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High Velocity Clouds Found to Dwell in Milky Way's Halo
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By NASA
Explore Hubble Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered AI and Hubble Science Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts Multimedia Images Videos Sonifications Podcasts e-Books Online Activities 3D Hubble Models Lithographs Fact Sheets Posters Hubble on the NASA App Glossary News Hubble News Social Media Media Resources More 35th Anniversary Online Activities 2 min read
Hubble Examines Low Brightness, High Interest Galaxy
This NASA/ESA Hubble Space Telescope image features a portion of the spiral galaxy NGC 45. ESA/Hubble & NASA, D. Calzetti, R. Chandar; Acknowledgment: M. H. Özsaraç This NASA/ESA Hubble Space Telescope image zooms in on the feathery spiral arms of the galaxy NGC 45, which lies just 22 million light-years away in the constellation Cetus (the Whale).
The portrait uses data drawn from two complementary observing programs. The first took a broad view of 50 nearby galaxies, leveraging Hubble’s ability to observe ultraviolet through visible into near-infrared light to study star formation in these galaxies. The second program examined many of the same nearby galaxies as the first, narrowing in on a particular wavelength of red light called H-alpha. Star-forming nebulae are powerful producers of H-alpha light, and several of these regions are visible across NGC 45 as bright pink-red patches.
These observing programs aimed to study star formation in galaxies of different sizes, structures, and degrees of isolation — and NGC 45 is a particularly interesting target. Though it may appear to be a regular spiral galaxy, NGC 45 is a remarkable type called a low surface brightness galaxy.
Low surface brightness galaxies are fainter than the night sky itself, making them incredibly difficult to detect. They appear unexpectedly faint because they have relatively few stars for the volume of gas and dark matter they carry. In the decades since astronomers serendipitously discovered the first low surface brightness galaxy in 1986, researchers have learned that 30–60% of all galaxies may fall into this category. Studying these hard-to-detect galaxies is key to understanding how galaxies form and evolve, and Hubble’s sensitive instruments are equal to the task.
Text Credit: ESA/Hubble
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Last Updated Aug 14, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Astrophysics Astrophysics Division Galaxies Galaxies, Stars, & Black Holes Hubble Space Telescope Spiral Galaxies Star-forming Nebulae Stars The Universe Keep Exploring Discover More Topics From Hubble
35 Years of Hubble Images
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By NASA
4 min read
NASA, JAXA XRISM Satellite X-rays Milky Way’s Sulfur
An international team of scientists have provided an unprecedented tally of elemental sulfur spread between the stars using data from the Japan-led XRISM (X-ray Imaging and Spectroscopy Mission) spacecraft.
Astronomers used X-rays from two binary star systems to detect sulfur in the interstellar medium, the gas and dust found in the space between stars. It’s the first direct measurement of both sulfur’s gas and solid phases, a unique capability of X-ray spectroscopy, XRISM’s (pronounced “crism”) primary method of studying the cosmos.
“Sulfur is important for how cells function in our bodies here on Earth, but we still have a lot of questions about where it’s found out in the universe,” said Lía Corrales, an assistant professor of astronomy at the University of Michigan in Ann Arbor. “Sulfur can easily change from a gas to a solid and back again. The XRISM spacecraft provides the resolution and sensitivity we need to find it in both forms and learn more about where it might be hiding.”
A paper about these results, led by Corrales, published June 27 in the Publications of the Astronomical Society of Japan.
Watch to learn how the XRISM (X-ray Imaging and Spectroscopy Mission) satellite took an unprecidented look at our galaxy’s sulfur. XRISM is led by JAXA (Japan Aerospace Exploration Agency) in collaboration with NASA, along with contributions from ESA (European Space Agency).
NASA’s Goddard Space Flight Center Using ultraviolet light, researchers have found gaseous sulfur in the space between stars. In denser parts of the interstellar medium, such as the molecular clouds where stars and planets are born, this form of sulfur quickly disappears.
Scientists assume the sulfur condenses into a solid, either by combining with ice or mixing with other elements.
When a doctor performs an X-ray here on Earth, they place the patient between an X-ray source and a detector. Bone and tissue absorb different amounts of the light as it travels through the patient’s body, creating contrast in the detector.
To study sulfur, Corrales and her team did something similar.
They picked a portion of the interstellar medium with the right density — not so thin that all the X-rays would pass through unchanged, but also not so dense that they would all be absorbed.
Then the team selected a bright X-ray source behind that section of the medium, a binary star system called GX 340+0 located over 35,000 light-years away in the southern constellation Scorpius.
This composite shows a section of the interstellar medium scientists X-rayed for sulfur using the Japan-led XRISM (X-ray Imaging and Spectroscopy Mission). X-ray binary GX 340+0 is the blue dot in the center. The composite contains a blend of imagery in X-rays (represented in deep blue), infrared, and optical light.DSS/DECaPS/eRosita/NASA’s Goddard Space Flight Center This composite shows a section of the interstellar medium scientists X-rayed for sulfur using the Japan-led XRISM (X-ray Imaging and Spectroscopy Mission). The X-ray binary 4U 1630–472 is highlighted at the center. The composite contains a blend of imagery in X-rays (represented in deep blue), infrared, and optical light.DSS/DECaPS/eRosita/NASA’s Goddard Space Flight Center Using the Resolve instrument on XRISM, the scientists were able to measure the energy of GX 340+0’s X-rays and determined that sulfur was present not only as a gas, but also as a solid, possibly mixed with iron.
“Chemistry in environments like the interstellar medium is very different from anything we can do on Earth, but we modeled sulfur combined with iron, and it seems to match what we’re seeing with XRISM,” said co-author Elisa Costantini, a senior astronomer at the Space Research Organization Netherlands and the University of Amsterdam. “Our lab has created models for different elements to compare with astronomical data for years. The campaign is ongoing, and soon we’ll have new sulfur measurements to compare with the XRISM data to learn even more.”
Iron-sulfur compounds are often found in meteorites, so scientists have long thought they might be one way sulfur solidifies out of molecular clouds to travel through the universe.
In their paper, Corrales and her team propose a few compounds that would match XRISM’s observations — pyrrhotite, troilite, and pyrite, which is sometimes called fool’s gold.
The researchers were also able to use measurements from a second X-ray binary called 4U 1630-472 that helped confirm their findings.
“NASA’s Chandra X-ray Observatory has previously studied sulfur, but XRISM’s measurements are the most detailed yet,” said Brian Williams, the XRISM project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Since GX 340+0 is on the other side of the galaxy from us, XRISM’s X-ray observations are a unique probe of sulfur in a large section of the Milky Way. There’s still so much to learn about the galaxy we call home.”
XRISM is led by JAXA (Japan Aerospace Exploration Agency) in collaboration with NASA, along with contributions from ESA (European Space Agency). NASA and JAXA developed Resolve, the mission’s microcalorimeter spectrometer.
Download images and videos through NASA’s Scientific Visualization Studio. By Jeanette Kazmierczak
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
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Last Updated Jul 23, 2025 EditorJeanette Kazmierczak Related Terms
Goddard Space Flight Center Astrophysics Stars The Universe X-ray Astronomy X-ray Binaries XRISM (X-Ray Imaging and Spectroscopy Mission) View the full article
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By USH
Some time ago, while visiting the Grand Canyon in Arizona, a photographer captured several short video clips of the landscape. In one of those clips, an unusual anomaly was discovered.
The original footage is only 1.9 seconds long, but within that moment, something remarkable was caught on camera. An unidentified aerial phenomenon (UAP) flashed across the frame, visible for less than a second, only noticeable when the video was paused and analyzed frame by frame.
The object was moving at an astonishing speed, covering an estimated two to three miles in under a second, far beyond the capabilities of any conventional aircraft, drone, or helicopter.
This isn’t the first time such anomalous flying objects have been observed. Their characteristics defy comparison with known aerial technology.
Some skeptics have proposed that the object might have been a rock thrown into the canyon from behind the camera. However, that explanation seems unlikely. Most people can only throw objects at speeds of 10 to 20 meters per second (approximately 22 to 45 mph). The velocity of this object far exceeded that range, and its near-invisibility in the unedited video suggests it was moving much faster.
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By NASA
5 min read
NASA Launching Rockets Into Radio-Disrupting Clouds
NASA is launching rockets from a remote Pacific island to study mysterious, high-altitude cloud-like structures that can disrupt critical communication systems. The mission, called Sporadic-E ElectroDynamics, or SEED, opens its three-week launch window from Kwajalein Atoll in the Marshall Islands on Friday, June 13.
The atmospheric features SEED is studying are known as Sporadic-E layers, and they create a host of problems for radio communications. When they are present, air traffic controllers and marine radio users may pick up signals from unusually distant regions, mistaking them for nearby sources. Military operators using radar to see beyond the horizon may detect false targets — nicknamed “ghosts” — or receive garbled signals that are tricky to decipher. Sporadic-E layers are constantly forming, moving, and dissipating, so these disruptions can be difficult to anticipate.
An animated illustration depicts Sporadic-E layers forming in the lower portions of the ionosphere, causing radio signals to reflect back to Earth before reaching higher layers of the ionosphere. NASA’s Goddard Space Flight Center/Conceptual Image Lab Sporadic-E layers form in the ionosphere, a layer of Earth’s atmosphere that stretches from about 40 to 600 miles (60 to 1,000 kilometers) above sea level. Home to the International Space Station and most Earth-orbiting satellites, the ionosphere is also where we see the greatest impacts of space weather. Primarily driven by the Sun, space weather causes myriad problems for our communications with satellites and between ground systems. A better understanding of the ionosphere is key to keeping critical infrastructure running smoothly.
The ionosphere is named for the charged particles, or ions, that reside there. Some of these ions come from meteors, which burn up in the atmosphere and leave traces of ionized iron, magnesium, calcium, sodium, and potassium suspended in the sky. These “heavy metals” are more massive than the ionosphere’s typical residents and tend to sink to lower altitudes, below 90 miles (140 kilometers). Occasionally, they clump together to create dense clusters known as Sporadic-E layers.
The Perseids meteor shower peaks in mid-August. Meteors like these can deposit metals into Earth’s ionosphere that can help create cloud-like structures called Sporadic-E layers. NASA/Preston Dyches “These Sporadic-E layers are not visible to naked eye, and can only be seen by radars. In the radar plots, some layers appear like patchy and puffy clouds, while others spread out, similar to an overcast sky, which we call blanketing Sporadic-E layer” said Aroh Barjatya, the SEED mission’s principal investigator and a professor of engineering physics at Embry-Riddle Aeronautical University in Daytona Beach, Florida. The SEED team includes scientists from Embry-Riddle, Boston College in Massachusetts, and Clemson University in South Carolina.
“There’s a lot of interest in predicting these layers and understanding their dynamics because of how they interfere with communications,” Barjatya said.
A Mystery at the Equator
Scientists can explain Sporadic-E layers when they form at midlatitudes but not when they appear close to Earth’s equator — such as near Kwajalein Atoll, where the SEED mission will launch.
In the Northern and Southern Hemispheres, Sporadic-E layers can be thought of as particle traffic jams.
Think of ions in the atmosphere as miniature cars traveling single file in lanes defined by Earth’s magnetic field lines. These lanes connect Earth end to end — emerging near the South Pole, bowing around the equator, and plunging back into the North Pole.
A conceptual animation shows Earth’s magnetic field. The blue lines radiating from Earth represent the magnetic field lines that charged particles travel along. NASA’s Goddard Space Flight Center/Conceptual Image Lab At Earth’s midlatitudes, the field lines angle toward the ground, descending through atmospheric layers with varying wind speeds and directions. As the ions pass through these layers, they experience wind shear — turbulent gusts that cause their orderly line to clump together. These particle pileups form Sporadic-E layers.
But near the magnetic equator, this explanation doesn’t work. There, Earth’s magnetic field lines run parallel to the surface and do not intersect atmospheric layers with differing winds, so Sporadic-E layers shouldn’t form. Yet, they do — though less frequently.
“We’re launching from the closest place NASA can to the magnetic equator,” Barjatya said, “to study the physics that existing theory doesn’t fully explain.”
Taking to the Skies
To investigate, Barjatya developed SEED to study low-latitude Sporadic-E layers from the inside. The mission relies on sounding rockets — uncrewed suborbital spacecraft carrying scientific instruments. Their flights last only a few minutes but can be launched precisely at fleeting targets.
Beginning the night of June 13, Barjatya and his team will monitor ALTAIR (ARPA Long-Range Tracking and Instrumentation Radar), a high-powered, ground-based radar system at the launch site, for signs of developing Sporadic-E layers. When conditions are right, Barjatya will give the launch command. A few minutes later, the rocket will be in flight.
The SEED science team and mission management team in front of the ARPA Long-Range Tracking and Instrumentation Radar (ALTAIR). The SEED team will use ALTAIR to monitor the ionosphere for signs of Sporadic-E layers and time the launch. U.S. Army Space and Missile Defense Command On ascent, the rocket will release colorful vapor tracers. Ground-based cameras will track the tracers to measure wind patterns in three dimensions. Once inside the Sporadic-E layer, the rocket will deploy four subpayloads — miniature detectors that will measure particle density and magnetic field strength at multiple points. The data will be transmitted back to the ground as the rocket descends.
On another night during the launch window, the team will launch a second, nearly identical rocket to collect additional data under potentially different conditions.
Barjatya and his team will use the data to improve computer models of the ionosphere, aiming to explain how Sporadic-E layers form so close to the equator.
“Sporadic-E layers are part of a much larger, more complicated physical system that is home to space-based assets we rely on every day,” Barjatya said. “This launch gets us closer to understanding another key piece of Earth’s interface to space.”
By Miles Hatfield
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Jun 12, 2025 Related Terms
Heliophysics Goddard Space Flight Center Heliophysics Division Ionosphere Missions NASA Centers & Facilities NASA Directorates Science & Research Science Mission Directorate Sounding Rockets Sounding Rockets Program The Solar System The Sun Uncategorized Wallops Flight Facility Weather and Atmospheric Dynamics Explore More
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By NASA
ESA/Hubble & NASA, C. Murray This NASA/ESA Hubble Space Telescope image features a sparkling cloudscape from one of the Milky Way’s galactic neighbors, a dwarf galaxy called the Large Magellanic Cloud. Located 160,000 light-years away in the constellations Dorado and Mensa, the Large Magellanic Cloud is the largest of the Milky Way’s many small satellite galaxies.
This view of dusty gas clouds in the Large Magellanic Cloud is possible thanks to Hubble’s cameras, such as the Wide Field Camera 3 (WFC3) that collected the observations for this image. WFC3 holds a variety of filters, and each lets through specific wavelengths, or colors, of light. This image combines observations made with five different filters, including some that capture ultraviolet and infrared light that the human eye cannot see.
The wispy gas clouds in this image resemble brightly colored cotton candy. When viewing such a vividly colored cosmic scene, it is natural to wonder whether the colors are ‘real’. After all, Hubble, with its 7.8-foot-wide (2.4 m) mirror and advanced scientific instruments, doesn’t bear resemblance to a typical camera! When image-processing specialists combine raw filtered data into a multi-colored image like this one, they assign a color to each filter. Visible-light observations typically correspond to the color that the filter allows through. Shorter wavelengths of light such as ultraviolet are usually assigned blue or purple, while longer wavelengths like infrared are typically red.
This color scheme closely represents reality while adding new information from the portions of the electromagnetic spectrum that humans cannot see. However, there are endless possible color combinations that can be employed to achieve an especially aesthetically pleasing or scientifically insightful image.
Learn how Hubble images are taken and processed.
Text credit: ESA/Hubble
Image credit: ESA/Hubble & NASA, C. Murray
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