Sinking slowly Mars polar ice cap is slowly pushing its north pole inward That, plus data from the InSight lander, gives us a new view into Mars' interior. John Timmer Feb 28, 2025 4:47 pm | 2 Mars polar ice cap. Credit: NASA/JPL-Caltech/MSSS Mars polar ice cap. Credit: NASA/JPL-Caltech/MSSS Story textSizeSmallStandardLargeWidth *StandardWideLinksStandardOrange* Subscribers only Learn moreThe north pole of Mars is slowly sinking under the weight of an ice cap that only formed within the past few million years. And, in the process, it's telling us something about what the planet's interior must be like, thanks in no small part to data obtained by hardware we landed in Mars' equatorial regions.That's the conclusion of a new modeling study that produces results that are broadly consistent with earlier work, although quite a bit more detailed. In the process, the work shows how it's possible to take data from radically different data sources and pull them together into a coherent picture.Weighted downWhile the crust of a planet is relatively solid, it bends and breaks in various ways under the strain of plate tectonics. It also flexes in response to ice. The long glacial period that preceded our current interglacial saw sheets of ice that pressed the crust down into the mantle under their difficult-to-conceive weight. With the ice gone, the crust is slowly rising again, in a process called glacial isostatic rebound.Given that Mars is significantly colder and further from the Sun, it's easy to imagine that its polar ice caps have been there for ages, and the planet is frozen and static. But that isn't likely to be the case. Working backward using orbital mechanics, it appears that the poles got more sunlight in the past; plugging that information into Martian climate models suggests the polar ice caps are probably less than 10 million years old.So, the polar ice caps may be new enough that the crust at the poles is still sinking. And, if that's the case, it can tell us something about the crust and the mantle underneath it.But it's not sinking fast enough for us to detect it from orbit. So, instead, researchers built a set of models of the evolution of Mars. These used different assumptions about the properties of Mars' interior, including the amount of heat in the crust, its thickness, etc. Given that there was a range of reasonable values for each of these properties, this resulted in 84 different models. So, the team had to figure out which of those 84 were likely to represent realistic conditions.To figure out which models might be valid, the researchers looked for constraints from other data that could rule some of these models out.Process of eliminationOne of the big constraints comes from NASA's InSight lander, which brought the first seismograph to Mars. If a marsquake that was higher than a 3.8 magnitude were to take place at the north pole, InSight should have picked it up at its equatorial location. Given that it hadn't seen any marsquakes of this sort, then that set a limit on how quickly the crust there is deforming.In addition, radar imaging from in orbit has created images of Mars' polar ice caps that extend down to the crust itself. This can provide information on how badly the shape of the area differs from what you might expect from a spherical surface.The orbiters that carried the radar hardware, along with one or two others, have been orbiting long enough that any major changes in Mars' gravity caused by ice accumulation or crustal displacement would have shown up in their orbital behavior. The orbital changes they do see, "indicates that the increase in the gravitational potential associated with long-term ice accumulation is higher than the decrease in gravitational potential from downward deflection." They calculate that the deformation has to be less than 0.13 millimeters per year to be consistent with the gravitational signal.Finally, the model had to have realistic conditions at the polar ice cap, with a density consistent with a mixture of ice and dust.Out of those 84 models, only three were consistent with all of these constraints. All three had a very viscous Martian interior, consistent with a relatively cold interior. That's not a surprise, given what we've already inferred about Mars' history. But it also suggests that most of the radioactive elements that provide heat to the red planet are in the crust, rather than deeper in the interior. That's something we might have been able to check, had InSight's temperature measurement experiment deployed correctly. But as it is, we'll have to wait until some unidentified future mission to get a picture of Mars' heat dynamics.In any case, the models also suggest that Mars' polar ice cap is less than 10 million years old, consistent with the orbitally driven climate models.In a lot of ways, the new information is an update of earlier attempts to model the Martian interior, given a few more years of orbital data and the information gained from the InSight lander, which also determined the thickness of Mars' crust and size of its core. But it's also a good way of understanding how scientists can take bits and pieces of information from seemingly unrelated sources and build them into a coherent picture.Nature, 2025. DOI: 10.1038/s41586-024-08565-9 (About DOIs).John TimmerSenior Science EditorJohn TimmerSenior Science Editor John is Ars Technica's science editor. He has a Bachelor of Arts in Biochemistry from Columbia University, and a Ph.D. in Molecular and Cell Biology from the University of California, Berkeley. When physically separated from his keyboard, he tends to seek out a bicycle, or a scenic location for communing with his hiking boots. 2 Comments

Dangerous disease Texas official warns against measles parties as outbreak keeps growing Twenty people have been hospitalized. Most cases are in children. Beth Mole Feb 28, 2025 4:16 pm | 60 A person walks past a sign at a health center where the MMR (measles-mumps-rubella) vaccine is administered in Lubbock, Texas, on February 27, 2025. Credit: Getty | RONALDO SCHEMIDT A person walks past a sign at a health center where the MMR (measles-mumps-rubella) vaccine is administered in Lubbock, Texas, on February 27, 2025. Credit: Getty | RONALDO SCHEMIDT Story textSizeSmallStandardLargeWidth *StandardWideLinksStandardOrange* Subscribers only Learn moreA Texas health authority is warning against "measles parties" as the outbreak in West Texas grew to at least 146 cases, with 20 hospitalized and one unvaccinated school-age child dead. The outbreak continues to mainly be in unvaccinated children.In a press briefing hosted by the city of Lubbock, Texas, on Friday, Ron Cook, chief health officer at the Texas Tech University Health Sciences Center in Lubbock, offered the stark warning for Texans in his opening statements."What I want you to hear is: It's not good to go have measles parties because what may happen iswe can't predict who's going to do poorly with measles, be hospitalized, potentially get pneumonia or encephalitis and or pass away from this," Cook said. "So that's a foolish idea to go have a measles party. The best thing to do is make sure that you're well-vaccinated."Lubbock sits about 90 miles northwest of the outbreak's epicenter in Gaines County, which is one of the state's least vaccinated counties. It has recorded 98 of the outbreak's 146 cases. While Lubbock has only reported two of the 146 cases, patients from elsewhere have been treated in Lubbock. That includes the first two cases in the outbreak as well as the child who died of the infection earlier this week, who was not a resident of Lubbock.It's unclear if any measles parties are occurring in Gaines or elsewhere; "It's mostly been... social media talk," Cook said in response to a follow-up question from Ars. He noted that measles parties and chickenpox parties were more common practices decades ago, before vaccines for both diseases were available. But he again warned about the dangers today. "Please don't do that. It's just foolishness; it's playing roulette," he said.Cook, along with Lubbock's director of public health, Katherine Wells, said they see no end in sight for the outbreak, which now spans nine counties in Texas, many of which have low vaccination rates. "This outbreak is going to continue to grow," Wells said, declining to forecast how high the final case count could go after a reporter raised the possibility of several hundred.So far, 116 of the 146 cases are under the age of 18, with 46 being between the ages of 0 and 4. Only five of the 146 were vaccinated with at least one dose of the Measles, Mumps, and Rubella (MMR) vaccine.MessagingOn a more positive note, Wells reported that the outbreak has seemed to sway some vaccine-hesitant parents to get their children vaccinated. Just yesterday in Lubbock, over 50 children came into the city's clinic for measles vaccines. Eleven of those children had vaccine exemptions, meaning their parents had previously gone through the state process to exempt their child from having to receive routine childhood vaccines to attend school. "Which is a really good sign; that means our message is getting out there," Wells said.So far in the outbreak, which erupted in late January, messaging about the disease and the importance of vaccination has exclusively come from state and local authorities. The Centers for Disease Control and Prevention only released a brief statement late Thursday, which was not sent through the agency's press distribution list. It did, however, note that "vaccination remains the best defense against measles infection."During a cabinet meeting Wednesday, US Health Secretary and anti-vaccine advocate Robert F. Kennedy Jr. responded to a question about the outbreak, offering a variety of inaccurate information. Kennedy downplayed the outbreak, falsely claiming that "it's not unusual." But, this is an unusual year for measles in the US. As epidemiologist Katelyn Jetelina noted on Bluesky, the number of US measles cases this year has already surpassed the total case counts from eight of the previous 15 years. And it is only February.Kennedy also said there had been two deathsfortunately, only one child has died. He further claimed that measles patients were being hospitalized "mainly for quarantine," which is false and a misuse of the word quarantine. A quarantine refers to separating people who have been exposed to an illness to see if they become sick. For people who are known to be sick, the term is "isolation."In the press briefing Friday, Cook refuted Kennedy's suggestion that infected people were being hospitalized largely for isolation purposes. He described measles patients being hospitalized with severe symptoms. "Most of them are either severely dehydrated from just the infection itself, and/or lots of low oxygen levelshypoxia. And that's from the inflammation in the lungs," Cook said. In some patients, their oxygen is so low they need supplemental oxygen or intubation and ventilator support, which can lead to antibiotic use to ward off secondary bacterial infections, he explained.While the end of the outbreak remains uncertain, so does the beginning. Rumors are reportedly circulating in Texas that the measles virus was brought into the area by an undocumented immigrant. Wells shot down that rumor, indicating that there is no evidence to support it and that most measles outbreaks in the US begin with an unvaccinated citizen traveling abroad and bringing the virus home with them.Beth MoleSenior Health ReporterBeth MoleSenior Health Reporter Beth is Ars Technicas Senior Health Reporter. Beth has a Ph.D. in microbiology from the University of North Carolina at Chapel Hill and attended the Science Communication program at the University of California, Santa Cruz. She specializes in covering infectious diseases, public health, and microbes. 60 Comments

GPT-4.5 is OpenAIs latest chatbot modelCFOTO/Future Publishing via Getty ImagesOpenAI has unveiled its latest AI model, GPT-4.5, but the firms boss says it is running out of hardware to power it. If ever-larger AI can no longer be run at scale, then are we looking at the end of the technologys rapid progress, and perhaps even the bursting of a bubble?There are certainly signs that things arent going as planned within OpenAI. As recently as 12 February, CEO Sam Altman acknowledged on X that the companys product offering had created a confusing picture at the

How do time and space relate to computation? We have a new answerXuanyu Han/Getty ImagesAn astonishing discovery about the relationship between the amount of memory a computation requires and how long it takes has wowed computer scientists although it isnt clear if there are any practical applications.It kind of shakes my world view, says Ryan Williams at the Massachusetts Institute of Technology, who made the discovery. Im still just shocked that it even exists.Time and memory space are the two main constraints on what we

Warren Buffett is preparing for his inevitable departure from Berkshire Hathaway.The investing icon told shareholders it "won't be long" before Greg Abel succeeds him as CEO.Buffett has praised Abel, cleared the decks for him, and taken steps to protect his personal legacy.Warren Buffett has spent the past 60 years transforming Berkshire Hathaway from a failing textile mill into a $1 trillion company that's more valuable than Tesla, Walmart, or JPMorgan.The legendary investor took control of Berkshire in 1965 and has steadily acquired scores of businesses including Geico and See's Candies, and built multibillion-dollar stakes in public companies including Apple and Coca-Cola.But at 94 years of age, the business titan knows the end of the Buffett era is near at hand and he's carefully paved the way for his departure.Buffett has warned his shareholders the clock is ticking on his time in charge. He's talked up Greg Abel and set the stage for his planned successor. He's also sought to protect his legacy and ensure his vast fortune isn't squandered once he's gone."Succession planning is the most important thing in corporate governance for a company led by an iconic CEO," Lawrence Cunningham, the director of the University of Delaware's Weinberg Center on Corporate Governance and the author of several books about Buffett and Berkshire, told Business Insider.Buffett's conglomerate is "providing an exemplary and under-appreciated model for how this can be done well," Cunningham continued, adding that it has "prepared the way not only for Greg to succeed Warren as CEO" but also prepared stockholders for their company to no longer have a controlling shareholder.Passing the baton"At 94, it won't be long before Greg Abel replaces me as CEO and will be writing the annual letters," Buffett said in his recent missive to Berkshire shareholders, making it explicit he'll hand over the reins soon.The billionaire bargain hunter has repeatedly reassured stockholders that Abel is a worthy successor. In his new letter, he wrote that in those rare moments when opportunities are everywhere, Abel has "vividly shown his ability to act at such times as did Charlie," referring to his late business partner, Charlie Munger.Buffett joked during last year's annual meeting that shareholders "don't have too long to wait" for a change in management. "I feel fine, but I know a little about actuarial tables," he quipped.The investor mentioned in his latest letter that he requires a cane to walk, perhaps because he's "considering the possibility of stepping down as CEO in the near future," David Kass, a finance professor at the University of Maryland who's been closely following Buffett's company for four decades, told BI. He added that the nonagenarian might announce the decision as soon as Berkshire's annual meeting in May.Paving the wayBuffett appears to be clearing the decks before the next captain takes over the ship.Berkshire's $334 billion cash mountain may reflect a "desire to hand a relatively clean slate to Greg" and enable him to "more easily perform the main function of a CEO, which is allocating capital," Kass told BI.More specifically, he and his investment managers have sold several small but long-held investments including General Motors and Procter & Gamble in recent years.They've also cashed in $158 billion worth of stocks on a net basis in just the past two years, which has helped to boost Berkshire's cash pile to record levels. Their efforts could leave plenty of dry powder for Abel to spend on stocks or finally bag the elephant-sized acquisition that has evaded Buffett for years.Buffett and his deputies might be pulling back on purchases, ramping up sales, and halting buybacks because stock valuations have grown too expensive. But they might also see value in leaving a treasure chest for Abel to draw from and deploy as he wishes.Protecting his legacyBuffett disclosed last year that when he dies, his roughly 14% stake in Berkshire worth more than $150 billion will pass into a trust that counts his three children as trustees, and they'll have to vote unanimously on how it's spent.The plan not only protects the money from the taxman and earmarks it for worthy causes, it also aims to thwart activist investors who might otherwise seek to buy up Buffett's shares once he's gone and clamor for his conglomerate to be dismantled."I regard Berkshire Hathaway sort of like a painter regards a painting, the difference being the canvas is unlimited," Buffett said in 2016, underlining his vision that the company will persist for generations.In fact, Buffett's efforts to prepare his shareholders for the inevitable, voice his confidence in Abel and set him up for success, and protect his personal stake in the business, all speak to his devotion to ensuring Berkshire thrives long after he's gone.

Jeff Bezos' newest op-ed shift at The Washington Post has reportedly cost it 75,000 subscribers in a couple of days.That's on top of even bigger subscriber losses last fall, when he ordered the paper to stop doing presidential endorsements.Bezos' moves seem like they are helping him win favor with Donald Trump. But if they're going to cost his paper money why own it at all?Let's stipulate that Jeff Bezos bought The Washington Post in 2013 for $250 million. So he can do anything he wants with it.Like ordering the paper's editors not to make a presidential endorsement. Or announcing that from now on the paper's op-ed pages would only publish stuff that supports "personal liberties and free markets," as he announced this week.That said, those decisions seem to be costing Bezos money, at the very least.When the billionaire announced his non-endorsement plans last fall, days before the election, hundreds of thousands of subscribers canceled their subscriptions in less than two weeks, NPR's David Folkenflik previously reported.Now Folkenflik reports that 75,000 subscribers have left the paper following Bezos' op-ed shift, announced on Wednesday. Though a Post executive told Folkenflik the paper signed up another 400,000 subscribers in between Bezos' announcements, numbers Folkenflik has seen indicate the Post has "a net loss of a couple hundred thousand subscribers," he reported. A Post rep declined to comment about subscription numbers.The important context here is that prior to Bezos' op-ed moves, he had installed new leadership at the Post, tasked with finding new readers and new ways to make money. Now, he appears to be making both things harder.It's always possible that Bezos' moves will generate more readership from people who want to read an op-ed page promoting a libertarian/conservative point of view. Though it's hard to believe that market is "underserved," as he argued in his memo announcing the changes: Among traditional media, both The Economist and The Wall Street Journal service that market today.And it's very easy to find that point of view on the wider internet (and particularly on Twitter, now that Elon Musk bought it, changed its name to X, and began amplifying right-learning accounts).It's also possible that after this newest controversy, the Post will eventually settle into another version of the Journal, which has a famously right-wing op-ed section and does respected, down-the-middle news reporting in the rest of its pages.And it's also worth noting that on Friday, two days after Bezos kicked off the latest unrest among his readers and his staff, WaPo op-ed writer Dana Milbank published a story arguing that "the single greatest threat to "personal liberties and free markets" in the United States today [is] President Donald Trump." So we really don't know how all of this will shake out.That said from outside the paper, Bezos' moves look like they're calculated to please a single reader. President Donald Trump.Ask Megyn Kelly, the former Fox News personality who now hosts a successful podcast/YouTube show: "He's doing what Joe [Scarborough] and Mika [Brzezinski] did. He's bending the knee," she said at an event hosted by Semafor this week, referring to the MSNBC hosts' visit to Trump days after last fall's election.Will that work? Maybe, says Kelly, who appeared onstage at a Trump rally during the last campaign."You win respect with Trump when you go to him and you tell him 'I like you,' which is clearly what Bezos did. The reporting is very clear," she said. "I think Trump and he will be fine. But that doesn't make any difference at all to somebody like me, who's actually looking for sincerity."So if you follow that critique, Bezos is in a bit of a pickle: He can steer his paper in a way that could make the president of the United States happy but will lose readers on the left, and won't gain them on the right.Maybe all of that is OK for the third-richest man in the world, who could buy another 100 Washington Posts and still have more money than Larry Ellison, who's currently one slot behind him on Forbes's tally of the world's billionaires.But then why own the Post at all? Then Bezos wouldn't have to worry about what Donald Trump, or Megyn Kelly, or anyone else including the paper's readers think about it.

This story appeared in the Logoff, a daily newsletter that helps you stay informed about the Trump administration without letting political news take over your life. Subscribe here.Welcome to The Logoff. Today Im focusing on a disastrous meeting between President Donald Trump, Vice President JD Vance, and Ukrainian President Volodymyr Zelenskyy. The hostile conversation had immediate consequences for Ukraines war effort and revealed much about how Trump sees the USs new global role.What was supposed to happen? Zelenskyy went to Washington, DC, in the hopes of signing a rare-earth minerals deal with Trump, a rapprochement between the two leaders after Trump had called the Ukrainian president a dictator and falsely accused him of starting the war with Russia. Zelenskyy was hoping that by offering the US access to his countrys minerals deposits, he could secure a better deal for his country in Trumps peace talks with Russia.What happened instead? What began as a polite meeting devolved into a de facto ambush after Zelenskyy questioned what would happen if Russias Vladimir Putin were to break a ceasefire. With cameras rolling, Trump and Vance berated Zelenskyy in the Oval Office, accusing him of ingratitude for US support. After the meeting, Zelenskyy left the White House with the minerals deal unsigned, and Trump released a statement saying the Ukrainian could come back when he is ready for Peace. What now? Trump says hes still pursuing a peace deal, but after Friday, Ukraine seems likely to have even less leverage. Ukraines key ask is a security guarantee from the US a request Putin opposes and Trump has resisted. Zelenskyys prospects are surely worse now than when he woke up this morning.Whats the big picture? The meeting was a shocking display of Trumps posture toward the world and the radical break he represents from the USs previous role in the global order. In a matter of a few highly charged minutes, he flouted the fragile US-Ukraine alliance, publicly humiliated a foreign leader, bound himself even more tightly to Putin, and summed it all up with: This is gonna be great television I will say that.And with that, its time to log off Watching that Trump-Vance-Zelenskyy video brought me perilously close to an anxiety-driven YouTube scroll session. I was rescued by Voxs Today, Explained podcast, which has a fascinating episode about the Oscars foreign films category. Specifically, its about a German film that was actually (and secretly) filmed in Iran with Iranian actors and an Iranian director. I hope you get a chance to enjoy it.Finally, thanks to everyone who signed up for our new Saturday Good News newsletter. If you missed it yesterday, its a weekly dose of hope for these troubled times. You can sign up here. Have a good weekend, and Ill see you back here on Monday.RelatedSee More:

Cleaning your house or apartment isnt an easy thing to do when your schedule is filled to the brim. A Roomba can take the load off for you with its complete four-stage cleaning system. It will vacuum and mop in just one pass, using a special brush to get in those tight corners so dust wont gather. Its small height lets it easily get under couches and coffee tables for a more thorough cleaning of your home. Amazon has the iRobot Roomba Q011 robot vacuum as part of a limited time deal which knocks $100 off the price. That brings it down from $250 to just $150. Thats a 40% discount.See at AmazonReady to Take on the Dirty WorkThe iRobot Roomba Q011 uses a smart navigation systemso, learning your homes layout so it can optimally do its job. Itll clean in neat rows and sensors help it find its way through and around furniture. It can sense when its approaching stairs so youll always come home to a clean home and not an upside down robot at the base of your steps. The robot vacuum uses three power levels which you can choose between depending on if you want to prioritize a quieter cleaning or a more powerful suction.The iRobot Home app lets you set and forget, allowing you to have your Roomba clean while youre away from the house. The app can suggest cleaning schedules and provide a clean map report so you can see exactly how well it covered every exposed surface on the floor of your home.Got a couple areas that need extra spot cleaning? Maybe a plant fell over or your tracked in a bunch of dirt on your shoes. In any case, the Roomba vacuum can easily target places where the floors need extra attention. The robot will spin in place, cleaning that single spot for up to two minutes as needed.The battery is super long lasting. It can provide up to two full hours of runtime to clean your home without you lifting a finger. When it reaches low power, the Roomba vac will on its own return to its charging station so it will be ready to go the next time its scheduled to clean up.Right now, you can get the iRobot Roomba Vac robot vacuum for a reduced price. Thanks to this Amazon limited time deal, the robot vacuum is down 40%. That brings the price down from $250 to just $150 a savings of $100. Enjoy being able to come home to clean floor every day.See at Amazon

From the start, Severance has offered a captivating take on how perspectives can change within a single story, and even within the minds of individual characters. As season two began, the show gave us back-to-back episodes that showed the immediate fallout of the season one finalein which the innies briefly awakened and experienced life as their outiesfrom different points of view, with the non-severed characters also getting space to share their reactions. As season two has progressed, Severance has continued to explore this aspect of its storytelling, giving us more time with the outies to balance out season ones innie focus, and presenting constant surprises to the audience as a result. Certain things that we believed to be true are in fact completely false, shaped by Lumon Industries unique ability to massage reality for its employees who arent able to access their full consciousness. And while the innies world is almost entirely fabricated, some of that massaging has happened in the outie world, too. This weeks episode, Chikai Bardo was perhaps Severances most poignant and wrenching to date. And a lot of that has to do with which character got to be its protagonist. Gemma (Dichen Lachman) was a peripheral character for most of season one. We first meet her as Ms. Casey, the counselor in Lumons Wellness Center. She has a stilted, almost robotic presenceand shes aware of it; I know Im strange, she says at one point. Midway through season one, of course, we discover that Ms. Casey is actually Gemma, the wife of main character Mark (Adam Scott).Gemmas death in a car accident two years prior is why Mark decided to get the severance procedure and take a job at Lumon. Shes alive, sure, but shes not living much of a life; shes somehow been absorbed into Lumon and isnt allowed to leave. How and especially why this occurred, and what it has to do with Marks yet-to-be-revealed true purpose at Lumon, have become the biggest mysteries looming over Severance season two. Marks innie knows Ms. Casey is his outies wife. And Marks outie has accepted the wonderful/horrible truth that Gemma is still alive, to the point that hes allowing his own brain to be mangled in an attempt to re-integrate its divided sides. But its all been about his pain until this point. In episode seven, we finally got Gemmas perspective on her (very grim) current state of existence, as well as her own memories of her relationship with Mark.Her different innie personas are awakened for the testing shes put through in Lumons sub-basement severed rooms; some of those we get to see, others we dont. But its Gemma herself thats the most intriguing. Before Chikhai Bardo, Gemma was a smiling woman in a wedding photograph. She was a woman her husband wistfully remembered as extraordinary, someone who made him a better person. So its startling that the first time we really meet her is as a Lumon lab rat. The precise levers that were pulled to get her there are still a mystery, but thanks to Chikhai Bardo we have an illuminating picture of her life before. Severance takes full advantage of this departure from its usual setting and style, transporting us through Gemmas memories using unfamiliar lighting (sunshine!), flowing camera movements, and even production design touches that prove stark winter isnt the only season in its world. We even hear birds chirping at one point. But that happy, gauzy montage soon spirals into something much darker and sadder: tension in the marriage that crops up as they navigate fertility struggles. This was never mentioned in season onein which Marks sister Devon gave birth to a daughterbut it was clearly and understandably a devastating issue for Mark and Gemma. The way Chikhai Bardo cuts from Gemma and Mark grieving their loss into a scene fans will instantly remember from season oneMs. Casey telling Marks innie that shes been detailed to his department to watch over the potentially suicidal Helly R.brings an entirely new meaning to their interaction. They dont recognize each other, but Ms. Caseys explanation that I am to watch her for signs of sadness is suddenly a thousand times more searing. Apple TV+ As Chikhai Bardo puzzle-pieces other aspects of Gemma and Ms. Caseys lives together (and stirs up fodder for dozens more Severance fan theories), it ends by shifting from Gemmas point of view back to Marks. Hes essentially been in a coma for the entire episode, and when he wakes up, a concerned Devon asks him where he went. He doesnt answer, and its actually unclear at first which version of Mark this is. But the camera shows us whats dancing through his mind, and theres no doubt: he was thinking only of Gemma, and we realize weve really been seeing both of their memories meshed together throughout the episode. As Severance season two heads into its final episodes, it will surely leave some dangling threads, if not a massive cliffhanger. So far Chikhai Bardo is the closest weve gotten to a flashback episode, and it feels possible that we might get more in that vein: a deep dive into Harmony Cobels psyche, or a look at Burts early days at Lumon, or the origins of Kier Eagans cult-leader aspirations. But even beyond that, this week was a vivid illustration of one big reason why Severance has hooked so many fans: its mysteries contain multitudes, with ever-changing context that somehow constantly stuffs even more layers of meaning into whats already a compelling story. Want more io9 news? Check out when to expect the latest Marvel, Star Wars, and Star Trek releases, whats next for the DC Universe on film and TV, and everything you need to know about the future of Doctor Who.

With a singular, long, spiraled tusk, narwhals really are the unicorns of the sea. The tusk, which is actually an elongated tooth, is mainly found in males and can grow up to 10 feet long. Many researchers believe that narwhals use the tusks in mating displays, though due to limited field observation, there is still much to learn about narwhals.A new study published in Frontiers in Marine Science used drones to monitor narwhals in the wild. With this footage, researchers may have a better understanding of this incredible arctic whale and what they use their tusks for.Narwhal Behavior From AboveFor this study, an international research team from Florida Atlantic Universitys Harbor Branch Oceanographic Institute, the Canadian Department of Fisheries and Oceans, and Inuit communities in Nunavut, in Canadas High Arctic, captured drone video of narwhals using their tusks against Arctic char, a large, salmon-like fish.The video shows narwhals using their tusks to jab and stun the fish, which could indicate how narwhals interact with their prey. The drone captured 17 unique narwhal behaviors, including how they interacted with other animals, such as avian competition.Other behaviors include what researchers consider as the first evidence of narwhals playing, more specifically, exploratory playing. The footage may have also given the researchers more of an insight into a narwhals social learning and personality differences.Narwhals are known for their tusking behavior, where two or more of them simultaneously raise their tusks almost vertically out of the water, crossing them in what may be a ritualistic behavior to assess a potential opponents qualities or to display those qualities to potential mates, said Greg OCorry-Crowe, a research professor at FAU Harbor Branch and a National Geographic Explorer and senior author of the study in a press release. But now we know that narwhal tusks have other uses, some quite unexpected, including foraging, exploration and play.Nimble NarwhalsBesides certain behaviors, the research team also noted that narwhals were especially dextrous when it came to maneuvering their tusks. As narwhals are hunting fish, they could quickly and precisely adjust their tusks to accommodate their prey moving or use their tusks to manipulate which direction a fish would go.I have been studying narwhal for over a decade and have always marveled at their tusks, said Cortney Watt, a research scientist and team lead at Fisheries and Oceans Canada and co-author of the study, in a press release. To observe them using their tusks for foraging and play is remarkable. This unique study where we set up a remote field camp and spent time filming narwhal with drones is yielding many interesting insights and is providing a birds eye view of their behavior that we have never seen before.A Changing ArcticSeeing how narwhals interact with other native Arctic species begged the question of how they could interact with new species in the Arctic as climate change continues, especially if that means fewer food resources.To understand how narwhals are being affected by and adapting to the changing Arctic, field studies using innovative, non-invasive tools like drones are essential to observe them in their natural environment without disturbing them, said OCorry-Crowe in a press release.Drones provide a unique, real-time view of their behavior, helping scientists gather crucial data on how narwhals are responding to shifts in ice patterns, prey availability, and other environmental changes. Such studies are key to understanding the impact of global warming on these elusive animals, OCorry-Crowe concluded in a press release.Article SourcesOur writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:Frontiers in Marine Science. Use of tusks by narwhals, Monodon monoceros, in foraging, exploratory, and play behaviorA graduate of UW-Whitewater, Monica Cull wrote for several organizations, including one that focused on bees and the natural world, before coming to Discover Magazine. Her current work also appears on her travel blog and Common State Magazine. Her love of science came from watching PBS shows as a kid with her mom and spending too much time binging Doctor Who.