Long-time Slashdot reader taiwanjohn shared this article from Live Science: The mind-bending calculations required to predict how three heavenly bodies orbit each other have baffled physicists since the time of Sir Isaac Newton. Now artificial intelligence (A.I.) has shown that it can solve the problem in a fraction of the time required by previous approaches.

Newton was the first to formulate the problem in the 17th century, but finding a simple way to solve it has proved incredibly difficult. The gravitational interactions between three celestial objects like planets, stars and moons result in a chaotic system -- one that is complex and highly sensitive to the starting positions of each body. Current approaches to solving these problems involve using software that can take weeks or even months to complete calculations. So researchers decided to see if a neural network -- a type of pattern recognizing A.I. that loosely mimics how the brain works -- could do better.

The algorithm they built provided accurate solutions up to 100 million times faster than the most advanced software program, known as Brutus. That could prove invaluable to astronomers trying to understand things like the behavior of star clusters and the broader evolution of the universe, said Chris Foley, a biostatistician at the University of Cambridge and co-author of a paper to the arXiv database, which has yet to be peer-reviewed.

An anonymous reader quotes Quanta magazine: A provocative paper published in the journal Nature Astronomy argues that the universe may curve around and close in on itself like a sphere, rather than lying flat like a sheet of paper as the standard theory of cosmology predicts. The authors reanalyzed a major cosmological data set and concluded that the data favors a closed universe with 99% certainty — even as other evidence suggests the universe is flat.

A group of astronomers have found direct evidence for the first time of the role of galactic winds -- ejections of gas from galaxies -- in creating the circumgalactic medium (CGM). "It exists in the regions around galaxies, and it plays an active role in their cosmic evolution," reports Phys.Org. "The unique composition of Makani -- meaning wind in Hawaiian -- uniquely lent itself to the breakthrough findings." From the report: "Makani is not a typical galaxy," noted [UC San Diego's Alison Coil], a physics professor at UC San Diego. "It's what's known as a late-stage major merger -- two recently combined similarly massive galaxies, which came together because of the gravitational pull each felt from the other as they drew nearer. Galaxy mergers often lead to starburst events, when a substantial amount of gas present in the merging galaxies is compressed, resulting in a burst of new star births. Those new stars, in the case of Makani, likely caused the huge outflows -- either in stellar winds or at the end of their lives when they exploded as supernovae." Coil explained that most of the gas in the universe inexplicably appears in the regions surrounding galaxies -- not in the galaxies. Typically, when astronomers observe a galaxy, they are not witnessing it undergoing dramatic events -- big mergers, the rearrangement of stars, the creation of multiple stars or driving huge, fast winds.

Coil and [Rhodes College's David Rupke], the paper's first author, used data collected from the W. M. Keck Observatory's new Keck Cosmic Web Imager (KCWI) instrument, combined with images from the Hubble Space Telescope and the Atacama Large Millimeter Array (ALMA), to draw their conclusions. The KCWI data provided what the researchers call the "stunning detection" of the ionized oxygen gas to extremely large scales, well beyond the stars in the galaxy. It allowed them to distinguish a fast gaseous outflow launched from the galaxy a few million year ago, from a gas outflow launched hundreds of millions of years earlier that has since slowed significantly. From the Hubble, the researchers procured images of Makani's stars, showing it to be a massive, compact galaxy that resulted from a merger of two once separate galaxies. From ALMA, they could see that the outflow contains molecules as well as atoms. The data sets indicated that with a mixed population of old, middle-age and young stars, the galaxy might also contain a dust-obscured accreting supermassive black hole. This suggests to the scientists that Makani's properties and timescales are consistent with theoretical models of galactic winds. The findings have been published in the journal Nature.

An anonymous reader quotes a report from Phys.Org: Just before the Big Bang launched the universe onto its ever-expanding course, physicists believe, there was another, more explosive phase of the early universe at play: cosmic inflation, which lasted less than a trillionth of a second. During this period, matter -- a cold, homogeneous goop -- inflated exponentially quickly before processes of the Big Bang took over to more slowly expand and diversify the infant universe. Recent observations have independently supported theories for both the Big Bang and cosmic inflation. But the two processes are so radically different from each other that scientists have struggled to conceive of how one followed the other.

Now physicists at MIT, Kenyon College, and elsewhere have simulated in detail an intermediary phase of the early universe that may have bridged cosmic inflation with the Big Bang. This phase, known as "reheating," occurred at the end of cosmic inflation and involved processes that wrestled inflation's cold, uniform matter into the ultrahot, complex soup that was in place at the start of the Big Bang. David Kaiser, the Germeshausen Professor of the History of Science and professor of physics at MIT, and his colleagues simulated in detail how multiple forms of matter would have interacted during this chaotic period at the end of inflation. Their simulations show that the extreme energy that drove inflation could have been redistributed just as quickly, within an even smaller fraction of a second, and in a way that produced conditions that would have been required for the start of the Big Bang. The team found this extreme transformation would have been even faster and more efficient if quantum effects modified the way that matter responded to gravity at very high energies, deviating from the way Einstein's theory of general relativity predicts matter and gravity should interact. The findings have been published in the journal Physical Review Letters.

'Spacetime foam' might just be the wildest thing in the known universe, and we're just starting to understand it. From a report: A persistent cosmological puzzle has been troubling physicists since 1917: what is the universe made of? Complicating this already-mind-boggling question is the fact that our best theories conflict with our observations of the universe. Albert Einstein, according to scientific folklore, felt a unique responsibility for introducing this entire problem, reportedly referring to it as his "biggest blunder." Essentially, Einstein's novel theory of general relativity didn't hold up when used to describe the universe as a whole. General relativity described the "geometry" of spacetime as being a trampoline-like surface; planets are heavy bowling balls that distort the surface, creating curves. If a less heavy ball (like a marble) was placed near the bowling ball, it would roll along the surface just like the motion of planets in orbit. Thus, orbits are explained not by a gravitational "force" but by curvature in spacetime.

This proposal worked when considering small regions of spacetime. But when Einstein applied it to the entire universe, its predictions didn't fit. So, Einstein introduced the "cosmological constant," a fixed value that represents a kind of anti-gravity, anti-mass, and anti-energy, counteracting gravity's effects. But when scientists discovered that the universe was expanding rather than static, as Einstein had believed, the cosmological constant was set to zero and more or less ignored. After we learned that the universe's expansion is accelerating, however, scientists could no longer conveniently cancel out Einstein's anti-gravity suggestion. What was previously assumed to be empty space in the universe now had to be filled with huge amounts of mysterious anti-energy in order to explain observations of the universe's ever-quickening expansion. Even so, observations of the universe's expansion suggest that the energy is 60 to 120 orders of magnitude lower than what recent quantum field theory predicts.

What this means is that all of this extra energy is somehow missing when we look at the universe as a whole; either it's effectively hidden or very different in nature to the energy we do know about. Today, theoretical physicists are trying to reconcile these mysteries by examining the structure of so-called "spacetime" in the universe at the smallest possible scale, with surprising findings: spacetime might not be the trampoline-like plane scientists once envisioned -- it might be a foamy mess of bubbles all containing mini-universes living and dying inside our own.

sciencehabit shares a report from Science Magazine: Scientists have long suspected that neutron stars, the superdense remnants of burned out suns, are needed for this sort of rapid neutron capture. But until 2 years ago, they had never witnessed such an event. That's when the GW170817 merger happened. Taking place 140 million light-years away, astronomers first detected it from the gravitational waves generated by the stars crashing together. Computer modeling revealed that strontium in the expanding ball of gas would absorb light at wavelengths of 350 and 850 nanometers. When they looked again at the X-shooter spectra, they found dips in the spectra at those wavelengths. The end result: five Earth masses worth of strontium. The work confirms that at least some of the heavier elements are produced by merging neutron stars, and that neutrons stars really are made of neutrons. The findings have been published in the journal Nature.

Scientists have directly observed the rocky guts of exoplanets, which are worlds from different star systems, by watching the fallout of these objects crashing into the corpses of dead stars. From a report: This mind-boggling technique has revealed that exoplanets are similar in composition to planets in our own solar system, implying that worlds like Earth may be plentiful in our galaxy, according to a study published on Thursday in Science. "It's pretty cool because this is really the only way to measure the geochemistry of exoplanetary bodies directly," said lead author Alexandra Doyle, a graduate student of geochemistry and astrochemistry at UCLA, in a phone call. Co-author Edward Young, a professor of geochemistry and cosmochemistry at UCLA, added that the study represents "the first time such an advanced way of looking at the geochemistry of these bodies has been used," in the same call.

We are living through a golden age of exoplanet discoveries. Thousands of exoplanets have been detected, including an Earth-sized world orbiting the closest star to the Sun. But it is still extremely difficult to capture details about the interior composition and dynamics of these worlds. Unlike other planetary properties such as mass or atmospheric composition, a planet's geochemistry cannot be deduced just by looking at an object passing in front of its host star. White dwarfs, as it turns out, can help plug this information gap. These objects are the remains of stars that have blown up and collapsed into tiny, dense spheres about the size of Earth (our own Sun will embark on this transition in about five billion years). The pyrotechnic deaths of these stars scramble the orbits of many objects in our solar system, such as asteroids and planets. Some of these worlds may end up hurtling toward the star's posthumous white dwarf, which tears them apart over the course of about 100,000 to one million years.

A miniature gravitational wave detector under development would measure higher-frequency waves than LIGO. From a report: Within one second of the big bang, the first newborn black holes may have announced their formation with gravitational waves that stretched and squeezed the fabric of existence as they rippled outward into the expanding universe. Now researchers at Northwestern University have begun planning a tabletop-size sensor that could detect these primordial howls for the first time. The gigantic $1-billion Laser Interferometer Gravitational-Wave Observatory (LIGO) first measured the spacetime ripples known as gravitational waves in 2016; these phenomena came from the collision and merging of distant supermassive black holes. Since then, massive detectors have also recorded gravitational waves from merging neutron stars. Northwestern's proposed mini detector, which received an influx of funding in July, could measure higher-frequency waves from objects that have never been measured before -- such as black holes in the earliest universe.

Current gravitational-wave detectors such as U.S.-based LIGO and Europe's Virgo use a sprawling system of mirrors and laser "arms" that stretch for kilometers to measure tiny changes in distance caused by passing gravitational waves. Northwestern's Levitated Sensor Detector would use lasers to suspend a glass bead inside a vacuum chamber, creating an extremely force-sensitive sensor with arms just a meter long. It would listen for echoes from the formation of primordial black holes and the activity of theoretical particles called axions, both of which are candidates for mysterious dark matter -- hidden materials that may constitute much of the universe's mass and are invisible except for their gravitational presence.

Space scientists are abandoning the heavens to help you decide what to wear and watch and listen to. Whether it's stars or Stitch Fix, it's all about machine learning. Wired: Chris Moody knows a thing or two about the universe. As an astrophysicist, he built galaxy simulations, using supercomputers to model the way the universe expands and how galaxies crash into one another. One night, not long after he'd finished his PhD at UC Santa Cruz, he met up with a few other astrophysicists for beers. But that night, no one was talking about galaxies. Instead, they were talking about fashion. A couple of Moody's astrophysicist pals had recently left academia to work for Stitch Fix, the online personal styling company now valued at $2 billion. Moody gawked at them. "They were like, 'You don't think this is an interesting problem?'" he says. Indeed, he did not. But when his friends described the work they were doing -- sprinkling in phrases like "Bayesian models" and "Poincare space" -- predicting what clothes someone might like started to sound eerily like the work he'd done during his PhD. Quantifying style, he discovered, "turns out to have really close analogues to how general relativity works."

Four years later, Moody works for Stitch Fix too. He belongs to a growing group of astrophysicist deserters, who have stopped researching the cosmos to start building recommendation algorithms and data models for the tech industry. They make up the data science teams at companies like Netflix and Spotify and Google. And even at elite universities, fewer astrophysics PhDs go on to take postdoctoral fellowships or pursue competitive professorships. Now, more of them go straight to work in Silicon Valley. To understand what's driving astrophysicists into consumer product startups, consider the recent explosion of machine learning. Astrophysicists, who wrangle massive amounts of data collected from high-powered telescopes that survey the sky, have long used machine learning models, which "train" computers to perform tasks based on examples. Tell a computer what to recognize in one intergalactic snapshot and it can do the same for 30 million more and start to make predictions. But machine learning can also be used to make predictions about customers, and around 2012, corporations started to staff up with people who knew how to deploy it.

The Nobel Prize in physics for 2019 was awarded to three scientists on Tuesday for groundbreaking work on the evolution of the universe and Earth's place in it. From a report: Their discoveries have forever "transformed our ideas about the cosmos" and helped answer fundamental questions about existence, said the Royal Swedish Academy of Sciences. Half of the award went to James Peebles, a physicist with Princeton University, for developing a theoretical framework that traces the the history of the universe, from the Big Bang to present day. His contributions to the Big Bang model and other work led to insights that just 5% of the universe is known matter -- everything from stars to plants to humans -- and the remaining 95% is unknown dark matter and dark energy. "When I started working in this subject -- I can tell you the date, 1964 -- at the invitation of my mentor, Professor Robert Henry Dicke, I was very uneasy about going into this subject because the experimental observational basis was so modest. ... I just kept going," Peebles said during a news conference, according to Princeton University. "Which particular step did I take? I would be very hard-pressed to say. It's a life's work."

The other half was jointly awarded to Michel Mayor, an astrophysicist with the University of Geneva, and Didier Queloz, an astronomer with the University of Geneva and University of Cambridge, for the first discovery of a planet outside our solar system. In October 1995, the two scientists discovered the first exoplanet in the Milky Way, planet 51 Pegasi b. Since their initial discovery, more than 4,000 exoplanets have been found in our home galaxy, according to the Royal Swedish Academy of Sciences.

An anonymous reader quotes Cinema Blend: At the beginning of 2019, approximately a half year after James Gunn was unceremoniously fired from Guardians of the Galaxy Vol. 3, it was officially confirmed that he'd be jumping to the DC universe to write and direct The Suicide Squad. Then, just two months later, Disney and Marvel reversed course and rehired Gunn to helm Guardians 3, though because he boarded The Suicide Squad in that interim period, he's tackling that DC tale first and then will jump back to the Marvel Cinematic Universe

Even though he's now working with the MCU's chief rival on the superhero movie front, James Gunn has revealed that the folks over at Marvel Studios are incredibly supportive of him working on The Suicide Squad for DC, and Gunn is advocating that DC and Marvel fans follow suit and stop feuding with one another about these companies...

"As I've said so many times, at the end of the day, Marvel & DC fans have a lot more in common than they do not. I am now & have been for almost all my life, both. Maybe you like one more than the other - that's cool - but that doesn't mean you can't enjoy them all or that you have to tear the other down. I know I & my partners at both Marvel & DC believe what's good for one studio is generally good for all: spurring each other on daily with heartfelt, spectacular & innovative entertainment that keeps audiences around the world loving movies based on or inspired by sequential art..."
Meanwhile Joker, the newest film in the DC Extended Universe, set a new box-office record for a film opening in October, beating the record previously set by Marvel's Spider-Man spinoff Venom.

Rotten Tomatoes currently shows Joker with an average critic's rating of 69%, placing it behind Dreamworks' Abominable, as well as Ad Astra, Hustlers, the Downton Abbey movie, and Judy -- but with a much higher audience score of 91%.

appedology.pk quotes Popular Mechanics: Warp drive is one of the many futuristic ideas proposed in Star Trek, allowing for faster-than-light travel across the galaxy. Einstein's Theory of Relativity prevents anything from moving faster than light. In 1994, a theoretical physicist proposed a workaround: creating a bubble within space-time that would twist distances, allowing anything within the bubble to travel long distances. Many think it makes theoretical sense, but is practically unworkable. An undergrad at the University of Alabama wants to restart the conversation, and he's focused on how much energy such a bubble would need...

"Mathematically, if you fulfill all the energy requirements, they can't prove that it doesn't work," he recently said at a standing-room only talk on the subject.... "People used to say, 'You're dealing in something that would be great, but it takes the mass of the entire universe to do it,'" Agnew said. "Now, we're down to where it is still an immense amount of energy and exotic matter is still a problem, but if we had that energy, we could do it."

After five to eight years of theoretical work, Agnew said, "it's been reduced by many, many orders of magnitude."

After briefly breaking up, Sony Pictures and Marvel have found a way to get back in the Spider-Man business together. From a report: Their new film even has a release date: July 16, 2021. "I am thrilled that Spidey's journey in the MCU will continue, and I and all of us at Marvel Studios are very excited that we get to keep working on it," said Marvel topper Kevin Feige. "Spider-Man is a powerful icon and hero whose story crosses all ages and audiences around the globe. He also happens to be the only hero with the superpower to cross cinematic universes, so as Sony continues to develop their own Spidey-verse you never know what surprises the future might hold."

Also, as part of the arrangement, Spider-Man will appear in a future Marvel movie. In 2015, Marvel and Sony unveiled an unprecedented intra-studio partnership that produced not only two well-regarded and massive hits with Spider-Man: Homecoming and this summer's Spider-Man: Far From Home, but it also took the character, whose movie rights are owned by Sony, and put him into the Marvel Cinematic Universe where the character became one of its key players. But the co-parenting deal fell apart not too long after the release of Far From Home, spilling into the open in August.

The world's largest single-dish radio observatory is preparing to open to astronomers around the world, ushering in an era of exquisitely sensitive observations that could help in the hunt for gravitational waves and probe the mysterious fleeting blasts of radiation known as fast radio bursts. From a report: The Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in southern China has just passed a series of technical and performance assessments, and the Chinese government is expected to give the observatory the final green light to begin full operations at a review meeting scheduled for next month. "We do not see any roadblocks for the remaining transition," says Di Li, the chief scientist of FAST. "I feel both excited and relieved." The complex project has not been without challenges â" it has a radical design and initially struggled to attract staff, in part because of its remote location. But the pay-off for science will be immense. FAST will collect radio waves from an area twice the size of the next-largest single-dish telescope, the Arecibo Observatory in Puerto Rico.

The Chinese observatory's massive size means that it can detect extremely faint radio-wave whispers from an array of sources across the Universe, such as the spinning cores of dead stars, known as pulsars, and hydrogen in distant galaxies. It will also explore a frontier in radioastronomy -- using radio waves to locate exoplanets, which may harbour extraterrestrial life. Since testing began in 2016, only Chinese scientists have been able to lead projects studying the telescope's preliminary data. But now, observation time will be accessible to researchers from around the world, says Zhiqiang Shen, director of the Shanghai Astronomical Observatory and co-chair of the Chinese Academy of Sciences' FAST supervisory committee. From two years ago, China Built the World's Largest Telescope, But Has No One To Run It.

Before Silicon Valley became the idea center of the internet, it was a group of factory towns, the blinking heart of "clean" manufacturing, the hallmark of the Information Age. A report adds: Silicon Valley was a major industrial center for much of the 20th century. Semiconductors and microprocessors rolled out of factories scattered all over the area (known on maps as Santa Clara County) from the 1950s to the early 1990s -- AMD, Apple, Atari, Fairchild, Hewlett-Packard, Intel, and Xerox, to name just a few. From the mid-1960s to the mid-1980s, Santa Clara County added 203,000 manufacturing jobs, 85 percent of them in tech. Beginning in the 1980s, as government contracts disappeared, Silicon Valley companies moved toward creating software, and beginning in the 1990s, companies there largely focused on internet-based applications. Now the area trades mostly in the rarefied and intangible realm of apps and software. It's hard to see that now, when glass-walled office buildings, corporate campuses, and strip malls along highways that bloom into concrete clovers dominate the landscape of this former industrial area. But all of that industrial history left something behind.

The Google Quad Campus looks way too nice to be contaminated with toxic waste: There are matching bikes, a pool with primary-colored umbrellas, and a contained universe that looks more like a college or a park than a satellite campus of one of the biggest companies in the world. But it turns out that this idyllic garden of corporate harmony sits on land that since 1989 has been a Superfund site, a designation the EPA gives some of the most contaminated or polluted land in the country. And while thousands of tons of contaminants have since been removed, it is still being cleaned up. For a few weeks at the end of 2012 and into 2013, toxic vapors got into two campus buildings, possibly exposing the office workers there to levels of chemicals above the legal limit set by the EPA. Santa Clara County has 23 active Superfund sites, more than any other county in the United States. All of them were designated as such in the mid to late 1980s, and most were contaminated by toxic chemicals involved in making computer parts. Completely cleaning up these chemicals may be impossible.

NBCUniversal's upcoming streaming service finally has a name -- Peacock -- and a whole bunch of newly announced programming. From a report: The long-in-the-works service will launch next April, anchored by more than 15,000 hours of content from the entertainment conglomerate's TV and movie vaults. In addition to a previously announced deal to take back The Office from Netflix in 2021, NBCU Tuesday said that starting next fall, Peacock will also be the exclusive streaming home for the Universal TV -- produced Parks and Recreation, which currently streams on Netflix, Hulu, and Amazon Prime Video. The new service has also locked down deals for a slew of originals with ties to existing NBCU brands, including a reboot of Battlestar Galactica overseen by Sam Esmail (Mr. Robot), revivals of Saved by the Bell and Punky Brewster, a comedy/talk show hosted by Late Night's Amber Ruffin, a new spinoff from The Real Housewives universe, and a new comedy from The Good Place creator Mike Schur starring The Office's Ed Helms.

The universe is looking younger every day, it seems. New calculations suggest the universe could be a couple billion years younger than scientists now estimate, and even younger than suggested by two other calculations published this year that trimmed hundreds of millions of years from the age of the cosmos. From a report: The huge swings in scientists' estimates -- even this new calculation could be off by billions of years -- reflect different approaches to the tricky problem of figuring the universe's real age. "We have large uncertainty for how the stars are moving in the galaxy," said Inh Jee, of the Max Plank Institute in Germany, lead author of the study in Thursday's journal Science. Scientists estimate the age of the universe by using the movement of stars to measure how fast it is expanding. If the universe is expanding faster, that means it got to its current size more quickly, and therefore must be relatively younger.

The expansion rate, called the Hubble constant, is one of the most important numbers in cosmology. A larger Hubble Constant makes for a faster moving -- and younger -- universe. The generally accepted age of the universe is 13.7 billion years, based on a Hubble Constant of 70. Jee's team came up with a Hubble Constant of 82.4, which would put the age of the universe at around 11.4 billion years. Jee used a concept called gravitational lensing -- where gravity warps light and makes far away objects look closer. They rely on a special type of that effect called time delay lensing, using the changing brightness of distant objects to gather information for their calculations. But Jee's approach is only one of a few new ones that have led to different numbers in recent years, reopening a simmering astronomical debate of the 1990s that had been seemingly settled.

Kate Marvel, writing for Scientific American: We are, I promise you, not doomed, no matter what Jonathan Franzen says. We could be, of course, if we decided we really wanted to. We have had the potential for total annihilation since 1945, and the capacity for localized mayhem for as long as societies have existed. Climate change offers the easy choice of a slow destruction through inaction like the proverbial frog in the slowly boiling pot. And there are times when the certainty of inevitability seems comforting. Fighting is exhausting; fighting when victory seems uncertain or unlikely even more so. It's tempting to retreat to a special place -- a cozy nook, a mountaintop, a summer garden -- wait for the apocalypse to run its course, and hope it will be gentle.

[...] It is precisely the fact that we understand the potential driver of doom that changes it from a foregone conclusion to a choice, a terrible outcome in the universe of all possible futures. I run models through my brain; I check them with the calculations I do on a computer. This is not optimism, or even hope. Even in the best of all possible worlds, I cannot offer the certainty of safety. Doom is a possibility; it may that we have already awakened a sleeping monster that will in the end devour the world. It may be that the very fact of human nature, whatever that is, forecloses any possibility of concerted action. But I am a scientist, which means I believe in miracles. I live on one. We are improbable life on a perfect planet. No other place in the universe has nooks or perfect mountaintops or small and beautiful gardens. A flower in a garden is an exquisite thing, rooted in soil formed from old rocks broken by weather. It breathes in sunlight and carbon dioxide and conjures its food as if by magic. For the flower to exist, a confluence of extraordinary things must happen. It needs land and air and light and water, all in the right proportion, and all at the right time. Pick it, isolate it, and watch it wither. Flowers, like people, cannot grow alone.

pgmrdlm shares a report from Live Science: In Douglas Adams' sci-fi series "The Hitchhiker's Guide to the Galaxy," a pair of programmers task the galaxy's largest supercomputer with answering the ultimate question of the meaning of life, the universe and everything. After 7.5 million years of processing, the computer reaches an answer: 42. Only then do the programmers realize that nobody knew the question the program was meant to answer. Now, in this week's most satisfying example of life reflecting art, a pair of mathematicians have used a global network of 500,000 computers to solve a centuries-old math puzzle that just happens to involve that most crucial number: 42.

The question, which goes back to at least 1955 and may have been pondered by Greek thinkers as early as the third century AD, asks, "How can you express every number between 1 and 100 as the sum of three cubes?" Or, put algebraically, how do you solve x^3 + y^3 + z^3 = k, where k equals any whole number from 1 to 100? This deceptively simple stumper is known as a Diophantine equation, named for the ancient mathematician Diophantus of Alexandria, who proposed a similar set of problems about 1,800 years ago. Modern mathematicians who revisited the puzzle in the 1950s quickly found solutions when k equals many of the smaller numbers, but a few particularly stubborn integers soon emerged. The two trickiest numbers, which still had outstanding solutions by the beginning of 2019, were 33 and -- you guessed it -- 42. Using a computer algorithm to look for solutions to the Diophantine equation with x, y and z values that included every number between positive and negative 99 quadrillion, mathematician Andrew Booker, of the University of Bristol in England, found the solution to 33 after several weeks of computing time.

Since his search turned up no solutions for 42, Booker enlisted the help of Massachusetts Institute of Technology mathematician Andrew Sutherland, who helped him book some time with a worldwide computer network called Charity Engine. "Using this crowdsourced supercomputer and 1 million hours of processing time, Booker and Sutherland finally found an answer to the Diophantine equation where k equals 42," reports Live Science. The answer: (-80538738812075974)^3 + (80435758145817515)^3 + (12602123297335631)^3 = 42.

With a population of over 87,000, Lower Duck Pond is the largest, friendliest, and oddest city that's not on the map. The Outline: Located somewhere on a plane of nonexistence, the rapidly growing town of Lower Duck Pond rests, isolated, without even an official city map. Its locals don't get lost, though. They know their way around quite well and discuss their comings and goings through postings on the subreddit r/HaveWeMet. The community's 87,000-plus "residents" share constant chatter about which buildings in the area need repairs, which sandwich shops have been changing up their menu, and which streets need repaving. It's not unusual for newcomers to feel confused by the whirlwind of information and every resident's seemingly picture-perfect memory of their surroundings. It helps to remember that they're all pretending.

Strange, new places do take some getting used to and it might take you a few minutes to get the hang of subreddit r/HaveWeMet's premise, where users roleplay as longtime neighbors in a non-existent town called "Lower Duck Pond." The joke's attracted over 87,000 users since the community started two years ago, making it the fastest-growing open-source fictional town on Earth. While the residents, streets, and buildings are fake, the absurdity, purity, and sense of community for its daily users has become very real. Reddit user u/Devuluh, who's really a sophomore computer science major named David (he declined to share his last name), started r/HaveWeMet in early 2017 when he was still in high school. The idea was to create an online space where everyone pretends to know each other. "The original idea for r/HaveWeMet was not a sub mimicking a fake town, but rather simply just people pretending to know each other, and later it evolved into much more than that," David told me. "If you want to have a deep involvement in r/HaveWeMet, it's almost necessary you get to know people's characters. Some even go as far as getting to know the members behind their characters, too. It's like one big universe created collaboratively, just through peoples' interactions with each other."