FreshRSS

Normální zobrazení

Jsou dostupné nové články, klikněte pro obnovení stránky.
PředevčíremPopular Science
  • ✇Popular Science
  • Egypt’s oldest pyramid may have been built using a hydraulic liftAndrew Paul
    The honor of Egypt’s oldest necropolis belongs to Pharaoh Djoser, a ruler who ushered in the Old Kingdom’s Third Dynasty during the 27th century BCE. Constructed around 2,680 BCE in Saqqara, northwest of the ruins of Memphis, the six-tier, four-sided Step Pyramid of Djoser stood amid a large courtyard filled with decorative ceremonial structures. And while ancient Egyptians relied on a number of tools to help build the roughly 205-foot-tall structure, a new study indicates at least one previousl
     

Egypt’s oldest pyramid may have been built using a hydraulic lift

5. Srpen 2024 v 20:00

The honor of Egypt’s oldest necropolis belongs to Pharaoh Djoser, a ruler who ushered in the Old Kingdom’s Third Dynasty during the 27th century BCE. Constructed around 2,680 BCE in Saqqara, northwest of the ruins of Memphis, the six-tier, four-sided Step Pyramid of Djoser stood amid a large courtyard filled with decorative ceremonial structures. And while ancient Egyptians relied on a number of tools to help build the roughly 205-foot-tall structure, a new study indicates at least one previously unknown aid—a hydraulic lift system utilizing a nearby, longgone lake.

The evidence was made available on August 5 by an interdisciplinary team at France’s CEA Paleotechnic Institute writing in the journal PLOS One. After combining satellite imagery, geospatial data analysis, watershed information, and other techniques, the researchers hypothesize a previously unexplained structure near the Step Pyramid likely functioned as a “check dam” for capturing water and sediment. An ancient engineering structure dating back millennia, check dams are comparatively simple designs used to interrupt and slow water flows.

Map of the Saqqara plateau showing the water course from the Gisr el-Mudir dam to the water treatment facility near Djoser pyramid. The water is then transferred to the pyramid's network of pipes to power the hydraulic elevator. Credit: Paleotechnic of Paris, France, CC-BY 4.0
Map of the Saqqara plateau showing the water course from the Gisr el-Mudir dam to the water treatment facility near Djoser pyramid. The water is then transferred to the pyramid’s network of pipes to power the hydraulic elevator. Credit: Paleotechnic of Paris, France, CC-BY 4.0
Schematic of pyramid hydraulic lift
The identified building process of the step pyramid: A hydraulic lift mechanism. Credit: Landreau et al., PLOS ONE

In the Pyramid of Djoser’s case, a water source appears to have channeled through multiple compartments, allowing the sediment to settle while passing through each successive chamber. After traveling through the compartments, some of the water then likely flowed into pyramid shafts built to help builders raise massive building stones to their desired positions. What is particularly interesting is that, although many societies didn’t use check dams for filtration, it appears the pyramid’s may have also served as an water treatment facility. Additionally, the Pyramid of Djoser’s dam predates some of the earliest known examples by hundreds, if not thousands, of years.

To illustrate the concept, researchers described a simple example of how ancient Egyptians may have operated such a hydraulic-check dam system. Based on their analysis, the team believes the lift’s floating platform rose to a maximum height of around 55 feet, but potentially employed modifications to ascend even higher using collapsible extension structures. After reaching the top of the pyramid, the lift platform may have also functioned as a counterweight through the use of pulley-and-rope systems. Combined with additional construction methods like ramps and levee systems, the hydraulic lift may have only been used intermittently when enough water was available. Even so, researchers stressed the lift’s potential existence fundamentally alters what experts believe ancient Egyptians were capable of creating.

[Related: ‘Screaming woman’ may solve a 3,500-year-old mummy mystery.]

“The hydraulic lift mechanism seems to be revolutionary for building stone structures and finds no parallel in our civilization,” they write in their paper, adding that its utility “is so significant that it seems beyond just building the Step Pyramid.” Combined with its water treatment capabilities, the architects’ planning would also “reflect their foresight in meeting various civil needs,” such as making the Saqqara region hospitable for permanent settlement, including agriculture, water access, and long term shelter.

The team argue their findings also raise the possibility that ancient Egyptians utilized similar systems in other Old Kingdom pyramids, and perhaps even earlier. The only way to know for sure, however, is to continue exploring and analyzing these ruins.

The post Egypt’s oldest pyramid may have been built using a hydraulic lift appeared first on Popular Science.

  • ✇Popular Science
  • Archeologists uncover hoard of gold coins linked to ancient mercenariesLaura Baisas
    A team of archaeologists and other researchers uncovered a cache of roughly 2,600-year-old gold coins that were likely an unknown mercenary’s salary. The gold was stored in a small pot in the ancient Greek city of Notion, located in western Turkey. The gold was discovered by the Notion Archaeological Project in July 2023, and the Turkish Ministry of Culture and Tourism has officially given permission for the discovery of the coins to be made public this month. [Related: Ancient, surprisingly
     

Archeologists uncover hoard of gold coins linked to ancient mercenaries

5. Srpen 2024 v 18:00

A team of archaeologists and other researchers uncovered a cache of roughly 2,600-year-old gold coins that were likely an unknown mercenary’s salary. The gold was stored in a small pot in the ancient Greek city of Notion, located in western Turkey. The gold was discovered by the Notion Archaeological Project in July 2023, and the Turkish Ministry of Culture and Tourism has officially given permission for the discovery of the coins to be made public this month.

[Related: Ancient, surprisingly well-preserved purple dye uncovered in Greece.]

What are darics?

According to University of Michigan archaeologist Christopher Ratté, the coins show a figure of a kneeling archer. This image is a characteristic design of the Persian daric–a type of gold coin that was issued by the Persian Empire. The coins were likely minted at Sardis, roughly 60 miles northeast of Notion. The hoard of coins will provide more data on the Persian daric’s timeline and history.

“The discovery of such a valuable find in a controlled archaeological excavation is very rare,” Ratté said in a statement. “No one ever buries a hoard of coins, especially precious metal coins, without intending to retrieve it. So only the gravest misfortune can explain the preservation of such a treasure.”

An aerial view of the house shows the different phases and the findspot of the coins as well as other artifacts. CREDIT: Notion Archaeological Project.

Darics were created from the late Sixth Century BCE up until Alexander the Great’s conquest of the Persian Empire in 330 BCE. The design of the coins stayed the same with very small stylistic differences. Researchers have attempted to arrange the coins in chronological order by analyzing these minor stylistic differences. This newly discovered hoard of coins sticks out because it is independently dated by other artifacts that are associated with it.

“This hoard will provide a firm date that can serve as an anchor to help fix the chronology of the (entire sequence of coins),” Ratté said.

According to the British Musuem’s former curator of coins and Oxford University classics historian Andrew Meadows the archaeological context for the hoard is likely, “if it can be established accurately by other means, to allow us to fine-tune the chronology of the Achaemenid gold coinage. This is a spectacular find… of the highest importance.”

The best-preserved remains of the ancient city of Notion date back to the city’s Hellenistic period, between Third and First centuries BCE. However, the excavation of a large courtyard house at the center of the city shows that it was likely inhabited earlier. Fragments of pottery likely from the Fifth Century BCE were found in earlier walls incorporated into the foundations of the house. In July 2023, a dig beneath one area of the courtyard revealed the gold coins, buried in a small pot.

“The hoard was found in the corner of a room in a structure buried beneath the Hellenistic house. Presumably, it was stored there for safekeeping and for some reason never recovered,” said Ratté. “According to the Greek historian Xenophon, a single daric was equivalent to a soldier’s pay for one month.”

A military city

According to Ratté, darics have been found by looters with little concern for their historical value.

“An archaeological find without contextual information is like a person suffering from amnesia—a person without memories,” Ratté said. “It is still interesting and important, but the loss of knowledge is incalculable.”

With this specific hoard, archaeologists and historians know precisely where it was found, so they have a great deal of circumstantial evidence for when it was deposited and what was going on at the time.

A map of western Antola. CREDIT: Notion Archaeological Project, University of Michigan.

The city of Notion was incorporated into the Persian Empire together with the other Greek cities on Turkey’s western coast in the Mid-Sixth Century BCE. It was eventually freed from Persian rule in the early Fifth Century BCE. However, it was reintegrated into the Persian Empire in the early Fourth Century BCE, where it remained until Alexander the Great’s conquest in 334 BCE. 

Military operations around the city have been frequently noted by ancient historians. During the Fifth Century BCE, Notion was under Athenian domination despite being freed from the Persians. The Greek historian Thucydides documented the dramatic and conflicting loyalties of the inhabitants of Notion and nearby cities. This area occupied a border region between the Persian and Athenian spheres of influence. 

[Related: These ‘fake’ ancient Roman coins might actually be real.]

Thucydides recounted that between 430 BCE. and 427 BCE., a group of Persian sympathizers from the city of Colophon had occupied part of Notion with the help of Greek and “barbarian” mercenaries. An Athenian general called Paches killed the pro-Persian mercenaries, after luring their commander into a trap in 247 BCE. Persian sympathizers were ultimately expelled, and the city of Notion was reorganized under Athenian supervision.

This type of event may have led to this hoard of coins being deposited and lost, but it is not the only possibility. In 406 BCE, a decisive naval battle during the conflict between Athens and Sparta was fought off the coast of Notion. The city was an Athenian naval base at the time. During the Great Satraps’ Revolt, several governors in Western Anatolia erupted into renewed conflict in the 360s BCE, and Notion’s harbor became an important military asset. The harbor was likely reinforced during this period. The accepted chronology of Persian coins would favor a Fourth Century BCE date for the hoard from Notion.

The coins themselves are now being studied and cared for by the Ephesus Archaeological Museum in Turkey. Researchers are currently excavating new areas of the city that could clarify more of the archaeological context of the coins.

The post Archeologists uncover hoard of gold coins linked to ancient mercenaries appeared first on Popular Science.

  • ✇Popular Science
  • What science actually says about seed oilsLauren Leffer
    If you consume social media, you may have heard: Seed oils are terrible for your health–even toxic! Cooking oils derived from seeds cause everything from heart disease to inflammation to fatigue to bad skin–according to a certain subset of Internet influencers. Yet contrary to the posts demonizing the common ingredients, a bevy of scientific research disagrees. Here’s how to understand the health “scare.”  What are seed oils? There’re many different types of plant-based cooking oils, but w
     

What science actually says about seed oils

5. Srpen 2024 v 15:27

If you consume social media, you may have heard: Seed oils are terrible for your health–even toxic! Cooking oils derived from seeds cause everything from heart disease to inflammation to fatigue to bad skin–according to a certain subset of Internet influencers. Yet contrary to the posts demonizing the common ingredients, a bevy of scientific research disagrees. Here’s how to understand the health “scare.” 

What are seed oils?

There’re many different types of plant-based cooking oils, but when people talk about seed oils, they’re often referencing a list of eight: Canola, corn, cottonseed, soybean, sunflower, safflower, grapeseed, and rice bran oils. (Note that things like olive, avocado, and coconut oil are absent from this list.) All of these eight oils contain fat and therefore fatty acids (an essential major nutrient group). And many (though not all) of these seed oils contain a relatively high proportion of omega-6 fatty acids.

A quick chemistry aside: fatty acids are the building blocks of triglycerides, or complete fat molecules. They are organic compounds made up of predominantly carbon and hydrogen chains with an acid group on the end. In saturated fats, every carbon except for the terminal ones have two hydrogens bonded to it. In unsaturated fats, some of those hydrogens are replaced with double bonds between adjacent carbons instead. Omega-6 fatty acids are unsaturated, and the first of those double bonds occurs at the 6th carbon from the end–hence the name.

There are multiple kinds of omega-6 compounds, but one particular type, called linoleic acid, is at the center of most of the scorn against seed soils. Linoleic acid is, again, an essential nutrient that our bodies need. We cannot synthesize it, and we need it to support healthy cell signaling, function, and immune systems.

But seed oil detractors argue that we are ingesting far too much linoleic acid, leading to the accumulation of byproducts like arachidonic acid, which they claim causes inflammation and also counteracts the benefits of eating omega-3 fatty acids. The domino impact of all of this, anti-seed oil advocates assert, is higher risk of diseases like type 2 diabetes, heart disease, and cancer. 

A kernel of truth

Inside the backlash against seed oils are a few kernels of truth. Eating fried and processed foods in excess is generally detrimental to your health. So if avoiding seed oils translates into eating fewer french fries and snack cakes, you might feel better. 

Plus, if you eat a typical western diet, you are probably at no risk of linoleic acid deficiency, and you likely ingest more omega-6 fatty acids than omega-3s. In recent decades the amount of linoleic acid in our diets has increased because many processed foods and restaurant meals are made with soy, sunflower, or safflower oils and animal feed now contains a lot of soy, which translates to more linoleic acid inside meat and dairy products, says Philip Calder, a nutrition scientist and professor at the University of Southampton in England. “Linoleic acid has permeated the food chain in the last 50 to 60 years,” he tells Popular Science. 

Additionally, Calder explains that there is “theoretical evidence” that linoleic acid can be partially converted into arachidonic acid, which is subsequently partially converted into compounds associated with inflammation. Additionally, omega-6s and omega-3s can compete for the same metabolic pathways. All those biological mechanisms exist in the human body. 

Yet here is where things get sticky: that theoretical argument doesn’t stack up to scientific observation. “That just really doesn’t happen in real life,” says Guy H. Johnson, a nutrition scientist and adjunct professor of food science and human nutrition at the University of Illinois Urbana-Champaign. “If you’ve got enough omega-3, the inflammatory environment isn’t increased by omega-6s.”

What the research indicates


Calder agrees. “Most human studies either show there isn’t a relationship between linoleic acid intake and inflammation biomarkers, or that the relationship is the opposite to what you might think would happen. You see higher linoleic acid and higher arachidonic acid are associated with lower levels of inflammation biomarkers,” he says. He co-authored a 2018 review study assessing the published literature on inflammation and omega-6s and concluded as much. 

“We didn’t find anything that demonstrates there’s a harmful association between omega-6’s and inflammatory markers in humans,” he adds. A 2012 review co-authored by Johnson found the same thing.

Many other review studies and meta-analyses have come to similar conclusions, and additionally finding pluses where you might expect minuses. “Every time anybody looks at blood levels of omega-6s and health outcomes–and we’ve done this several times with thousands of people… you find that people with the highest levels of omega-6s have the best outcomes,” says William S. Harris, a professor at the University of South Dakota’s Sanford School of Medicine and president of the Fatty Acid Research Institute

Harris has co-authored multiple human cohort studies as well as large review papers assessing the impacts of omega-6 fatty acids on health. In a 2017 meta-analysis, he and his co-authors found that omega-6 consumption actually lowers risk of type 2 diabetes. In a 2020 review of 30 observational studies, Harris and his colleagues concluded that higher linoleic acid levels are associated with reduced risk of cardiovascular disease. 

In fact, higher linoleic acid intake is associated with lower risk of death from all causes including heart disease and cancer, according to another 2020 meta-analysis that assessed 38 different studies. I could keep linking studies–there are dozens of them, but you probably get the point. 

The way fatty acids and metabolic processes unfold in the body is complicated. “There’s a nuanced interplay between omega-6s, omega-3s, and a variety of other metabolites,” Harris says. The view that omega-3s are good and omega-6s are bad “is not true and is far too simplistic,” he adds. 

There are a couple of legitimate, contrary bits of research out there, say both Harris and Calder. Including two, often-cited papers published by lead author Christopher Ramsden, chief of the Lipid Peroxidation Unit in the National Institute on Aging. In these studies, Ramsden uncovered previously unpublished research from the late 1960’s and early ‘70’s wherein two groups of people fed a diet high in seed oils and margarine showed worse health outcomes. 

However, there are big caveats to these findings. For one, the study participants were fed much higher levels of omega-6-containing oils than is common in diets today, notes Harris. Plus many of the solid margarines the study used likely contained high amounts of trans fats, which are uniformly understood to be harmful to human health, says Calder.

Another concern that the seed oil skeptics cite is the use of hexane in production. “It’s true that hexane is used to extract vegetable oils from whatever their source is,” notes Johnson, who has written multiple health claim petitions on various oils. “But the product that consumers buy in the grocery store has no hexane in there at all. It’s gone,” he adds– removed during processing. 

All in all, the vast majority of scientific evidence indicates that cooking with omega-6 containing oils is harmless and probably good for you. 

So, what should you eat?

Given the above, it might sound like you start chugging safflower oil, but that’s not exactly the case. Since the western diet already includes so much omega-6, you’re probably covered. “We’re getting plenty of omega-6s. I’m not really advocating that people start supplementing their diet with omega-6,” says Harris. “But what I would say is efforts to reduce the intake of omega-6 are going to have an adverse effect on health,” he adds. This because less omega-6 means less of the observed protective benefits of linoleic acid, Harris explains. 

And it may also be that those seeking to swap out seed oils inadvertently end up swapping in less healthy alternatives. Often, influencers combine their disdain for seed oils with other health fads, like promoting the “carnivore diet,” anti-sunscreen sentiment, or even sometimes all three in one. This pile of misinformation would have viewers eschewing sun protection and vegetables, while chowing down on whole t-bone steaks and sticks of butter daily. Nothing in the vast amount of scientific research on human health and nutrition indicates any of the above is a good idea. 

Saturated fats may not be as harmful to heart health as once thought, but a diet very high in saturated fats and animal products can still raise your risk of high cholesterol and cardiovascular disease. And again, we already eat a lot of saturated fat. In order from most to least healthy in the context of the modern western diet, Calder says that omega-3s are the best option, omega-6s come second, and saturated fats are at the bottom of the pyramid of things you need to eat more of. 

Harris, too, recommends people try to eat more omega-3’s, particularly the kind found in seafood (seaweed and algae can provide a plant-based source for vegans and vegetarians). 

And broadly, the best path to a healthy diet is probably what you’d expect. A diet rich in fruits and vegetables, with whole grains and lots of fiber, is best, say Calder and Johnson. “It’s what your mother told you,” Johnson adds. Moving more and eating slightly less overall, are probably also good ideas for most Americans, notes Harris. “It’s not sexy, but that’s the way it is.” 

Finally, to stay your sharpest, be mindful of the health claims you see online. Always remember correlation doesn’t equal causation, one person’s experience is not equivalent to a robust scientific study, and there is no simple quick-fix for every health problem. “If it sounds too good or simple to be true, then it probably is,” says Johnson. 

The post What science actually says about seed oils appeared first on Popular Science.

  • ✇Popular Science
  • The terrible Radio Shack computer that became your phonePopular Science Team
    Apple, Microsoft, Intel, Dell, IBM, HP, Samsung…Tandy? Tech history is filled with stories of companies that survived industry turbulence and came out stronger on the other side. There’s also no shortage of companies that fizzled out spectacularly and became little more than footnotes. Such is the story of Tandy and its TRS-80 Pocket Computer. Sold exclusively through Radio Shack, the TRS-80 was part of a a new generation of tiny, lightweight personal computers you could take on the go. Sure,
     

The terrible Radio Shack computer that became your phone

4. Srpen 2024 v 19:04

Apple, Microsoft, Intel, Dell, IBM, HP, Samsung…Tandy? Tech history is filled with stories of companies that survived industry turbulence and came out stronger on the other side. There’s also no shortage of companies that fizzled out spectacularly and became little more than footnotes. Such is the story of Tandy and its TRS-80 Pocket Computer.

Sold exclusively through Radio Shack, the TRS-80 was part of a a new generation of tiny, lightweight personal computers you could take on the go. Sure, in 2024, we don’t think twice about the personal computers (aka smartphones) we all carry everywhere, but in the early-1980s, these devices sounded like the future. Popular Science even dedicated its November 1980 cover to the gadgets with columnist V. Elaine Smay writing: “At home, in the office, on the road–these small computers give you brainpower to go.”

a popular science magazine cover with the cover story "hand-held computers'
The November 1980 cover of Popular Science.

If you’ve never heard of Tandy or the TRS-80 Pocket Computer, that’s understandable. Tandy the company gots its name from Dave Tandy and his son, Charles, who ran the Hinckley-Tandy Leather Company in Texas. Yes, a leather goods company that eventually acquired Cost Plus Imports (which would eventually become Pier 1), Color Tile, Leonard’s, and Radio Shack in 1962. It was the purchase of Radio Shack that propelled Charles Tandy into the tech industry.

In 1977, the releases of the Commodore PET 2001, the Apple II, and the TRS-80 desktop marked the first time that fully-assembled, programmable computers could be easily purchased by… pretty much everyone. Before that, hardcore enthusiasts had to put together their own minicomputer kit. And of course everyone knows Apple today, but in 1977, Tandy was as significant as Apple is now. They even had a built-in distribution system through the massively successful Radio Shack, which had more retail locations than McDonald’s. They dominated early personal computer sales by owning 60 percent of the PC market.

So what went wrong? In our latest Popular Science video, host Kevin Lieber not only unravels the history of the TRS-80 Pocket Computer but also slowly descends into a state of unrelenting frustration by trying to use one. Can Kevin find the correct cables to play games on his TRS-80? Why don’t we all scroll Instagram on a Tandy smartphone? The answers provide a lesson in why some companies are lost to time, regardless of how successful or influential they once were.

Want more original Popular Science videos? Subscribe on YouTube. See you in the future.

The post The terrible Radio Shack computer that became your phone appeared first on Popular Science.

  • ✇Popular Science
  • 19 magnificent images from the Astronomy Photographer of the Year shortlistPopular Science Team
    A galactic worm gobbles stars. A plasma whale slides across the sun‘s surface. And an eerie dragon dances with an aurora. It’s not the plot to a fantasy novel, it’s our incredible universe captured in stunning detail. The Royal Observatory Greenwich has announced the shortlisted images for the 2024 Astronomy Photographer of the Year. The finalists were selected from more than 3,500 images submitted from professional and amateur photographers from 58 countries. The winner will be announced Se
     

19 magnificent images from the Astronomy Photographer of the Year shortlist

4. Srpen 2024 v 00:05

A galactic worm gobbles stars. A plasma whale slides across the sun‘s surface. And an eerie dragon dances with an aurora. It’s not the plot to a fantasy novel, it’s our incredible universe captured in stunning detail.

The Royal Observatory Greenwich has announced the shortlisted images for the 2024 Astronomy Photographer of the Year. The finalists were selected from more than 3,500 images submitted from professional and amateur photographers from 58 countries. The winner will be announced September 12 and an exhibition of the top images will be on display in London at the National Maritime Museum starting September 14.

the stages of an eclipse showing the moon as a black dot and pink colors of the sun behind it
Total Solar Eclipse”
 Gwenaël Blanck travelled to Australia in April 2023 to see the 62-second long total solar eclipse. In this collage he shows the corona and the pink chromosphere, the prominences and Baily’s beads, chinks of sunlight that shine through due to the Moon’s rugged landscape. The image is made of seven superimposed pictures, one overexposed for the background and six others for the chromosphere and prominences. Image: © Gwenaël Blanck (France)
meteors look like rain with red bursts of light seen above a building
A Cosmic Firework: the Geminid Meteor Shower” 
This photograph of the Geminid meteor shower was taken under perfect conditions on La Palma. During the peak of the night, Sahner could easily spot two or three or more meteors per minute within the field of view. The panorama shows the entire winter Milky Way as seen from La Palma in RGB natural colour with extra details in H-alpha. Image: © Jakob Sahner (Germany)
a swirly galaxy on the backdrop of a black sky and dots of stars
M81, a Grand Design Spiral Galaxy”
M81, also known as Bode’s Galaxy, is about 11.75 million light years away in the constellation Ursa Major. It is one of the brighter galaxies in the night sky. In the image’s background, some Integrated Flux Nebula (IFN) can be seen. IFN is dust outside the Milky Way’s galactic plane that is illuminated only by the stars in the Milky Way. Image: © Holden Aimar (USA), aged 14 
a rainbow aurora above a mountain near a lake. to the left is a person
“A Night with the Valkyries”
A view of the Eystrahorn Mountain (Iceland) on the night of a KP7 storm (a strong geomagnetic storm that can cause aurorae and upset electrical power systems). The intensity of the storm resulted in the impressive range of colours in the sky. Image: © Jose Miguel Picon Chimelis (Spain) JOSE CHIMELIS
a swirling aurora that resembles a dragon's head turning back
The Fire-Spitting Dragon
The photographer was able to capture the aurora in motion when it turned into something resembling a dragon’s head on a clear night. Telser chose to use black and white to emphasise the contrast of the aurora against the dark sky. Image: © Moritz Telser (Italy) MORITZ TELSER
swirls on the sun's surface, including a chunk of plasma in the shape of an upside-down whale
A Whale Sailing the Sun
This image shows the details of the Sun’s surface. The photographer views the shape of the filament to the left of the disc as an immense plasma whale traversing the solar surface. Eduardo Schaberger Poupeau captured this photo by recording two videos (one for the disc and another for the prominences), each consisting of 850 frames. Image: © Eduardo Schaberger Poupeau (Argentina) 
the milky way and thousands of stars above an abandoned house and dead tree
Abandoned House”
This image shows an abandoned house in the middle of the Namib Desert with the Milky Way rising above it. The sky was captured with a star tracker to lower the ISO. The veil of clouds and halos around the stars create a dreamlike effect. Image: © Stefan Liebermann (Germany) 
a green and purple aurora above rock structures shaped like upside-down Vs
Arctic Dragon
This impressive aurora, which seemingly takes the form of a dragon, was the result of a geomagnetic storm (level G2) generated by a coronal mass ejection. The photo was captured at the Arctic Henge, which was one of the only places in Iceland with clear skies that night. Image: © Carina Letelier Baeza (Chile) Cari Letelier
the international space station looks tiny in front of a full moon
Hunter’s Moon and the ISS
This image captures the International Space Station (ISS) in transit across October’s Full Moon, the Hunter’s Moon, approximately 12 hours after a partial lunar eclipse. The striking beauty of the Full Moon is on display, with its mix of rugged highlands, bright crater rays and darker maria. Image:  © Tom Glenn (USA) 
volcanic fire emerges in the foreground with stars and skies in background
Earth and Milky Way Galaxy Show”
Mount Aso in Kumamoto Prefecture is the collective name for the five peaks often called the ‘Five Mountains of Aso’. One of the peaks, Nakadake, has a volcanic crater that is still active. Abe wanted this image to show how the Milky Way has watched over activity on Earth since prehistoric times. This is a composite photograph with the foreground and sky photographed separately but without moving the tripod. Image: © Yoshiki Abe (Japan)
a swirling galaxy on black sky with bright stars
M100 (The Blowdryer Galaxy) and Ceres
In this image the photographer was able to capture a dwarf planet, Ceres, more than a billion times smaller than its galactic counterpart, transit beyond the galaxy’s spiralling arms. Ceres shines brighter than the galaxy and moves quickly across the night sky. For this image, multiple long exposures were captured over an eight-hour period to showcase the beauty of the Blowdryer Galaxy and the relatively quick speed of the dwarf planet Ceres. Image: © Damon Mitchell Scotting (UK) 
a cloud shaped like a large worm with its mouth open on the backdrop of a dark sky and stars
The Galaxy Devourer
CG4 (Cometary Globule 4) is a complex of nebulosity and dust with a very peculiar shape, located in the southern constellation of Puppis. The ‘head’ of the galactic worm has dimensions of about 1.5 light years. This image is the result of the work of a team of astrophotographers: they joined forces to rent the powerful Newtonian 500-mm telescope from Chilescope service, processing the raw files and then voted for the best images. Image: © ShaRa
time-lapse photograph of stars moving in the sky shown as streaks with a cracked desert in the foreground
Serpentine
This image was taken at Snettisham Beach, famous for its vast tidal mudflats that attract migrating birds in staggering numbers. The foreground subject is a dilapidated jetty, which was built in the Second World War to allow gravel extracted from the nearby pits to be moved by boat. The curved channel in the mudflat mirrors the trailing stars. Image: © Paul Haworth (UK) 
a statue of a person walking under the milky way
Run to Carina”
This photograph captures a sculpture in north-west Namibia. Made of stone, this is one of a group of sculptures known as the ‘Lone Men of Kaokoland’ [as the region was formerly known]. No one knows who has put them there. A long exposure of the stone running man was taken first, then the tripod was moved for a clear view of the horizon. Image: © Vikas Chander (India) 
a rainbow of color appears around the sun above mountains
The Palette of the Himalayas
During the Spring Festival, the Sun and altostratus clouds acted together to create this huge corona, soaring above the Himalayas. The result is an enormous colour palette above the snowy peaks. Image: © Geshuang Chen (China) 
a ringed planet on a black sky
Saturn with Six Moons”
Saturn’s decreasing ring tilt means the moon Titan is closer to Saturn from our viewpoint than it has been in over a decade. At the centre of the image, Tethys is just about to disappear behind Saturn, while Rhea, Enceladus and Mimas are on the left, and Dione is to the lower right. The planet’s shadow on the rings is prominent, as are the Cassini and Encke divisions. Image: © Andy Casely (Australia) 
a pancake-shaped galaxy
The Inner Dust Lanes of M104 (The Sombrero Galaxy)
 The intense brightness of M104’s core often hides the details that lie inside the encircling ring of dust. In this image the dust appears to spiral into that core, floating on a wafer-thin layer as it falls towards the massive central black hole. The brighter, more colourful stars in the image are actually in the foreground − a part of our Milky Way galaxy. Image: © Kevin Morefield (USA)
red and blue bursts of color
The Scream of a Dying Star”
The Cygnus supernova afterglow is a popular object with astrophotographers, but the idea here was to take advantage of the high quality of the sky and the long exposure time to highlight details that are rarely seen, such as the outer envelope of the supernova remnant. The image’s name is a nod to The Scream, the famous painting by Edvard Munch, symbolising the scream that continues to echo through space after the star’s death. Image: © Yann Sainty (France) 

The post 19 magnificent images from the Astronomy Photographer of the Year shortlist appeared first on Popular Science.

  • ✇Popular Science
  • Yes, the moon has an atmosphere—and it’s metal as hellTom Hawking
    When you learn about the moon in school, you’re generally taught that its gravity is insufficient to capture and retain any significant atmosphere. The moon is nonetheless surrounded by a thin, ephemeral halo of gasses—an exosphere. This surprising fact was first discovered using instruments carried by astronauts who visited the moon with the Apollo program. The moon’s weak gravity means that the exosphere’s constituent atoms are constantly draining away into space—and, as such, its continuou
     

Yes, the moon has an atmosphere—and it’s metal as hell

2. Srpen 2024 v 20:00

When you learn about the moon in school, you’re generally taught that its gravity is insufficient to capture and retain any significant atmosphere. The moon is nonetheless surrounded by a thin, ephemeral halo of gasses—an exosphere.

This surprising fact was first discovered using instruments carried by astronauts who visited the moon with the Apollo program. The moon’s weak gravity means that the exosphere’s constituent atoms are constantly draining away into space—and, as such, its continuous presence means that the supply of these atoms is being constantly replenished.

A new study published in Science Advances on August 2 looks at exactly how this replenishment happens. It examines a group of elements whose presence in the lunar atmosphere might come as a surprise to anyone who’s studied chemistry: alkali metals.

Alkali metals form the first group of the periodic table, and include lithium, sodium, potassium, rubidium, and caesium (along with francium, which is never found in macroscopic quantities because it’s so radioactive). Why is their presence a surprise? On Earth, they’re famous for their reactivity, as evidenced by the classic high school demonstration of what a piece of sodium does when it encounters water. On the moon, however, things are very different. 

As Prof. Nicole Nie, lead author of the paper, tells Popular Science, “In lunar soils and rocks, alkali metals are bound in minerals, forming stable chemical bonds with oxygen and other elements. But when they are released from the surface, they usually become neutral atoms. There is no liquid water or substantial atmosphere [on the moon], so these metals can remain in their elemental form—[and] because the number of atoms in the lunar atmosphere is so small, the atoms can travel a long distance freely without colliding with one another.”

This does, however, raise the question of how the atoms are released from the surface in the first place. The paper seeks to answer this question—and, specifically, the relative contributions of three processes known collectively as “space weathering.” The uniting factor in these three processes is that they involve something striking the lunar surface and knocking the alkali metal elements out of the mineral compounds in which they’re bound. (These processes also release other elements, but the volatility of alkali metals makes them particularly easy to liberate.)

The first of these processes is micrometeorite impacts, where tiny pieces of space debris rain down with sufficient force to vaporize a small piece of the lunar surface and launch its component atoms into orbit. The second is ion sputtering, where charged particles driven by the solar wind strike the lunar surface. And finally there’s photon-stimulated desorption, where it’s high-energy photons from the sun that knock the alkali metals loose.

As the paper notes, while each process has been well-characterized, previous research has “not conclusively disentangled their [relative] contributions” to the lunar atmosphere. To go about doing this, Nie and her team went right back to the source of the question: the Apollo program. The various crewed missions to the moon in the late 1960s and early ‘70s brought back a total of 382 kg of lunar soil samples, and decades later, these samples are still revealing their secrets to researchers. Nie’s study involved examining 10 samples from five different Apollo missions, including several from Apollo 8, the first manned moon landing.

The team used these samples to look at the relative proportions of different isotopes of potassium and rubidium in the soil. (Sodium and cesium only have one stable isotope each, while lithium is less volatile than its heavier cousins.) As Nie explains to Popular Science, “Lighter isotopes of an element are preferentially released during these processes, leaving the lunar soils with relatively heavier isotopic compositions. For elements that are affected by space weathering, we would expect lunar soils to show heavy isotopic compositions, compared to deeper rocks that are not affected by the process.”

The different space weathering processes produce different ratios of isotopes, and the team’s results indicate that it appears that micrometeorite impacts make the largest contribution to the lunar atmosphere, “likely contributing more than 65% of atmospheric [potassium] atoms, with ion sputtering accounting for the rest.”

This provides a valuable insight into how the moon’s atmosphere has evolved over billions of years—while its composition may well vary over shorter timescales, these results suggest that in the long run, micrometeorite impacts play the dominant role in the constant replenishment of the atmosphere. The study also points to how similar research might be carried out on other objects similar to the moon, like Phobos, one of Mars’s two satellites.

The post Yes, the moon has an atmosphere—and it’s metal as hell appeared first on Popular Science.

  • ✇Popular Science
  • A breakthrough in fighting bacteria that causes ‘flesh-eating’ illnessLaura Baisas
    An international team of scientists has developed a new family of compounds that can clear bacterial infections in mice. Some of these infections can result in serious “flesh-eating” illnesses. There are about 700 to 1,100 cases of flesh-eating illnesses every year in the United States. The new family of compounds could also represent the beginning of a new class of antibiotics and are described in a study published August 2 in the journal Science Advances. Growing resistance For decades,
     

A breakthrough in fighting bacteria that causes ‘flesh-eating’ illness

2. Srpen 2024 v 20:00

An international team of scientists has developed a new family of compounds that can clear bacterial infections in mice. Some of these infections can result in serious “flesh-eating” illnesses. There are about 700 to 1,100 cases of flesh-eating illnesses every year in the United States. The new family of compounds could also represent the beginning of a new class of antibiotics and are described in a study published August 2 in the journal Science Advances.

Growing resistance

For decades, clinicians have been sounding the alarm about pathogens that are increasingly becoming more resistant to drugs currently available. This makes them more dangerous and according to the Centers for Disease Control and Prevention (CDC), over 2.8 million antimicrobial-resistant infections occur in the US every year. More than 35,000 people die from these infections. To combat this, newer antimicrobial compounds will be needed to replace the ones that bacteria have become resistant to. 

Molecular microbiologists Scott Hultgren and Michael Caparon from Washington University School of Medicine in St. Louis and chemist Fredrik Almqvist from the University of Umeå in Sweden collaborated on this new family of compounds called GmPcides

[Related: These flesh-eating bacteria are finding new beaches to call home.]

GmPcides work by targeting gram-positive bacteria. These types of bacteria can cause various drug-resistant staph infections, toxic shock syndrome, and other bacterial illnesses that can turn deadly. 

“All of the gram-positive bacteria that we’ve tested have been susceptible to that compound. That includes enterococci, staphylococci, streptococci, C. difficile, which are the major pathogenic bacteria types,” Caparon said in a statement. “The compounds have broad-spectrum activity against numerous bacteria.”

A ‘happy accident’

The new GmPcide compounds are based on a type of molecule called ring-fused 2-pyridone that was developed by what the team calls a happy accident. Caparon and Hultgren had asked Almqvist to develop a chemical compound that can prevent bacterial films from latching onto the surface of urethral catheters. These are a common cause of urinary tract infections in hospital settings

The resulting compound also had infection-fighting properties against multiple types of bacteria. Some of their earlier research showed that GmPcides can kill bacteria strains in petri dish experiments. 

In this new study, they took those petri dish experiments one step further by testing how compounds work on necrotizing soft-tissue infections. These fast-spreading infections usually involve multiple types of gram-positive bacteria. Necrotizing fasciitis–or flesh-eating disease–is the best known of these infections. It can rapidly damage tissue so severely that limb amputation is often necessary to control its spread. Roughly 20 percent of patients with flesh-eating disease die.

The team focused on one pathogen that is responsible for about 500,000 deaths every year–Streptococcus pyogenes. A group of mice was infected with S. pyogenes. One group was treated with GmPcide, while the other wasn’t. Those that received the GmPcide treatment fared better than the untreated mice in almost every metric. They lost less weight, had smaller ulcers, and fought off the infection faster. Damaged areas of skin also appeared to heal quicker post-infection.

While it is still not fully clear how GmPcides did all of this, a microscopic examination showed that the treatment has a significant effect on bacterial cell membranes. These are the outer wrapping of the microbes.

[Related: ‘Bacterial glitter’ shimmers without pigments.]

“One of the jobs of a membrane is to exclude material from the outside,” Caparon said. “We know that within five to ten minutes of treatment with GmPcide, the membranes start to become permeable and allow things that normally should be excluded to enter into the bacteria, which suggests that those membranes have been damaged.”

This can alter the bacteria’s own functions, including actions that damage the host and make the bacteria less effective at taking down the host’s immune response to infections. 

GmPcides also may be less likely to lead to drug-resistant strains. The experiments designed to create resistant bacteria found that very few cells can withstand treatment. This means they are less likely to pass on their advantages to the next generation of bacteria.

The road ahead

According to Caparon, there are still numerous steps before GmPcides will be available at your local pharmacy. The team has patented the compound used and licensed it to QureTech Bio, a company that Caparon, Hultgren and Almqvist have an ownership stake in. The license was contingent on the expectation that they will collaborate with a separate company that can manage the pharmaceutical development and clinical trials to bring it to market.

According to the team, the kind of collaborative science that created GmPcides will be needed to treat the problems like antimicrobial resistance.
“Bacterial infections of every type are an important health problem, and they are increasingly becoming multi-drug resistant and thus harder to treat,” Hultgren said in a statement. “Interdisciplinary science facilitates the integration of different fields of study that can lead to synergistic new ideas that have the potential to help patients.”

The post A breakthrough in fighting bacteria that causes ‘flesh-eating’ illness appeared first on Popular Science.

❌
❌