mission uncovered evidence that Ceres had been home to a subsurface reservoir of brine and may still be transferring brines from its interior to the surface. The recent research offers insights into processes on Ceres but focuses on Vesta, where ice and salts may produce briny liquid when heated by an impact, scientists said.
      Re-creating Vesta
      To re-create Vesta-like conditions that would occur after a meteoroid impact, the scientists relied on a test chamber at JPL called the Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE. By rapidly reducing the air pressure surrounding samples of liquid, they mimicked the environment around fluid that comes to the surface. Exposed to vacuum conditions, pure water froze instantly. But salty fluids hung around longer, continuing to flow before freezing.
      The brines they experimented with were a little over an inch (a few centimeters) deep; scientists concluded the flows on Vesta that are yards to tens of yards deep would take even longer to refreeze.
      The researchers were also able to re-create the “lids” of frozen material thought to form on brines. Essentially a frozen top layer, the lids stabilize the liquid beneath them, protecting it from being exposed to the vacuum of space — or, in this case the vacuum of the DUSTIE chamber — and helping the liquid flow longer before freezing again.
      This phenomenon is similar to how on Earth lava flows farther in lava tubes than when exposed to cool surface temperatures. It also matches up with modeling research conducted around potential mud volcanoes on Mars and volcanoes that may have spewed icy material from volcanoes on Jupiter’s moon Europa.
      “Our results contribute to a growing body of work that uses lab experiments to understand how long liquids last on a variety of worlds,” Scully said.
      Find more information about NASA’s Dawn mission here:
      https://science.nasa.gov/mission/dawn/
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      Last Updated Dec 20, 2024 Related Terms
      Dawn Asteroids Ceres Jet Propulsion Laboratory Vesta Explore More
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    • By European Space Agency
      Stare deeply at these galaxies. They appear as if blood is pumping through the top of a flesh-free face. The long, ghastly ‘stare’ of their searing eye-like cores shines out into the supreme cosmic darkness.
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    • By NASA
      Mars: Perseverance (Mars 2020) Perseverance Home Mission Overview Rover Components Mars Rock Samples Where is Perseverance? Ingenuity Mars Helicopter Mission Updates Science Overview Objectives Instruments Highlights Exploration Goals News and Features Multimedia Perseverance Raw Images Images Videos Audio More Resources Mars Missions Mars Sample Return Mars Perseverance Rover Mars Curiosity Rover MAVEN Mars Reconnaissance Orbiter Mars Odyssey More Mars Missions The Solar System The Sun Mercury Venus Earth The Moon Mars Jupiter Saturn Uranus Neptune Pluto & Dwarf Planets Asteroids, Comets & Meteors The Kuiper Belt The Oort Cloud 2 min read
      A Spooky Soliday: Haunting Whispers from the Martian Landscape
      NASA’s Mars Perseverance rover acquired this image, which was selected by the public as the rover’s “Image of the Week,” of the martian landscape on the Jezero crater rim using its Left Mastcam-Z camera. The image was acquired on Oct. 22, 2024 (Sol 1306) at the local mean solar time of 13:45:41. NASA/JPL-Caltech/ASU The Perseverance rover lurks in the quiet, cold, desolate landscape of Jezero crater on Mars, a place masked in shadows and haunted by past mysteries. Built to endure the planet’s harsh conditions, Perseverance braves the thin atmosphere and extreme temperature swings. Its microphone captures the eerie whispers of martian winds, sending shivers down your spine, and records ghostly dust devils swirling across the barren terrain. Has the microphone caught the sound of a skeleton rattling its bones? We’ll leave that up to your imagination.
      Recently, Perseverance navigated the sinister slopes of the Jezero crater rim, seeking out a series of ramshackle ridges to uncover the rim’s hidden geological secrets. The rover emerged from the shadows to descend into a field of light-toned rocks, illuminating the landscape reminiscent of bones and tombstones. Along the way, the rover encountered dark bedrock at Mist Park. Perseverance will then face another daunting climb back up the crater rim, venturing deeper into the great unknown.
      Unlike vampires or other creatures of the night, Perseverance needs rest after long days of exploring the mystifying martian landscape. As night falls, the rover sleeps after watching the Sun sink below the horizon, casting ominous shadows across the landscape. The chilling winds howl through the night like a haunting lullaby for the fearless explorer. However, Perseverance sometimes wakes up from things that go bump in the night. While instruments mostly conduct their scientific measurements during the day, they are not afraid of the dark, often tasked with observing what lurks in the shadows and gazing at the martian night sky. Perseverance occasionally looks up to image the auroras and to get a glimpse of Phobos and Deimos, Mars’ two Moons.
      Mars is like a hotel you can check in and out of, but you can never leave. It has become a graveyard of long-dead landers and rovers, but Perseverance is nowhere near ready to leave the land of the living. In fact, the ghosts of past rovers and landers guide Perseverance on its journey. As we continue to uncover the secrets of Mars, we are reminded of its past and the mysteries that still linger. Join us in pondering the mysteries of Mars as we explore its haunted history.   
      Written by Stephanie Connell, Ph.D. Student Collaborator at Purdue University
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      Mars Perseverance Sol 1306: Left Mastcam-Z Camera
      Oct 30, 2024
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      Last Updated Oct 30, 2024 Related Terms
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    • By NASA
      4 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      Science in Space: October 2024
      Cultures around the world celebrate Halloween on Oct 31. In many places, in addition to people wearing costumes and eating candy, this day is associated with spooky decorating using fake blood, skeletons, flies, and spiders, some of them glow-in-the-dark.
      Crew members on the International Space Station have been known to indulge in a bit of dressing up and candy consumption to mark the day, and the research they conduct year-round occasionally involves these iconic Halloween themes. No tricks, just treats.
      JAXA astronaut Koichi Wakata and NASA astronauts Frank Rubio, Nicole Mann, and Josh Cassada dressed up for Halloween 2022.NASA A current investigation, Megakaryocytes Flying-One or MeF1, investigates how components of real blood known as megakaryocytes and platelets develop and function during spaceflight. Megakaryocytes are large cells found in bone marrow and platelets are pieces of these cells. Both play important roles in blood clotting and immune response. Results could improve understanding of changes in inflammation, immune responses, and clot formation in spaceflight and on the ground.
      Creepy crawlies
      Fake spiders and flies are popular Halloween decorations (and fodder for fun pranks). Several investigations on the space station have used real ones.
      Fruit Fly Lab-02 used fruit flies, Drosophila melanogaster, to examine the cellular and genetic mechanisms that affect heart health during spaceflight. The flies experienced several effects on cardiac function, including changes in muscle fibers, that could be a fundamental response of heart muscles to microgravity.
      MVP Fly-01 looked at how spaceflight affects immune function and resulting changes to the nervous system of the same type of flies, along with the value of artificial gravity as a countermeasure. Researchers found that artificial gravity provided some protection to physical changes to the central nervous system from spaceflight. Spiders, Fruit Flies and Directional Plant Growth (CSI-05) compared the weaving characteristics of golden orb-web spiders on the space station and the ground. Under natural conditions, the spiders build asymmetric webs with the hub near the upper edge, where they wait for prey. In microgravity, most but not all webs were quite symmetric, although webs built when the lights were on were more asymmetric and the spiders waited facing away from the lights. This could mean that in the absence of gravity, the spiders orient to the direction of light.
      A golden-orb weaver and its web on the space station.NASA Bad to the bones
      Everyone needs healthy bones and skeletons, and not just on Halloween. But spaceflight and aging on Earth can cause loss of bone mass. Space station research has looked at the mechanisms behind this loss as well as countermeasures such as exercise and nutrition.
      Bisphosphonates as a Countermeasure to Bone Loss examined whether a medication that blocks the breakdown of bone, in conjunction with the routine in-flight exercise program, protected crew members from bone mineral density loss during spaceflight. The research found that it did reduce loss, which in turn reduced the occurrence of kidney stones in crew members.
      Assessment of the Effect of Space Flight on Bone (TBone) studied how spaceflight affects bone quality using a high-resolution bone scan technique. Researchers found incomplete recovery of bone strength and density in the tibia (a bone in the lower leg), comparable to a decade or more of terrestrial age-related bone loss. The work also highlighted the relationship between length of a mission and bone loss and suggested that pre-flight markers could identify crew members at greatest risk.
      In a merging of blood and bones, CSA’s Marrow looked at whether microgravity has a negative effect on bone marrow and the blood cells it produces. Decreased production of red blood cells can lead to a condition called space anemia. Findings related to the expression of genes involved in red blood cell formation and those related to bone marrow adipose or fat tissue, which stores energy and plays a role in immune function, could contribute to development of countermeasures. Marrow results also suggested that the destruction of red blood cells (known as hemolysis) is a primary effect of spaceflight and contributes to anemia. Bad news for vampires.
      ESA astronaut Thomas Pesquet storing Marrow samples in MELFI.NASA It glows in the dark
      Fluorescence – a cool effect at a ghoulish party – also is a common tool in scientific research, enabling researchers to see physical and genetic changes. The space station has special microscopes for observing glow-in-the-dark samples.
      For Medaka Osteoclast 2, an investigation from JAXA (Japan Aerospace Exploration Agency), researchers genetically modified translucent Medaka fish with fluorescent proteins to help them observe cellular and genetic changes the fish experience during spaceflight. One analysis revealed a decrease in the mineral density of bones in the throat and provided insights into the mechanisms behind these changes.
      A translucent Medaka fish with fluorescent proteins showing its bone structure.Philipp Keller, Stelzer Group, EMBL Biorock, an investigation from ESA (European Space Agency), examined how microgravity affects the interaction between rocks and microbes and found little effect on microbial growth. This result suggests that microbial-supported bioproduction and life support systems can perform in reduced gravity such as that on Mars, which would be a perfect place for an epic Halloween celebration.
      Preflight fluorescence microscopy image of a biofilm for the Biorock experiment.NASA Keep Exploring Discover More Topics From NASA
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    • By NASA
      4 min read
      NASA’s Fermi Finds New Feature in Brightest Gamma-Ray Burst Yet Seen
      In October 2022, astronomers were stunned by what was quickly dubbed the BOAT — the brightest-of-all-time gamma-ray burst (GRB). Now an international science team reports that data from NASA’s Fermi Gamma-ray Space Telescope reveals a feature never seen before.
      The brightest gamma-ray burst yet recorded gave scientists a new high-energy feature to study. Learn what NASA’s Fermi mission saw, and what this feature may be telling us about the burst’s light-speed jets. Credit: NASA’s Goddard Space Flight Center
      Download high-resolution video and images from NASA’s Scientific Visualization Studio

      “A few minutes after the BOAT erupted, Fermi’s Gamma-ray Burst Monitor recorded an unusual energy peak that caught our attention,” said lead researcher Maria Edvige Ravasio at Radboud University in Nijmegen, Netherlands, and affiliated with Brera Observatory, part of INAF (the Italian National Institute of Astrophysics) in Merate, Italy. “When I first saw that signal, it gave me goosebumps. Our analysis since then shows it to be the first high-confidence emission line ever seen in 50 years of studying GRBs.”
      A paper about the discovery appears in the July 26 edition of the journal Science.
      When matter interacts with light, the energy can be absorbed and reemitted in characteristic ways. These interactions can brighten or dim particular colors (or energies), producing key features visible when the light is spread out, rainbow-like, in a spectrum. These features can reveal a wealth of information, such as the chemical elements involved in the interaction. At higher energies, spectral features can uncover specific particle processes, such as matter and antimatter annihilating to produce gamma rays.
      “While some previous studies have reported possible evidence for absorption and emission features in other GRBs, subsequent scrutiny revealed that all of these could just be statistical fluctuations. What we see in the BOAT is different,” said coauthor Om Sharan Salafia at INAF-Brera Observatory in Milan, Italy. “We’ve determined that the odds this feature is just a noise fluctuation are less than one chance in half a billion.”
      A jet of particles moving at nearly light speed emerges from a massive star in this artist’s concept. The star’s core ran out of fuel and collapsed into a black hole. Some of the matter swirling toward the black hole was redirected into dual jets firing in opposite directions. We see a gamma-ray burst when one of these jets happens to point directly at Earth. NASA’s Goddard Space Flight Center Conceptual Image Lab GRBs are the most powerful explosions in the cosmos and emit copious amounts of gamma rays, the highest-energy form of light. The most common type occurs when the core of a massive star exhausts its fuel, collapses, and forms a rapidly spinning black hole. Matter falling into the black hole powers oppositely directed particle jets that blast through the star’s outer layers at nearly the speed of light. We detect GRBs when one of these jets points almost directly toward Earth.
      The BOAT, formally known as GRB 221009A, erupted Oct. 9, 2022, and promptly saturated most of the gamma-ray detectors in orbit, including those on Fermi. This prevented them from measuring the most intense part of the blast. Reconstructed observations, coupled with statistical arguments, suggest the BOAT, if part of the same population as previously detected GRBs, was likely the brightest burst to appear in Earth’s skies in 10,000 years.
      The putative emission line appears almost 5 minutes after the burst was detected and well after it had dimmed enough to end saturation effects for Fermi. The line persisted for at least 40 seconds, and the emission reached a peak energy of about 12 MeV (million electron volts). For comparison, the energy of visible light ranges from 2 to 3 electron volts.
      So what produced this spectral feature? The team thinks the most likely source is the annihilation of electrons and their antimatter counterparts, positrons.
      “When an electron and a positron collide, they annihilate, producing a pair of gamma rays with an energy of 0.511 MeV,” said coauthor Gor Oganesyan at Gran Sasso Science Institute and Gran Sasso National Laboratory in L’Aquila, Italy. “Because we’re looking into the jet, where matter is moving at near light speed, this emission becomes greatly blueshifted and pushed toward much higher energies.”
      If this interpretation is correct, to produce an emission line peaking at 12 MeV, the annihilating particles had to have been moving toward us at about 99.9% the speed of light.
      “After decades of studying these incredible cosmic explosions, we still don’t understand the details of how these jets work,” noted Elizabeth Hays, the Fermi project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Finding clues like this remarkable emission line will help scientists investigate this extreme environment more deeply.” 
      The Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership managed by Goddard. Fermi was developed in collaboration with the U.S. Department of Energy, with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the United States.
      By Francis Reddy
      NASA’s Goddard Space Flight Center, Greenbelt, Md.
      Media Contact:
      Claire Andreoli
      301-286-1940
      claire.andreoli@nasa.gov
      NASA’s Goddard Space Flight Center, Greenbelt, Md.
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      Last Updated Jul 25, 2024 Related Terms
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