Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
M83: The Southern Pinwheel
Explanation: Beautiful and bright spiral galaxy M83 lies some twelve million light-years away, near the southeastern tip of the very long constellation Hydra. Prominent spiral arms traced by dark dust lanes and blue star clusters lend this galaxy its popular name, the Southern Pinwheel. Still, reddish star forming regions that dot this cosmic pinwheel’s spiral arms have suggested another nickname, the Thousand-Ruby Galaxy. A mere 40,000 light-years across, smaller than the Milky Way, M83 is a member of a group of galaxies that includes active galaxy Centaurus A. In fact, the core of M83 itself is bright at x-ray energies, showing a high concentration of neutron stars and black holes left from an intense burst of star formation. This sharp, groundbased telescopic view also features foreground Milky Way stars and distant background galaxies.
The Republic of Djibouti will sign the Artemis Accords during a ceremony at 11 a.m. EDT, Monday, Sept. 14, at NASA Headquarters in Washington, becoming the 72nd country signatory.
NASA Deputy Administrator Matt Anderson will host Ambassador of Djibouti to the United States Mohamed Siad Douale for the ceremony, together with U.S. State Department Assistant Secretary for African Affairs Frank Garcia.
In 2020, during the first Trump Administration, the United States, led by NASA and the State Department, joined with seven other founding nations to establish the Artemis Accords, responding to the growing interest in lunar activities by both governments and private companies.
The accords introduced the first set of practical principles aimed at enhancing the safety, transparency, and coordination of civil space exploration on the Moon, Mars, and beyond.
NASA’s Life-Saving Technology Where Cell Signals Can’t Go
Rescued after more than four hours in the water, Easton Barrett (center, red shorts) and his friend were picked up by the U.S. Coast Guard thanks to a personal locator beacon (PLB). The devise sends a distress signal to satellites that are relayed back to Earth, launching a rescue operation.
Credits: Easton Barrett
Memorial Day weekend 2024 started with a blue sky and a mild three- to four-foot chop in the water off the Gulf Coast of Mississippi — a perfect day for a fishing competition. A team of five was about 40 miles offshore checking their sonar, and 30 seconds later the boat was gone. They were in the water struggling to pull on life jackets and grab the coolers as they bobbed up. When a boat sinks, survivors can be virtually invisible amid the vast expanse of water.
When their fishing trip went wrong, Easton Barrett had the only mobile phone and no cell service. He recorded a brief farewell, planning to put his phone in a cooler in hopes someone would find it.
Another team member activated a personal locator beacon (PLB) that had been stowed at the last minute, which sent a distress signal to the Search and Rescue Satellite-Aided Tracking (SARSAT) technology carried by multiple satellites in Earth orbit. In the SARSAT system, developed partly by NASA, an emergency signal containing the transmitter’s location is directed to the nearest available ground station.
406 megahertz is the wavelength dedicated for PLB distress signals. On the annual 406 Day, Easton Barrett posts videos and messages on his social media accounts to help raise awareness about essential survival gear.
Credit: ACR
A mission control center then alerts rescue coordination centers to mobilize search and rescue crews. For Barrett and his crew, that was a Florida Coast Guard boat.
“Ever since, I have tried to teach others about safety on the water and in the outdoors by using a PLB,” said Barrett. “If that will save one life, it’s worth the effort.”
A beacon like the one that saved his crew, a registered ResQLink PLB developed by ACR Electronics Inc. of Fort Lauderdale, Florida, also notifies the device owner’s emergency contact, indicating a distress call was activated. All emergency beacons must meet the same requirements to ensure they work when needed. Every rugged, buoyant, handheld devices have a five- to 10-year battery life.
SARSAT began operations in 1982, becoming an international collaboration in 1985. The flight and ground technologies used globally were originally developed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Now there are 62 satellites in the program and 45 nations contributing services, from operating ground stations to providing rescue crews. More than 63,000 lives have been saved.
Turning on a ResQLink View PLB from ACR Electronics will automatically “ping” orbiting satellites that send location and GPS information
to the nearest search and rescue station. Whether on land or water, the appropriate resources will be dispatched to help anyone in distress
anywhere in the world.
Credit: ACR
SARSAT by the Numbers
The Search and Rescue Satellite-Aided Tracking system developed over several decades by NASA and other government agencies saves lives on land or at sea.
1982 — the start of U.S. operations
1985 — the start of international operations
62 operational satellites
45 nations contributing services
63,000+ lives saved
One rescue in 2024 demonstrates how it all comes together.
40 miles off the Mississippi Gulf Coast
5-person team participating in a fishing competition
30 seconds for a boat to sink
200 pounds of bait dumped to make a cooler buoyant
3 close encounters with wildlife, likely sharks and eels
4 hours in the water
1 personal locator beacon
1 Coast Guard rescue boat
5 lives saved
“If it has anything to do with NASA, it's got to be awesome.”
A dust storm obscures the ground in Mali in this image, acquired with the MODIS (Moderate Resolution Imaging Spectroradiometer) on NASA’s Terra satellite on September 5, 2026.
NASA Earth Observatory/Lauren Dauphin
As summer winds down in West Africa, so does much of the region’s dust activity. Dust storms can still occur, though, as one did in early September 2026, when a plume covered parts of Mali and neighboring countries.
The MODIS (Moderate Resolution Imaging Spectroradiometer) on NASA’s Terra satellite captured this image on September 5, 2026. According to Tianle Yuan, an atmospheric scientist at NASA’s Goddard Space Flight Center, storms like this one are often associated with haboobs—powerful dust storms driven by strong convective winds.
In the days after this image was acquired, a wider satellite view showed aerosols from the region moving westward and spilling over the Atlantic Ocean. However, a full transatlantic crossing is unlikely. Such crossings are more common from late spring through summer, when the Saharan Air Layer—a dry, dusty mass of air—can carry dust thousands of miles westward from Africa, riding high in the atmosphere.
Looking ahead, the developing El Niño could reshape these patterns. For instance, Yuan noted that the phenomenon can affect dust over the Sahel and Mali by shifting the Intertropical Convergence Zone and altering convection patterns, though the influence cuts both ways. Drier conditions can leave more loose sediment available for winds to lift, but less convective activity also means fewer intense storms (haboobs) to kick up large dust plumes in the first place. “The connection can be real,” Yuan said, “but hard to pin down for individual events.”
NASA Earth Observatory image by Lauren Dauphin, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview.Story by Kathryn Hansen.
A NASA Launch Services (NLS) II contract has been awarded by the agency to Relativity Space Inc., and its Terran R launch service in accordance with the contract’s on-ramp provision. The Terran R launch service will be available to NASA’s launch services to use for future missions.
The NLS II contracts are multiple-award, indefinite-delivery/indefinite-quantity contracts with an ordering period through June 2030 and an overall period of performance through December 2032. The NLS II contracts include an on-ramp provision that provides an opportunity annually for new launch service providers to compete for future missions and allows existing contractors to introduce launch vehicles not currently on their NLS II contracts.
The NLS II contracts support the goals and objectives of the agency’s Human Spaceflight Mission Directorate, Science Mission Directorate, and the Research and Technology Mission Directorate. Under the contract, NASA also can provide launch services to other government agencies, such as the National Oceanic and Atmospheric Administration.
NASA’s Launch Services Program Office at the agency’s Kennedy Space Center in Florida manages the NLS II contracts. For more information about NASA, visit:
X-ray: NASA/CXC/Univ. of Alabama/M. Muhibullah et al.; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/N. Wolk
Using NASA’s Chandra X-ray Observatory, scientists have discovered a new class of objects behaving unlike any they have seen before. Astronomers suggest these newly spotted objects in other galaxies may help solve not one, but two long-standing questions in astrophysics.
These mysterious objects give off unusually low-energy X-rays but intense levels of ultraviolet radiation. This discovery is featured in a paper published Wednesday in Nature Astronomy.
“We’ve never encountered a group of objects that act like this,” said Mustafa Muhibullah of the University of Alabama who led the study. “Of course, the next step was to try to figure out what these things are.”
M101 with illustrated circles calling out seven of the newly-discovered objects.
X-ray: NASA/CXC/Univ. of Alabama/M. Muhibullah et al.; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/N. Wolk
The researchers found a total of 84 of these “hypersoft X-ray sources” – so named because they give such low-energy X-rays – in the six different galaxies they searched, using data openly available to the public in the Chandra archive. Two of the galaxies are spirals, M31 (the Andromeda galaxy) and M101 (the Pinwheel galaxy), while the other four are ellipticals. They found hypersoft X-ray sources both in regions of active star formation and areas where there are older stars.
The team spotted the sources by finding objects that appeared in Chandra images taken at the lowest X-ray energies but vanished in higher-energy images. That means these objects give off far more low-energy X-rays than high-energy ones. Because low-energy X-rays border energetic ultraviolet radiation on the electromagnetic spectrum, the researchers determined that these sources are producing large amounts of energetic ultraviolet radiation as well.
It is unclear what types of objects are responsible for these low-energy X-rays and intense ultraviolet radiation. The team thinks they most likely involve a black hole, neutron star, or white dwarf pulling material from a companion star. The material pulled from the companion star is heated up to produce X-rays before falling onto the white dwarf or neutron star, or into the black hole. Such binary systems have been seen before, but not with such bright ultraviolet radiation and low-energy X-rays.
The discovery suggests that there may be large populations of binary systems with energetic ultraviolet radiation that have been undetected until now.
“These clandestine X-ray sources are actually among the most energetic objects in galaxies, and they could be solving two cosmic mysteries at once,” said Muhibullah.
Scientists think that some white dwarf systems pulling material from companion stars may eventually explode as a supernova – known as a Type Ia – that is critical for measuring the expansion of the universe. These supernovae played a key role in discovering that this expansion is accelerating. Astronomers have been looking for the stars that turn into Type Ia supernovae for many years, so far without success.
“If we could find a way to spot these Type Ia supernova explosions before they go off, that would be really important,” said co-author Jimmy Irwin, also of the University of Alabama. “Right now, we study them after they’ve exploded, and astronomers have struggled to understand what is actually ignited.”
The other mystery these hypersoft X-ray sources might explain is what strips electrons from gas between the stars in some galaxies. This stripping of electrons is important to probe because it can affect how quickly stars form and influence the life cycles of galaxies. Hot, massive stars play a role, but they do not completely explain what is causing this stripping. The intense levels of ultraviolet radiation from the hypersoft X-ray sources may play a vital role.
Why were these hypersoft X-ray sources not found until now? In addition to the low-energy X-ray output, which is very difficult for X-ray telescopes to detect, the high-energy ultraviolet radiation is readily absorbed by helium and hydrogen gas that fills the space between the stars, creating a nearly impenetrable barrier to look through.
“By combing through the Chandra archive, we were able to eliminate what used to be a blind spot for telescopes,” said co-author Rosanne Di Stefano of the Center for Astrophysics | Harvard & Smithsonian. “That’s how we found what appears to be a new class of cosmic objects with remarkable qualities.”
NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
This release features a composite image of a spiral galaxy, M101; one of six identified galaxies housing a new class of mysterious objects that give off unusually low-energy X-rays.
In this composite image, M101 faces us directly. It has multiple arms in shades of purple, spiraling clockwise around a golden yellow core. Scattered along and between the arms are scores of tiny specks in white and purple. Most of those specks are pairs of stars, but seven of them are a mystery.
To casual observers, the unusual objects are visually indistinguishable from the other specks of light in the galaxy. An annotated version of the composite image is included in this release, with red circles around the mysterious specks for easy identification.
These mystery specks behave like no other class of object discovered before. The curious objects give off X-rays of such low energy, they in fact produce large amounts of ultraviolet radiation, as UV radiation borders X-rays on the electromagnetic spectrum. Searching images of galaxies with low-energy X-rays in the Chandra Observatory archive, scientists have found a total of 84 such objects spread across M101 and five other galaxies. They have dubbed these mysterious objects “hypersoft X-ray sources.”
Curiosity Blog, Sols 4995-5001: 5,000 (Martian) Days on Mars
NASA’s Mars rover Curiosity acquired this image along Chocolatal ripple using its Right Navigation Camera on Aug. 28, 2026 — Sol 4998, or Martian day 4,998 of the Mars Science Laboratory mission — at 13:58:36 UTC.
NASA/JPL-Caltech
Written by William Farrand, Senior Research Scientist, Space Science Institute
Earth planning date: Friday, Aug. 28, 2026
The span of sols spanned by this blog post is noteworthy in several ways. First, Curiosity became a world-class (for Mars at least) mountaineer by passing the 1 kilometer mark of elevation from its landing site on the floor of Gale crater. This writer was on the Mars Exploration Rover science team and we were excited when the Spirit rover got to the top of Husband Hill in Gusev crater in August 2005. But that was a climb of 106 meters (about 348 feet) above its landing site, and Curiosity has passed 1000 meters (about 0.62 miles).
Second, Saturday, Aug. 29, marked 5,000 Martian days (or sols) since Curiosity landed on Mars (that’s more than 5,137 Earth days, because a day on Mars lasts 24.6 hours). Congratulations are in order to the engineers and scientists who have made this landmark possible.
Finally, in terms of its science activities Curiosity is examining a wind-formed, long, narrow, large ripple which has been named “Chocolatal.” Further examination will help determine if this feature could be classified as a “transverse aeolian ridge” or TAR. TARs have been observed across the Martian surface based on orbital imaging. The long axis of a TAR is oriented perpendicular to the local predominant wind direction. While this is not the first potential TAR that has been examined by Curiosity, its location, higher on the slopes of Mount Sharp invites questions about whether it will be composed of the same types of granular materials found in the lower TARs, or whether it has a different range of grain sizes and/or layering.
Other questions to be addressed include how the ridge formed, whether it is active, how it has migrated, and, if it is immobile, then how has it stabilized?
At the start of the planning week, Curiosity was en route to the sand ripple and encountered interesting science targets along the way. In Monday’s two-sol plan, in-situ examinations were planned of the light-toned bedrock occurring along the rover’s path. Some of the rocks encountered near the rover had dark-toned thick coatings or remnant layers, and these were targeted for chemical examination by the rover’s ChemCam Laser Induced Breakdown Spectroscopy (LIBS) instrument. Mastcam and ChemCam Remote Micro Imager (RMI) mosaics were planned, for layers in buttes along the rover’s path, and on more distant sets of sand ripples.
A midweek planning session took advantage of the last drive, leaving the rover only a few meters from Chocolatal. ChemCam was able to target sand at the base of Chocolatal as well as nearby bedrock. Stand-off Mastcam high-resolution image mosaics of the ripple were also targeted. The drive planned midweek took the rover right into Chocolatal with one of its wheels and then backing off a little, so in the end-of-week plan, contact science could be planned within the trenched region.
The final planning session of the week, which extended through the landmark Sol 5000, involved MAHLI mosaics of the right wall of the trench to see if there is layering, and to assess any variations in grain size. It’s noteworthy that these MAHLI mosaics are being named in honor of our late colleague Paul Geissler, who was one of the foremost experts on the study of Martian TARs and who was working with the MAHLI team before his untimely passing earlier in the year. In-situ APXS measurements were planned of the coarse-grained surface of the ripple, and ChemCam LIBS measurements were planned on the top of Chocolatal, a sinuous feature looking like a “mohawk” haircut (see the accompanying image). LIBS was also planned on a dark band on its flank and at the back of the scuff/trench. Other activities in the three-sol plan included Mastcam mosaics, an AM Navcam dust-devil survey, Navcam suprahorizon survey, and APXS atmospheric measurements.
With 5000 sols of outstanding scientific accomplishments, the Curiosity science and engineering team looks forward to the next 5000 sols.
