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By NASA
3 min read
NASA Solar Observatory Sees Coronal Loops Flicker Before Big Flares
For decades, scientists have tried in vain to accurately predict solar flares — intense bursts of light on the Sun that can send a flurry of charged particles into the solar system. Now, using NASA’s Solar Dynamics Observatory, one team has identified flickering loops in the solar atmosphere, or corona, that seem to signal when the Sun is about to unleash a large flare.
These warning signs could help NASA and other stakeholders protect astronauts as well as technology both in space and on the ground from hazardous space weather.
NASA’s Solar Dynamics Observatory captured this image of coronal loops above an active region on the Sun in mid-January 2012. The image was taken in the 171 angstrom wavelength of extreme ultraviolet light. NASA/Solar Dynamics Observatory Led by heliophysicist Emily Mason of Predictive Sciences Inc. in San Diego, California, the team studied arch-like structures called coronal loops along the edge of the Sun. Coronal loops rise from magnetically driven active regions on the Sun, where solar flares also originate.
The team looked at coronal loops near 50 strong solar flares, analyzing how their brightness in extreme ultraviolet light varied in the hours before a flare compared to loops above non-flaring regions. Like flashing warning lights, the loops above flaring regions varied much more than those above non-flaring regions.
“We found that some of the extreme ultraviolet light above active regions flickers erratically for a few hours before a solar flare,” Mason explained. “The results are really important for understanding flares and may improve our ability to predict dangerous space weather.”
Published in the Astrophysical Journal Letters in December 2024 and presented on Jan. 15, 2025, at a press conference during the 245th meeting of the American Astronomical Society, the results also hint that the flickering reaches a peak earlier for stronger flares. However, the team says more observations are needed to confirm this link.
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The four panels in this movie show brightness changes in coronal loops in four different wavelengths of extreme ultraviolet light (131, 171, 193, and 304 angstroms) before a solar flare in December 2011. The images were taken by the Atmospheric Imaging Assembly (AIA) on NASA’s Solar Dynamics Observatory and processed to reveal flickering in the coronal loops. NASA/Solar Dynamics Observatory/JHelioviewer/E. Mason Other researchers have tried to predict solar flares by examining magnetic fields on the Sun, or by looking for consistent trends in other coronal loop features. However, Mason and her colleagues believe that measuring the brightness variations in coronal loops could provide more precise warnings than those methods — signaling oncoming flares 2 to 6 hours ahead of time with 60 to 80 percent accuracy.
“A lot of the predictive schemes that have been developed are still predicting the likelihood of flares in a given time period and not necessarily exact timing,” said team member Seth Garland of the Air Force Institute of Technology at Wright-Patterson Air Force Base in Ohio.
Each solar flare is like a snowflake — every single flare is unique.
Kara kniezewski
Air Force Institute of Technology
“The Sun’s corona is a dynamic environment, and each solar flare is like a snowflake — every single flare is unique,” said team member Kara Kniezewski, a graduate student at the Air Force Institute of Technology and lead author of the paper. “We find that searching for periods of ‘chaotic’ behavior in the coronal loop emission, rather than specific trends, provide a much more consistent metric and may also correlate with how strong a flare will be.”
The scientists hope their findings about coronal loops can eventually be used to help keep astronauts, spacecraft, electrical grids, and other assets safe from the harmful radiation that accompanies solar flares. For example, an automated system could look for brightness changes in coronal loops in real-time images from the Solar Dynamics Observatory and issue alerts.
“Previous work by other researchers reports some interesting prediction metrics,” said co-author Vadim Uritsky of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the Catholic University of Washington in D.C. “We could build on this and come up with a well-tested and, ideally, simpler indicator ready for the leap from research to operations.”
By Vanessa Thomas
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Jan 15, 2025 Related Terms
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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
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
A digital rendering of the Starlab, which includes a large habitation and laboratory module with a smaller service module for power and propulsion.Credits: Starlab A NASA-funded commercial space station, Starlab, recently completed four key developmental milestones, marking substantial progress in the station’s design and operational readiness.
The four milestones are part of a NASA Space Act Agreement awarded in 2021 and focused on reviews of the habitat structural test article preliminary design, systems integration, integrated operations, and a habitat structural test plan.
“These milestone achievements are great indicators to reflect Starlab’s commitment to the continued efforts and advancements of their commercial destination,” said Angela Hart, program manager for NASA’s Commercial Low Earth Orbit Development Program. “As we look forward to the future of low Earth orbit, every successful milestone is one step closer to creating a dynamic and robust commercialized low Earth orbit.”
The commercial space station is designed to launch on a single flight and includes a large habitation and laboratory module with a smaller service module for power and propulsion.
Earlier this year, Starlab Space completed a structural test article preliminary design review, supported by NASA. The structural test article is an engineering development unit of the station’s habitation module, which is where astronauts will spend most of their time living and working aboard the future commercial destination. An engineering development unit is a physical model that is used to test and verify the design of a project, such as a space station.
A digital rendering of the Starlab free-flying commercial destination, which continues to be developed as part of a Space Act Agreement with NASACredits: Starlab Starlab also recently shared a test plan for the structural test article, which included defining qualification tests of the development unit from welding verifications to proof pressure and static load testing, among others. During proof pressure tests, a spacecraft component or system is pressurized to a significantly higher than normal operating pressure to verify its structural integrity, and a static load test measures the response of a component or system under an applied load.
In addition, Starlab completed integration operations and systems integration reviews. These reviews included updates on system and station architecture, segment interfaces, and program goals, as well as a comprehensive look into the program’s requirements.
Starlab also is set to complete a preliminary design review and phase 1 safety review by the end of the year. This review is meant to demonstrate that the station’s design meets system requirements, including human spaceflight verification, with acceptable risk. The safety review will summarize the current design and general safety approach for the destination.
NASA is supporting the design and development of multiple commercial space stations, including Starlab, through funded and unfunded agreements. The current design and development phase will be followed by the procurement of services from one or more companies, where NASA aims to be one of many customers for low Earth orbit destinations.
NASA’s low Earth orbit microgravity strategy builds on the agency’s extensive human spaceflight experience to advance future scientific and exploration goals. As the International Space Station nears the end of operations, NASA plans to transition to a new low Earth orbit model to continue leveraging microgravity benefits. Through commercial partnerships, NASA aims to maintain its leadership in microgravity research and ensure continued benefits for humanity.
Learn more about NASA’s low Earth orbit microgravity strategy at:
https://www.nasa.gov/leomicrogravitystrategy
News Media Contacts:
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By NASA
Hubble Space Telescope Home NASA’s Hubble Sees… Hubble Space Telescope Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts E-books Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More Online Activities 5 Min Read NASA’s Hubble Sees Aftermath of Galaxy’s Scrape with Milky Way
This artist’s concept shows a closeup of the Large Magellanic Cloud, a dwarf galaxy that is one of the Milky Way galaxy’s nearest neighbors. Credits:
NASA, ESA, Ralf Crawford (STScI) A story of survival is unfolding at the outer reaches of our galaxy, and NASA’s Hubble Space Telescope is witnessing the saga.
The Large Magellanic Cloud, also called the LMC, is one of the Milky Way galaxy’s nearest neighbors. This dwarf galaxy looms large on the southern nighttime sky at 20 times the apparent diameter of the full Moon.
Many researchers theorize that the LMC is not in orbit around our galaxy, but is just passing by. These scientists think that the LMC has just completed its closest approach to the much more massive Milky Way. This passage has blown away most of the spherical halo of gas that surrounds the LMC.
Now, for the first time, astronomers been able to measure the size of the LMC’s halo – something they could do only with Hubble. In a new study to be published in The Astrophysical Journal Letters, researchers were surprised to find that it is so extremely small, about 50,000 light-years across. That’s around 10 times smaller than halos of other galaxies that are the LMC’s mass. Its compactness tells the story of its encounter with the Milky Way.
“The LMC is a survivor,” said Andrew Fox of AURA/STScI for the European Space Agency in Baltimore, who was principal investigator on the observations. “Even though it’s lost a lot of its gas, it’s got enough left to keep forming new stars. So new star-forming regions can still be created. A smaller galaxy wouldn’t have lasted – there would be no gas left, just a collection of aging red stars.”
This artist’s concept shows the Large Magellanic Cloud, or LMC, in the foreground as it passes through the gaseous halo of the much more massive Milky Way galaxy. The encounter has blown away most of the spherical halo of gas that surrounds the LMC, as illustrated by the trailing gas stream reminiscent of a comet’s tail. Still, a compact halo remains, and scientists do not expect this residual halo to be lost. The team surveyed the halo by using the background light of 28 quasars, an exceptionally bright type of active galactic nucleus that shines across the universe like a lighthouse beacon. Their light allows scientists to “see” the intervening halo gas indirectly through the absorption of the background light. The lines represent the Hubble Space Telescope’s view from its orbit around Earth to the distant quasars through the LMC’s gas. NASA, ESA, Ralf Crawford (STScI)
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Though quite a bit worse for wear, the LMC still retains a compact, stubby halo of gas – something that it wouldn’t have been able to hold onto gravitationally had it been less massive. The LMC is 10 percent the mass of the Milky Way, making it heftier than most dwarf galaxies.
“Because of the Milky Way’s own giant halo, the LMC’s gas is getting truncated, or quenched,” explained STScI’s Sapna Mishra, the lead author on the paper chronicling this discovery. “But even with this catastrophic interaction with the Milky Way, the LMC is able to retain 10 percent of its halo because of its high mass.”
A Gigantic Hair Dryer
Most of the LMC’s halo was blown away due to a phenomenon called ram-pressure stripping. The dense environment of the Milky Way pushes back against the incoming LMC and creates a wake of gas trailing the dwarf galaxy – like the tail of a comet.
“I like to think of the Milky Way as this giant hairdryer, and it’s blowing gas off the LMC as it comes into us,” said Fox. “The Milky Way is pushing back so forcefully that the ram pressure has stripped off most of the original mass of the LMC’s halo. There’s only a little bit left, and it’s this small, compact leftover that we’re seeing now.”
As the ram pressure pushes away much of the LMC’s halo, the gas slows down and eventually will rain into the Milky Way. But because the LMC has just gotten past its closest approach to the Milky Way and is moving outward into deep space again, scientists do not expect the whole halo will be lost.
Only with Hubble
To conduct this study, the research team analyzed ultraviolet observations from the Mikulski Archive for Space Telescopes at STScI. Most ultraviolet light is blocked by the Earth’s atmosphere, so it cannot be observed with ground-based telescopes. Hubble is the only current space telescope tuned to detect these wavelengths of light, so this study was only possible with Hubble.
The team surveyed the halo by using the background light of 28 bright quasars. The brightest type of active galactic nucleus, quasars are believed to be powered by supermassive black holes. Shining like lighthouse beacons, they allow scientists to “see” the intervening halo gas indirectly through the absorption of the background light. Quasars reside throughout the universe at extreme distances from our galaxy.
This artist’s concept illustrates the Large Magellanic Cloud’s (LMC’s) encounter with the Milky Way galaxy’s gaseous halo. In the top panel, at the middle of the right side, the LMC begins crashing through our galaxy’s much more massive halo. The bright purple bow shock represents the leading edge of the LMC’s halo, which is being compressed as the Milky Way’s halo pushes back against the incoming LMC. In the middle panel, part of the halo is being stripped and blown back into a streaming tail of gas that eventually will rain into the Milky Way. The bottom panel shows the progression of this interaction, as the LMC’s comet-like tail becomes more defined. A compact LMC halo remains. Because the LMC is just past its closest approach to the Milky Way and is moving outward into deep space again, scientists do not expect the residual halo will be lost. NASA, ESA, Ralf Crawford (STScI)
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The scientists used data from Hubble’s Cosmic Origins Spectrograph (COS) to detect the presence of the halo’s gas by the way it absorbs certain colors of light from background quasars. A spectrograph breaks light into its component wavelengths to reveal clues to the object’s state, temperature, speed, quantity, distance, and composition. With COS, they measured the velocity of the gas around the LMC, which allowed them to determine the size of the halo.
Because of its mass and proximity to the Milky Way, the LMC is a unique astrophysics laboratory. Seeing the LMC’s interplay with our galaxy helps scientists understand what happened in the early universe, when galaxies were closer together. It also shows just how messy and complicated the process of galaxy interaction is.
Looking to the Future
The team will next study the front side of the LMC’s halo, an area that has not yet been explored.
“In this new program, we are going to probe five sightlines in the region where the LMC’s halo and the Milky Way’s halo are colliding,” said co-author Scott Lucchini of the Center for Astrophysics | Harvard & Smithsonian. “This is the location where the halos are compressed, like two balloons pushing against each other.”
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contacts:
Claire Andreoli (claire.andreoli@nasa.gov)
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Last Updated Nov 14, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
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