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The following is adapted from Built on Bones by Brenna Hassett

Like many bioarchaeologists, I have a fondness for plagues. They upend the natural order of things, cutting across the normal risk factors for ending up in archaeological samples and giving a snapshot, captured in death, of not just the old and the infirm but also a sample of the whole (unlucky) population. The tragedy of mass causalities exposes lives that would, statistically, rarely be unearthed, including the adolescents and adults who form the bulk of a living population, so rarely represented in a cemetery. Calamities such as plague that knock everyone into the grave with one indiscriminate sweep are one of the few chances bioarchaeologists have to overcome something known as the Osteological Paradox, a term coined by researcher James Wood and colleagues to cover the very awkward point that, in studying past lives, the evidence bioarchaeologists actually have to go on are past deaths. Without access to modern medical care, the greatest potential for mortality comes in old age and in infancy and early childhood. Death is less of a risk for adolescents and reproductive-age adults, until something comes along to level those odds.

Built on Bones by Brenna Hassett. Bloomsbury

It’s possible to break the infectious diseases that kill humans down into different categories; these might be dependent on transmission vector (what you get it from), disease agent (bacteria or virus) or even climate and geography (it’s difficult to get malaria if malarial mosquitoes aren’t around). People (lots of people) offer a great opportunity for a disease on the make to become a full-fledged plague. What makes a plague? Dead people–and lots of them–in unusual places. As we go wandering back in time, there are few candidates to fit this description: the disease we know as Plague-with-a-capital-P, and the plague that came before it, smallpox.

Smallpox manages to be both the oldest archaeologically known epidemic and by far the deadliest recent epidemic. It is caused by infection with one of two species of virus, Variola major or Variola minor. The latter causes alastrim, a relatively benign form of dermatological disease which is rarely fatal and is endemic to parts of Central America. The former has killed by some estimates 500 million people, and leaves a disfiguring rash in many of those who were lucky enough to survive; this is the disease we are interested in. Smallpox is a disease that acts first on the skin: there are spots, then there are fluid-filled blisters. These blisters are what cause the horrific scarring associated with smallpox. Subsequently, the infection can progress even into bones, causing osteomyelitis, though this occurs only in a very small percentage of cases.

Osteomyelitis is a very broad category of pathology; the term is used to describe any infection of the bone itself. It is the one sign accessible to bioarchaeologists who work on bone of potential smallpox infections. When bone is infected, it has an inflammatory response just like other tissues of the body, met in turn by a repair response that results in characteristic changes to bone shape. The infection may simply be evident as reactive bony changes on the interior or exterior surfaces of the bone. It can form an abscess, a pus-filled lesion, which may force the formation of a channel all the way out through the bone, along which said pus can suppurate. The clinical term for this channel is ‘cloaca’, which is Latin for ‘sewer’ and every bit as disgusting as you might imagine a Roman sewer to be. New bone formation on the surface in response to the infection can change the width or thickness of the bone, so when compared to an opposite number, say from the other side of the body, the shape is very much changed.

Of course, the majority of cases of osteomyelitis are not caused by smallpox but by a host of bloodstream-borne infections, with about 90 per cent of modern infections caused by the bacterium Staphylococcus aureus.

Despite smallpox only rarely leaving telltale signs of bony infection, bioarchaeology has another avenue for detecting the disease in antiquity: mummies. In 1979 physician Donald Hopkins was granted special permission to examine the upper half of the unwrapped body of the Egyptian pharaoh Ramses V, who died in 1143 BC. The mummy’s skin showed evidence of a pustular rash, very akin to smallpox, and subsequently Ramses V became famous not for a perfectly sensible large-scale tax survey he carried out in his limited reign, but for being the first archaeological evidence of smallpox.

This is an academic translation of ‘argue violently about’. 

Or, in some slightly less credible accounts, rains of vertically dislocated amphibians, grasshoppers, etc. 

I do not recommend image-searching this. 

Though variable, 2 to around 35 percent. 

He has more names, all of which translate to variations on the theme of ‘honourable’, ‘rich’, ‘long-lived’ and ‘strong like a bull’. 

Excerpted from Built on Bones: 15,000 Years of Urban Life and Death by Brenna Hassett. Copyright © Brenna Hassett, 2023. Published by Bloomsbury Sigma, an imprint of Bloomsbury Publishing. Reprinted with permission.

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Microsoft’s New Video Authenticator Could Help Weed Out Dangerous Deepfakes

Deepfakes can be fun. Those videos that perfectly inserted Jim Carrey into Jack Nicholson’s role in The Shining were endlessly entertaining. As the upcoming U.S. election closes in, however, analysts expect that deepfakes could play a role in the barrage of misinformation making its way out to potential voters.

This week, Microsoft announced new software called Video Authenticator. It’s designed to automatically analyze videos to determine whether or not algorithms have tampered with the footage.

The software analyzes videos in real-time and breaks it down frame-by-frame. In a way, it works similarly to familiar photographic forensic techniques. It looks for inconsistencies in edges, which can manifest as subtle changes in color or small pixel clusters (called artifacts) that lack color information. You would be hard-pressed to notice them with your own eyes, especially when dozens of frames are zipping by every second.

As the software performs its analysis, it spits out either a percentage or a confidence score to indicate how sure it is about an image’s legitimacy. Faking an individual frame is relatively simple at this point using modern AI techniques, but movement introduces an extra level of challenge, and that’s often where the software can glean its clues.

Research has shown that errors typically happen when subjects appear in profile, quickly turn more than 45 degrees, or if another object rapidly travels in front of the person’s face. While these happen relatively commonly in the real world, they rarely happen during candidate speeches or video calls, which are prime targets during an election season.

To train the Video Authenticator, Microsoft relied on the FaceForensics++ dataset—a collection of manipulated media specifically to help train people and machines to recognize deepfakes. It contains 1.5 million images from 1,000 videos. Once built, Microsoft tested the software on the DeepFake Detection Challenge Dataset, which Facebook AI created as part of a contest to build automated detection tools. Facebook paid 3,426 actors to appear in more than 100,000 total video clips manipulated with a variety of techniques, including everything from deep learning methods to simple digital face swaps.

Facebook’s challenge ended earlier this year and the winning entrant correctly identified the deepfakes 82 percent of the time. The company says it’s already using internal tools to sniff out deepfakes, but it hasn’t publicly given any numbers about how many have shown up on the platform.

For now, average users won’t have access to Microsoft’s Video Authenticator. It will be available exclusively to the AI Foundation as part of its Reality Defender 2023 program, which allows candidates, press, campaigns, parties, and social media platforms to provide suspected fake media for authentication. But, down the road, these tools could become more available to the public.

Another big tech company—Google—has been hard at work on ways to detect face swaps; last year it hired actors and built its own dataset using paid actors similar to Facebook’s methods. While Google doesn’t have public plans for a specific deepfake detection site for everyday users, it has already implemented some image manipulation tools as part of its Image Search function, which is often the first step in trying to figure out if a photo is fake.

Microsoft didn’t share specific numbers about the success rate its AI-driven tool achieved, but the benchmark isn’t all that high when you survey the top performing players. The winner of Facebook’s challenge achieved its 82-percent success rate on familiar data—once it was applied to new clips taken in the real world with fewer controlled variables, its accuracy dropped to around 60 percent. Canadian company Dessa had similar success with the Google-produced videos with controlled variables. With videos pulled from other places on the web, however, it struggled to hit the 60 percent success mark.

We still don’t know how big a role deepfakes will play in the 2023 election, and with social media platforms doing their own behind-the-scenes detection, we may never know how bad it could have been. Maybe by the next election, computers will be better at recognizing the handiwork of other automated manipulators.

How Google Can Help You Win The Moment

Understanding Google’s latest research on micro-moments and the implications for your marketing

It’s no secret that mobile has dramatically impacted how we do business and how consumers interact with brands online – the latest mobile adoption data indicates that mobile is still on course to overtake fixed internet access and that mobile ad spending accounts for 49% of digital ad spending.

As a result of this mobile shift, Google has conducted some interesting ethnographic research over the last year to explore how consumer behaviour is changing and gain an understanding into the needs of real people. Some of the stand out insights from the research includes:

82% of smartphone users use their phones to influence a purchase decision in a store

62% of smartphone users are more likely to take action right away to solve an unexpected problem or task because they have a smartphone

90% of smartphone users have used their phone to make progress towards a long-term goal or multi-step process while out and about

91% of smartphone users turn to their phone for ideas while doing a given task

Google’s research has led them to the conclusion that consumer decisions don’t happen in a defined, logical order, if they ever did. Instead, they happen at seemingly random times in a consumer’s life – what Google have defined as ‘micro-moments’.

What exactly are ‘Micro-moments’?

Micro-moments are moments when consumers act on a need, e.g. to learn something, do something, discover something, watch something or buy something. They are intent-rich moments where decisions are being made and preferences shaped.

Google recommends marketers consider four key moments and explain the importance of Moments in relation to mobile devices:

“We turn to our phones with intent and expect brands to deliver immediate answers. It’s in these I-want-to-know, I-want-to-go, I-want-to-do, I-want-to-buy moments that decisions are made and preferences are shaped”.

Research presenting the increasing importance of these four ‘Moments’ is summarised in the visual below.

It’s not just Google who are pushing this concept. Forrester analyst Jeffrey Hammond tells us that ‘Consumer Engagement Is Shifting Toward Micro Moments’ whilst Brian Solis of Altimeter Group has explained ‘Why CMOs Need to Invest in Micro-Moments’.

From the Zero Moment of Truth to Micro-moments – an evolution

The introduction of the Zero Moment of Truth (ZMOT) challenged marketers to consider new, intentional strategies to enable brands to become discoverable and capture attention in the discovery stage before guiding consumers through to purchase.

Micro-moments is follow-up to ZMOT and influenced by the increasingly ubiquitous nature of mobile among consumers. Instead of thinking about one common Zero Moment of Truth in any given situation, Micro-moments encourages marketers to consider many different, real-time, intent-driven micro-moments related to hundreds of different scenarios, all of which give marketers an opportunity to shape consumer decisions.

How do micro-moments influence modern marketing?

In many ways the underlying theme of Google’s Micro-moments research is not new. The idea that the consumer journey no longer follows a predictable, linear model, and the need to create more fluid, bespoke personas for our customer groups, has been covered before:

However, where I think Micro-moments is particularly interesting is in the mind-set shift it encourages us to adopt. Living in a mobile-orientated world has dramatically impacted how consumers think, search and buy online and as a result marketers must respond accordingly in order to succeed.

Micro-moments in action

With Google’s data and research in mind, let’s consider some examples of Google’s Micro-moments in action and how they may influence marketing decision-making:

People evaluate purchase decisions ‘in-the-moment’

Consumers have their smartphone to hand at all times and this has implications for brands who sell products in physical locations. According to Google, 1/3 of online consumers aged 18-34 say information discovered through search caused them to buy a more expensive product in a store if that product is more effective.

This insight provides a clear opportunity with search. Mobile means consumers can instantly search and compare products in the moment, meaning marketers must win these moments by providing timely and relevant information, such as product details, reviews and testimonials.

People solve problems ‘in-the-moment’

If something breaks or goes wrong, or if a consumer suddenly thinks of something they might need in a given moment, they’re likely to pick up their smartphone to take action. Google has found that online consumers purchase in unexpected places – 39% in the kitchen; 28% in the car; 21% in the bathroom.

In moments like this it’s important to be found so search is again a key consideration. However, in order to seal the deal marketers must also ensure that the mobile experience is consistent from start to finish. The user experience and shopping process must make things easy for the consumer, meaning products are first easy to find, followed by a painless checkout process.

People pursue big goals in small moments

We often think that buying a large purchase, such as a new piece of technology, car or even house, as something that requires dedicated research time carried out in one go. However, nowadays research is conducted in ‘stolen moments’ spread across the day, for example waiting in a queue, during a lunchtime break or sitting in an airport or train station.

Google has found that mobile queries for mortgage calculators have grown 66% since last year, illustrating the demand for research tools such as these ‘on the go’. Mobile moments are critical within long consideration journeys, with people chipping away at bits of research in free moments. Marketers must therefore ask:

• Do I offer the right experience for the screen and the context?

The micro-moment action plan 1. Make a moments map

Identify a set of moments you want to win or can’t afford to lose by examining all key phases of the consumer journey.

2. Understand customer needs in-the-moment

For each moment you want to win, put yourself in the consumer’s shoes. Ask “What would make this easier or faster? What content or features would be most helpful for this moment?”

3. Use context to deliver the right experience

Leverage contextual signals like location and time of day to deliver experiences and messages that feel tailor-made for the moment.

4. Optimise across the journey

People move seamlessly across screens and channels. Ensure your brand delivers seamlessly in return and don’t let competing objectives or department silos stand in the way.

5. Measure every moment that matters

While the return on investment for certain moments may not yet be directly measurable, use credible estimates to ensure nothing’s falling through the cracks.

What Is Causing Vitalik To Delay The Ethereum Upgrade Past June?

The Ethereum upgrade delay is driving investors more anxious by the day amid volatile price fluctuations

Ethereum is one of the most significant altcoins in the market and one of Bitcoin’s biggest competitors. For the past few months, since the fall of the BTC price, the crypto investor community has been rooting for Ethereum to take over Bitcoin as the world’s most prominent cryptocurrency. Even though both Ethereum and Bitcoin’s prices have sunk by over 20% within a period of just seven days, with BTC falling under US$30,000, and the Ether price diving below US$1,800, investors have been consistently wishing that Ether would finally bring respite to the crypto market. But with the Ethereum upgrade being constantly delayed, crypto users are now getting impatient and some are even ready to leave the market! The Ethereum creator, Vitalik Buterin, has constantly delayed the Ethereum transition to proof-of-stake (PoS). The upgrade was postponed to June of this year, but then in a recently announcement the Ether team announced that its ‘difficulty bomb’ will be facing further delay, making investors even more skeptical and anxious.

The delay on the ‘difficulty bomb’ brings more bad news for Ethereum investors who were wishing for the completion of the Ethereum Merge upgrade in August. The upgrade was first started by ConsenSys researcher Mikhail Kalinin, but as days passed by, the Ethereum upgrade work has been undertaken by several developers from the broader community. The Merge aims to migrate Ethereum from its energy-intensive proof-of-work algorithm to the proof-of-stake algorithm. Buterin has signified that the upgrade will most probably be launched by August, in case there are no significant issues.

What does the Merge upgrade intend to serve?

Ethereum developers have demonstrated that the ‘shadow fork’, meaning the transfer to PoS has been under successful development. The Merge intends to make Ethereum one of the most sustainable cryptocurrencies in the market. ETH Merge is the first of Ethereum’s major upgrades, which comes after the London upgrade. After the Merge, the developers have lined up a series of other upgrades aimed to make the ETH network much more robust, namely The Surge, The Verge, The Purge, and finally The Splurge. Various tests have been going on for several months as developers test the Beacon Chain, but reports say that there aren’t enough updates and reformations in place to make the official merge upgrade.

The ‘difficulty bomb’ is a piece of code that when activated gradually boots miners off the blockchain through increasing mining difficulty, until it becomes absolutely impossible to mine Ethereum. ETH developers have already put the difficulty bomb in place which was already delayed previously. Even though it is quite understandable that transforming the second-largest cryptocurrency in the market might be a complex and critical task, this delay is causing Ethereum to lose the opportunities that might enable the crypto to overtake BTC.

Delays in the Difficulty Bomb

Last week Friday, several issues emerged which drove ETH developers to roll back the Ethereum upgrade’s release further later. The developers found bugs on the Ropsten testnet, one of the oldest testnets for ETH. Around 14 network validators, including those that oversee the security of the network had to be taken offline when the new code was deployed. Since then, the developers have deployed extra cautiousness until all the issues are resolved until the final launch.

The Ethereum upgrade will surely be deployed this year, but the delay is harming the network more than the developers, or even Buterin could actually anticipate. Investors growing more anxious by the day as they have started to believe that the Ethereum upgrade might not even come due to technical glitches and it is just a piece of consolation to overshadow the falling prices of Ether. The upgrade has become a double-edged sword for Ethereum, only time will tell how investors will react to further delays to this much-awaited Ether development.

A Strange Object From Outside Our Solar System Just Zoomed Past The Sun

Travelling between the stars has been a dream of humanity for generations. But while our species might not be able to make that trek for a long while, there are some seasoned travelers whizzing around the galaxy, and one of them stopped by our solar system this week.

Astronomer Rob Weryk, a postdoctoral researcher at the University of Hawaii Institute for Astronomy was working with data collected from the university’s Pan-STARRS 1 telescope on October 19 when he first noticed the strange moving object, and reported it to the Minor Planet Center, which compiles reports of minor planets, moons, natural satellites, and comets from all over the world.

The Pan-STARRS 1 telescope helps NASA identify and track near-Earth objects, like asteroids, which head into Earth’s neighborhood. Until now, all of those objects have originated from our own solar system. But this discovery was different. Instead of staying roughly in the same plane as most of the other planets, this object jetted in almost perpendicular to…basically everything else in the Solar system.

Other telescopes and astronomers around the world made similar observations and sent in reports tracking the movement of the object on its journey. It was decidedly odd, and incredibly exciting.

“This is the most extreme orbit I have ever seen,” Davide Farnocchia, a scientist at NASA’s Center for Near-Earth Object Studies (CNEOS) says in a statement. “It is going extremely fast and on such a trajectory that we can say with confidence that this object is on its way out of the solar system and not coming back.”

The object, temporarily called A/2024 U1, is less than a quarter mile long, and when it was entering the solar system it was speeding along at 15 miles per second. At first, people thought it might be a comet, but it doesn’t have a comet’s distinctive tail. Astronomers calculate that it passed closest to the Sun on September 9, passing just inside the orbit of Mercury.

The Sun’s gravity changed its course and speed, sending it hurtling out of our star system and towards the constellation Pegasus. It came closest to Earth on October 14, zipping by just 15 million miles from our planet. To put that in perspective, that’s less than half the distance between Earth and Mars.

We don’t know much about the object, and as it’s moving away from us at about 27 miles per second, astronomers won’t get many more chances to make detailed observations, though there’s a chance the Hubble Space Telescope might be able to catch a glimpse of it as it flies away.

“A/2024 U1 is already faint and fading quickly. We can still use large telescopes to track its position for a month or maybe two,” Farnocchia says in an e-mail. “The object may already be too faint for physical characterization and measuring its size, mass or composition.”

Scientists are poring over the data they do have and trying to get a few last glimpses of the object before it fades from view. The early results are tantalizing. In addition to not being a comet, it seems to have a distinctly reddish color, similar to asteroids in the Kuiper Belt.

Spectrum of A/2024 U1 obtained on Wednesday night with the @INGLaPalma 4.2m WHT. Colour is red like Kuiper Belt Objects, featureless. chúng tôi Alan Fitzsimmons (@FitzsimmonsAlan) October 27, 2023

Even as observations continue to pile up, researchers are thrilled to see evidence of something that had been often discussed and theorized about, but that some astronomers didn’t expect to see in their careers, or at least, in the next few decades.

The observations so far do line up with published theories. In a 2024 paper, astronomers including Darin Ragozzine of Brigham Young University predicted that an interstellar object might initially be considered a Near Earth Object based on how it was moving. That’s what researchers thought A/2024 U1 might be initially, before they got additional glimpses of the object.

As researchers are celebrating the discovery and gathering more information about A/2024 U1, they’re also looking forward to finding other interstellar visitors. The eccentric path of A/2024 U1 tells researchers that it was probably flung out of another, distant solar system long ago.

“Observing ISOs [interstellar objects] in our solar system means we are probing the dynamics and formation of other solar systems! If these objects are getting kicked out of their home systems and into ours, we can learn about their home systems formation histories.” Bonnie Meinke, Deputy Project Scientist of the James Webb Space Telescope says in an e-mail. “This is similar to how planetary scientists learn about Mars by studying the Martian meteorites that hit Earth.”

In the future, the next generation of large telescopes, including the Large Survey Synoptic Telescope, currently under construction in Chile could help researchers like Ragozzine learn more about where those objects are coming from, giving us a better idea about whether they’re zipping in directly from a star that cast them away, or if they’ve wandered the galaxy, roving from star to star for billions of years.

“NASA has been searching for hazardous asteroids for about twenty years now, so a simple extrapolation would say one ISO discovery every twenty years, possibly more frequently as new surveys with more powerful telescopes come online in the future,” Farnocchia says. ”But we only have one discovery so far, too few to do any statistics, and so it’s not easy to reliably predict the rate at which new interstellar objects visit the solar system and we can discover them.”

Glimpse The Gold Mine Where Scientists Are Searching For Dark Matter

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There was a pause, just before the cage doors came rattling closed and we began our 15-minute descent 4,850 feet into the earth. We were packed in tight: a crew of some 30 physicists, engineers, biologists, and—mostly—miners. Ex-miners, actually. This hadn’t been an active mine for 18 years. The guy working the lift let the winch operator above us know that the cab was full, that we were a go. For a brief, delirious moment, suspended at the top of what was once the largest, deepest gold mine in North America, everything went quiet. Somewhere overhead, the frigid South Dakota winds whistled faintly, whipping through the Black Hills on this February day. A reminder of everything, the whole world we were leaving, as we began to drop.

And drop.

And drop.

The cage moved slowly and steadily, covering about five feet a second. We passed openings to shallower floors, dark and dripping with water. Biologists worked a few of these, scraping up bacteria from the muck, studying extremophiles to consider life-forms that might exist on other planets. An epic mystery, sure, but our destination was farther below: floor 4850 in the former Homestake Mine in Lead, outside of Deadwood, South Dakota, now the Sanford Underground Research Facility, or SURF. Here physicists from around the globe are trying to solve a puzzle more fundamental than life itself. Namely, what is the universe mostly made of?

A tank that will be filled with xenon awaits transport to its home in a former gold mine below Lead, South Dakota. Nick Hubbard/Sanford Underground Research Facility

Protons, neutrons, electrons—these are familiar to us. Elementary, even. We have also accounted for the weirder, smaller, subatomic stuff: the alpha and beta particles, the quarks, the neutrinos. Still, they don’t add up. Not by a long shot. In order for existence to, well, exist, for galaxies to spin the way they do, for light from distant stars to bend the way it appears to, there must be quite a bit more out there than we’ve seen so far. The Standard Model, which classifies all elementary particles, accounts for just 16 percent of the universe’s mass. That leaves another 84 percent. There are several theories as to what this remainder might be, but it all goes by the same name: dark matter.

The actual nature of dark matter is the subject of much debate. It could be one thing, one type of particle, sort of like a proton; or it could be several different things, like an electron and also a quark. Until we’ve found concrete evidence, we won’t really know for sure. The purpose of the elaborate experiment this cage was descending toward is to find that evidence.

Here in the deep, tucked away from the humming interference radiating from everything around us, sits a wildly complex detector—let’s call it a camera trap. It was designed and built to record the presence of the lead contender for dark matter, a physics unicorn called a WIMP, for weakly interacting massive particle. The endeavor includes at its heart a five-foot-tall tank filled with about one-quarter of the world’s annual supply of liquid xenon. If a WIMP passes through, there’s a chance it might glance off a xenon nucleus, which would emit a flash of light, a photon. Once the setup comes online—as soon as late 2023—it will run for five years. At that point the team will have either found proof of a particle that could be dark matter, or…not. The project is known as LUX-ZEPLIN, or LZ. LUX stands for Large Underground Xenon, ZEPLIN for ZonEd Proportional scintillation in LIquid Noble gases. It may well be our best shot yet at spotting a WIMP.

“This is the most exciting time for physics, because we still have the really big mysteries in front of us,” says Kevin Lesko, a senior physicist at the Lawrence Berkeley National Laboratory, who coordinates the LZ project. In early 2023, the detector was in the final throes of assembly. Teams of six to 12 physicists and engineers worked in two shifts every day, from 8 a.m. to midnight, on an experiment that over five years has required experts in fields as diverse as photon detection and computer modeling, and from some 37 institutions across seven countries. “People like to say we know how to explain the universe. And now we’re trying to figure out the big map of the universe,” Lesko says of the massive collective effort.

The xenon tank is the crucial tool for filling in that map by determining what most matter might be. In October 2023, it traveled down the shaft via the cage in a highly orchestrated daylong event that left little room for error or jostling. A single slip and crash, years of planning, plus millions of dollars in research and development, would have gone down the mine shaft.

Mine carts transport new kinds of workers and equipment. Ryan Bradley

The evidence of dark matter is everywhere, even though we’ve yet to glimpse the stuff itself. In 1933, Fritz Zwicky, a Swiss astronomer based at Caltech, noticed that the velocities of galaxy clusters seemed to make no sense: The gravitational forces of visible matter wouldn’t be enough to keep the groupings from scattering. For these celestial bodies to congregate the way they do, some unseen mass (plus gravity) must be helping pull them together. In the 1970s, astronomers Vera Rubin and Kent Ford were studying the spirals of the Andromeda galaxy and found, to everyone’s astonishment, that the stars at the outermost edges moved just as quickly as those at the center, violating Kepler’s third law of planetary (in this case, galactic) rotation, which holds that the objects revolving around a core should move more slowly as the distance from the middle increases. That they don’t suggests that some farther-away mass influences these bodies. There are other clues out there, like the way light from remote stars bends on its journey to us, and the consistency of the cosmic microwave background, and the elliptical and spiraling shapes of galaxies. All this points to the existence of a great, nonluminous, unseen mass.

Peering out into space gives us a sense of the effect dark matter has on the form and appearance of our universe, but all that evidence is indirect, a shadow of a shadow. This invisible stuff will remain a mystery until physicists can observe the particle or particles that account for it, which they’ve been trying to do for about 30 years. Some experiments attempt to plot a chart that points to dark matter by searching out evidence of its decay through high-flying instruments like the Fermi Gamma-ray Space Telescope. They call this approach indirect detection.

Other techniques instead try to create dark matter. Since 2012, physicists have been running experiments that could do just that—on the Large Hadron Collider particle accelerator at CERN, near Geneva, Switzerland. The efforts, collectively called ATLAS, smash together protons to mimic the circumstances of the big bang, when everything in our universe formed, including, theoretically, dark matter. By comparing the energy they know went into the accelerator with the measurements of what comes out, the scientists might prove its existence.

Physicists wire up a ­photon-​­detector array to transmit potential WIMP signals out of the xenon tank. Matthew Kapust/Sanford Underground Research Facility

More often, dark matter sleuths want hard evidence. That is, they want to directly detect it. But again, no one is precisely sure what it is they’re looking for. Aside from the WIMP, there is another potential culprit: a theoretical particle called an axion. If they exist, axions would help explain how neutrons, even those with charged quarks kicking around inside them, manage to remain neutral. They’d also be around one trillion times less massive than an electron, meaning trillions would fit in a space the size of a sugar cube. Physicists think the trick to spying them is speeding up their otherwise glacial decay into photons, which are relatively easy to spot. A detector built by a team at the University of Washington wields a huge and incredibly powerful magnet to hasten that pace, while a resonator tuned to the microwave frequency of the possible decay keeps watch.

Yet amid the broad field of dark matter makeups that scientists have floated over the years—including candidates from primordial black holes to MACHOs (massive astrophysical compact halo objects) half the bulk of our sun—WIMPs have remained a primary target. If they’re out there, they would neatly align with another popular notion in theoretical physics called supersymmetry, the idea that for every bit of mass we can see there is also a counterpart that is not luminous, the yin to its yang. If that idea’s correct, what we’ve added up from everything covered by the Standard Model would be mirrored by the WIMP presence. The universe, unknowable and chaotic as it may seem, tends toward elegant solutions like this one. Or elegant solutions like this one tend to explain the universe.

Still, even within the world of WIMPs, questions remain. The particles might exist in a range of masses, from about one proton to 100,000 protons. One experiment, called SuperCDMS, is searching for wee-er WIMPs than the LZ. Based in a nickel mine in Ontario, Canada, it relies on six detectors made of silicon or germanium crystals; if a WIMP hits one and disturbs a crystal’s electrons, the interaction will create vibrations, a signal that can be amplified. The rig runs at –450°F to cut out the noise generated by thermal energy. And it also sits deep underground—6,800 feet—shielded from the radioactivity of day-to-day life, the cosmic buzz coming off everything from stars to the soles of your Chuck Taylors.

The sensors of a single array; two of them peer into the vessel from above and below. Matthew Kapust/Sanford Underground Research Facility

There’s another xenon-based WIMP detection attempt, an international effort located under Italy’s Gran Sasso mountain—and aptly named XENON. The scientists involved announced in June 2023 that their experiment was registering extra background signals, which could wind up proving there are axions. Or it might be neutrinos. Or the result of contamination. As with much in dark matter, the data can seem to be on the brink of reality-shifting, but turn out to be nothing at all.

Lesko, who’s been working on such subterranean experiments—including the LZ’s smaller predecessor, LUX—for the better part of 30 years, explains why these efforts always happen so deep underground. Imagine, he says, “you’re trying to hear a whisper. You do it in the middle of New York City, you’re not going to hear it, there’s just too much noise. You want to get away from our backgrounds—the cosmic rays and junk we’re bombarded by would hide the very rare signals we’re looking for.” But here Lesko stops himself: The signal, the particle, “isn’t necessarily rare, what’s rare is the interactions with things we can observe.”

The observational challenges beget a borderline obsession with eliminating every iota of potential interference. That’s why, when Lesko would fly out to Lead (pre-pandemic, of course) to visit the mine-turned-lab for a week every month, a lot of what he and the crews would work on was keeping absolutely everything as exceptionally clean as possible. It’s a difficult task anywhere, but it’s absurdly so way down inside a tunnel carved into the rock.

The LZ’s xenon tank slips into its housing. Nick Hubbard/Sanford Underground Research Facility

The cage doors opened on level 4850, and we all marched out. Crews of scientists and staff piled into electrified carts—mine carts!—to travel a quarter-mile-long, unlit, dirt-floored passageway toward more distant labs. Closer to where the lift had delivered us, I exchanged my boots for a pair of very clean trail runners that never left this space. I wiped down my phone, pen, notebook, and hands and stepped across a sticky floor to remove any dust from the shoes, then down a long hallway that led to the room where the LZ was coming together. Through the doors came a long, high whistle that sounded like a terrible scream.

“That’s the liquid nitrogen we’re running through the pipes—it’s loud!” yelled Aaron Manalaysay, a physicist at the Lawrence Berkeley National Laboratory, over the gassy wails. Manalaysay was down here with a crew of graduate students, working over several months to finish assembling all of LZ’s thousands of component parts, which took up nearly all the room.

When the screaming died down, we walked through a set of double doors and into the space. I expected first to see the tank at the center of the LZ experiment, huge and gleaming. Instead there were rows of pipes and wires running from sensors to stacks of computers outside the container; a cryogenics panel for cooling the xenon gas to just below –163°F (the temperature at which it liquefies) and helping to lower background interference within the tank itself; plastic curtains draped around areas still undergoing assembly; air ducts and lockers and orange cones and caution signs. At the middle of all this sat a 20-foot-tall, curving stainless-steel structure: the first layer of the LZ’s tank. This would be filled with 70,000 gallons of water to further buffer the inner xenon chamber—in a sense, a gigantic thermos.

How to spot dark matter. The quest to capture proof of WIMPs, a lead candidate for the makeup of dark matter, sends the physicists behind the LUX-ZEPLIN experiment below ground. Nearly a mile down, background noise is minimal, but spying the particles still requires a rig looking for a very specific interaction. A. Set a target: Dark matter particles, possibly WIMPS, surround and move through everything, the LZ included, even if we don’t notice them. B. Eliminate noise: To up their chances of spotting one, physicists buffer the WIMP trap with many layers, the innermost of which is a titanium tank. C. Wait quietly: Nonreactive, some 11 tons of liquid xenon housed within the tank creates a placid space in which to watch for dark matter activity. D. Interact: Should a WIMP glance off the nucleus of a ­xenon atom, the collision will elicit sparks of energy: a burst of photons. E. Grab the flash: Hundreds of 3-inch-wide photon detectors nestled into circles at the top and bottom of the structure amplify any activity. F. Record the signal: The array ­converts the burst into ­electrons—data points that indicate the spot within the tank where the ­interaction occurred. Maxwell Erwin

Peering into a small, heavy, swung-open porthole revealed the inner sanctum, the xenon tank. Why xenon? It’s extremely dense and, as one of the noble gases, it’s inert. Most of the time, it doesn’t react to most things it comes into contact with. It is, in other words, extremely quiet. So reactions within the element tend to stand out, which is exactly what you want when trying to spot a sudden flash that might end up proving the existence of dark matter. Inside this titanium vessel were photon detectors—the “cameras” in the trap: several hundred 3-inch-wide tubes honeycombed into two nearly 5-foot-diameter circles at the top and bottom of the huge canister.

We stepped back from the porthole and climbed a ladder to a mezzanine level midway up the outer tank, where Theresa Fruth, a physics research fellow at University College London, was working on the detectors. She was testing how they would function within the rest of the system. The tubes act as capture and amplification devices, she explained. When a particle, WIMP or otherwise, moves through the tank and hits the nucleus of a xenon atom, the result is energy, in the form of light: a photon, or more likely many. The arrays absorb these and convert them into electrons. Each one represents a data point—X, Y, and Z coordinates—that shows where in the area an interaction is coming from.

The vast majority of the events will stem from the decay in the surrounding rock walls. “That will happen,” Fruth said. “We don’t care.” Physicists know what those signals look like and can easily ignore them. Besides, one of the benefits of having such a huge amount of xenon, she explained, is that its outer edges—in addition to the tank itself, and the water, and the other tank, and the mile of earth above—act as a buffer. “If we go closer to the center, we get much quieter.” This was the spot where they might find dark matter. Or where “we can reasonably search for a rare interaction.”

The Black Hills flank Lead, South Dakota. Nick Hubbard/Sanford Underground Research Facility

A rare interaction, were it to happen inside the tank, could blip without anyone even noticing. The final trick, perhaps the trickiest of all, is to make certain that we do spot this flash of activity amid all the others. Once the LZ comes online, it will register approximately a billion interactions per year. This petabyte worth of data is the responsibility of Maria Elena Monzani. She works at the SLAC National Accelerator Laboratory at Stanford and manages the software and computing infrastructure of LUX-ZEPLIN.

Because no one has seen a dark matter interaction before, it’s important to try to be sure about everything we have actually seen. Monzani coordinates the cataloging and modeling of all the “knowns” in order to make it easier for the unknowns to stand out. “We’re going to have a few billion events, and dark matter will be a handful,” Monzani says. “It’s very important we understand what those few billion events are. Once you know that, then you can know, ‘Ah, this is something.’”

Monzani oversees what is, in essence, an inoculation against the mind’s urge to see things (patterns, particles) that aren’t really there. She’s got several platoons’ worth of physicists spread around the globe, working on two data centers running full simulations of the LZ. They’re calibrating the machine, the algorithms, and, yes, the humans. To calibrate a person, Monzani and her team churn out datasets from a simulation of the LZ tank, then, diabolically, add extra data that looks just like the real thing—a method called salting.

Monzani’s crew drops in data that, say, looks like the energy a WIMP would leave in its wake. They know these markers are fake, but their analysts don’t, thus creating a blind test to reduce the bias that may come about from physicists’ very real desire to find an exciting interaction. When the trial run is done, Monzani’s team reveals which of the signals were placebos. What’s left is, in this case, the “real” ones created by the LZ simulation (they’ll repeat the process when the experiment turns on and live data starts coming in). Everyone wants to find dark matter. Salting trains them to be honest.

The crew watches as the tank lowers into the spot where it might finally nab dark matter. Nick Hubbard/Sanford Underground Research Facility

Running simulation after simulation of the LZ systems became the bulk of the effort in midspring. In March 2023, the COVID-19 pandemic forced the facility to shut down on-site work aside from critical maintenance. Some of the scientists stayed in town, since travel—particularly internationally—seemed dicey, and Lead (population 3,021) was a pleasant enough place to be stranded for however long they would hang in this virus-induced limbo.

There’s still plenty to do aboveground, plenty of calibrations to perfect. No matter when they start, it’ll take five years of WIMP sniffing to gather enough data to know if the particle is in the LZ’s detection range. And besides, as project coordinator Lesko points out, all those months of double shifts had paid off: They’d nearly completed assembly down on 4850, and the project was in a stable and safe spot. Few places are more secure during a pandemic than one close to a mile underground.

Still, like the rest of us, they wonder when this all might be over: when they can get fully back to the experiment, and if, once they do—with the LZ tank sealed and detector arrays watchfully waiting—they’ll find anything at all. None of the nearly one dozen prior attempts to nab a glimmer of a WIMP over the past three decades have worked. Yet team members like Fruth, the photon detector specialist, are sanguine about the possibility of their life’s work netting nothing. “Knowing that it’s not something is still worth something,” she says. When you aren’t sure exactly what a WIMP is, there’s value in finding out what it isn’t.

Living with uncertainty and pondering the unknown is a comfortable space for them to be in, because that’s what scientists do—especially physicists on this particular ongoing hunt. Fruth likens dark matter to the unfilled portion of a map, the “here be monsters” bits. “We draw this line,” she says, “and we say, ‘Look, we don’t know anything beyond this line.’ And then we push a little farther, and know a little more. And the line moves, and we move with it.”

This story appears in the Fall 2023, Mysteries issue of Popular Science.

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