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Since their discovery by NASA’s James Webb Space Telescope in 2022, little red dots (LRDs) have been the subject of great interest to astronomers. Understanding the nature of these extremely distant, compact red sources has been a puzzling scientific endeavor.
One popular theory is that little red dots are supermassive black holes known as active galactic nuclei, although they display characteristics unlike nearby active galactic nuclei. While they appear abundant at high redshift early in the universe, they rapidly decrease in number at lower redshifts. (The higher the redshift, the greater the distance the light has traveled across the universe.) This perplexing shift in number raises the question: What happens to little red dots as the universe matures?
A team of researchers led by Pierluigi Rinaldi of the University of Arizona’s Steward Observatory, now at the Space Telescope Science Institute (STScI) in Baltimore, has built upon their previous research in a new study published on July 29 in The Astrophysical Journal and proposed one pathway LRDs can follow as the universe ages: Though they may look like a unique galaxy population, these dots are affected by observational bias — some features just don’t appear at higher redshifts with current technology.

Their conclusions are based on their analysis of lower-redshift spiral galaxy WISEA J123635.56+621424.2, nicknamed the “Saguaro” for its prominent arms, like the cactus native to the Sonoran Desert in the Southwestern United States. A particularly intriguing feature of this redshift 2 galaxy, which corresponds to approximately 3.3 billion years after the big bang, is its little red dot-like center that is reminiscent of the ruby red fruit produced by the desert plant.
“Everything created in the early universe must evolve into something around us. We have had little idea of what LRDs become, but these results finally show us how to find their progeny,” said co-author George Rieke of the University of Arizona. Previous studies by NASA’s retired Spitzer Space Telescope provided the first hint of the dust-obscured, compact galaxy population in the lower-redshift universe that the Saguaro belongs to, paving the way for NASA’s Hubble and James Webb space telescopes’ high-resolution analyses.
“The Saguaro is important because it’s a prototypical little red dot and is one of the few we have found at lower redshift. It can be used to study the pathway of these dots throughout cosmic time,” said Fabio Pacucci of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and a co-author of the study.
Among the thousands of sources Rinaldi looked at across several surveys, the Saguaro was an example of the right place — with one of Webb’s microshutter arrays perfectly framed over the galaxy’s core to take spectroscopic data — and right time — being at lower redshift. To get as broad a view of the spiral galaxy as possible across the electromagnetic spectrum, the team used Hubble’s ultraviolet- and Webb’s infrared-imaging and spectroscopic archival data, respectively.
“Because the Saguaro is at lower redshift, we can see the very beautiful and bright host galaxy in high resolution and detail with Webb and Hubble,” said Zihao Wu of the Harvard-Smithsonian Center for Astrophysics, and a co-author of the study. “Webb’s observations can help us understand how the galaxy and its little red dot-like nucleus are connected.”
The team took multiple approaches to verify that the Saguaro’s compact red nucleus matched the characteristics of a prototypical LRD. In particular, the Hubble and Webb data showed that the nucleus is brighter in both ultraviolet and infrared light than in visible light, just like distant LRDs. The team also carefully disentangled the light emitted from the host and nucleus, and considered the presence of X-ray emission from the source.
Although the majority of little red dots at high redshift are not detectable in X-ray light, NASA’s Chandra X-ray Observatory detected weak X-ray emission from the Saguaro.
“What the X-ray light observations show is that this galaxy has an active galactic nucleus, and a very obscured one at that,” said Carys Gilbert, a Master’s student at the University of Cape Town in South Africa and a co-author of the paper. “It’s not only obscured but also X-ray weak. That kind of combination could explain the lack of X-ray emission that we see from all other little red dots. It fits the puzzle of little red dots nicely.”
In addition to demonstrating how the Saguaro’s central compact red source fits the little red dot criteria, the team synthetically shifted the galaxy to a higher redshift to explore how this galactic environment would appear to observers if located in the early universe. As expected, the Saguaro’s surrounding galactic structure fades so that only the bright, LRD-like source at its center is visible.
“Our theory is that most of these distant sources are affected by this cosmological effect, creating an observational bias,” said Rinaldi. “We simply are not able to sample the immediate environment of high-redshift little red dots because their surroundings are just too faint to be observed even with Webb. Little red dots are far more complex than just being a dot. They’re just the tip of the iceberg — of a supermassive black hole interacting with its nearby surroundings.”

Considering the Saguaro case study, the team believes that LRDs may not be a unique galaxy population, but instead a temporary phase of highly active supermassive black holes. Could this theory be the link between the populous high-redshift little red dots seen by Webb and the local universe?
While the Saguaro is not representative of all LRDs, the team proposes that this is one phase of these compact red sources. To build more confidence, further study of the Saguaro is necessary, as well as seeking other Saguaro-like galaxies at lower redshift. The team also intends to comb through Webb’s bountiful archival data to build a census of little red dots to study how their environments may impact how they mature. These different approaches are all geared to helping uncover the family tree of little red dots.
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
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, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
To learn more about Webb, visit:
To learn more about Hubble, visit:
https://science.nasa.gov/hubble
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Scientists have proposed one pathway little red dots can follow as the universe matures based on their analysis of spiral galaxy WISEA J123635.56+621424.2, nicknamed the “Saguaro.” They suggest little red dots may be a temporary phase of highly active supermassive black holes.

Scientists synthetically shifted the Saguaro, a lower-redshift spiral galaxy, to a higher redshift to find out how it would appear if it was in the early universe. Its compact red appearance suggests that little red dots are a phase of highly active supermassive black holes.
Read more: Webb Science: Galaxies Through Time
Read more: Galaxies Over Time
Explore more: ViewSpace: Connecting Little Red Dots
Watch: Sonification of Gas Velocity Around a Supermassive Black Hole
Watch: JWST Science Simulations: Galaxy Formation
More Webb: News | Images | Science | Home Page
Laura Betz
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
laura.e.betz@nasa.gov
Abigail Major
Space Telescope Science Institute
Baltimore, Maryland
Hannah Braun
Space Telescope Science Institute
Baltimore, Maryland
2026-07-29 13:32

Ray Williams’ progression at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, has uniquely prepared him for his new role.
As part of NASA’s plan to restore core competencies by converting contractors to civil service, the New Orleans native and Grambling State University graduate now works as a supervisor for test operations support at the agency’s E-Complex.
This propulsion testing facility provides mission-critical engineering capabilities to NASA. Through the use of high- and low-pressure propellant systems, engineers are able to focus on development testing of propulsion system components before integration into complete engine systems. Thanks to the versatility of its infrastructure and test team, the complex is uniquely equipped to support projects for the growing commercial aerospace industry and is capable of supporting a wide range of component, engine, and stage test activities.
“Ultimately, my goal is to continue to grow within my own abilities as an engineer and as a supervisor, and to help grow those that I have the opportunity to lead,” said Williams. “I want to align myself with the agency’s goals as a whole to continue to utilize our unique skillset to grow, build, evolve, and innovate.”
Williams began his career at the E-Complex in 1998 as an electrical technician contractor during the facility’s design and build phase. He quickly became familiar with the facility layout, the various systems under development, and the requirements involved in designing, building, and integrating those systems. He later advanced to the role of instrumentation and electrical engineer, gaining extensive institutional knowledge while developing expertise in the principles and importance of data validation.
In total, he brings 28 years of experience to NASA, along with an intimate understanding of the daily challenges his team of technicians faces.
Williams’ primary work location is the E-1 test stand, which is able to handle extremely high pressures and massive flow rates of super cold cryogenics.
Unlike the A and B test complexes at NASA Stennis, where a fully built engine or stage can be installed, fueled, and fired, the E-Complex is highly adaptable.
When commercial partners need to validate large, complex components, they provide specific requirements. The team then customizes the test facility to replicate the exact extreme conditions the hardware is expected to encounter during operation. NASA collects and analyzes data from these precisely controlled test conditions to validate design predictions and determine whether design modifications are needed throughout the development process, from subscale testing through full-scale testing.
Whether validating valve timings, ensuring facility instrumentation is properly calibrated, supporting ultra-high pressure pumping and cryogenic transferring operations, or troubleshooting electrical and mechanical support systems, Williams and his team must execute each task with precision. By retaining Williams’ facility specific expertise in-house as a civil servant, NASA reduces long term operational risk.
Williams describes the opportunity to perform this mission critical work in public service as a dream come true, a dream that began decades ago during an elementary school field trip to NASA Stennis. Today, he finds himself working at NASA just as the agency returns to the Moon to stay through Artemis missions and builds a Moon Base, humanity’s first lunar outpost.
“Having the opportunity to play a role at NASA means a lot,” said Williams. “To this day, I am still a kid at heart looking out at the sky and the galaxy. Being a part of the mission and doing things I know we are capable of doing is an amazing, but also humbling, opportunity.”
2026-07-29 04:00
Sargassum, a type of brown floating algae, has shifted its range in recent decades, thinning out in the North Atlantic’s Sargasso Sea while proliferating in the tropical Atlantic. That trend, underway since 2011, continued in 2026 as the algae, commonly known as a type of seaweed, reached its annual peak in June across a stretch of ocean known as the Great Atlantic Sargassum Belt.
The belt’s Sargassum abundance in June 2026 made it the second-highest Sargassum year in the satellite record, slightly behind 2025, according to scientists at the University of South Florida (USF) College of Marine Science. Regionally, the Caribbean Sea and the Gulf of America (Gulf of Mexico) both hit record highs, according to USF’s June 2026 Sargassum outlook. The western and eastern Caribbean saw 3.6 and 9 million metric tons, respectively, while the Gulf saw 5 million metric tons—nearly double its previous record, also set in 2025.
“The belt is a basin-scale phenomenon that can have devastating local-scale impacts throughout the Caribbean and Gulf, and satellite observations are the only method that captures both scales on a daily basis,” said Brian Barnes, a marine scientist at the Optical Oceanography Laboratory at USF. “The tracking done by our lab helps communities know the current extent of Sargassum and prepare for what’s to come.”
In moderate amounts in the open ocean, Sargassum provides habitat for turtles, invertebrates, fish, and birds, and adds oxygen to the water through photosynthesis. But too much of it near shore can tangle and suffocate marine life, and mats that sink can smother corals and seagrasses. On beaches, decomposing Sargassum releases hydrogen sulfide, a rotten-egg-smelling gas that’s a potential problem for both ecosystems and tourism.
The map above shows Sargassum density in the tropical Atlantic Ocean in June 2026. Red and orange areas are where Sargassum densities were the highest. Note that although the “belt” appears continuous, discrete Sargassum mats are scattered across the ocean surface. The map is based on satellite measurements of how much of the ocean surface was covered by the seaweed, averaged per pixel across all observations made in June by the OCI (Ocean Color Instrument) on NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite.
Ocean currents and winds shape the Sargassum belt, which, despite the patchiness, stretches nearly continuously from West Africa to the Gulf and holds a fairly steady “width” from the western tropical Atlantic westward, explained Chuanmin Hu, also an optical oceanographer at USF. The ocean currents have also spared Florida’s west coast from inundation this summer, while delivering large amounts of seaweed to the Florida Keys and the state’s east coast. The bulk of the Sargassum, however, is visible in the Caribbean Sea, shown in detail above, where problems associated with inundation have been more severe, Hu said.
Data for the maps were provided by Lin Qi, an oceanographer at NOAA’s Center for Satellite Applications and Research, who has been working to generate Sargassum maps based on data from PACE, which was launched in February 2024. The work extends that of Qi and colleagues at USF’s Optical Oceanography Laboratory. This team first developed Sargassum detection techniques using MODIS (Moderate Resolution Imaging Spectroradiometer) on NASA’s long-running Terra and Aqua satellites and VIIRS (Visible Infrared Imaging Radiometer Suite) on the NOAA-20 satellite—data that have been a key component of USF’s Sargassum Watch System and of research into the seaweed’s longer-term trends.
Satellites detect Sargassum by its signals in reflected sunlight. Because of its plant structure and chlorophyll pigments, Sargassum reflects more near-infrared light than water. Scientists flag pixels where the reflectance spikes above the levels produced by plain seawater, and then they use the strength of this spike to estimate Sargassum density, which refers to the fraction of ocean surface covered by the seaweed in each pixel. Density estimates can then be converted into biomass, or the total weight of Sargassum present within a pixel, which is how the longer-term trends in the chart below are tracked.
The chart above uses the continuous MODIS record since March 2000 to show how Sargassum biomass across the Great Atlantic Sargassum Belt has changed through June 2026. Notice the uptick beginning around 2011, when the belt was first developing, and the seasonal dips in winter and peaks in spring and summer. The record high in July 2025 stands out, followed by the quick rise in early 2026—especially in the first four months of the year—that culminated in the year’s peak in June. More recent observations, not yet reflected in the chart, indicate Sargassum biomass declined through the following month of July.
“Since the initial appearance of the Great Atlantic Sargassum Belt in 2011, the total Sargassum amount in the Atlantic Ocean has increased substantially, more than doubling every five years,” Hu said. He added that the exact mechanism is still being investigated, but it’s possibly related to ocean warming, multiple nutrient sources, and the fact that large Sargassum mats attract other organisms—such as nitrogen-fixing bacteria—that can supply additional nutrients to sustain further growth.
Alongside data from MODIS and VIIRS, OCI data from PACE now feeds into the Sargassum Watch System’s near-real-time daily and weekly composite maps. A recent study of the central-west Atlantic led by Qi, spanning May through August 2024, found that OCI offers several advantages over its predecessors, observing more of the ocean and detecting Sargassum with greater sensitivity.
Hu noted that the added pixels from OCI can improve near-real-time monitoring and analyses of short-term fluctuations. And its higher sensitivity, he said, will also lead to improved maps during winter months, “thus helping understand Sargassum changes over time.”
Additionally, the study’s authors found that OCI’s hyperspectral capability makes it the only sensor able to spectrally discriminate Sargassum pixels across the Atlantic Ocean “without ambiguity,” adding confidence to the interpretation of detected image features—especially in parts of the Atlantic where another type of floating algae, Trichodesmium, has been reported.
“I think I can speak for all project members, past and present, in sharing how rewarding it is to see the promise of PACE’s advancements come to life,” said Jeremy Werdell, PACE project scientist at NASA’s Goddard Space Flight Center. “OCI has started a true renaissance in aquatic ecosystem monitoring from space.”
NASA Earth Observatory maps and chart by Lauren Dauphin, using PACE and MODIS data courtesy of Lin Qi (NOAA), and Brian Barnes and Chuanmin Hu (University of South Florida, Optical Oceanography Laboratory). Story by Kathryn Hansen.
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Something is brewing in shallow waters offshore of Delaware, New Jersey, Maryland, and Virginia.

Phytoplankton added a milky blue hue to the waters of the Black Sea and nearby waterways in spring and summer…

Satellite observations of sea surface height indicated that the 2026 event continued to strengthen in early June.
2026-07-28 04:01
Dry thunderstorms that popped up over the Cascade Range on the evening of July 15, 2026, peppered Oregon and Washington with thousands of lightning strikes as they moved east across the states. By the following day, NASA satellites had begun to detect large numbers of wildland fires burning throughout central and eastern Oregon.
Though initially small, these blazes strengthened as they were fanned by gusty winds and raced through landscapes parched by extreme drought and baking in summer heat. When NASA’s Aqua satellite captured the image shown above on the afternoon of July 26, smoke poured northeast from dozens of large fires that had collectively charred hundreds of square miles. The fires produced a blanket of haze, prompting state officials to issue air quality advisories for eastern Oregon.
Many communities faced evacuation orders as more than 10,000 firefighters battled wildfires throughout the state. On the day the image was captured, the largest active fires were the Hay Creek Complex, Brewer, Big Grass, Akawa Butte, and Powder River fires. Several of these blazes were less than 5 percent contained, according to the National Interagency Fire Center. State officials invoked Oregon’s Emergency Conflagration Act to protect communities as they responded to particularly threatening fires such as the Shingle, Bench, Beachcomb, and Second Flat fires.
Government satellite data are part of a global system of observations used to track fire behavior and analyze emerging trends. Among the real-time wildfire monitoring tools that NASA makes available are FIRMS (Fire Information for Resource Management System), the Worldview browser, and the Fire Event Explorer.
As of July 27, 2026, fires in Oregon had burned more than one million acres, according to news outlets. Meanwhile, the National Interagency Fire Center reported that fires had burned more than 4 million acres across the United States. The 10-year average (2016-2025) for this point in the season is 3.4 million acres.
NASA Earth Observatory image by Michala Garrison, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Adam Voiland.
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Dry, warm, and windy conditions across the U.S. Great Plains led to extreme fire activity in March 2026.

The blaze burned more than 150 square miles and swept through parts of a ski resort.

Firefighters are battling two destructive blazes in the southern part of the state as drought grips the U.S. Southeast.
2026-07-27 18:49

NASA astronaut Chris Williams will recap his recent eight-month mission aboard the International Space Station during a news conference at 2:45 p.m. EDT Tuesday, Aug. 4, from the agency’s Johnson Space Center in Houston.
NASA will stream this event live through a variety of platforms. Learn where to watch online:
United States-based media interested in attending in person must contact the NASA Johnson newsroom no later than 5 p.m., Friday, July 31, at jsccommu@mail.nasa.gov.
Media wishing to participate by phone must contact the Johnson newsroom no later than two hours before the start of the event. To ask a question by phone, media must dial into the news conference no later than 15 minutes prior to the start of the call. NASA’s media accreditation policy is available online.
Williams returned to Earth on July 26, after logging 241 days as an Expedition 73/74 flight engineer during his first spaceflight. He returned along with Roscosmos cosmonauts Sergey Kud-Sverchkov and Sergei Mikaev, completing 3,856 orbits of the Earth over the course of their more than 102-million-mile journey. They also saw the arrival of six visiting spacecraft and the departure of eight.
During his mission, Williams supported a wide range of scientific investigations and technology demonstrations. He helped advance research for new cancer treatments and improved in-space manufacturing of materials used in high-performance computers and electronics. Williams also completed two spacewalks to prep for space station power system upgrades and to replace a faulty joint on the Canadarm2 robotic arm. The crew’s work aboard the space station helps improve life on Earth and prepare for future human missions to the Moon and Mars.
To learn more about International Space Station research, operations, and its crews, visit:
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Joshua Finch
Headquarters, Washington
202-358-1100
joshua.a.finch@nasa.gov
Anna Schneider
Johnson Space Center, Houston
281-483-5111
anna.c.schneider@nasa.gov
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