Month: June 2023

Utah’s Fly’s Eye Telescope Array

June 2, 2023

Closing in on the cosmic origins of the “OMG Particle”

The helicopter was flying high through the night sky with its door slightly ajar. Johannes Eser and Matthew Rodencal were in the back controlling a laser pointing out through the gap. They aimed towards a balloon 35 kilometers above them and fired.

It sounds like a scene from a spy movie, but Eser and Rodencal, then at the Colorado School of Mines, were actually testing a plan to spot ultra-high-energy cosmic rays, the most energetic particles ever discovered. They stream across the universe before slamming into our atmosphere and emitting a tiny flash of light. The laser was supposed to mimic that flash.

This twilight helicopter ride happened nearly a decade ago, but is part of a saga that goes back to at least 1991. In October that year, we detected the single most energetic particle ever seen. It had the kinetic energy of a bowling ball dropped from shoulder height, crammed into a subatomic-sized package. It quickly became known as the “Oh-My-God particle” and, naturally enough, scientists were desperate to know where it came from.

Since then, we have spotted many similar particles. Huge ground-based detectors have provided us with maps of where they might come from, together with a shortlist of the extreme cosmic objects that could produce them. But truth be told, we still don’t have all the answers. That is why scientists now want to take the cosmic ray hunt into the atmosphere – and ultimately into space – in an effort to solve the mystery … once and for all.

This story really began with another balloon in 1911. At that time, physicist Victor Hess climbed into a hot air balloon, taking with him instruments to measure levels of radiation as he ascended. He found the readings increased as he went up – contrary to the prevailing belief that they would decline with altitude – and concluded that this radiation must be caused by something coming from space, not Earth. That something became known as cosmic rays, though we now know them to be particles, often protons or clusters of protons and neutrons.

Cosmic rays

When cosmic rays hit our atmosphere, they usually collide with molecules in the atmosphere, producing a shower of energetic particles that rain down. (These descendants of the original particle still contain a lot of energy and have been suspected of interfering with the electronics of aircraft.) It is this shower of secondary particles that we have learned to detect, allowing us to infer the energy of the cosmic ray that produced it. We now know that cosmic rays come in a range of energies. The least energetic are the most common, with each square centimeter of the outer atmosphere being hit once a minute by one of them. The most energetic are much rarer – they strike only once a century per square kilometer.

David Keida

The rays that Hess detected were relatively modest in energy, it turns out, measuring less than 1 gigaelectronvolt (GeV). It wasn’t until the 1960s that more extreme versions were found, when physicist John Linsley used an array of ground detectors in New Mexico to spot the shower created by a cosmic ray with the vastly greater energy of 100 exaelectronvolts (EeV).

That was a staggering find. But the best was yet to come. In the 1980s, a larger project called the Fly’s Eye telescope array was built in Utah [at Dugway Proving Ground, see photo above]. It had more than 100 detectors, each equipped with a 1.5-meter-wide mirror to look for the flash of particles colliding in the atmosphere. Each of the telescope’s detectors were designed to point at a different part of the field of view, in a similar way to insects’ compound eyes. It was this that earned the telescope its name. “We were hoping we might pick up something really unusual,” says David Kieda at the University of Utah, who worked on the telescope at the time.

 

Read the full article at New Scientist (subscription required).

An Unexpected Climate Solution

June 2, 2023

The Wilkes Center Student Innovation Prize

Nicholas Witham is the first-place winner of the Wilkes Center Student Innovation Prize, awarded earlier this month at the University of Utah. The competition invited students to propose creative solutions for tackling the climate crisis, along with presentations that detail their potential impact, benefits, and practicality. Three other prizes, one for second place and two for third place, were also given during the inaugural Wilkes Climate Summit at the University of Utah, May 17-18.

A graduate student at the U, Witham is currently pursuing his Ph.D. in biomedical engineering, as well as running his company Gaia Technologies which makes prosthetic components. For the Wilkes Center Prize, he designed an innovative renewable electric generator that relies on natural fluctuations in the Earth’s temperature. “The type of generator I’ve designed works with thermo-motive artificial muscles,” he says. “That means that they contract when you heat them. Every day the Earth gets hotter and colder which will make them move, and they can pull on a turbine, generating power. The great thing about this is that cooling also generates power, so you can make energy day and night.” This potential for around-the-clock power generation could help to bridge the energy gap that is common with renewable energy sources. 

One of the first places Witham hopes to put his generators is in Southern Utah where the day-to-night temperature change is ideal for this technology 10 months out of the year. And although natural temperature fluctuations may not always be enough to run the generators, Witham believes that they could be used to complement existing renewables such as solar and geothermal energy: “You can use highly efficient geothermal heat pumps to actuate them without needing to have a temperature change caused by the environment. The excess heat that they are wasting, not spinning a turbine, just cooling down before they pump it back into the Earth–we could use that to increase the energy output of our generators tenfold,” he says. 

In fact, installing these generators at pre-existing geothermal plants or solar farms may be the most ideal option to maximize the efficiency and cost of these sites. “I ran the numbers, and I believe that this could be a solution that could cost less than solar, and you can scale it vertically,” explains Witham. “So you could use existing solar infrastructure, place the solar panels on top, and any time you want to reinvest in the site without having to run new electric lines to it, you could just stack them higher.” 

Not only is the generator a potentially powerful form of renewable energy, but it also incorporates carbon capture into its design. “These are polymer textiles. So they’re made out of a plastic called linear low-density polyethylene (LLDPE), which is a type of plastic that can be bio-derived. That means you can use corn husks to make this plastic as an indirect form of carbon capture. Every kilogram of LLDPE sequesters 3 kilograms of carbon.” 

Witham carefully considered the environmental impact of these generators, ensuring that they contribute to carbon sequestering efforts instead of creating more waste: “In the decommissioning of solar panels, for example, you generate quite a lot of e-waste. This system is designed to be recycled and decommissioned in an environmentally safe practice.” 

Witham plans to house the entire generator inside a shipping container, and he estimates that one of these generators could be expected to last over 25 years with very minimal maintenance. Due to their self-contained nature, the impact and effect of these units on the surrounding environment is very minimal. “It’s essentially a big black box that we plan to put in the middle of the desert. I contacted the local EPA office about this to see if there was anything I was missing, and they had no real concerns. Because we’re putting it in a box, any microplastics that might be generated by the textiles shearing or breaking catastrophically would be contained,” he states.

The capacity for incorporating these devices in urban areas, according to Witham, may be limited to apartment buildings or skyscrapers. “I don’t think anybody really wants to use a shipping-container-sized portion of their yard to make power,” he jokes. The weight of these containers also limits their ability to be placed on top of roofs, or buildings, as each unit weighs roughly 18 metric tons. However, there is potential for them to be incorporated underneath buildings. “You can absolutely put it underground if you have a heat pump HVAC system to regulate it, but that would be a bit less efficient.” Though the generators wouldn’t function as well as in the remote desert environment Witham has planned, there is still a possibility for urban incorporation. 

With a purse of $20,000 from the Wilkes Center Prize, Witham is one step closer to getting his design up and running at full scale. His lab already has the capability to mass-produce the necessary artificial muscle technology, so a prototype will soon follow. “The assumption is that we can make a nine-megawatt-hour generator at scale to test it in the field. From there we could make a generator field just like you would see for a solar field. And then with a 2.4-year doubling period – which is typical for renewables in this area – that would mean that by 2050 we would have sequestered and offset a total of 15 million tons of CO2.” Witham’s consideration of sustainability, feasible scaling, and collaboration with other renewables make his design both practical and effective as a climate solution.  

Textile artificial muscle in thermo-mechanical testing set-up. Photo credit: Nick Witham

Clearly, the judges of the Wilkes Center Prize thought so as well. Witham’s design is a unique and impressive fusion of renewable energy with pre-existing biomedical technologies, showcasing that the nature of climate solutions will likely be interdisciplinary. Witham jokes that a sleepless night at work is to thank for his idea to incorporate his biomedical work into a renewable energy source: “I was having a sleep-deprived night in the lab, as you do as a graduate student,” says Nicholas Witham, “and I crunched the numbers because I thought, ‘hey, the Earth heats up!’ I connected all the dots because we use a type of plastic that is a lot more energy efficient and is not typically used for these artificial muscles. And that energy efficiency really allowed this idea to have merit.” 

Witham’s creative application of biomedical engineering shows that the most powerful climate solutions may come from unexpected places and that no branch of knowledge is too isolated to make an impact. His impressive design stands alongside dozens of other projects from creative and dedicated students that rose to meet this innovation challenge. With prizes such as this, the Wilkes Center for Climate Science and Policy is leading the way toward creating a powerful forum for interdisciplinary climate solutions and collaboration, essential for tackling a multifaceted issue like climate change.  

 

By Julia St. Andre
Intern Science Writer

 

Jon Wang

June 2, 2023

Jon Wang

Vulnerable forests and the carbon budget

 

Jon Wang is an Earth systems scientist and recently joined the faculty of the School of Biological Sciences as an assistant professor. 

Born and raised in California, Wang’s undergraduate degree took him across the country to Brown University where he studied biology and geology. “It was the major that had the most field trips,” jokes Wang. “And if I could go outside as part of school, that sounded great. It really set me down on this path of trying to understand the Earth system overall, and how biogeochemical cycles like the carbon cycle or nutrient cycles interact and form the world as we know it today.” 

Wang’s current research revolves around understanding environmental changes to ecosystems in places like Canada and Alaska, where rapidly warming temperatures are re-shaping the variety of plant life that grows in those areas. “In the far north, it's warming faster than anywhere else on the planet. And that's causing what we call a biome shift,” explains Wang. By utilizing decades of satellite data from sources such as NASA, Wang is able to observe changes to these ecosystems over long periods of time by combining machine learning and data science to transform the satellite information into useful datasets. Having a big-picture view of these ecosystems helps inform these scientists about where, when, and why certain ecosystems have changed, and what that means for addressing climate change.

Wang recalls the course that compelled him to dive into the trove of forest and ecosystem data:  “There was one course I took at the end of my time at Brown called Environmental Remote Sensing which was focused on trying to understand how we use satellites to measure changes on the Earth's surface. I decided that that was one of the best combinations of geology, biology, physics, and engineering. So I decided to go back to grad school and pursue a Ph.D. and try to advance this kind of research.” 

With climate change at the forefront of global conversation as he began his Ph.D. at Boston University, Wang says he felt compelled to be more involved with research surrounding climate solutions. “Things were starting to feel pretty serious, and I felt like I was really outside of all of it, you know, working and trying to pay off student loans. I decided that I wanted to try to understand that whole issue a lot better. So that's how I got connected into trying to understand forests and the role they play in the Earth system, and how they may potentially serve as a solution for the climate crisis.”

Wang began his career by researching urban heat islands and forestry in an effort to understand the role that trees play in urban ecology, carbon capture, and human health. Though there are fewer trees in cities, they play an important role in the absorption of carbon emissions. “We were working towards a better understanding of urban ecology so we can account for the urban forest part in this carbon budget, and that can in turn improve our ability to evaluate these carbon emissions programs that cities are trying to implement,” says Wang. Closer to home, Wang also studied the California wildfires and their impact on both urban and wild areas.  

As he begins this new chapter as a professor, Wang is excited to teach a new generation of scientists as they explore everything Earth science has to offer. During his undergrad, Wang was a participant in the NASA Airborne Science Program (SARP) which maintains a fleet of aircraft used for studying Earth system processes, calibration/validation of space-borne observations, and prototyping instruments for possible satellite missions. After returning to the SARP program as a mentor, Wang was compelled to start teaching. “I loved that experience where I just got to meet a lot of different young minds. They don't know what they want yet, but it's really cool to see that they have this whole world of Earth Science open to them. It was really inspiring.”

Related to his experience with airborne data collection, Wang is planning on using unmanned aerial systems (UAS), to generate very high resolution maps of forest structure and stress for calibrating space-borne satellite data. UAS's, commonly known as "drones," can help measure the temperatures of leaves to understand climate-induced stress and mortality or measure greenness to track the changing of the seasons at a tree-by-tree level. "It's fun," he says, "because it's like playing video games, but outside and for science!"

Catching a drone that is landing on uneven ground after imaging an alpine meadow. Banner photo above: Holding a high-precision GPS unit to support drone flight in Norway. Credits: Brian J. Enquist

As his work deals heavily with climate change, Wang is careful to remain optimistic when it comes to the future. “I think there is a big shift in the broader culture about how these systems work, and there's a better understanding of how everything's connected. We're worried that this biospheric carbon sink is vulnerable to climate change, but it's there, and there's a capacity for the Earth to take the carbon back, to mitigate this climate change, and to give us some ability to reverse the damage. And in the meantime, there's all this research and motivation to learn how to adapt to what's going on. So I think there's a lot of hope. There's a lot of reasons to be skeptical and a lot of reasons to be concerned for sure, but despair is definitely not going to get us anywhere.”

As he begins his time in the School of Biological Sciences at the U, Wang is thrilled to be joining a community of scientists with complementary areas of research and looks forward to working closely with them to expand our understanding of our changing world. “There’s a really neat hub of carbon cycle and Earth science research that I knew I wanted to be part of. And so I feel really lucky that I have the opportunity to join this department and really plug into that whole world of research.”

Wang draws inspiration from many sources, including Utah’s beautiful mountain scenery, as well as the work of Katharine Hayhoe at the Nature Conservancy and Texas Tech and Michael Mann, a professor, and author from the University of Pennsylvania. Wang admires their pioneering public discussions of climate change and commitment to awakening the public to a more nuanced view of the issue.

When Jon Wang's not busy looking out for the future of our planet, he enjoys Taiko, a type of athletic ensemble made up of drums called wadaiko. Known as “The Japanese Art of Drumming,” the exciting and vibrant Taiko is witnessed globally, but it is most often performed in Japan, where it originated. He also enjoys mountain biking and caring for his new puppy "Muesli." 

By Julia St. Andre
Science Writer Intern

 

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