People who tend crops in Lebanon and people who tend particle detectors on the border of France and Switzerland have a need in common: large-scale humidity and temperature monitoring. A scientist who noticed this connection is working with farmers to try to use a particle physics solution to solve an agricultural problem.

Farmers, especially those in dry areas found in the Middle East, need to produce as much food as possible without using too much water. Scientists on experiments at the Large Hadron Collider want to track the health of their detectors—a sudden change in humidity or temperature can indicate a problem.

To monitor humidity and temperature in their detector, members of the CMS experiment at the LHC developed a fiber-optic system. Fiber optics are wires made from glass that can carry light. Etching small mirrors into the core of a fiber creates a “Bragg grating,” a system that either lets light through or reflects it back, based on its wavelength and the distance between the mirrors.

“Temperature will naturally have an impact on the distance between the mirrors because of the contraction and dilation of the material,” says Martin Gastal, a member of the CMS collaboration at the LHC. “By default, a Bragg grating sensor is a temperature sensor.”

Scientists at the University of Sannio and INFN Naples developed a material for the CMS experiment that could turn the temperature sensors into humidity monitors as well. The material expands when it comes into contact with water, and the expansion pulls the mirrors apart. The sensors were tested by a team from the Experimental Physics Department at CERN.

In December 2015, Lebanon signed an International Cooperation Agreement with CERN, and the Lebanese University joined CMS. As Professor Haitham Zaraket, a theoretical physicist at the Lebanese University and member of the CMS experiment, recalls, they picked fiber optic monitoring from a list of CMS projects for one of their engineers to work on. Martin then approached them about the possibility of applying the technology elsewhere.

With Lebanon’s water resources under increasing pressure from a growing population and agricultural needs, irrigation control seemed like a natural application. “Agriculture consumes quite a high amount of water, of fresh water, and this is the target of this project,” says Ihab Jomaa, the Department Head of Irrigation and Agrometeorology at the Lebanese Agricultural Research Institute. “We are trying to raise what we call in agriculture lately ‘water productivity.’”

The first step after formally establishing the Fiber Optic Sensor Systems for Irrigation (FOSS4I) collaboration was to make sure that the sensors could work at all in Lebanon’s clay-heavy soil. The Lebanese University shipped 10 kilograms of soil from Lebanon to Naples, where collaborators at University of Sannio adjusted the sensor design to increase the measurement range.

During phase one, which lasted from March to June, 40 of the sensors were used to monitor a small field in Lebanon. It was found that, contrary to the laboratory findings, they could not in practice sense the full range of soil moisture content that they needed to. Based on this feedback, “we are working on a new concept which is not just a simple modification of the initial architecture,” Haitham says. The new design concept is to use fiber optics to monitor an absorbing material planted in the soil rather than having a material wrapped around the fiber.

“We are reinventing the concept,” he says. “This should take some time and hopefully at the end of it we will be able to go for field tests again.” At the same time, they are incorporating parts of phase three, looking for soil parameters such as pesticide or chemicals inside the soil or other bacterial effects.

If the new concept is successfully validated, the collaboration will move on to testing more fields and more crops. Research and development always involves setbacks, but the FOSS4I collaboration has taken this one as an opportunity to pivot to a potentially even more powerful technology.

In particle physics, scientists study the properties of the smallest bits of matter and how they interact. Another branch of physics—astrophysics—creates and tests theories about what’s happening across our vast universe.

While particle physics and astrophysics appear to focus on opposite ends of a spectrum, scientists in the two fields actually depend on one another. Several current lines of inquiry link the very large to the very small.

The seeds of cosmic structure

For one, particle physicists and astrophysicists both ask questions about the growth of the early universe. 

In her office at Stanford University, Eva Silverstein explains her work parsing the mathematical details of the fastest period of that growth, called cosmic inflation. 

“To me, the subject is particularly interesting because you can understand the origin of structure in the universe,” says Silverstein, a professor of physics at Stanford and the Kavli Institute for Particle Astrophysics and Cosmology. “This paradigm known as inflation accounts for the origin of structure in the most simple and beautiful way a physicist can imagine.” 

Scientists think that after the Big Bang, the universe cooled, and particles began to combine into hydrogen atoms. This process released previously trapped photons—elementary particles of light. 

The glow from that light, called the cosmic microwave background, lingers in the sky today. Scientists measure different characteristics of the cosmic microwave background to learn more about what happened in those first moments after the Big Bang.

According to scientists’ models, a pattern that first formed on the subatomic level eventually became the underpinning of the structure of the entire universe. Places that were dense with subatomic particles—or even just virtual fluctuations of subatomic particles—attracted more and more matter. As the universe grew, these areas of density became the locations where galaxies and galaxy clusters formed. The very small grew up to be the very large.

Scientists studying the cosmic microwave background hope to learn about more than just how the universe grew—it could also offer insight into dark matter, dark energy and the mass of the neutrino.

“It’s amazing that we can probe what was going on almost 14 billion years ago,” Silverstein says. “We can’t learn everything that was going on, but we can still learn an incredible amount about the contents and interactions.”

For many scientists, “the urge to trace the history of the universe back to its beginnings is irresistible,” wrote theoretical physicist Stephen Weinberg in his 1977 book The First Three Minutes. The Nobel laureate added, “From the start of modern science in the sixteenth and seventeenth centuries, physicists and astronomers have returned again and again to the problem of the origin of the universe.”

Searching in the dark

Particle physicists and astrophysicists both think about dark matter and dark energy. Astrophysicists want to know what made up the early universe and what makes up our universe today. Particle physicists want to know whether there are undiscovered particles and forces out there for the finding.

“Dark matter makes up most of the matter in the universe, yet no known particles in the Standard Model [of particle physics] have the properties that it should possess,” says Michael Peskin, a professor of theoretical physics at SLAC. “Dark matter should be very weakly interacting, heavy or slow-moving, and stable over the lifetime of the universe.”

There is strong evidence for dark matter through its gravitational effects on ordinary matter in galaxies and clusters. These observations indicate that the universe is made up of roughly 5 percent normal matter, 25 percent dark matter and 70 percent dark energy. But to date, scientists have not directly observed dark energy or dark matter.

“This is really the biggest embarrassment for particle physics,” Peskin says. “However much atomic matter we see in the universe, there’s five times more dark matter, and we have no idea what it is.” 

But scientists have powerful tools to try to understand some of these unknowns. Over the past several years, the number of models of dark matter has been expanding, along with the number of ways to detect it, says Tom Rizzo, a senior scientist at SLAC and head of the theory group.

Some experiments search for direct evidence of a dark matter particle colliding with a matter particle in a detector. Others look for indirect evidence of dark matter particles interfering in other processes or hiding in the cosmic microwave background. If dark matter has the right properties, scientists could potentially create it in a particle accelerator such as the Large Hadron Collider.

Physicists are also actively hunting for signs of dark energy. It is possible to measure the properties of dark energy by observing the motion of clusters of galaxies at the largest distances that we can see in the universe.

“Every time that we learn a new technique to observe the universe, we typically get lots of surprises,” says Marcelle Soares-Santos, a Brandeis University professor and a researcher on the Dark Energy Survey. “And we can capitalize on these new ways of observing the universe to learn more about cosmology and other sides of physics.”

Forces at play

Particle physicists and astrophysicists find their interests also align in the study of gravity. For particle physicists, gravity is the one basic force of nature that the Standard Model does not quite explain. Astrophysicists want to understand the important role gravity played and continues to play in the formation of the universe.

In the Standard Model, each force has what’s called a force-carrier particle or a boson. Electromagnetism has photons. The strong force has gluons. The weak force has W and Z bosons. When particles interact through a force, they exchange these force-carriers, transferring small amounts of information called quanta, which scientists describe through quantum mechanics. 

General relativity explains how the gravitational force works on large scales: Earth pulls on our own bodies, and planetary objects pull on each other. But it is not understood how gravity is transmitted by quantum particles. 

Discovering a subatomic force-carrier particle for gravity would help explain how gravity works on small scales and inform a quantum theory of gravity that would connect general relativity and quantum mechanics. 

Compared to the other fundamental forces, gravity interacts with matter very weakly, but the strength of the interaction quickly becomes larger with higher energies. Theorists predict that at high enough energies, such as those seen in the early universe, quantum gravity effects are as strong as the other forces. Gravity played an essential role in transferring the small-scale pattern of the cosmic microwave background into the large-scale pattern of our universe today.

“Another way that these effects can become important for gravity is if there’s some process that lasts a long time,” Silverstein says. “Even if the energies aren’t as high as they would need to be sensitive to effects like quantum gravity instantaneously.” 

Physicists are modeling gravity over lengthy time scales in an effort to reveal these effects.

Our understanding of gravity is also key in the search for dark matter. Some scientists think that dark matter does not actually exist; they say the evidence we’ve found so far is actually just a sign that we don’t fully understand the force of gravity.  

Big ideas, tiny details

Learning more about gravity could tell us about the dark universe, which could also reveal new insight into how structure in the universe first formed. 

Scientists are trying to “close the loop” between particle physics and the early universe, Peskin says. As scientists probe space and go back further in time, they can learn more about the rules that govern physics at high energies, which also tells us something about the smallest components of our world.

Artwork for this article is available as a printable poster.

Researchers from the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University have for the first time shown that neural networks—a form of artificial intelligence—can accurately analyze the complex distortions in spacetime known as gravitational lenses 10 million times faster than traditional methods.

“Analyses that typically take weeks to months to complete, that require the input of experts and that are computationally demanding, can be done by neural nets within a fraction of a second, in a fully automated way and, in principle, on a cell phone’s computer chip,” says postdoctoral fellow Laurence Perreault Levasseur, a co-author of a study published today in Nature.

Lightning-fast complex analysis

The team at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), a joint institute of SLAC and Stanford, used neural networks to analyze images of strong gravitational lensing, where the image of a faraway galaxy is multiplied and distorted into rings and arcs by the gravity of a massive object, such as a galaxy cluster, that’s closer to us. The distortions provide important clues about how mass is distributed in space and how that distribution changes over time – properties linked to invisible dark matter that makes up 85 percent of all matter in the universe and to dark energy that’s accelerating the expansion of the universe.

Until now this type of analysis has been a tedious process that involves comparing actual images of lenses with a large number of computer simulations of mathematical lensing models. This can take weeks to months for a single lens.

But with the neural networks, the researchers were able to do the same analysis in a few seconds, which they demonstrated using real images from NASA’s Hubble Space Telescope and simulated ones.

To train the neural networks in what to look for, the researchers showed them about half a million simulated images of gravitational lenses for about a day. Once trained, the networks were able to analyze new lenses almost instantaneously with a precision that was comparable to traditional analysis methods. In a separate paper, submitted to The Astrophysical Journal Letters, the team reports how these networks can also determine the uncertainties of their analyses.

Prepared for the data floods of the future

“The neural networks we tested—three publicly available neural nets and one that we developed ourselves—were able to determine the properties of each lens, including how its mass was distributed and how much it magnified the image of the background galaxy,” says the study’s lead author Yashar Hezaveh, a NASA Hubble postdoctoral fellow at KIPAC.

This goes far beyond recent applications of neural networks in astrophysics, which were limited to solving classification problems, such as determining whether an image shows a gravitational lens or not.

The ability to sift through large amounts of data and perform complex analyses very quickly and in a fully automated fashion could transform astrophysics in a way that is much needed for future sky surveys that will look deeper into the universe—and produce more data—than ever before.

The Large Synoptic Survey Telescope (LSST), for example, whose 3.2-gigapixel camera is currently under construction at SLAC, will provide unparalleled views of the universe and is expected to increase the number of known strong gravitational lenses from a few hundred today to tens of thousands.

“We won’t have enough people to analyze all these data in a timely manner with the traditional methods,” Perreault Levasseur says. “Neural networks will help us identify interesting objects and analyze them quickly. This will give us more time to ask the right questions about the universe.”

A revolutionary approach

Neural networks are inspired by the architecture of the human brain, in which a dense network of neurons quickly processes and analyzes information.

In the artificial version, the “neurons” are single computational units that are associated with the pixels of the image being analyzed. The neurons are organized into layers, up to hundreds of layers deep. Each layer searches for features in the image. Once the first layer has found a certain feature, it transmits the information to the next layer, which then searches for another feature within that feature, and so on.

“The amazing thing is that neural networks learn by themselves what features to look for,” says KIPAC staff scientist Phil Marshall, a co-author of the paper. “This is comparable to the way small children learn to recognize objects. You don’t tell them exactly what a dog is; you just show them pictures of dogs.”

But in this case, Hezaveh says, “It’s as if they not only picked photos of dogs from a pile of photos, but also returned information about the dogs’ weight, height and age.”

Although the KIPAC scientists ran their tests on the Sherlock high-performance computing cluster at the Stanford Research Computing Center, they could have done their computations on a laptop or even on a cell phone, they said. In fact, one of the neural networks they tested was designed to work on iPhones.

“Neural nets have been applied to astrophysical problems in the past with mixed outcomes,” says KIPAC faculty member Roger Blandford, who was not a co-author on the paper. “But new algorithms combined with modern graphics processing units, or GPUs, can produce extremely fast and reliable results, as the gravitational lens problem tackled in this paper dramatically demonstrates. There is considerable optimism that this will become the approach of choice for many more data processing and analysis problems in astrophysics and other fields.”    

Editor's note: This article originally appeared as a SLAC press release.

Although CERN physicist Andrea Latina had always been interested in the arts, he had never really thought about dance before. 

While at a local film festival in 2015, he happened upon a flyer that quoted Persian poet Rumi about the “dance of particles.” Curious, he reached out to its author, Iranian dancer and choreographer Sahar Dehghan, to learn more.

Dehghan says that even as a child she was fascinated by both physics and dance. 

When she moved to France at a young age, she started taking dance classes, focusing on a meditative form called Sufi dancing and later concentrating on contemporary dance. But she also kept her fascination with physics, reading books and articles and having conversations with scientists she befriended in Paris as a young adult. 

“I became interested in quantum mechanics and its relation to physics, and I really started experimenting physically in my dance with a lot of these concepts,” she says.

Dehghan and Latina developed a friendship, meeting to chat about physics and dance. 

Virtual particles

Dehghan says that she was inspired by ideas such as the confinement of quarks via the strong force. 

“If you try to separate quarks, this force will be so strong that new particles will be created to prevent separation,” Latina says. “The density of energy is so high that a new pair of quark and antiquark will form so that the new quarks pair up with the original ones, just to avoid there being a single quark isolated in nature.”

In the winter of 2016, Dehghan visited CERN to learn more about its goals and how scientists are working to achieve them. One of the most inspiring things, she says, was seeing thousands of scientists from different backgrounds uniting to further our understanding of the universe.

“There are more than 11,000 people of more than 110 nationalities coming together with a common goal,” she says. “Instead of seeing superficial differences caused by cultural, religious, political or sexual preference, they respect and collaborate with each other, learning from each other for a greater purpose.”

Latina says that conversations with Dehghan gave him insight into physics as well. 

“I’m very enthusiastic about CERN and my work,” he says. “In drawing parallels between ancient philosophies, Sahar reminded me that what we are doing is the same thing humans have been doing for millennia: questioning where we come from, where we are going and what our role in the universe is. She was able to evoke this ancestral wonder and help me rediscover the poetry of what we do at CERN. We are incessantly trying to answer the same questions; we just use different tools and the language of mathematics.” 

Dehghan says she would love to communicate these themes through dance. Through artistic mediums, she says, new ideas can be heard, seen and felt in a deeper, more meaningful way.

“It would be great if we could all see beyond our own illusions into the fascinating particle interactions happening in everything and everyone at all times and the true unity that connects us in this great quantum dance, whirling at all times in rhythm with the music of the entire cosmos,” she says.

She has begun to choreograph a show called WHIRL Quantum Dance. Through scenes in her show, she tries to illustrate concepts such as quantum chromodynamics (with colored lights) or quantum entanglement (with pairs of dancers). She is even trying to create a collision scene with spinning dancers in a large circle representing an accelerator.

“I am not a scientific expert in anything so I am not trying to teach anyone,” she says. “What I want to do with this show is open some doors for the audience to go out there and search for more and learn about not just about quantum and particle physics, but also go out there and physically experiment and see how we’re all connected. 

“Even if I open just one door for one person in the audience to go in that direction, I will have achieved my goal.”

WHIRL: Quantum Dance, which is being presented by Sangram Arts, will premiere in the San Francisco Bay Area at the School of Arts & Culture at Mexican Heritage Plaza on September 22 and 23, with dancers Shahrokh Moshkin Ghalam and Rakesh Sukesh. Dehghan says that she hopes to make a film of the show to tour at different venues in cities around the world.

For more information, visit Dehghan's Facebook page.

Sometimes it takes lot of people working together to make discovery possible. More than 7000 scientists, engineers and technicians worked on designing and constructing the Large Hadron Collider at CERN, and thousands of scientists now run each of the LHC’s four major experiments.

Not many experiments garner such numbers. On August 15, the Deep Underground Neutrino Experiment (DUNE) became the latest member of the exclusive clique of particle physics experiments with more than a thousand collaborators.

Meet them all:

4,000+: Compact Muon Solenoid Detector (CMS) Experiment

CMS is one of the two largest experiments at the LHC. It is best known for its role in the discovery of the Higgs boson.

The “C” in CMS stands for compact, but there’s nothing compact about the CMS collaboration. It is one of the largest scientific collaborations in history. More than 4000 people from 200 institutions around the world work on the CMS detector and use its data for research.

About 30 percent of the CMS collaboration hail from US institutions. A remote operations center at the Department of Energy’s Fermi National Accelerator Laboratory in Batavia, Illinois, serves as a base for CMS research in the United States.

3,000+: A Toroidal LHC ApparatuS (ATLAS) Experiment

The ATLAS experiment, the other large experiment responsible for discovering the Higgs boson at the LHC, ranks number two in number of collaborators. The ATLAS collaboration has more than 3000 members from 182 institutions in 38 countries. ATLAS and CMS ask similar questions about the building blocks of the universe, but they look for the answers with different detector designs. 

About 30 percent of the ATLAS collaboration are from institutions in the United States. Brookhaven National Laboratory in Upton, New York, serves as the US host.

2,000+: Linear Collider Collaboration

The Linear Collider Collaboration (LCC) is different from CMS and ATLAS in that the collaboration’s experiment is still a proposed project and has not yet been built. LCC has around 2000 members who are working to develop and build a particle collider that can produce different kinds of collisions than those seen at the LHC.

LCC members are working on two potential linear collider projects: the compact linear collider study (CLIC) at CERN and the International Linear Collider (ILC) in Japan. CLIC and the ILC originally began as separate projects, but the scientists working on both joined forces in 2013.

Either CLIC or the ILC would complement the LHC by colliding electrons and positrons to explore the Higgs particle interactions and the nature of subatomic forces in greater detail.

1,500+; A Large Ion Collider Experiment (ALICE)

ALICE is part of LHC’s family of particle detectors, and, like ATLAS and CMS, it too has a large, international collaboration, counting 1500 members from 154 physics institutes in 37 countries. Research using ALICE is focused on quarks, the sub-atomic particles that make up protons and neutrons, and the strong force responsible for holding quarks together.

1,000+: Deep Underground Neutrino Experiment (DUNE)

The Deep Underground Neutrino Experiment is the newest member of the club. This month, the DUNE collaboration surpassed 1000 collaborators from 30 countries.

From its place a mile beneath the earth at the Sanford Underground Research Facility in South Dakota, DUNE will investigate the behavior of neutrinos, which are invisible, nearly massless particles that rarely interact with other matter. The neutrinos will come from Fermilab, 800 miles away.

Neutrino research could help scientists answer the question of why there is an imbalance between matter and antimatter in the universe. Groundbreaking for DUNE occurred on July 21, and the experiment will start taking data in around 2025.

Honorable mentions

A few notable collaborations have made it close to 1000 but didn’t quite make the list. LHCb, the fourth major detector at LHC, boasts a collaboration 800 strong. Over 700 collaborators work on the Belle II experiment at KEK in Japan, which will begin taking data in 2018, studying the properties of B mesons, particles that contain a bottom quark. The 600-member BaBar collaboration at SLAC National Accelerator Laboratory also studies B mesons. STAR, a detector at Brookhaven National Laboratory that probes the conditions of the early universe, has more than 600 collaborators from 55 institutions. The CDF and DZero collaborations at Fermilab, best known for their co-discovery of the top quark in 1995, had about 700 collaborators at their peak.

Thirty-one years ago, scientists made their first attempt to find dark matter with a particle detector in a South Dakota mine. 

Since then, researchers have uncovered enough clues to think dark matter makes up approximately 26.8 percent of all the matter and energy in the universe. They think it forms a sort of gravitational scaffolding for the galaxies and galaxy clusters our telescopes do reveal, shaping the structure of our universe while remaining unseen. 

These conclusions are based on indirect evidence such as the behavior of galaxies and galaxy clusters. Direct detection experiments—ones designed to actually sense a dark matter particle pinging off the nucleus of an atom—have yet to find what they’re looking for. Nor has dark matter been seen at the Large Hadron Collider. That invisible, enigmatic material, that Greta Garbo of particle physics, still wants to be alone. 

It could be that researchers are just looking in the wrong place. Much of the search for dark matter has focused on particles called WIMPs, weakly interacting massive particles. But interest in WIMP alternatives has been growing, prompting the development of a variety of small-scale research projects to investigate some of the most promising prospects. 

In March more than 100 scientists met at the University of Maryland for “Cosmic Visions: New Ideas in Dark Matter,” a gathering to take the pulse of the post-WIMP dark matter landscape for the Department of Energy. That pulse was surprisingly strong. Organizers recently published a white paper detailing the results.

The conference came about partly because, “it seemed a good time to get everyone together to see what each experiment was doing, where they reinforced each other and where they did something new,” says Natalia Toro, a theorist at SLAC National Accelerator Laboratory and a member of the Cosmic Visions Scientific Advisory Committee. What she and many other participants didn’t expect, Toro says, was just how many good ideas would be presented. 

Almost 50 experiments in various stages of development were presented during three days of talks, and a similar number of potential experiments were discussed.

Some of the experiments presented would be designed to look for dark matter particles that are lighter than traditional WIMPs, or for the new fundamental forces through which such particles could interact. Others would look for oscillating forces produced by dark matter particles trillions of times lighter than the electron. Still others would look for different dark matter candidates, such as primordial black holes. 

The scientists at the workshop were surprised by how small and relatively inexpensive many of the experiments could be, says Philip Schuster, a particle theorist at SLAC National Accelerator Laboratory.

“‘Small’ and ‘inexpensive’ depend on what technology you’re using, of course,” Schuster says. DOE is prepared to provide funding to the tune of $10 million (still a fraction of the cost of a current WIMP experiment), and many of the experiments could cost in the $1 to $2 million range.

Several factors work together to lessen the cost. For example, advances in detector technology and quantum sensors have made technology cheaper. Then there are small detectors that can be placed at already-existing large facilities like the Heavy Photon Search, a dark-sector search at Jefferson Lab. “It’s basically a table-top detector, as opposed to CMS and ATLAS at the Large Hadron Collider, which took years to build and weigh as much as a battleship,” Schuster says.

Experimentalist Joe Incandela of the University of California, Santa Barbara and one of the coordinators of the Cosmic Visions effort, has a simple explanation for this current explosion of ideas. “There’s a good synergy between the technology and interest in dark matter,” he says. 

Incandela says he is feeling the synergy himself. He is a former spokesperson for CMS, a battleship-class experiment in which he continues to play an active role while also developing the Light Dark Matter Experiment, which would use a high-resolution silicon-based calorimeter that he originally helped develop for CMS to search for an alternative to WIMPs. 

“It occurred to me that this calorimeter technology could very useful for low-mass dark matter searches,” he says. “My hope is that, starting soon, and spanning roughly five years, the funding—and not very much is needed—will be available to support experiments that can cover a lot more of the landscape where dark matter may be hiding. It’s very exciting.”

While most people are marveling at Monday’s eclipse, a group of researchers will be measuring its effects on cosmic rays—particles from space that reach collide with the earth’s atmosphere to produce muons, heavy cousins of the electron. But these researchers aren’t the usual PhD-holding suspects: They’re still in high school.

More than 25 groups of high school students and teachers nationwide will use small-scale detectors to find out whether the number of cosmic rays raining down on Earth changes during an eclipse. Although the eclipse event will last only three hours, this student experiment has been a months-long collaboration.

The cosmic ray detectors used for this experiment were provided as kits by QuarkNet, an outreach program that gives teachers and students opportunities to try their hands at high-energy physics research. Through QuarkNet, high school classrooms can participate in a whole range of physics activities, such as analyzing real data from the CMS experiment at CERN and creating their own experiments with detectors.

“Really active QuarkNet groups run detectors all year and measure all sorts of things that would sound crazy to a physicist,” says Mark Adams, QuarkNet’s cosmic ray studies coordinator. “It doesn’t really matter what the question is as long as it allows them to do science.”

And this year’s solar eclipse will give students a rare chance to answer a cosmic question: Is the sun a major producer of the cosmic rays that bombard Earth, or do they come from somewhere else?

“We wanted to show that, if the rate of cosmic rays changes a lot during the eclipse, then the sun is a big source of cosmic rays,” Adams says. “We sort of know that the sun is not the main source, but it’s a really neat experiment. As far as we know, no one has ever done this with cosmic ray muons at the surface.”

Adams and QuarkNet teacher Nate Unterman will be leading a group of nine students and five adults to Missouri to the heart of the path of totality—where the moon will completely cover the sun—to take measurements of the event. Some QuarkNet groups will stay put, measuring what effect a partial eclipse might have on cosmic rays.  

Most cosmic rays are likely high-energy particles from exploding stars deep in space, which are picked up via muons in QuarkNet detectors. But the likely result of the experiment—that cosmic rays don’t change their rate when the moon moves in front of the sun—doesn’t eclipse the excitement for the students in the collaboration.

“They’ve been working for months and months to develop the design for the measurements and the detectors,” Adams says. “That’s the great part—they’re not focused on what the answer is but the best way to find it.”

What exactly is dark matter, the invisible substance that accounts for 85 percent of all the matter in the universe but can’t be seen even with our most advanced scientific instruments?

Most scientists believe it’s made of ghostly particles that rarely bump into their surroundings. That’s why billions of dark matter particles might zip right through our bodies every second without us even noticing. Leading candidates for dark matter particles are WIMPs, or weakly interacting massive particles.

Scientists at SLAC National Accelerator Laboratory are helping to build and test one of the biggest and most sensitive detectors ever designed to catch a WIMP: the LUX-ZEPLIN or LZ detector. The following video explains how it works.