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Scientists Reveal Secrets of Desert Star Dunes

A view of the Lala Lallia star dune of the Sahara Desert, in Erg Chebbi, Morocco, as seen in an undated handout image from 2008 and obtained by Reuters on March 1, 2024. Charlie Bristow/Handout via REUTERS
A view of the Lala Lallia star dune of the Sahara Desert, in Erg Chebbi, Morocco, as seen in an undated handout image from 2008 and obtained by Reuters on March 1, 2024. Charlie Bristow/Handout via REUTERS
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Scientists Reveal Secrets of Desert Star Dunes

A view of the Lala Lallia star dune of the Sahara Desert, in Erg Chebbi, Morocco, as seen in an undated handout image from 2008 and obtained by Reuters on March 1, 2024. Charlie Bristow/Handout via REUTERS
A view of the Lala Lallia star dune of the Sahara Desert, in Erg Chebbi, Morocco, as seen in an undated handout image from 2008 and obtained by Reuters on March 1, 2024. Charlie Bristow/Handout via REUTERS

They are among the wonders of our deserts: star dunes, the vaguely pyramid-shaped sand formations up to about 1,000 feet (300 meters) tall with arms stretching out from a central peak to give them a star-like appearance when viewed from above.
Scientists on Monday unveiled the first in-depth study of a star dune, revealing the internal structure of these geological features and showing how long it took for one of them to form - more quickly than expected but still a process unfolding over many centuries.
The study focused upon a star dune in eastern Morocco called Lala Lallia, meaning "highest sacred point" in the local Berber language, situated within the Sahara Desert in a small sand sea called Erg Chebbi about 3 miles (5 km) from the town of Merzouga, close to the border with Algeria.
Lala Lallia rises about 330 feet (100 meters) above the surrounding dunes and is approximately 2,300 feet (700 meters) wide, containing about 5-1/2 million metric tons of sand.
According to Reuters, he researchers used ground-penetrating radar to peer inside the dune and employed luminescence dating to determine how long Lala Lallia has taken to form, a method based on the amount of energy trapped inside the grains of sand. The answer: about 900 years, accumulating roughly 6,400 metric tons annually as wind relentlessly blows sand through the desert.
Star dunes make up just under 10% of the dunes in Earth's deserts and are the tallest ones, surpassing other types such as crescent-shaped barchan dunes and straight and lengthy linear dunes. They also have been spotted on Mars and on Saturn's large moon Titan.
"I first encountered star dunes in Namibia 20 years ago, and was instantly amazed at the size of them. I have a vivid memory of the long climb to the top, struggling up very loose sand in the heat of the day," said geographer Geoff Duller of Aberystwyth University in Wales, co-author of the study published in the journal Scientific Reports.
"I find desert dunes very beautiful," Duller added. "The sight of the sinuous curves, and the way that the light and shadow changes with the sun mean that they always look different, whether that is in the cool of the morning, the midday sun or near sunset. The different colors of sand in different deserts are also very striking, with yellow, white, red and even black dunes in different parts of the world."
The ground-penetrating radar revealed the layers within the Lala Lallia dune, showing how it was constructed over time through accumulating sand and how parts of its internal structure resembled other types of dunes.
"Star dunes are formed in areas with complex wind regimes, which means winds blowing from different directions, and net sand accumulation, points within the desert where big piles of sand can be blown around to form giant dunes," said Birkbeck University of London sedimentologist and study co-author Charlie Bristow.
The researchers also determined that Lala Lallia is moving westerly at a speed of about 1.6 feet (0.5 meters) annually.
While many star dunes are known today, only a single ancient one has been found preserved as sandstone in the geological record, dating to about 250 million years ago, in Scotland. By revealing their internal structure, the researchers said their findings provide a guide for geologists to identify more sandstone remnants of ancient star dunes.
Earth's largest star dunes are found in the Badain Jaran desert in western China. Star dunes also are found in places including the Namib Sand Sea in Namibia, large sand seas in Algeria such as the Grand Erg Oriental and Grand Erg Occidental, and Rub' al Khali in Saudi Arabia. In North America, Great Sand Dunes National Park in Colorado contains a series of them.
"They form extraordinary and awe-inspiring landscapes," Bristow said. "From the ground they can be intimidating, mobile mountains of sand."

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US: Shark Attack on Alabama Teen Inspires Start of National Alert System

This undated photo courtesy of the Gribbin family shows Lulu Gribbin, who lost her hand and part of her leg in a shark attack off the coast of Florida in 2024. (Courtesy of Gribbin family)
This undated photo courtesy of the Gribbin family shows Lulu Gribbin, who lost her hand and part of her leg in a shark attack off the coast of Florida in 2024. (Courtesy of Gribbin family)
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US: Shark Attack on Alabama Teen Inspires Start of National Alert System

This undated photo courtesy of the Gribbin family shows Lulu Gribbin, who lost her hand and part of her leg in a shark attack off the coast of Florida in 2024. (Courtesy of Gribbin family)
This undated photo courtesy of the Gribbin family shows Lulu Gribbin, who lost her hand and part of her leg in a shark attack off the coast of Florida in 2024. (Courtesy of Gribbin family)

Lulu Gribbin was 15 when she survived a shark attack off the coast of Florida. She lost her left hand, part of her right leg and almost her life.

What she didn’t know when she entered the water on that day in 2024 was that another woman had been bitten by a shark 90 minutes earlier and just 3 miles (4.8 kilometers) down the beach. Had she known about the earlier attack, there is no way she would have been swimming, she said.

Gribbin’s story has inspired new federal legislation to authorize emergency alerts to mobile phones to warn beachgoers when a shark has bitten someone in the area.

President Donald Trump last week signed “Lulu’s Law,” which requires the Federal Communications Commission to allow the emergency messages. The legislation, which Gribbin advocated for, authorizes the warnings by classifying a shark attack as an event for which an emergency alert can be issued. It is up to states to implement the warnings.

Gribbin’s home state of Alabama approved such a warning system last year.

“It’s really just common-sense legislation. It says that whenever there has been a shark attack in a certain area where you are near, it will send an alert to your phone, exactly like how an Amber Alert system works when a child is abducted,” The Associated Press quoted her as saying.

Gribbin said she hopes the alert system will help prevent attacks like hers. “I definitely see this law working in the future and I'm really excited to hopefully save lives,” she said.

A fight to survive Gribbin was one of three people bitten by a shark on June 7, 2024, off the Florida Panhandle.

She was on a mother-daughter trip to the Florida Panhandle. Gribbin said she and her friend had been diving for sand dollars.

“All of the sudden my best friend yelled, ‘Shark!’ and so we all started swimming for our lives,” Gribbin recalled. She said she remembered that sharks are attracted to frantic splashing and yelled for everyone to be calm. Gribbin, who was closest to the shark, was bitten.

“The shark bit off my hand first, and I raised my arm out of the water, and there was just flesh and bone there,” Gribbin said. The shark then latched onto her leg. A man punched the shark off her and strangers on the beach rushed to help. She was flown by helicopter to a nearby hospital.

Doctors were able to save the teen's life but had to amputate part of her right leg.
Choosing positivity throughout her recovery In the hospital, Gribbin made a deliberate decision to choose joy and to never give up.

Gribbin was fitted with prosthetic limbs, quickly regained her ability to walk, returned to sports and got her driver’s license. She has gone back in the water and learned to surf, meeting Bethany Hamilton, a professional surfer who lost her arm in a shark attack.

US Sen. Katie Britt, the Alabama Republican who sponsored the legislation, said the legislation happened because of the teen's “courage, perseverance, and advocacy to protect future beachgoers.”

“Because of her strength, lives will be changed. We should all be inspired by her,” Britt said.

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Three Wallabies Saved from Spanish Cannabis Farm Hell

Children cool off at an urban beach of Madrid Rio park in Madrid, Spain, Thursday, July 2, 2026. (AP Photo/Andrea Comas)
Children cool off at an urban beach of Madrid Rio park in Madrid, Spain, Thursday, July 2, 2026. (AP Photo/Andrea Comas)
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Three Wallabies Saved from Spanish Cannabis Farm Hell

Children cool off at an urban beach of Madrid Rio park in Madrid, Spain, Thursday, July 2, 2026. (AP Photo/Andrea Comas)
Children cool off at an urban beach of Madrid Rio park in Madrid, Spain, Thursday, July 2, 2026. (AP Photo/Andrea Comas)

Three traumatized wallabies living far from their usual Australian habitat were recovering in a Spanish zoo on Thursday after being rescued from a rural cannabis plantation full of rotting animals, AFP reported.

Police said the marsupials, similar to but smaller than kangaroos, were saved alongside 14 dogs, three calves and two deer from their ordeal in the central municipality of Malagon on Tuesday.

During their raid, "the officers came across an unusual scene when they found dozens of animals in woeful hygiene and sanitary conditions", police said in a statement.

The trapped animals lived alongside the corpses of other creatures, "some of them in an advanced state of decomposition", including "hundreds of chickens" who were tossed in bags to the dogs as food.

The wallabies and the deer shared a garden used by the suspects and their young children, the police added.

The wallabies were later taken to a zoo in the central province of Toledo.

Officers seized almost 1,000 cannabis plants from the site, which included an underground production area and was illegally connected to the power grid.

Two suspects were arrested on charges including animal abuse and offences against flora, fauna and public health.

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French Scramble to Find Air Conditioners before Next Heatwave

A sign reading 'During intense heat protect yourself' is seen inside an air-conditioned room open to the public inside the 17th district city hall as temperatures rise in Paris, during a heatwave affecting a majority of the country, in France, June 25, 2026. REUTERS/Alice Sacco
A sign reading 'During intense heat protect yourself' is seen inside an air-conditioned room open to the public inside the 17th district city hall as temperatures rise in Paris, during a heatwave affecting a majority of the country, in France, June 25, 2026. REUTERS/Alice Sacco
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French Scramble to Find Air Conditioners before Next Heatwave

A sign reading 'During intense heat protect yourself' is seen inside an air-conditioned room open to the public inside the 17th district city hall as temperatures rise in Paris, during a heatwave affecting a majority of the country, in France, June 25, 2026. REUTERS/Alice Sacco
A sign reading 'During intense heat protect yourself' is seen inside an air-conditioned room open to the public inside the 17th district city hall as temperatures rise in Paris, during a heatwave affecting a majority of the country, in France, June 25, 2026. REUTERS/Alice Sacco

Hundreds of people were besieging Lidl supermarkets in and around Paris Thursday, with scuffles and shouting matches breaking out as residents scrambled to get their hands on bargain air-cooling units before the next heatwave hits the French capital.

With few air conditioners on sale elsewhere for less than 1,200 euros ($1,400), police were called to at least two stores as huge crowds descended on Lidl supermarkets trying to get their hands on basic models on sale for as low as 179 euros, AFP said.

Mousa Traore, who had been waiting for more than an hour along with some 200 other customers at a small Lidl store in a northern Paris neighborhood, said he had been told there were only two units on sale, AFP .

"But then the police came and we were told there were none. The police officers took them I think," he said laughing.

France has just been through a record heatwave that led to excess deaths, overwhelmed hospitals, closed schools and cancelled music festivals, and weather services are forecasting another round of hot weather this coming weekend.

Due to historically mild summers, few homes and schools in France are equipped with air conditioning, making them ill-equipped to face increasingly frequent heatwaves that scientists say are linked to human-induced climate change.

- 'It's madness' -

Even so, the crowd at the Lidl store was mostly good-humored, but some disputes broke out as people tried to jump the queue.

"I am not opening the store unless you leave," a manager shouted, as customers harangued her, with another member of staff telling AFP only two air conditioners had been delivered.

He refused to say if they had already been sold.

Hundreds more descended on a supermarket in Sevran, with cars queuing for the store blocking the center of the poor northern suburb. It was much the same story in nearby suburb of Livry-Gargan.

"I give up, it's madness. I abandoned my car several streets away to get there on foot but there is already a huge queue of people in the car park. It's impossible," one local called Lolo told AFP.

The rush for cooling units comes despite longstanding skepticism towards air conditioning in France.

Eight in 10 people view it as environmentally unfriendly, according to a survey of more than 1,000 people published last month.

But attitudes appear to be shifting as temperatures climb, with cooling units flying off shelves.

In the midst of the heatwave on June 22, hypermarket operator Carrefour had sold 30,000 units by 6:30 pm - "a thousand times more than on a normal day", CEO Alexandre Bompard said.

The share of French households equipped with air conditioning rose from 18 percent in 2023 to 24 percent in 2025, according to the state environment agency Ademe.

Air conditioning has emerged as a political weather vane in France, with the main far-right opposition party criticizing the government for not having prepared for hotter weather, and ecologists warning of the heavy energy demands of running air conditioners.