Nebraska’s Wide, Rolling Domain

Editor’s Note: Today’s story is the answer to the June Puzzler.

The undulating landscape of north-central Nebraska may be easy to overlook among the iconic dune fields of the world. Far from any coast or desert, the Nebraska Sandhills—comprising the Western Hemisphere’s largest system of sand dunes—bring their own brand of beauty and value. Grasslands blanket the rolling hills, providing grazing grounds for livestock, while lakes and wetlands dot the landscape, supporting diverse plant and animal life.

Much of the sand forming the hills originated in the Rocky Mountains. Rivers carried the eroded material down from the mountains and deposited it across the Great Plains during the Pleistocene. In times of drought, winds blowing predominantly from the north or south lofted sand out of dried riverbeds, gradually building and shaping dunes. About 3,500 years ago, grassland vegetation stabilized the features. Today, the rippled pattern spans about 20,000 square miles (52,000 square kilometers), about one-quarter of the state of Nebraska.

Some of the largest dunes occur in and around the area shown in the detailed image above, near the northern edge of the Sandhills region. These transverse dunes stand as high as 400 feet (120 meters) and extend for several miles. Their northern slopes are gentler than their southern slopes, reflecting the dominant influence of northerly winds. In other areas, dunes are more symmetric, suggesting that winds blew with nearly equal strength from the north and south, alternating with the seasons.  

The grasslands that now cover the hills constitute pastureland for grazing livestock. Ranching expanded significantly in the area after passage of the Kinkaid Act in 1904, which allotted 640-acre parcels of land to ranchers who would settle it. Today, far more cattle than humans occupy the region, and half of Nebraska’s nearly 23 million acres of rangeland and pastureland are in the Sandhills. Some ranchers graze their cattle in patterns meant to approximate the large bison herds that once roamed the land.

Though much of the land in the Sandhills is privately owned, some is set aside in protected public lands. One of these areas, Crescent Lake National Wildlife Refuge on the southwestern edge of the Sandhills region, is shown above. Wetlands, including shallow lakes, marshes, and wet meadows, fill some of the valleys between the dunes. The land here is sponge-like, with precipitation seeping down through the soil and recharging groundwater instead of flowing off through stream channels.

Located along the Central Flyway, the refuge is a haven for migratory birds, and dozens of species of waterfowl, marsh birds, and shorebirds utilize the area. Among other wildlife, several types of turtles thrive in the ponds and prairies. Wetlands across the Sandhills support rare species such as the whooping crane, western prairie fringed orchid, and Topeka shiner.

NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.

Downloads

August 19, 2025

JPEG (10.71 MB)

References & Resources

• Nebraska Game and Parks, Sandhills wetlands. Accessed June 15, 2026.
• University of Nebraska–Lincoln (2024, October 23) Groundwater: How the High Plains Aquifer Shapes the Sandhills. Accessed June 15, 2026.
• University of Nebraska–Lincoln (2024, October 23) Rotational Grazing and Sustainable Grasslands. Accessed June 15, 2026.
• University of Nebraska–Lincoln (2024, October 23) What It Takes to Form a Giant Dune Field. Accessed June 15, 2026.
• U.S. Fish and Wildlife Service, Crescent Lake National Wildlife Refuge. Accessed June 15, 2026.
• USDA Forest Service, History of the Nebraska Sandhills. Accessed June 15, 2026.

You may also be interested in:

Stay up-to-date with the latest content from NASA as we explore the universe and discover more about our home planet.

Fires Tear Through Nebraska Grasslands

3 min read

Dry, warm, and windy conditions across the U.S. Great Plains led to extreme fire activity in March 2026.

Article

Farming in Ancient Lake Agassiz

3 min read

The glacial lake left a layer of silt and clay in southeastern Manitoba, creating fertile farmland that was divided during…

Article

America’s Emerald Isle

3 min read

Beaver Island is one in a string of verdant and scenic jewels in a northern Lake Michigan archipelago.

Article

Keep Exploring

Discover More from NASA Earth Science

Subscribe to Earth Observatory Newsletters

Subscribe to the Earth Observatory and get the Earth in your inbox.

Earth Observatory Image of the Day

NASA’s Earth Observatory brings you the Earth, every day, with in-depth stories and stunning imagery.

Explore Earth Science

Earth Science Data

Open access to NASA’s archive of Earth science data

Powered by WPeMatico

Get The Details…

Explore JPL to Take Place Oct. 10, 11

Celebrating its 90th anniversary this year, NASA’s Jet Propulsion Laboratory invites the public to its campus at the base of the San Gabriel Mountains in Southern California for an open-house event, Explore JPL. On Oct. 10 and 11, from 9:30 a.m. to 4 p.m. PDT, visitors will get the chance to visit JPL’s most iconic facilities and explore four thematic areas: Missions That Changed the World, Moon to Mars, In Flight, and Makerspace. 

Tickets are free but very limited and have gone quickly for past Explore JPL events. They will be available on the Explore JPL webpage at 9 a.m. PDT Sunday, Aug. 29, and will be distributed on a first-come, first-served basis, with a maximum of five tickets per requestor. Orders for more than five tickets may be subject to cancellation. Tickets will be provided for specific time slots and must be reserved for specific names. Attendees will not be admitted to JPL before the designated time printed on their ticket. 

A division of Caltech in Pasadena, California, JPL traces its origins to rocket-propulsion development in 1936. By 1958, the lab had built and helped launch America’s first satellite, Explorer 1. That same year, Congress established NASA, and JPL became a part of the agency. Since then, JPL has managed such historic missions as Voyager, Galileo, Cassini, the Mars Exploration Rover program, the Perseverance Mars rover, Europa Clipper, and many more.

Among other highlights, Explore JPL guests will get to: 

• Visit JPL’s legendary Space Flight Operations Facility, a National Historic Landmark where engineers send commands and receive data from spacecraft billions of miles away. 

• Discover the Spacecraft Assembly Facility and JPL Machine Shop, where precision spacecraft components are crafted. 

• See the latest cutting-edge innovations in robotics research, from autonomous lunar rovers to search-and-rescue robots. 

• Get up close with full-scale models of the Mars Perseverance rover, Voyager, and Galileo. 

• Step inside the Microdevices Laboratory to see how miniature technologies developed there are shaping the future of space exploration and Earth science. 

To attend Explore JPL, visitors must have their tickets in hand and anyone age 18 or over must show government-issued identification. Tickets are not transferable and cannot be sold. Children under age 2 do not require a ticket, but experiences at the event are not intended for very young guests. 

Visitors may not bring these items to JPL: weapons or explosives of any kind, incendiary devices, glass containers, alcohol, cannabis or illegal drugs, pets (except certified service animals), banners or signs, flags, boom boxes, air horns, musical instruments, and professional camera equipment with detachable telephoto lenses. Use of laser pointers or whistles is not allowed. No bags, backpacks, or hard-sided coolers are permitted, either, except small purses and diaper bags. Drones are not allowed to fly over JPL under any circumstances. Skates, skateboards, scooters, Segways, and bicycles are not permitted inside the event, as the venues are crowded with pedestrians. 

Vehicles entering JPL property are subject to inspection. Parking is free. 

Follow JPL on Facebook, X, and Instagram. 

To get a virtual tour of JPL, visit:

https://www. jpl.nasa.gov/virtual-tour/

Media Contact 
JPL-media@jpl.nasa.gov

Keep Exploring

Discover More Topics From NASA

Jet Propulsion Laboratory

Voyager

Voyager 1 and its twin Voyager 2 are the only spacecraft ever to operate outside the heliosphere, the protective bubble…

Mars 2020: Perseverance Rover

NASA’s Mars Perseverance rover seeks signs of ancient life and collects samples of rock and regolith for possible Earth return.

Europa Clipper

Powered by WPeMatico

Get The Details…
Stephen Carney

NASA’s Chandra Finds Unexpected Fireworks in Aftermath of Stellar Explosions

6 Min Read

NASA’s Chandra Finds Unexpected Fireworks in Aftermath of Stellar Explosions

The aftermath of a supernova, a stellar explosion, is usually a slowly fading cloud of hot gas. So when astronomers pointed NASA’s Chandra X-ray Observatory at the nearby galaxy Messier 83 (M83), they did not expect to find a population of supernova remnants, or the debris from these explosions, showing dramatic changes in their brightness. The new results were presented at the American Astronomical Society meeting in Pasadena, California, and published in The Astrophysical Journal.

The galaxy M83, located about 15 million light-years from Earth, is forming stars at a high rate. Researchers analyzed 14 years of Chandra data of the galaxy, spanning 2000 to 2014.

Using this extensive set of data, the researchers caught surprising variations in the X-ray brightness of sources previously identified as supernova remnants. The researchers expected supernova remnants older than a century or so to fade gradually in X-rays, but not change dramatically in brightness.

The team found that roughly half of the 22 X-ray sources associated with supernova remnants in their sample showed changes in X-ray brightness over the 14-year span of observations — a result that was completely unexpected.

“We knew that individual X-ray sources could vary dramatically,” said Andrea Prestwich, of the Catholic University of America who led the study. “But finding that so many supernova remnants were behaving this way was a real surprise. Something unusual is going on in these objects. Pinpointing the cause remains a challenge, as M83’s distance limits the detail we can observe.”

One of the 22 variable supernova remnants has a straightforward explanation: SN 1957D, the debris from a supernova first observed nearly 70 years ago, is ramming into material surrounding the explosion site, producing the observed X-ray flares. But this cannot explain the rest of the sample. There is no evidence to suggest that all 22 remnants were formed within the last century. Something else must be driving the variability.

The most likely explanation is that the team has uncovered a population of stellar survivors stars that lived through their partner’s destruction in a supernova explosion. In this scenario, each variable X-ray source began as a pair of massive stars orbiting each other. The more massive star collapsed and exploded as a supernova, leaving behind a black hole or ultra-dense neutron star. Its companion survived.

“It may be that this galaxy contains a collection of supernova remnants where one massive star survives the supernova and becomes locked into an orbit with a black hole or neutron star,” said co-author Michael McCollough of the Center for Astrophysics | Harvard & Smithsonian (CfA). “The neutron star or black hole can then start pulling material from the massive star’s surface.”

That infalling material is superheated by the intense gravitational pull, producing the X-rays Chandra detects. These types of systems, known as high-mass X-ray binaries (HMXBs), are among the most variable X-ray sources in the universe. Researchers say they may be the cause of the variations seen in M83’s supernova remnants.

Astronomers have known about HMXBs for decades, but the difference with this group in M83 is their connection to supernova remnants. Previously, only a handful of supernova remnants associated with HMXBs had been identified across observations of all galaxies. It is unprecedented to find more than 20 strong candidates in just one galaxy.

The authors found that the variable supernova remnants are in regions with higher concentrations of massive stars than in other parts of the galaxy, increasing the chances of a link between the remnants and HMXBs.

There is another possible explanation: Instead of pulling in material from a companion star, the black hole or neutron star may be recapturing some of the material blasted outward by the original explosion.

“This could be an example of cosmic recycling, where debris from the explosion falls back onto the very object the supernova created,” said co-author Roy Kilgard of Wesleyan University. “And it’s quite possible that both explanations are at play — different sources in our sample may have different origins.”

These results are not unique to M83. A follow-up study of the nearby star-forming galaxy M51 by Zoe Hoiland of Vassar College and Kilgard has uncovered a similar population of variable X-ray sources associated with supernova remnants, suggesting that such systems may be a feature of galaxies undergoing vigorous star formation.

The Chandra data for M83 began with single observations in 2000 and 2001, followed by 10 observations from 2010 to 2011 and another observation in 2014.

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.

Visual Description

This release features a composite image of the nearby galaxy Messier 83, and short timelapse videos of two curious supernova remnants hidden inside.

In the composite image, Messier 83, or M83, is shown to have a spiral structure, viewed straight on. At the center is a brilliant white and yellow pool of light. From that light, spiral arms of hot pink cloud corkscrew out in wide, sweeping arches. The galaxy is covered in a faint grey haze, and flecked with red, green, blue, white, and yellow dots.

In an annotated version of the composite image, two tiny dots to our lower right of center are highlighted by white circles. These are two of the supernova remnants being considered by researchers. Each is examined further in a separate timelapse video.

Over a 14-year period from 2000 to 2014, astronomers pointed NASA’s X-ray observatory at the M83 galaxy. They discovered that about half of the X-ray sources believed to be supernova remnants, the aftermath of stellar explosions, were exhibiting dramatic changes in brightness. This result was entirely unexpected.

Those changes in brightness are highlighted in the timelapse videos. In each video, a series of static images flashes by, focused on one of the two X-ray sources once believed to be supernova remnants. In the videos, the X-ray sources appear as bright blue blobs with glowing cores. But in each image, taken months or years apart, the shapes change, as does the intensity of the blue color, and the brightness of the core. By presenting the substantively different images of the same objects one after another in quick succession, short timelapse videos are created.

The most likely explanation for the changes in brightness is that the team has uncovered a population of stellar survivors, stars that lived through an orbiting partner’s destruction in a supernova explosion. Material is being pulled from the surviving star onto the black hole or neutron star that formed in the supernova, a process known to cause rapid changes in X-ray brightness.

Read more from NASA’s Chandra X-ray Observatory

To learn more about NASA’s Chandra mission, visit:

https://science.nasa.gov/chandra

https://chandra.si.edu

News Media Contact

Megan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu

Joel Wallace
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
joel.w.wallace@nasa.gov

Explore More

5 min read

NASA’s Chandra Discovers Possible Supernova Remnant in Galactic Center

Article


4 days ago

1 min read

Pretty in Pink

Saturn and its rings are prominently shown in this color image, along with three of…

Article


22 years ago

4 min read

NASA Connects Little Red Dots with Chandra, Webb

Article


2 months ago

Keep Exploring

Discover More Topics From NASA

Chandra X-ray Observatory

The Chandra X-ray Observatory is the world’s most powerful X-ray telescope.

James Webb Space Telescope

Webb is the premier observatory of the next decade, serving thousands of astronomers worldwide. It studies every phase in the…

Hubble Space Telescope

Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.

Universe

Powered by WPeMatico

Get The Details…

NASA Astronauts to Answer Questions from New Jersey Students

Students in New Jersey will hear from NASA astronauts Chris Williams and Jessica Meir as they answer prerecorded STEM questions while aboard the International Space Station.

The Earth-to-space call will begin at 12:05 p.m. EDT, Thursday, June 18, and will stream live on the agency’s Learn With NASA YouTube channel.

This event is hosted by Newton Public Schools in Newton, New Jersey, for students in grades K-12 and members of the community. This unique opportunity aims to deepen understanding of space exploration and enhance awareness of STEM careers.

Media interested in covering the event must RSVP no later than 5 p.m. EDT, Wednesday, June 17, to Dr. Joseph Piccirillo at: 973-383-7392, x4229 or jpiccirillo@newtonnj.org.

For more than 25 years, astronauts have continuously lived and worked aboard the space station, testing technologies, performing science, and developing skills needed to explore farther from Earth. Astronauts communicate with NASA’s Mission Control Center in Houston 24 hours a day through SCaN’s (Space Communications and Navigation) Near Space Network.

Research and technology investigations taking place aboard the space station benefit people on Earth and lay the groundwork for other agency deep space missions. As part of NASA’s Artemis program, the agency will send astronauts to the Moon to prepare for future human exploration of Mars, inspiring the world through discovery in a new Golden Age of innovation and exploration.

For more information on NASA in-flight calls, visit:

https://www.nasa.gov/stemonstation

Powered by WPeMatico

Get The Details…
Gerelle Q. Dodson