strange

Dark matter has been a mystery for decades. A strange event from 2019 could be the evidence we were looking for to unravel it

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December 18, 2019. A star of the great Magellanic cloud increases its brightness. It does so in a way that is intense enough not to go unnoticed by scientists analyzing the data from the Víctor M. Blanco telescope at the Inter-American Observatory of Cerro Tololo (Chile), but not so intense that it corresponds to an explosion. Rather, it is a gentle increase in brightness, followed by a symmetrical decrease in brightness. The entire process lasts 1 hour and baffles scientists, who baptize the object causing this phenomenon as Phoebe. Since then, Phoebe’s origin has been a mystery. Now, the same scientists who made the discovery they have answers that point to what would be one of the oldest objects that have ever been detected. Phoebe’s origin. There are three hypotheses for Phoebe’s origin. For one thing, it could be a free floating planet in the Milky Way. That is, a planet that was expelled from its solar system and now wanders through our galaxy. It could also be exactly the same, but in the Large Magellanic Cloud instead of the Milky Way. Finally, it could be a primordial black hole. That is, a very small black hole that, instead of being formed by the collapse of a star, was caused by fluctuations in the density of matter in the cosmos during the first seconds of the Big Bang. The authors of the study that has just been published have calculated the probabilities of each hypothesis and the third one beats the rest by a factor of 100,000. A gravitational microlens. While Phoebe’s origin has been a mystery all this time, it didn’t take long for scientists to understand the phenomenon that had caused the star’s brightness to fluctuate in 2019. It must have been gravitational microlensing. This is a phenomenon which is formed when a very massive object is placed between our telescopes and another object. The mass of the central object is so great that its gravity is capable of bending space-time, forming a kind of lens that magnifies the image of what is behind it. On the other hand, if what is behind it is a very distant star, what is magnified is its brightness. That is why this increase in brightness occurred, because Phoebe was passing between the star and the telescopes of the Chilean observatory. The key is in the duration. Previous studies with gravitational lensing show that the duration of the event can give us an idea of ​​the mass of the body that causes the lens to form. The lighter the object, the faster it moves and the shorter the increase in brightness lasts. In this case, the phenomenon lasted an hour. It may seem like a lot to us, but in cosmic terms it is quite little. In fact, it is just above the detectable limit. This tells us that the object that caused this increase in brightness must have been very light. According to calculations made by scientists at Swinburne University taking into account fluctuations in brightness, it would have approximately the mass equivalent to three moons. A winning option. Black holes that form from stars usually have at least the mass of about 5 suns. 3 moons is much less. It is also too small an object to correspond to a planet wandering in the Milky Way or the large Magellanic cloud. This, together with the geometry of the event and the expected spatial distribution, has led the probability calculation to lean so clearly towards the primordial black hole. Primordial black holes Big news about something very small. Primordial black holes are theoretical phenomena. It is believed plausible that could have formed in the first seconds of the Big Bang, when fluctuations in the density of matter in the cosmos caused an accumulation of matter dense enough to collapse. Most of them would be very small. They would have most of the characteristics of a black hole, but radically smaller in size. They would form before there were stars or matter as we know it, but they could be related to one of the greatest mysteries of astrophysics: dark matter. Only 5% of the cosmos is made up of “normal” atoms. The rest is unknown. One part is known as dark matter and another as dark energy. It is not known what they are, but one of the hypotheses about dark matter is that it could be composed in part of primordial black holes. Therefore, if it is shown that Phoebe is really a primordial black hole, we would perhaps be facing one of the first demonstrations of the composition of dark matter. And now what? Logically, this is just the beginning. We will have to continue looking for more objects like Phoebe to be able to prove that these scientists are right. For this, You have to know well where to point the telescopes. To begin with, not any of them will do. They need to be sensitive enough to detect gentle changes in the brightness of stars. They also need to be able to focus on large fields of vision. And, if possible, focus on places with a large concentration of stars, since it is easier for the gravitational lensing phenomenon to occur there. It is expected that some observatories, such as the Vera Rubin, will provide interesting data in this regard. Now we will have to analyze them and look for points in common with Phoebe. That December 18, 2019, a pandemic was brewing on Earth, but in space the clue could be jumping that would resolve one of the greatest mysteries in the history of astrophysics. Image |Martin Bernardi |NASA In Xataka | We have been deceived by the distances of the Solar System: the closest neighbor to Neptune is Mercury

Something strange happened inside the Earth in 2011 and 27 years of data have not solved the mystery

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In 2011, scientists observed an unexpected change in the flow of molten iron and nickel that makes up the earth core external. While its surface flow normally moves westward, it was detected to be moving just eastward. It was something totally unusual and mysterious. As a result of this observation, a study was launched, the results of which have recently been published. The objective was to know the reasons, but now there are only a few certainties and still many doubts. 27 years of observations. In this study 27 years of behavior of the Earth’s core were retrospectively analyzed, between 1997 and 2025. The core cannot be directly observed. However, its behavior directly influences that of the Earth’s magnetic field. Therefore, fluctuations in one can be detected in the other using satellite observations. It was seen that while the Earth’s outer core moves normally westward, there was a portion of it that went from a weak westward flow in 2010 to a much stronger eastward flow in 2012. It remained that way until 2020 and now appears to be starting to weaken again. Three options. When this change in movement was detected in 2011, it was thought that it could be due to three reasons. On the one hand, it could be a one-off fluctuation. On the other hand, it is possible that it is part of a periodic oscillation. And finally, it could be due to a way of establishing a balance in the circulation of the core. The only thing we see at the moment with the satellite observations is that the change was progressive. The behavioral modification began in 2010 and was already very clear in 2012. In 2011, when it was observed, it was in full transition. Other simultaneous observations. When analyzing the data from that period, it was seen that, coinciding with this change of direction, there were also some seismic signals that agree with the dates. Even geomagnetic shocks have been detected that correspond to a turbulent activity in the earth’s core. It’s not a whirlpool. This change of direction has not occurred throughout the core. For a start, the earth’s core consists of two parts: the internal and the external. The internal one is subjected to so much pressure that the metals are in a solid state despite the high temperatures. On the other hand, on the outside they are in a liquid state and, therefore, in motion. Even so, it wasn’t the entire outer core that changed its movement either. It corresponds to a specific region, located under the Pacific Ocean. It could be seen as a whirlpool, but these scientists have concluded that it is not, since the movement is part of a larger, wavy structure. Something like if an entire section of this part of the core suddenly began to move against expectations. Why is it important. The movement of the molten metal in the core generates electrical currents, which in turn give rise to a geomagnetic field that extends into space. Therefore, thanks to the movement of the Earth’s core we have an entire magnetic shield around the Earth that protects our atmosphere from the erosion caused by particles from the solar winds. For this nucleus to change its movement is not dangerous. We are not going to run out of atmosphere, because the core is still there. However, understanding its fluctuations can help us also understand the fluctuations of the magnetic field. This not only protects the atmosphere from erosion. It also helps us keep away a good part of the particles that could affect our telecommunications systems. Therefore, understanding how this shield works can help us prevent those more extreme events that do cause some technological havoc. That’s why, while this study has given us a lot of interesting data, it’s still not enough. We must continue monitoring the Earth’s core, what caused this anomaly of 2011. Image | THAT In Xataka | The Webb and Hubble telescopes simultaneously observed Jupiter’s auroras. The problem is that they didn’t see the same thing

A medieval poet and some buried trees have just revealed something very strange to us about the 13th century Sun

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At the beginning of the 13th century, the Sun was passing through a solar cycle much shorter than those that exist today, but extremely intense. Having such specific details is complicated for such a distant time, when scientists did not have instruments to measure this type of activity. However, there is something that today’s scientists do have and that has helped them detect this event: a book of poetry and many trees. Art and science. A team of scientists from Okinawa Institute of Science and Technology has described this event using two types of data. On the one hand, a poem written in 1204 by the Japanese writer Fujiwara no Teika. On the other hand, the observation of the rings of buried tree trunks in northern Japan. The conclusion is clear. While today solar cycles are usually around 11 years, back then there were some 6 or 7 years, but the activity was high enough to lead to the formation of auroras in Japan. A proton explosion. When solar activity is very intense, phenomena such as solar flares or the coronal mass ejections. The first is a sudden release of electromagnetic radiation from the solar surface, while the second consists of the expulsion of matter, normally charged plasma particles, from the Sun’s corona. Associated with these phenomena, proton explosions occur, in which these charged particles move at high speed. rare isotopes. Normally, a good part of these charged particles and cosmic rays fail to pass through the Earth’s magnetic field. However, when they are very intense they can reach our atmosphere in greater quantities and interact with the gases in it. In this reaction, isotopes such as beryllium-10 or carbon-14 can be formed. These are beryllium or carbon atoms with a different number of neutrons in their nuclei than the beryllium and carbon that are most abundant on Earth. Knowing this process is useful, because it can give us clues on two levels. On the one hand, beryllium-10 is deposited in ice sheets, while carbon-14 It oxidizes, transforming into carbon dioxide and becoming part of the carbon cycle. In this cycle, living beings incorporate it into their cells in different ways. For example, plants do this through photosynthesis. And this is where what has been so useful to these scientists begins. Solar dating and meteorology. Carbon-14 is often used to date fossils, since they come from living beings that once incorporated that isotope into their tissues. The moment a living being dies it stops incorporating carbon-14. From that moment on, it begins to disintegrate at a known rate, so it can be estimated approximately when it died. The point is that, beyond that, if carbon-14 levels are unusually high, it can also be determined if there was an extreme solar event. The poem describes a dawn The poem. in his diary Meigetsukithe poet Fujiwara no Teika described the observation of “red lights in the sky over northern Kyoto.” This city is at a latitude too far south for auroras to form, but that is clearly what it describes. The auroras They are the result of a type of interaction between the gases in the atmosphere and the charged particles of the Sun that causes the emission of visible light. They are normally formed at the poles, as they are the points on the Earth where the magnetic field is most vertical, so that it acts as a funnel, so that these particles can pass through it. When they occur far from the poles it is because solar activity has been very intense and the resistance normally opposed by the magnetic field has been exceeded. What the trees tell. The rings of tree trunks are a kind of natural calendar. They are formed from the inside out, so we can count them and calculate how the years have passed. For this reason, the authors of the study that has just been published They wanted to analyze the equivalent buried tree rings at the beginning of the 13th century. In the rings from the period from winter 1200 to spring 1201 they found an increase in carbon-14 levels. This also agrees with the levels of beryllium-10 found in ice deposits from that same period. Everything agrees. Also in China. There are historical records from the time when Chinese astronomers also described red lights in the sky. Therefore, it seems clear that there were auroras at unusual latitudes. A very rare case. The most curious thing about all this is that this phenomenon did not occur at the peak of the solar cycle. It possibly took place around its periodic minimum. If there was less activity, why so much aurora and carbon-14? This is something that, at the moment, scientists have not been able to explain. Perhaps there were also many auroras at the peak, but no poet stopped to write about them. Tree rings would have to be analyzed to see what carbon-14 tells us. What is clear is that the Sun was burning in those medieval times. Image | Masaaki Komori (Unsplash)/Wikimedia Commons | Kush Dwivedi (Unsplash) In Xataka | A sunspot 17 times larger than Earth caused red auroras across half the world. It is a very rare event

We thought platypuses were strange animals. We just discovered that they are even rarer

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The platypus has been a box of surprises since we formally “discovered” it almost 230 years ago, when the first stuffed specimen arrived in Europe and the naturalist George Shaw thought which was a hoax sewn up by some Chinese taxidermist. And let’s see, the platypus is truly unique in its species: it is a mammal that lays eggs, detects electric fields with its beak and glows under ultraviolet light. As if the above were not enough, a research team just found a surprising explanation for the color of his coat. What’s new about the platypus. The research, led by biologist Jessica Leigh Dobson from Ghent University, has identified that the platypus has melanosomes holes in their fur. What is this exactly? The organelles responsible for giving us color in our skin, hair or eyes. Until now, science assumed that hollow melanosomes existed only in birds and that those of mammals were always solid. Curiously, in birds those melanosomes are the ones that produce iridescent colors, but the platypus is dark brown, without flashes or shine. Furthermore, their melanosomes are mostly spherical, a morphology that in other animals is associated with red or orange tones, but not brown. The reason is a mystery. Why it is important. Melamine is the standard for vertebrates to provide color and protect from the sun, but what is truly key is its packaging. For decades the shape of melanosomes has served as an evolutionary fingerprint to differentiate the branches of birds and mammals. The platypus just killed it, but of course, it is so disconcerting from the beginning that it took researchers 80 years to agree on what it was, as its scientific name summarizes. The most reasonable hypothesis What this research team proposes is that the hollow melanosomes could have been an adaptation to the aquatic lifestyle of the platypus, a kind of thermal insulation mechanism in the fur for life in cold waters. But of course, if this is the case, why doesn’t the same happen with other semi-aquatic mammals? If confirmed, it would imply that this condition of hollow melanosomes evolved independently in birds and only in this mammal. The platypus continues to go on its own. Context. The platypus deserves a separate chapter in biology books: it is one of only five species of mammals that lay eggs, the monotremes. And what can we say about its appearance: it has the beak of a duck and the tail of a beaver. Although it seems harmless, it is not: it has venom like snakes and the males also have poisonous spurs on their hind legs capable of causing intense pain in humans. The icing on the cake is that the animal is capable of detecting the electric fields generated by the muscles of its prey underwater. But the platypus is different outside and inside: He is a genetic rebel. While humans have only two sex chromosomes (XX or XY), he has ten. This complexity makes their system for determining sex totally different from that of other mammals. It is, literally, one of the few animals that forces science to consider pre-established laws. How they discovered it. The discovery was almost a coincidence: Jessica Dobson was building a database of melanosomes from different mammal species when her thesis supervisor detected this platypus anomaly. The scientist passed the samples through a high-resolution microscope to examine the melanosomes inside the hairs of 12 platypus specimens taken from different parts of the body. He then extended the comparison to echidnas, marsupials such as wombats and opossums, and a hundred more mammals. No trace of hollow melanosomes, and for example their cousins, the echidnas, also lay eggs. In Xataka | The “Spanish platypus” exists and is on the verge of extinction: the very rare animal that only lives on the peninsula In Xataka | A 24-year-old platypus challenges what we knew about the longevity of the strangest mammals Cover | Dr Philip Bethge

the strange atmosphere of the Mutua Madrid Open

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The Caja Mágica is, on paper, one of the best-conceived tennis venues on the circuit in Spain. Modern facilities, first-class slopes, careful organization. And yet, each edition of the Mutua Madrid Open sparks the same conversation: why are the stands so empty? Why is the atmosphere more like a corporate event than a Masters 1000? The answers are uncomfortable and point in very specific directions. What is the Madrid Open. The Mutua Madrid Open celebrates its 25th edition in 2026. Since 2009 it has been played in the Caja Mágica, the venue designed by Dominique Perrault in the Parque Lineal del Manzanares, and since 2019 it has been directed by Feliciano López, who combines that role with his last seasons as a professional player. It is a combined Masters 1000 tournament, which means it simultaneously hosts the ATP men’s draw and the WTA women’s draw: one of nine events of that category in the world, one step below the four Grand Slams. The prices. Tickets for the Manolo Santana Stadium, the center court of the tournament, with capacity for just under 10,000 spectators, oscillate between 10 euros in the first days and 176 euros in the semis and final. They are not scandalous numbers, but at Roland Garros, tickets for the main draw with assigned seating on the Philippe-Chatrier court (the equivalent of Manolo Santana, with capacity for more than 14,000 spectators) They start at 95 euros in day sessions. Tickets for the semifinals started at 120 euros, and the final at 220 euros. In other words: The semifinal of the most important clay Grand Slam in the world has a price similar to what Madrid asks for a final round match in a Masters 1000. And Paris is Paris. From here, prices skyrocket: a second week pass has a starting price of more than 850 euros, which places the Madrid Open in a league of exclusivity that its weight on the circuit does not fully justify. Furthermore, the sales model (separate sessions, stadiums with differentiated access, multiplication of premium categories) turns the purchase of a ticket into a labyrinth for deep pockets. When the VIP is empty. In May 2024, one of the most commented images on social networks was the image of the Manolo Santana VIP boxes during the women’s final, played between the two best tennis players in the world at that time, with dozens of empty seats. Complaints from fans were especially directed at that area, occupied largely by guests, with low attendance that was visible both in smaller matches and in meetings with the most popular figures of the tournament: tickets sell out quickly, resellers raise prices, and at the same time there are dozens of seats reserved for guests who end up not showing up. Image problems. Outside, the tournament projects an exclusive and aspirational image. But inside, the empty stands do not go unnoticed. When Feliciano López himself spoke this month about the controversies over the invitations, his explanation pointed directly to the structure that owns the event: “The owners of the tournament are not us; they are other companies, with other interests, clients who have to help.” Tennis and networking. The tournament’s own official website describes its premium spaces as ideal for combining “leisure, sports and networking with the idea of ​​satisfying the needs of the most demanding fans.” It is not an oversight in the writing, it is just that this is the business model: in a tournament with the relatively short tradition of the Madrid tournament, the imbalance between the space conceived as a social experience and as a sporting spectacle is even more evident. The result is an atmosphere that lifelong fans criticize with phrases like “I’m going to take a photo, I don’t care about tennis.” Attending the Open has become a social event where tennis is the decoration. Gamblers in the stands. Another type of networking: in the 2025 Madrid Challenger (a minor category tournament held at the Country Club) incidents related to bettors they marked the entire week. During the quarterfinals, comments such as “Gaubas is going to pay me” could be heard as attendees looked at their phones to check live betting apps. The Slovak tennis player Norbert Gombos even stopped the match to directly rebuke a group of young people in the stands. It was a semi-final, and a scene difficult to imagine at Roland Garros or Wimbledon. LaLiga’s Integrity Director warned that tennis and basketball are the sports where the pressure of bettors on the atmosphere in the stands becomes more evident, due to the pace of the game and the proliferation of micro-event markets (point-to-point betting, per game, per set). The public no longer cheers out of hobby: they are getting excited or angry depending on the money they win or lose. An attitude that degrades the atmosphere of a sport that requires concentration and silence. The drama. Neither the Madrid Open is a failure nor the Caja Mágica is a bad venue. But there are doubts about the tournament model that has been built: prices that leave out the average fan, stands that look like corporate meeting rooms, a poorly maintained invitation policy and results that give a bad image… an atmosphere that does not accompany the quality of the tennis played on the court. In Xataka | If Carlos Alcaraz is not allowed to wear a smart bracelet, Whoop has provided him with the solution: underwear with sensors

the strange medieval epidemic that paralyzed Europe for two centuries

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At some point in the late 14th century, Charles VI of France stopped moving. Not because of paralysis or fear of his enemies, but because he was convinced that his body was made of glass, and that any touch could shatter it. It was not an isolated case. Those affected by this collective delusion believed that all or part of their body was made of glass. The phenomenon has its own name in the history of psychiatry: the crystal delirium. And his story says disturbing things about how the sick mind always speaks the language of its time. Charles VI, nicknamed El Loco for whatever he may be Charles VI inherited the French throne in 1380, aged eleven. When he turned twenty, he removed his corrupt uncles from power and restored stability to the kingdom’s finances. The people called him le Bien-Aiméthe Beloved. Twelve years later, his definitive nickname would be different: le Fou, the Fool. In August 1392, during a military campaign towards Brittany, the king (23 years old at the time) was riding through the forest of Le Mans when a page dropped a spear. The metallic roar was enough to trigger a violent crisis: Carlos attacked his own knights and killed four before being subdued. It was the first of dozens of episodes that would accompany him until his death in 1422. Pope Pius II wrote that there were times when Carlos believed he was made of glassand that was why he tried to protect himself in multiple ways to avoid breaking, going so far as to have iron rods sewn into his clothes. Something else happened shortly after the onset of the crystalline delirium. In January 1393, the king and several nobles attended a party disguised as “wild men,” wearing linen suits covered in pitch and branches. An errant spark ignited a costume and the fire spread among the men. Only the king and another companion escaped alive, in an event that inspired Edgar Allan Poe to write his macabre story ‘Hop-Frog’. The event went down in history as the Bal des Ardentsthe Dance of the Burning Men. Whether or not that trauma accelerated his mental deterioration is something that historians still debate. When his crises took hold of him, Carlos became a different man: He could sit still for hours and, if he moved, he did so with extreme caution. This had a tremendous political cost: the monarch instability It weakened the French court and allowed rival factions to vie for power, exacerbating the challenges France faced in the midst of the Hundred Years’ War with England. In 1415 his troops were crushed at Agincourt, and in 1420 he signed the Treaty of Troyes, by which he disinherited his own son. The crystal generation Charles VI was, according to historian Gill Speak probably the first documented case of someone believing their entire body was made of glass. But he was far from the only one. The first medical text that records delirium as a recognizable condition dates from 1561, work of the Dutch doctor Levinus Lemnius. The phenomenon belonged to a broader category called “scholar’s melancholy”, an ailment that mainly affected men of letters and nobles from the 15th to 17th centuries. The documented cases are as extravagant as they are revealing. A man was convinced that his buttocks were made of glass and that sitting down would make them burst, so he avoided leaving the house in case a glazier tried to melt it to turn it into a window. Another traveled to Murano, the Italian island famous for its glass, with the intention of throwing himself into a furnace and being transformed into a glass. Engraving of ‘The Stained Glass Licensed’ A third nobleman (always unemployed people, the core issue of the topic) believed he was a glass vessel and spent the day lying on a bed of straw. His doctor ordered the bed to be set on fire with the door closed: when the nobleman pounded on the door asking for help, the doctor asked why it had not shattered with so much fuss. The cure was brutal but, apparently, effective. Transparent glass was not, in the 15th century, an everyday occurrence. It was in that century when the Venetian glassmaker Angelo Barovier invented the cristalloa clear, colorless glass that was extraordinarily rare and was seen by many as something almost magical. Before this innovation, neuroses were different: men who believed they were made of clay and later, in the 19th century, people who believed they were made of cement. The content of delusions reflects the culture of each moment: glass was a new material and therefore became the object of delusions. Glass, specifically, offered transparency: being made of glass meant being precious and fragile, a form of grandeur and isolation at the same time. Miguel de Cervantes published ‘El licensed Vidriera’, one of his ‘Exemplary Novels’, in 1613. The protagonist, Tomás Rodaja, is a brilliant and poor student who, after ingesting a love potion, is convinced that his body is made of glass due to the delicacy and subtlety of the material, with an admirable and delirious internal logic. It is a clear sign that delirium has its corresponding literature at the time: Robert Burton cataloged the phenomenon in ‘Anatomy of Melancholy’ (1621) as a symptom of melancholy, and Descartes, in his ‘Meditations on First Philosophy’ (1641), used the “glass man” as an example of madness to distinguish his own philosophical doubts from the delusions of a sick brain. In Xataka | The Middle Ages have a reputation for being a dark period. Until you discover the names they had for their pets

60 years ago, NASA took a look at the Sahara from space and found a very strange “perfect eye”

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Although we tend to think that the unknown is in space and we focus our exploration on what is outside the Earth, our planet continues to surprise us: from the 50,000 volcanoes hidden in the seabed to shapes and constructions that seem too curious to have appeared out of nowhere… especially when we see them from space. It is the case of Great Dam of Zimbabwe (which by the way, is not a dam). We are not leaving the African continent because there is another scar of land with a shape so precise that it is disconcerting. It can’t be seen from the ground, but as you gain height it can be seen better. However, it is from space where it is best appreciated, as NASA has already photographed. There it is simply shocking: it is the inexplicable eye of the Sahara. It is a kind of giant eye that looks at the sky engraved in the rock of the Sahara, it is actually called Richat structure. As says French astronaut Thomas Pesquetalmost all astronauts have taken a photo of it from space simply because it can’t be missed. The Britannica Encyclopedia assures that World War II pilots used it as a reference point. Tap to go to the post After all, they are almost 50 kilometers in diameter. To get an idea, if we moved it to Madrid, it would cover the entire city and reach surrounding municipalities. However, it is in Mauritania, at the western end of the Sahara. More specifically, it sits on the Adrar plateau, on the northwestern edge of the Taoudenni basin, about 500 meters above sea level and in an inhospitable area. As a curiosity, the closest town is Ouadane, it is about 17 kilometers from the edge of the structure and it is not just any city: it was founded in 1147 by the Idalwa el Hadj Berber tribe and its old part has been a UNESCO World Heritage Site since 1996. The first time we “discovered” it (that is to say, because it was already there) was in the 1930s and 1940s and the person who studied it in depth at that time was the French geographer Jacques Richard-Molard. Later, astronauts James McDivitt and Ed White, aboard the Gemini IV mission, were the first to photograph it from space in 1965. However, the image that illustrates the cover was taken on July 10, 2020 by an astronaut aboard the International Space Station, during the Expedition 63 mission, with a Nikon D5 camera with a 50 millimeter lens. Richat’s structure from the inside. Clemens Schmillen What is the Richard Structure and how was it formed? From that orbital height the image shows something that would be impossible to capture from the ground: a series of perfect concentric rings, like the waves left by a stone when it falls into water, but petrified in the desert. The tones of that figure range from ocher to bluish gray, from almost pristine white to rusty red. Each color is a different rock and belongs to a different era. Surrounding the structure, a sea of ​​dunes: on the right, longitudinal dunes that stretch in long parallel tongues and on the left, transverse dunes, wider and more arched. The set is truly strange to have formed naturally. POT Because it is not a lake that has dried up over time. It is neither a volcano nor the crater of a meteorite (the hypothesis which was most popular initially). It’s something much slower but just as violent: is the result of millions of years of geological forces working silently beneath the planet’s surface. And although the group as such was formed about 100 million years ago, those rocks are up to 2.5 billion years old. Or in other words, the Eye of the Sahara was forged in the Cretaceous, but the rocks belong to the time when there were no animals, only bacteria and algae. The Richat Structure is a deeply eroded geological anticline dome that was formed by a subsurface igneous intrusion, which deformed the overlying sedimentary rock layers, exposing concentric rings with the oldest rocks in the center. In a simplified way, a bubble of rock that never burst: the magma from inside the Earth pushed up the layers of rock above it and cooled without reaching the surface. The passage of time eroded that bubble as if it were an onion, exposing the rings of each layer. The hardest rocks resisted and formed the relief, the soft ones disappeared. Hence the circles. The most recent studies They confirm that there was also hot water circulating inside the structure, which accelerated and modeled the final shape. In Xataka | A 2.5 billion-year-old geological wonder: Zimbabwe’s Great Dam seen by NASA from space In Xataka | This is the impressive interactive map to see the Earth in 4K live from space and monitor satellites Cover | POT

Something strange happens with recreational bluefin tuna fishing in Spain. And yes, ‘rare’ in this headline means (presumably) ‘fraud’

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In Spain, recreational bluefin tuna fishing has many rules and regulations, but there is something essential that starts from the same name: it is (and should be) ‘recreational’. That is, Spanish rules only allow the capture and release of Thunnus thynnus. And yet, the quota of accidental deaths (about 39.9 tons in 2025) is being exhausted very quickly (It lasted three days that same 2025). That is to say, (according to the available data) almost all the tunas that get hooked at the beginning of the closed season end up dead. Spanish fishermen They are unable to return almost any of them alive.. It’s already bad luck. On the other hand, in the United Kingdom, they return up to 99%. It’s not a fish story. Although it may seem like it, this is not about fish, no. It involves mandatory training, required equipment, handling protocols and, above all, effective control. Although it may not seem like it, this is about how it is possible for two European countries to produce such radically different results. And, above all, it is about how we can solve it. Because it is undeniable that we have a problem. It makes no sense that recreational fishing in Spain has become a race to go fishing first. In the last five years, the longest effective fishing season was seven days in 2021. That is to say, it took the fishermen a week to accidentally kill so many tuna that the fishery was over. In 2022 and 2023 there were five days and In the following years, three. 75% of last year’s accidents, by the way, took place in the Valencian Community. With tougher regulations, this does not happen. It is true, however, that the data is somewhat unfair. While Spain has 1,900 special licenses, the United Kingdom has with barely 81 boats with active permits. That, whether we like it or not, simplifies things. But it’s not just a question of size. It is, above all, a question of why The reason the British system is different is also interesting: until a handful of years ago (about 2017) there was no bluefin tuna in its waters. There was nothing to fish. Since then it has started to come back (as It has happened with many other species) and the authorities were able to create a more guaranteeing system without the pressure of an already consolidated industry. Hence a smaller number of boats, the specific training of skippers and, above all, the boats are obliged to have independent observers and cameras to record what happens inside (at least, with new skippers). So there is no hope? Something is being done and it is good to recognize it: this January it came into force a regulation that tries to digitize the capture record and close the “statistical black hole”. The experts are worse They are not very optimistic either.. They fear that in this context (three days of closure and an implicit mortality that is around 100%), it is clear that recreational pressure is only going to complicate things. And, in the end, the solution will only come when the current system bursts at the seams. It is not an anomaly: we are specialists in it. The good news and the bad news are the same: that this is going to happen soon. Image | Aristos Aristidou | Jordan Whitfield In Xataka | Spain is going to continue fishing for eels until we have no more eels to catch

Someone paid for the bus in England with a strange coin in the 50s. It turned out to be a treasure from Cádiz from 2,000 years ago

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In the 1950s, public transportation in the English city of Leeds functioned as that of any other large citywith tickets costing a few pence and collectors checking the change. One day, someone took out a strange coin to pay his ticket and the person responsible for collecting the ticket immediately noticed that it was not a legal British currency. And instead of throwing it away, he decided to keep it. The story. What this cashier who kept the coin did not know, and what it would take his relative seven decades to discover, is that that bus ticket It had been paid with a relic from more than 2,000 years ago and of Spanish origin. From a wooden box to the museum. The story of this peculiar discovery has recently come to light thanks to Leeds Museums and Galleriesnoting that for about 70 years, the coin was forgotten in a small wooden box. The important thing here is that, after the death of James Edwards, who was the one who collected this bus ticket, the piece passed into the hands of his grandson, Peter Edwards, who is now 77 years old. Intrigued by the ancient and worn appearance of the object, Peter decided to investigate its provenance with the help of experts from the University of Leeds, and this is where it was discovered that it was not a piece of scrap metal, but a bronze coin from the 1st century BC. Where it came from. Analysis of the coin revealed that it was not minted in the United Kingdom, but that its origin was thousands of miles away. Specifically in Gadir, present-day Cádiz, in one of the oldest and most prosperous Phoenician settlements in the West. The design of the coin is a classic of Carthaginian and Phoenician-Punic influence in the Iberian Peninsula, with an obverse that shows the profile of Melqart, a deity of the Phoenicians and recognizable for wearing the mythical skin of the Nemean Lion. On its reverse, the coin shows two tunas, the indisputable symbol of the ancient Cádiz fishing industry, accompanied by inscriptions in the Phoenician alphabet. How he came to England. There are many doubts that arise when we talk about a coin from the 1st century BC that ended up being a payment method at a bus station in England. The main hypothesis used by the researchers is the result of the recent historical context, since it is believed that the coin was found in the Mediterranean region by a British soldier during or just after World War II. After taking it to the United Kingdom as a souvenir or amulet, the piece must have ended up mixed with everyday change. From there, it was exchanged as legal tender until it ended up in the box of a curious person who knew that this coin had something unique. Your new home. After unraveling the mystery, Peter Edwards has decided to donate his grandfather’s piece to the local authorities and today, the Gadir coin is part of the Leeds Discovery Centre, an institution that houses thousands of historical coins. And, although it is not a great treasure, it is undoubtedly an artifact that perfectly shows the migrations of everyday objects thousands of years ago. Images | Leeds Museums and Galleries In Xataka | North Africa was off the map in the Bronze Age. A metallic waste has put it at the center of History

Magnetic maps had been marking something strange under Antarctica for centuries. So we’ve started drilling to find it

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For years, magnetic maps of East Antarctica have shown something strange about the region from Princess Elizabeth Land: a large amplitude linear magnetic anomaly under kilometers of ice that runs along the coast parallel to the margin of the continent. It was something that satellites and planes could detect, but no one knew exactly what rock was producing it until now. Discovering it. If the problem is that this anomaly was under a large amount of ice, a team of researchers within the framework of a Russian-Chinese cooperation He has done the most logical thing to find what was happening: start drilling. What they have found after putting a large drill to work is not only a magnetic rock that gave that peculiar pattern, but it is the geological “scar” of an ancient island arc that collided with the continent almost 1,000 years ago, when the supercontinent was forming. Rodinia. A challenge. The study that includes this discovery focuses mainly on the Rayner tectonic province, an area that is geologically critical because it is considered a “mobile belt.” That is, it is a collision zone where ancient blocks of crust were crushed against each other. The problem with Antarctic geology is that almost everything they are interested in is buried, and in this case the team had to cross 541 meters of ice to be able to reach the rock that interested them. What did they find? What they took from the bottom of Antarctica was not common granite as can occur in other areas, but rather the core recovered is a mafic granulite. Something that is very important, since granulites are metamorphic rocks that have suffered infernal temperatures and pressures. After power analyze this rock So interesting, it was seen that this was what was causing the linear anomalies seen from space. And as we say, it is not a very normal stone, since it is rich in ferromagnetic minerals, capable of altering the magnetic field locally. Investigating Rodinia. Once with the sample in hand, the team applied geochemistry techniques and dating to be able to counterbalance these data with everything that was known in previous research. What was seen is that there was a great violent history behind it, since it was known that the rock was originally born as magma about 970 million years ago. From its birth, that rock was pushed into the depths and “cooked.” The data indicate that it was subjected to temperatures between 650 and 790 ºC and pressures equivalent to depths of 15 to 18 kilometers. In this way, the researchers’ conclusion is that this rock was part of a volcanic arc of islands like those of Japan. But the most interesting thing is that this arc was not originally in Antarctica, but was forcibly “stuck” against the ancient continent during a massive collision that gave rise to the formation of Rodinia. The Indian connection. To understand the magnitude of the find, you have to look beyond Antarctica, as geologists have long suspected that the Rayner Province in Antarctica and the Eastern Ghats Province in India They are twins separated at birth. And the new data reinforces this theory, since the conditions of “high temperature” metamorphism found in this drilling are almost identical to those documented in India. This leads us to conclude that 900 million years ago, the east coast of India and this part of Antarctica were joined, forming a huge mountain range created by the collision of tectonic plates. Images | 66 north In Xataka | In the United States there is an incredible river that does what seems impossible: defy the laws of gravity

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