Billions of years ago, an hours-long Martian sandstorm blew so intensely that sand ripples began to climb upon one another as they moved across the surface. These layers of sediment eventually hardened into the multilayered rocks seen in this image, which was taken by NASA’s Curiosity rover on Dec. 12, 2024, the 4,391st Martian day, or sol, of the mission.
Scientists believe this is the first evidence of climbing wind ripple strata on the Red Planet. Spotted at a location nicknamed “Jawbone Canyon,” these rocks are a rare time capsule preserving a dramatic wind event early in Martian history. A paper detailing the discovery was featured on the cover of the journal Geology on July 1, 2026.
This orbital map shows the path NASA’s Perseverance Mars rover took to get to a location the science team has dubbed the “Broom Point member,” a sequence of layered bedrock likely more than 3.9 billion years old. As planned, the rover landed inside Jezero Crater on Feb. 18, 2021. It investigated the crater’s western delta and inlet river valley, Neretva Vallis, before summiting the crater rim in December 2024 following a rim-to-crest climb of 2,620 feet (800 meters).
The Broom Point region is situated on the outer edge of the crater rim and was visited by the rover in mid-2025. The yellow dot indicates location where the rover took a selfie.
NASA’s Jet Propulsion Laboratory, which is managed for the agency by Caltech in Pasadena, California, built and manages operations of the Perseverance rover. Arizona State University leads the operations of the Mastcam-Z instrument, working in collaboration with Malin Space Science Systems in San Diego, on the design, fabrication, testing, and operation of the cameras, and in collaboration with the Niels Bohr Institute of the University of Copenhagen on the design, fabrication, and testing of the calibration targets.
JPL manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate in Washington as part of NASA’s Mars Exploration Program portfolio. Lockheed Martin Space in Denver built MRO and supports its operations. The University of Arizona, in Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., in Boulder, Colorado.
Temperatures soared in the Western U.S. on July 12, 2026, as shown in this map of modeled air temperatures from the GEOS (Goddard Earth Observing System). Numerous weather stations in Montana, Utah, and Wyoming recorded their highest temperatures since record-keeping began.
NASA Earth Observatory/Michala Garrison
It’s still relatively early in the summer season in the Northern Hemisphere, but several parts of North America were sweltering in mid-July.
The latest purveyor of heat was a strong ridge of high pressure that lingered in the upper atmosphere over the northern Rockies on the weekend of July 11-12, 2026. This pushed hot air toward the surface and trapped it there—a weather phenomenon meteorologists call a heat dome.
Heat domes put the brakes on convection and suppress clouds and precipitation. This allows sunlight to reach Earth’s surface relatively unhindered and further elevate air temperatures. As a result of the July heat dome, sites in Montana, Wyoming, and Utah broke all-time temperature records.
The map above shows air temperatures across the United States on July 12, 2026, at 2 p.m. Mountain Time, modeled at 2 meters (6.5 feet) above the ground. It was produced by combining satellite observations with temperatures predicted by a version of the GEOS (Goddard Earth Observing System) model, which uses mathematical equations to represent physical processes in the atmosphere. The darkest reds indicate areas where temperatures approached or exceeded 45 degrees Celsius (113 degrees Fahrenheit).
A preliminary analysis from the National Weather Service office in Billings found that temperature sensors at airports in Billings and Miles City, Montana (111°F and 115°F, respectively), and Sheridan, Wyoming (109°F), all recorded new all-time record highs on July 12. Each of these stations topped its previous record by at least 2°F, with Miles City breaking its record by a full 4°F. The Montana records date to the 1930s; the Sheridan record begins in 1907.
Multiple locations in Utah broke all-time records as well, according to the National Weather Service office in Salt Lake City, including Deseret (111°F), Salt Lake City (109°F, or 4°F above the previous record), and Randolph (100°F, or 6°F above the previous record). These stations in Utah have records that date back to the 1890s.
Extreme heat doesn’t just make people uncomfortable. It can have serious health consequences, particularly for older people. Extreme heat worsens common age-related health conditions such as heart, lung, and kidney disease. Health tracking data from the U.S. Centers for Disease Control and Prevention shows that the rate of heat-related emergency department visits in the Mountain states spiked tenfold during the July heat.
Heat waves like this one have become more frequent in the United States in recent decades, according to researchers at NASA’s Goddard Space Flight Center. Using a NASA modeling system called MERRA-2 (Modern-Era Retrospective analysis for Research and Applications-2), one NASA team found that summer heat waves in the U.S. roughly doubled in number between 1980 and 2023, increasing from an average of two to four per month.
Forecasters expect the heat dome to spread east into the Midwest, New England, and the Mid-Atlantic in the coming days, where triple-digit temperatures are likely in some areas. The United States isn’t alone in facing significant heat. Parts of both Western Europe, Central Asia, and East Asia are also facing heat waves.
The Republic of Serbia will sign the Artemis Accords at 5 p.m. EDT Thursday, July 16, during a ceremony at NASA Headquarters in Washington.
NASA Deputy Administrator Matt Anderson will host Serbia’s Minister of Foreign Affairs Marko Đurić and U.S. State Department Assistant Secretary for Oceans and International Environmental and Scientific Affairs Wesley Brooks for the ceremony.
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. Serbia will be the 69th country to sign the Artemis Accords.
A glowing landscape of gas and dust is heated and illuminated by a thriving population of young stars in the LH 95 region of the Large Magellanic Cloud.
NASA, ESA, and N. Da Rio (The University of Virginia), G. De Marchi (European Space Agency – ESTEC), and D. Gouliermis (Universitat Heidelberg); Processing: Gladys Kober (NASA/Catholic University of America)
Blue and white stars shine brilliantly against a crimson background of glowing gas in this July 3, 2026, image of stellar nursery LH 95 from NASA’s Hubble Space Telescope. LH 95 is a region in the Large Magellanic Cloud, a dwarf galaxy that orbits the Milky Way. Low-mass infant stars live alongside massive blue giant stars in what is known as a stellar association, one of many in the Large Magellanic Cloud.
Image credit: NASA, ESA, and N. Da Rio (The University of Virginia), G. De Marchi (European Space Agency – ESTEC), and D. Gouliermis (Universitat Heidelberg); Processing: Gladys Kober (NASA/Catholic University of America)
How do black holes at the center of galaxies form and grow over time? To answer this question, scientists need to detect and study supermassive black holes at great distances, which existed much earlier in the universe’s history. New research suggests NASA’s Nancy Grace Roman Space Telescope, which is on track to launch Aug. 30, 2026, will be able to detect these distant, ancient black holes that existed up to 11 billion years ago.
This artist’s concept portrays a Sun-like star being shredded by a supermassive black hole — a phenomenon known as a tidal disruption event. During these events, the region around a black hole can brighten and become visible across great distances. NASA’s Nancy Grace Roman Space Telescope will be able to spot and study tidal disruption events that occurred early in the universe’s history. By characterizing an earlier population of supermassive black holes, astronomers can learn about their origins.
NASA, Ralf Crawford (STScI)
Black holes are best studied by looking for the light emitted from their accretion disk — the matter that swirls around them before being consumed. Lighter supermassive black holes are challenging to observe because they tend to be less luminous due to less accretion. But occasionally, they shred and consume an entire star, brightening to outshine their entire host galaxy — known as a tidal disruption event (TDE). By characterizing that population of early supermassive black holes and how they evolve and grow for billions of years, Roman will provide clues to the ultimate origin of these behemoths.
“The Roman Space Telescope is going to be transformative for transient science,” said lead author Mitchell Karmen of the Johns Hopkins University, a graduate student and National Science Foundation Graduate Research Fellow. “Thanks to Roman’s high sensitivity, we can find multiple tidal disruption events out to greater distances and earlier cosmic times than ever before.”
Roman’s High-Latitude Time-Doman Survey, one of three core community surveys, is particularly well suited to find and study TDEs in the early universe. This survey will cover about 18 square degrees on the sky, an area equivalent to 90 full moons, at a regular cadence. By revisiting the same regions repeatedly, astronomers can find large numbers of transient events like TDEs.
Tidal disruption events are phenomena unique to lighter supermassive black holes. Heftier black holes weighing more than 1 billion Suns will swallow incoming stars whole. But lighter black holes of about 100,000 to 100 million Suns can shred a star before consuming it, creating a beacon that brightens over a couple of weeks before gradually fading away.
The rate of TDEs fluctuates over cosmic time. Previous work predicted that the rate of TDEs would decrease with increasing distance because most young black holes were too light to generate a TDE. However, this new research takes into account numerous factors that evolve over time, like the frequency of galaxy (and hence black hole) mergers as well as the number of stars within the core of each galaxy and how closely packed they are.
Karmen and his colleagues modeled these and other effects to predict how many tidal disruption events Roman could observe, as well as other observatories like the ground-based National Science Foundation-Department of Energy Vera C. Rubin Observatory and NASA’s James Webb Space Telescope. The team forecasts that astronomers will see the rate of TDEs increase as Roman probes greater distances and earlier times until “cosmic noon,” about 11 to 12 billion years ago when star formation peaked throughout the universe, before decreasing again.
This visualization shows the average number of tidal disruption events NASA’s Nancy Grace Roman Space Telescope is predicted to detect in a year, based on simulations. Roman is expected to record about 100 such events in a year.
Video: NASA, STScI. Visualization: Christian Nieves (STScI). Sound: Christian Nieves (STScI). Designer: Dani Player (STScI). Animation: Greg Bacon (STScI)
Complementary Observations
Roman will observe near-infrared wavelengths of light. Light from distant TDEs becomes stretched to longer wavelengths by the expansion of the universe, a phenomenon known as cosmological redshift. As a result, Roman is inherently optimized to detect TDEs whose light traveled anywhere from 8 billion to 11 billion years to reach us.
The Rubin Observatory also will scan large swaths of the sky and pick up many new TDEs. However, it will observe visible light, which limits it to closer TDEs than Roman.
The research by Karmen’s team finds that Rubin will detect thousands to tens of thousands of TDEs per year. While Roman is expected to find up to 100 TDEs per year, those black holes will be much more distant, within the realm of cosmic history that is most important for distinguishing among black hole origin scenarios.
“Just by counting the number of TDEs as a function of redshift, you can put meaningful constraints on the population of million-solar-mass black holes,” said co-author Suvi Gezari, an associate professor of astronomy at the University of Maryland. “Roman will be transformative in that it can probe tidal disruption events out to greater distances, so you can look at how the rate of TDEs evolves over time.”
Origins of supermassive black holes
Astronomers have observed truly gargantuan black holes very early in the history of the universe — so early that theories struggle to explain how they could have become so large, so quickly. They must have started smaller and grown over time, but how much smaller?
One theory, known as “light seeds,” begins with black holes that are created from the deaths of massive stars. Such black holes might weigh up to a few hundred times our Sun. These black holes then would merge over time, as well as consume surrounding gas at an astonishing rate. In this scenario, every young galaxy would be expected to have a massive black hole at its center.
A second theory, known as “heavy seeds,” suggests that a black hole could be born with a much higher mass, up to a million times our Sun, through a process such as the direct collapse of a gas cloud. This process should be less common, though, which would result in supermassive black holes being much rarer in early galaxies.
“Tidal disruption events help us probe the population of light supermassive black holes, which can help us discriminate between these models,” Karmen said.
Ultimately, Roman’s tally of tidal disruption events will help researchers trace global effects that impact the black hole population over time.
Once Roman and Rubin begin regular science operations, the team looks forward to comparing their forecasts to the actual detections those observatories make.
“Just like Webb has transformed our understanding of distant, high-redshift galaxies, Roman is poised to transform our understanding of high-redshift transients,” Gezari said.
The Nancy Grace Roman Space Telescope is managed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with participation by NASA’s Jet Propulsion Laboratory in Southern California; Caltech/IPAC in Pasadena, California; the Space Telescope Science Institute in Baltimore; and a science team comprising scientists from various research institutions. The primary industrial partners are BAE Systems, Inc. in Boulder, Colorado; L3Harris Technologies in Melbourne, Florida; and Teledyne Scientific & Imaging in Thousand Oaks, California.
By Christine Pulliam Space Telescope Science Institute, Baltimore, Md.
Alluvial fans form along a braided river channel on Severny Island in the Russian Arctic in an image acquired on August 1, 2025, by the OLI (Operational Land Imager) on Landsat 9.
NASA Earth Observatory/Lauren Dauphin
Editor’s Note: Today’s story is the answer to the July Puzzler.
Call it an alluvial face-off. On the southern end of Severny Island in the Russian Arctic, rivers rush down from rugged terrain flanking a broad valley. Upon reaching flatter ground, the waters slow and distribute sediment into cone-shaped features called alluvial fans. Several appear in opposing orientations alongside a braided river in this Landsat 9 image.
Severny Island (Ostrov Severnyy) is a mountainous, uninhabited landmass in the frigid high latitudes of the Northern Hemisphere. Part of the Novaya Zemlya archipelago, the island is largely covered in glacial ice. Some glaciers, especially in the north, terminate in the sea, while others end on land, feeding meltwater into glacial streams.
Sediment-laden streams, along with the island’s topography, create favorable conditions for the formation of alluvial fans. The features typically appear at the base of steep mountain ranges, where narrow river channels open onto flatter terrain. There, rivers can slow, divide into smaller channels, and deposit sediment. Over time, the channels migrate back and forth to build up fan-shaped deposits. Dueling fans line several northwest-southeast-trending valleys in the wider view below.
A wide view of southern Severny Island in the Russian Arctic shows ice-capped mountains interrupted by broad valleys lined with alluvial fans. The image was acquired on August 1, 2025, by the OLI (Operational Land Imager) on Landsat 9.
NASA Earth Observatory/Lauren Dauphin
Seasonal snowmelt and glacial runoff likely keep Severny’s rivers supplied with ample fan-building material. Hydrologists note that higher river flows during the warmer months, driven by snowmelt, can carry more sediment out of the mountains. Glaciers also produce large volumes of eroded material as they grind downslope, some of which flushes out in meltwater.
Smaller, land-terminating mountain glaciers, like those on southern Severny Island, are particularly prone to melting as the atmosphere warms. Severny’s ice is relatively understudied due to its remoteness, but satellite observations give scientists an understanding of its health. Recent analyses incorporating digital elevation models found that land-terminating glaciers across the Novaya Zemlya archipelago thinned during the 2000s and 2010s, especially at lower elevations.
NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.
