Physics

Institute of Biomedical Engineering

Leah Cowen

Sinai Health

Sunnybrook Health Sciences Centre

Temerty Faculty of Medicine

Unity Health

Cell and Systems Biology

Anthropology

Astronomy & Astrophysics

Biochemistry

Centre for Addiction and Mental Health

Chemistry

Computer Science

Dalla Lana School of Public Health

Ecology and Evolutionary Biology

Faculty of Applied Science & Engineering

Hospital for Sick Children

Laboratory Medicine and Pathobiology

Leslie Dan Faculty of Pharmacy

Mathematics

Psychology

University Health Network

UTIAS

Subheadline

From better batteries to preventing memory loss, nearly four dozen projects at ��˾��ֱ�� and its partner hospitals are being supported by the Ontario Research Fund

Researchers in the University of Toronto’s Thermal Management Systems (TMS) Laboratory are working to improve the way battery systems handle heat and develop structural battery pack components. 

“Whether they are being used for electric vehicles or for stationary energy storage systems that reduce strain on the grid, lithium-ion batteries are transforming the way we use electricity,” said Carlos Da Silva, senior research associate at the TMS Lab in the Faculty of Applied Science & Engineering and executive director of ��˾��ֱ��’s Electrification Hub.

“Unfortunately, today’s batteries are still sensitive to temperature: if they get too cold or too hot, it can degrade their performance and even present safety risks. We are working on new technologies that make batteries more resilient to thermal fluctuations.”

The battery-related research is among nearly four dozen projects at ��˾��ֱ�� and its partner hospitals that are receiving almost $35 million in support through the Ontario Research Fund – Research Excellence (ORF-RE) and the Ontario Research Fund – Small Infrastructure (ORF-SIF). (See the full list of projects and their principal researchers below).

"Research at the University of Toronto and at all universities and colleges across Ontario is the foundation of the province’s competitiveness now and in the future,” said Leah Cowen, ��˾��ֱ��’s vice-president, research and innovation, and strategic initiatives.

“This investment protects and advances cutting-edge, made-in-Ontario research in important economic sectors and helps ensure universities can continue to train, attract and retain the world’s top talent."

At ��˾��ֱ�� Engineering’s TMS Lab, researchers led by Cristina Amon, a University Professor in the department of mechanical and industrial engineering, are working on two funded projects. They are developing advanced computational modelling and digital twin methodologies that predict and optimize how heat flows through battery packs. The methodologies are carefully calibrated and validated through industry-relevant experiments in the lab.

Senior Research Associate Carlos Da Silva, left, and University Professor Cristina Amon, right, chat in the Faculty of Applied Science & Engineering's Thermal Management Systems Laboratory (photo by Aaron Demeter)

These methodologies will help battery designers anticipate and prevent thermal management challenges before they arise. It can also enable them to optimize the design and deployment of fire mitigation measures, such as ultra-thin heat barriers, within their battery systems.

The team is also collaborating with Ford Canada and several other companies in the energy storage space. For example, they have worked with Jule (powered by eCAMION) on the development of direct current electric vehicle fast chargers with integrated battery energy storage systems, one of which was recently unveiled on the ��˾��ֱ�� campus.

“We are grateful for this ORF-RE funding, which will accelerate our research and help us further expand our partnerships, ensuring that battery thermal innovations have a seamless transition from the lab to the marketplace,” Amon said.

“As a result of this work, the next generation of batteries will be safer and more resilient than ever before, which is especially important in colder climates like ours here in Ontario.” 

Ontario Research Fund – Research Excellence:

Cristina Amon in the department of mechanical & industrial engineering in the Faculty of Applied Science & Engineering – Powering Ontario’s grid transformation and electric vehicle fast charging with thermally resilient battery energy storage & Next-gen electric vehicle battery systems: Lightweight, thermally performant and fire safe for all climates
Morgan Barense in the department of psychology in the Faculty of Arts & Science – HippoCamera: Digital memory rehabilitation to combat memory loss
Aimy Bazylak in the department of mechanical & industrial engineering in the Faculty of Applied Science and Engineering – RECYCLEAN: Critical minerals recycling & re-manufacturing for the energy transition
Ian Connell at University Health Network and the department of medical biophysics in the Temerty Faculty of Medicine – MRI-compatible innovations for neuromodulation
Simon Graham at Sunnybrook Health Sciences Centre and the department of medical biophysics in the Temerty Faculty of Medicine – Technological innovations for clinical MRI of the brain at 7 tesla
Clinton Groth in the Institute for Aerospace Studies in the Faculty of Applied Science & Engineering – Hydrogen as a sustainable aviation fuel – combustion research to remove impediments to adoption in gas turbine engines
James Kennedy at Centre for Addiction and Mental Health and the department of psychiatry in the Temerty Faculty of Medicine – Clinical utility and enhancements of a pharmacogenomic decision support tool for mental health patients
Shaf Keshavjee at University Health Network and the department of surgery in the Temerty Faculty of Medicine – Advanced solutions to human lung preservation and assessment using artificial intelligence
Aviad Levis in the department of computer science in the Faculty of Arts & Science – AI and quantum enhanced astronomy
JoAnne McLaurin at Sunnybrook Health Sciences Centre and the department of laboratory medicine & pathobiology in the Temerty Faculty of Medicine – Conversion of astrocytes to neurons to treat neurodegenerative diseases of the brain and the eye
R. J. Dwayne Miller in the department of chemistry in the Faculty of Arts & Science – PicoSecond InfraRed Laser (PIRL) “cancer knife” with complete biodiagnostics via spatial imaging mass spectrometry
Javad Mostaghimi in the department of mechanical & industrial engineering in the Faculty of Applied Science & Engineering – A new generation of compact, transportable mass spectrometers for rapid, in-field sample analysi
Xiao Yu (Shirley) Wu in the Leslie Dan Faculty of Pharmacy – Molecular dynamics modeling and screening of excipients for designing amorphous solid dispersion formulations of poorly–soluble drugs

Ontario Research Fund – Small Infrastructure Fund:

Celina Baines in the department of ecology & evolutionary biology in the Faculty of Arts & Science – Impacts of environmental change on organismal movement
Sergio de la Barrera in the department of physics in the Faculty of Arts & Science – Facility for quantum materials and device assembly from atomically thin van der Waals layers
Michelle Bendeck in the department of laboratory medicine & pathobiology in the Temerty Faculty of Medicine – 4D quantitative cardiovascular physiology centre
Laurent Bozec in the department of laboratory medicine & pathobiology in the Temerty Faculty of Medicine – 21st Century challenge for Dentistry: Breaking the cycle of irreversible dental tissue loss
Mark Chiew at Sunnybrook Health Sciences Centre and the department of medical biophysics in the Temerty Faculty of Medicine – Next generation computational MRI for rapid neuroimaging and image-guided therapy
Haissi Cui in the department of chemistry in the Faculty of Arts & Science – A molecule to mouse approach to study the intracellular localization of genetic code interpretation in mammalian cells
Andy Kin On DeVeale at the University Health Network and the Dalla Lana School of Public Health – Sarcopenia and musculoskeletal interactions (sami) collaborative hub
Ali Dolatabadi in the department of mechanical & industrial engineering in the Faculty of Applied Science & Engineering – Advanced cold spray facility
Spencer Freeman at the Hospital for Sick Children and the department of biochemistry in the Temerty Faculty of Medicine – Imaging biophysical determinants of the innate immune response
Liisa Galea at the Centre for Addiction and Mental Health and the Institute of Medical Science in the Temerty Faculty of Medicine – Sex and sex-specific factors influencing brain health across the lifespan
Maged Goubran at Sunnybrook Health Sciences Centre and the department of medical biophysics in the Temerty Faculty of Medicine – AI platform for mapping, tracking and predicting circuit alterations in Alzheimer’s disease
Eitan Grinspun in the departments of computer science and department of mathematics in the Faculty of Arts & Science – A computer graphics perspective on entanglement of slender structures
Levon Halabelian in the Department of Pharmacology and Toxicology in the Temerty Faculty of Medicine – Enabling a high-throughput drug discovery pipeline for targeting disease-related human proteins
Ziqing Hong in the department of physics in the Faculty of Arts & Science – Ultra-sensitive cryogenic detector development for dark matter and neutrino experiments
Eno Hysi at the Unity Health Toronto and the department of medical biophysics in the Temerty Faculty of Medicine – Structural and functional assessments of diabetic skin microvasculature using photoacoustic imaging
Lewis Kay in the department of biochemistry in the Temerty Faculty of Medicine – Helium recovery system for the biomolecular NMR facility
Xiang Li in the department of chemistry and the department of physic in the Faculty of Arts & Science – Real-time multi-faceted probes of quantum materials
Qian Lin in the department of cell & systems biology in the Faculty of Arts & Science – 2p-RAM for whole-brain single-neuron imaging of behaving zebrafish to study neural mechanisms of cognitive behaviours
Xilin Liu in the Edward S. Rogers Sr. department of electrical and computer engineering in the Faculty of Applied Science & Engineering – Integrated circuits for wireless brain implants with multi-modal neural interfaces
Stephen Lye at the Sinai Health System and the department of physiology in the Temerty Faculty of Medicine – Healthy Life Trajectories Initiative (HeLTI) analytics platform
Caitlin Maikawa in the Institute of Biomedical Engineering in the Faculty of Applied Science & Engineering – Biointerfacing materials for drug delivery lab
Emma Master in the department of chemical engineering & applied chemistry in the Faculty of Applied Science & Engineering – Accelerating biomanufacturing innovation through enhanced capacity for scale-up and downstream bioprocess engineering
Roman Melnyk at the Hospital for Sick Children and the department of biochemistry in the Temerty Faculty of Medicine – The H-SCREEN: A platform for high throughput and high content imaging-based small molecule screens for disease modulation
Juan Mena-Parra in the department of astronomy & astrophysics in the Faculty of Arts & Science – An advanced laboratory to enable novel radio telescopes for cosmology and time-domain astrophysics
Seyed Mohamad Moosavi in the department of chemical engineering and applied chemistry in the Faculty of Applied Science & Engineering – Machine learning for nanoporous materials design
Enid Montague in the department of mechanical & industrial engineering in the Faculty of Applied Science & Engineering – Automation and equity in healthcare laboratory
Michael Norris in the department of biochemistry in the Temerty Faculty of Medicine – Infrastructure for structural and functional virology research hub
Amaya Perez-Brumer in the Dalla Lana School of Public Health – 3P lab: Centering power, privilege and positionality for health equity research
Monica Ramsey in the department of anthropology at the University of Toronto Mississauga – Ramsey Laboratory for Environmental Archaeology (RLEA): How human-environment interactions shaped plant-food
Arneet Saltzman in the department of cell & systems biology in the in the Faculty of Arts & Science – Heterochromatin regulation in development and inheritance
Mina Tadrous in the Leslie Dan Faculty of Pharmacy – Developing a centre for real-world evidence to improve the use of medications for Canadians
Shurui Zhou in the department of electrical & computer engineering in the Faculty of Applied Science & Engineering – Improving collaboration efficiency for fork-based software development
Olena Zhulyn at the Hospital for Sick Children and the department of molecular genetics in the Temerty Faculty of Medicine – Targeting translation for tissue regeneration and repair
Christoph Zrenner at the Centre for Addiction and Mental Health and the Institute of Biomedical Engineering in the Faculty of Applied Science & Engineering – Next-generation real-time closed-loop personalized neurostimulation

Geoffrey Hinton wins Nobel Prize in Physics

davidlee1 — Tue, 08 Oct 2024 19:35:09 +0000

Geoffrey Hinton wins Nobel Prize in Physics

davidlee1 Tue, 10/08/2024 - 15:35

Cutline

(Photo by Johnny Guatto/University of Toronto)

Rahul Kalvapalle

Topic

Global Lens

Artificial Intelligence

Computer Science

Geoffrey Hinton

Nobel Prize

Subheadline

A ��˾��ֱ�� University Professor Emeritus, Hinton shared the honour with Princeton University's John J. Hopfield for discoveries and inventions that enable machine learning with artificial neural networks

Geoffrey Hinton, a University Professor Emeritus of computer science at the University of Toronto, has won the 2024 Nobel Prize in Physics.

Widely regarded as the “godfather of AI,” Hinton shared the prize with John J. Hopfield of Princeton University for foundational discoveries and inventions that enable machine learning with artificial neural networks.

Hinton said he was “flabbergasted” at the honour as messages poured in from around the world.

“I had no expectations of this,” he told ��˾��ֱ�� News shortly after the win was announced in Stockholm Tuesday morning. “I am extremely surprised and I'm honoured to be included.”

He later told reporters at a press conference he was “in a cheap hotel in California” with no Internet and a poor phone connection when he was notified about his Nobel Prize.

“I was going to get an MRI scan today, but I think I’m going to have to cancel that.”

Hinton and Hopfield are credited with wielding tools from physics to advance basic research in the field. Specifically, Hopfield created an associative memory that can store and reconstruct images in data, while Hinton invented a way to find properties in data and perform tasks such as identifying specific elements in pictures.

“On behalf of the University of Toronto, I am absolutely delighted to congratulate University Professor Emeritus Geoffrey Hinton on receiving the 2024 Nobel Prize in Physics,” said ��˾��ֱ�� President Meric Gertler. “The ��˾��ֱ�� community is immensely proud of his historic accomplishment.”

Hinton was selected for the high-profile award for his use of the Hopfield network – invented by his co-laureate – as the foundation for a new network called the Boltzmann machine that can learn to recognize elements within a given type of data.

The Boltzmann machine can classify images and generate new examples of the pattern on which it was trained, with Hinton and his graduate students later building on this work to help usher in today’s rapid development of machine learning – a technology that now underpins a host of applications ranging from large language models such as ChatGPT to self-driving cars.

Johan Jarnestad/The Royal Swedish Academy of Sciences

“The laureates’ work has already been of the greatest benefit. In physics we use artificial neural networks in a vast range of areas, such as developing new materials with specific properties,” said Ellen Moons, chair of the Nobel Committee for Physics.

The win by Hinton and Hopfield was covered by media and other organizations around the globe, with The New York Times describing the Nobel committee’s decision as “an acknowledgement of AI’s growing significance in the way people live and work,” and the prestigious journal Nature noting Hinton’s innovations now “form the basis of many state-of-the-art AI tools.”

Hinton joined ��˾��ֱ�� as a professor of computer science in 1987 after working in various universities in the U.K., where he was born, and in the United States. He went on to be named a University Professor – ��˾��ֱ��’s highest academic appointment – in 2006.

Driven by a desire to understand the human brain, Hinton and his graduate students built on his early efforts with an array of developments that paved the way for an explosion in deep learning. One of the first cohort of researchers supported by the Canadian Institute for Advanced Research (CIFAR), Hinton’s work helped catapult Canada to its current status as a global leader in AI development.

The Royal Swedish Academy of Sciences, which awards the Nobel Prize in Physics, noted Hinton persisted with his research even as the scientific community lost interest in artificial neural networks during the 1990s, and ultimately “helped start the new explosion of exciting results” in the 2000s.

Hinton, for his part, said during a ��˾��ֱ�� press conference Tuesday evening that his achievements wouldn’t have been possible without support for curiosity-based research – something he said Canada was good at.

He added that his shock at winning the Nobel stemmed from the fact that, while his work has drawn on statistical physics, he isn’t a physicist himself – and even “dropped out of physics after my first year in university because I couldn’t do the complicated math.”

He also said that he plans to donate the money associated with the prize to various charities, including one that provides jobs for neurodiverse young adults.

Hinton likened the influence of AI to that of the Industrial Revolution during a virtual press conference with the academy earlier in the day – “But instead of exceeding people in physical strength, it’s going to exceed people in intellectual ability.”

He added that the rise of AI “is going to be wonderful in many respects,” citing health care and workplace productivity as two areas poised to benefit hugely from the technology. “But we also have to worry about a number of possible bad consequences, particularly the threat of these things getting out of control,” Hinton said.

In early 2023, Hinton quit his job at Google and focused on sounding the alarm about the risks of rapid and unfettered AI development. He outlined his reasoning in a 46-minute ��˾��ֱ�� video last year, urging young researchers to focus their efforts on the emerging field of AI safety – a message he repeated in media interviews following his Nobel win.

He has continued to tackle the issue at lectures and public appearances around the world, including at ��˾��ֱ�� and at Cambridge University, his alma mater.

“I am thrilled Geoffrey Hinton, an esteemed colleague and dear friend has been awarded the Nobel Prize in Physics,” said Melanie Woodin, dean of ��˾��ֱ��’s Faculty of Arts & Science.

“Geoff is an historic visionary whose groundbreaking work in deep learning and neural networks has made ��˾��ֱ�� and the Toronto region a leading global centre for AI. And it speaks volumes about his integrity that while he helped lay the foundation for the artificial intelligence revolution, he is also one of the leading voices urging that we develop this technology responsibly and ethically.”

Similarly, Prime Minister Justin Trudeau lauded Hinton for his efforts to realize responsible AI development, releasing a statement and writing on X: “Geoffrey, we’re glad to have a mind like yours developing safe and responsible AI for the world.”

Geoffrey Hinton delivers a lecture about responsible AI to ��˾��ֱ�� students and faculty (photo by Johnny Guatto)

Hinton, who is co-founder and chief scientific adviser at the Vector Institute in Toronto, joins an illustrious list of past Nobel Prize in Physics winners that includes Albert Einstein and Marie Curie (who also won a Nobel in chemistry). The prestigious award is the latest in a long list of accolades for Hinton. They include the Association for Computing Machinery’s A.M. Turing Award – widely considered “the Nobel Prize of computing” – in 2019 alongside collaborators Yann LeCun and Yoshua Bengio.

Hinton is the fourth ��˾��ֱ�� faculty member to win a Nobel Prize over the years.

Sir Frederick Banting and J.J.R Macleod won a Nobel Prize in Physiology or Medicine for their work with Charles Best in 1923 to isolate insulin. In 1986, John Polanyi was one of three winners of the Nobel Prize in Chemistry for the development of the new field of reaction dynamics.

Other members of the ��˾��ֱ�� community, including several alumni, have received or been associated with the international honour.

Oliver Smithies, a past professor at ��˾��ֱ��, was a joint winner of the Nobel Prize in Physiology or Medicine in 2007 for discovering the “principles for introducing specific gene modifications in mice by the use of embryonic stem cells.”

Also in 2007, Professor Robert Jefferies shared in the Nobel Peace Prize awarded to the Intergovernmental Panel on Climate Change (IPCC), in which he was a key Canadian representative as an international leader in Arctic science and global change biology.

In 1999, ��˾��ֱ�� Professor James Orbinski accepted the Nobel Peace Prize on behalf of Doctors Without Borders, which was recognized for its humanitarian work.

Anti-nuclear activist and ��˾��ֱ�� alumna Setsuko Thurlow accepted the Nobel Peace Prize in Norway in 2017 on behalf the International Campaign to Abolish Nuclear Weapons (ICAN).

In 2001, Michael Spence, an alumnus of University of Toronto Schools, was one of three joint winners of the Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel for his contributions to analyses of markets with asymmetrical information.

Bertram Brockhouse, who completed two degrees at ��˾��ֱ��, was a co-winner of the Nobel Prize in Physics in 1994 for the development of neutron scattering techniques for studies of condensed matter.

Arthur Schawlow, an alumnus, was one of three winners of the same prize in 1981 for his contribution to the development of laser spectroscopy.

In 1998, ��˾��ֱ�� alumnus Walter Kohn was a co-winner of the Nobel Prize in Chemistry for development of the density-functional theory.

Former Prime Minister Lester B. Pearson, who received a bachelor’s degree from ��˾��ֱ��, won the Nobel Peace Prize in 1957.

16-year-old physics grad completes ‘incredible journey’ at ��˾��ֱ��

Christopher.Sorensen — Mon, 03 Jun 2024 15:33:09 +0000

16-year-old physics grad completes ‘incredible journey’ at ��˾��ֱ��

Christopher.Sorensen Mon, 06/03/2024 - 11:33

Cutline

Daniel Honciuc Menendez, 16, is the youngest to graduate from the Faculty of Arts & Science, ��˾��ֱ�� Scarborough or U of Mississauga since at least 1979 (photo by Diana Tyszko)

Topic

Convocation 2024

International Students

University College

Subheadline

Daniel Honciuc Menendez carried out research on dark matter detection and theoretical quantum optics

Daniel Honciuc Menendez was 11 years old when he took part in a summer program in theoretical physics at the Perimeter Institute in Waterloo, Ont., in 2019.

“I’d known for a long time that I wanted a career in physics. But it was in this program that I learned for sure that this was what I wanted to do with my life,” says Honciuc Menendez, who is Ecuadorean and was living in the country's capital Quito at the time.

The trip was his first visit to Canada – and made a big impression. “I liked the openness of the people and the diversity. So I decided that when I applied to universities, I would make sure to apply to universities in Canada.”

After completing high school at age 12, Honciuc Menendez received offers of admission from 12 post-secondary institutions in Canada, the U.S. and Ecuador. He chose the University of Toronto, where he received an International Scholars Award, and began his undergraduate studies as a member of University College.

Honciuc Menendez at 11 years old at the launch of one of his experiments on a rocket with the NASA Cubes in Space program at the Wallops Flight Facility (photo courtesy Daniel Honciuc Menendez)

Now 16 years old, Honciuc Menendez is graduating with a specialist in physics and a major in mathematics with high distinction. He’s the youngest to graduate from the Faculty of Arts & Science, ��˾��ֱ�� Scarborough or ��˾��ֱ�� Mississauga since at least 1979, the year the university began tracking such data.

“I’m proud and excited to be graduating,” he says. “It’s the culmination of four years of hard work, research and volunteer experiences. I’m really looking forward to convocation.”

Faculty of Arts & Science writer Chris Sasaki spoke to Honciuc Menendez before his convocation.

When did your interest in science begin?

I started reading at an early age. When I was very young, my mother and I moved often to different countries because of her career. During this time, I was surrounded by a variety of books, including math books, puzzle books, encyclopedias and atlases. They became my early companions and mentors. Also, even before starting school, I was captivated by educational videos, websites and apps about math, physics, chemistry and other subjects. Then, at 4 years old, while living in the U.K., I gained early entrance into grade school and became interested in programming and robotics. I attended every science festival I could. It became clear to me that I wanted to pursue a life in the sciences.

What was your early education like?

Early entrance into grade school in the U.K. was my first ‘grade-skip.’ When I was six years old, we moved back to Ecuador and I wanted to learn more challenging material during my classes. After meetings with my new school, I was encouraged to apply to the Johns Hopkins University (JHU) Centre for Talented Youth. Upon passing the entrance tests, I was admitted into the program, which allowed me to take advanced courses.

At nine years old, I skipped another grade and started auditing International Baccalaureate (IB) diploma classes in physics and music. Then, when I was 10 years old, I also took the SAT and with its results, I was allowed to skip four more grades to 11th grade and was also able to join other programs like JHU’s Study of Exceptional Talent. From there, I took a full IB diploma program and graduated from high school at 12 years old.

What research projects were you able to take part in at ��˾��ֱ��?

The first was with Professor Miriam Diamond in dark matter detection with the Super Cryogenic Dark Matter Search experiment at SNOLAB, an underground research facility near Sudbury for neutrino and dark matter studies. I developed and tested dark matter detector simulations and conducted data analysis on remote servers.

The second was in theoretical quantum optics with Professor John Sipe at the Centre for Quantum Information & Quantum Control, in which I investigated the theoretical optical response for waveguide-quantum dot systems that could be used as the basis for optical quantum computers.

Throughout both experiences, the collaborative and inclusive spirit of the physics community really inspired me. The professors and researchers provided invaluable mentorship to me and have significantly shaped my decision to pursue a physics research career involving high-energy physics and quantum information.

Honciuc Menendez pursued his interest in music with the Hart House Chamber Strings ensemble (photo courtesy Daniel Honciuc Menendez)

What field are you most interested in now?

I’m interested in quantum information and high-energy physics. Quantum information is a unique field that has applications to various disciplines, since quantum computers can solve various problems that classical computers cannot. I want to specialize in quantum algorithms since they’re essential to realizing the potential of quantum information in its applications, including in my other field of interest, high-energy physics. The more I learn about quantum information's capabilities and its synergy with high-energy physics, the more I realize the significant impact these technologies could have on our understanding of the universe and on advancing computational sciences.

What are your plans after graduation?

I was honored to receive a full scholarship from the European Union to pursue a master's of science in physics with a concentration in quantum science and technology. The program will take place over two years at the Sapienza University of Rome in Italy, then at Université Paris-Saclay in France, and lastly at ��˾��ֱ��. I’ll be taking courses and developing my career in quantum technology in academia and industry, and exploring the interdisciplinary possibilities of the quantum science landscape, including in high-energy physics, medicine, cybersecurity and finance. Later, I want to pursue a PhD in physics where I can go deeper into the intersection between quantum information and high-energy physics.

What are your thoughts as you look back at the past four years?

Throughout these years, the support from my friends, professors and mentors at ��˾��ֱ��, and the resources provided by University College and ��˾��ֱ��’s Accessibility Services have been invaluable and have helped me navigate the complexities of academic life and the personal challenges of being a young student. Plus, all of this would not have been possible without the unconditional support from my mother, a single mom who has been my constant source of strength and inspiration, and who accompanied me as I pursued my studies in Canada.

These past four years have been transformative for me — not just academically but also personally — and were filled with challenges, achievements and growth. It’s been an incredible journey, and I step forward with a heart full of gratitude for the ��˾��ֱ�� community, ready for the next chapter of my life.

Students tackle impact of climate change at ��˾��ֱ�� Climate Impacts Hackathon

Christopher.Sorensen — Mon, 06 May 2024 16:44:57 +0000

Students tackle impact of climate change at ��˾��ֱ�� Climate Impacts Hackathon

Christopher.Sorensen Mon, 05/06/2024 - 12:44

Cutline

Students, instructors and organizers participate in the inaugural Climate Impacts Hackathon (photo by Milan Ilnyckyj, CC BY-NC-SA 2.0 DEED)

Topic

Institutional Strategic Initiative

Climate Positive Energy

Data Sciences Institute

Climate Change

Faculty of Applied Science & Engineering

Undergraduate Students

Subheadline

Teams of undergraduate and graduate students grappled with problems that ranged from altering irrigation practices in Sudan to adapting snow-clearing plans in Ottawa

In the wake of Toronto’s warmest winter on record, students at the University of Toronto recently gathered for the inaugural ��˾��ֱ�� Climate Impacts Hackathon.

The event asked students to tackle several challenges brought by a warming planet: How should the City of Ottawa adapt its snow clearing plan in response to increased precipitation caused by our warming atmosphere? How should irrigation practices in Sudan change in response to higher temperatures and reduced rainfall? And where should new cooling stations – swimming pools, libraries, community centres, shopping malls – be located in an increasingly sweltering City of Toronto?

Participants included undergraduate and graduate students from a range of natural science and engineering disciplines, as well as from the humanities and social sciences. They were divided into teams and competed for prizes.

The hackathon was led by Paul Kushner, a professor of Earth, atmospheric and planetary physics in the department of physics in the Faculty of Arts & Science; and Karen Smith, an associate professor, teaching stream, in the department of physical and environmental sciences (DPES) at ��˾��ֱ�� Scarborough. Co-organizers included Michael Morris, a PhD candidate in the department of physics, and Francisco Camacho, a masters of environmental science student at DPES.

The event was hosted by the department of physics and the DPES; sponsors included Climate Positive Energy (CPE) – a ��˾��ֱ�� institutional strategic initiative – the Centre for Climate Science and Engineering (CSE) and the Cosmic Future Initiative.

The event kicked off with a wide-ranging discussion from a panel of climate experts with diverse perspectives.

Steve Easterbrook, director of the School of the Environment in the Faculty of Arts & Science, spoke about how climate models work and why we can trust them. Lisa MacTavish, project lead in resilience, climate resilience policy and research for the City of Toronto, shared how the city uses climate projections to manage infrastructure and crisis planning. And Daniel Posen, an associate professor in the department of civil and mineral engineering in the Faculty of Applied Science & Engineering, talked about his expertise at the intersection of climate change and engineering.

To develop their solutions, students used the University of Toronto Climate Downscaling Workflow (UTCDW) which includes the UTCDW Guidebook developed by Morris, Smith and Kushner, and the UTCDW Survey, a project design tool. The UTCDW was developed with the support of the CSE, CPE and the Data Sciences Institute, another ��˾��ֱ�� institutional strategic initiative.

Climate models or simulations typically work on a global scale; the UTCDW is designed to help researchers “downscale” what the models do in order to understand how smaller regions and even individual cities are being affected by climate change. The resulting projections can then inform decisions on a local level.

“In our proposal for support to develop these tools, we committed to holding this hackathon to roll them out,” says Kushner. “The intent is to encourage a better understanding of climate change impacts on different domains of application in an atmosphere of fun engagement and community cohort building.”

First prize was awarded to a team that tackled the cooling centre challenge. Using the downscaling tool, the team made detailed projections using temperature and humidity data. They considered vulnerable groups including children, the elderly, refugees and the underhoused; and they factored in education and income levels.

After surveying the current locations of the city’s cooling centres, the team came up with recommendations for six new centres located in areas that are currently underserved.

“We were very pleased and impressed at how far the student participants got in their analysis – how they creatively overcame technical and conceptual obstacles, and how they maintained a constructive and positive attitude as they grappled with the serious issues of climate change,” Kushner says.

��˾��ֱ�� visiting scholar pairs Afghanistan advocacy with a passion for physics

Christopher.Sorensen — Wed, 27 Mar 2024 15:41:32 +0000

��˾��ֱ�� visiting scholar pairs Afghanistan advocacy with a passion for physics

Christopher.Sorensen Wed, 03/27/2024 - 11:41

Cutline

Tahir Shaaran, a visiting scholar in ��˾��ֱ��’s department of physics in the Faculty of Arts & Science, is teaching the next generation of scientists (photo by Johnny Guatto)

Tabassum Siddiqui

Topic

Global Lens

Afghanistan

Global

Arts & Science news staff

Subheadline

A former director-general of Afghanistan's nuclear energy agency, Tahir Shaaran is keen to use education to help his country and drive change

Growing up in Afghanistan, Tahir Shaaran was endlessly curious about the world around him – including the seemingly endless conflicts that engulfed his country.

“I was always thinking about the connection between me and my surroundings and how the universe is functioning – ‘What is the meaning of being here?’ – and those kinds of complicated philosophical questions,” he says.

Shaaran found at least some of the answers he was seeking in physics – and quantum physics in particular. He would go on to spend nearly two decades studying and working around the world before returning to Afghanistan to work as director-general of its nuclear energy agency – an effort, he says, to use his knowledge to help his country.

Now a visiting scholar in the University of Toronto’s department of physics in the Faculty of Arts & Science, Shaaran is teaching the next generation of scientists and says he’s once again reminded of education’s power to drive change and social progress.

“So many people who had the right education and skills to help Afghanistan in terms of development ended up having to leave,” he says. “At the end of the day, it’s about humanity – the crisis in Afghanistan is not just local to that country. Even though it feels like something may not directly affect us, the consequences of such situations are much bigger than for just one place or group of people.

“A lot of the time, we’re looking for quick fixes, but we have to advocate for long-term, sustainable solutions – and we can only do that through education.”

Born during the Soviet invasion in Afghanistan in the 1980s, Shaaran left his native Bamyan province with his family when he was still a young child due to civil unrest in the region. He was raised in Mazar-e-Sharif in northern Afghanistan and later fled to Europe in 1999 following persecution and attacks on the minority Hazara community to which his family belonged.

Settling in the United Kingdom, Shaaran completed several degrees in physics at University College London. Throughout his studies, he collaborated with international institutions, including the Rutherford Appleton Laboratory in the U.K. and the neutron-scattering facility at Institut Laue–Langevin in France.

He went on to work abroad on atomic and nuclear physics, including at the Max Planck Institute for Nuclear Physics in Germany, the French Alternative Energies and Atomic Energy Commission (CEA) and the Institute of Photonic Science in Spain.

Yet, Afghanistan was never far from his mind – and he began thinking about how his studies could help improve the economic and social situation back home.

“I had met the vice-president of Afghanistan in Germany and told him about my plan: the dream of building a national research centre for science and technology back in Afghanistan,” Shaaran says.

“I wanted to have a bigger impact, so I thought the research centre was something that could help more people.”

He was invited to Kabul to meet then-president Ashraf Ghani. While there was no money to fund his research centre dream, Shaaran was tapped to become director-general of Afghanistan’s Nuclear Energy Agency in 2018 – a job he hoped to slowly expand to include a research element. At first, he says was encouraged by the government’s stated openness to scientific progress and development, but soon found himself disillusioned as the political and security situation in the country deteriorated.

“I didn’t receive the support the president had promised,” Shaaran recalls. “Some of it was understandable, as there was a war and a complicated political situation, but I had a feeling the system was going to collapse so I resigned in early 2021.”

Looking back, he says his exit came just in time – the Taliban captured Kabul later that year and the United States withdrew its military. The situation remains volatile, with a crackdown on women’s rights, threats of terrorism, extreme poverty and other challenges.

“In a way, we are all responsible for what has happened to Afghanistan – from human rights activists to the police to policymakers – [because] we didn’t think about how we could build the country independently without relying on anyone from the outside,” says Shaaran, who has been a longtime advocate for human rights and the rights of Afghanistan’s minority Hazara population.

Shaaran says teaching at ��˾��ֱ�� helps keep him inspired and optimistic about the future – thanks in no small part to a steady stream of engaged physics students. He also leads an advanced physics lab this semester that offers 40 different experiments for five different courses.

“His expertise allows him to supervise a range of projects, covering topics from optics to particle physics, and help students progress through their experiments. In addition to that, he is a great colleague – willing to learn from more experienced members from the team, while sharing his expertise with teaching assistants and junior colleagues,” says Shaaran’s colleague Ania Harlick, an assistant professor, teaching stream.

“Tahir brings considerable expertise in theoretical and nuclear physics from his work in academia and at Afghanistan’s nuclear agency,” adds Professor Kimberly Strong, chair of the department of physics.

“He has been actively engaged in the life of the department this year, and it has been such a great pleasure hosting him here.”

As for his ongoing advocacy efforts, Shaaran continues to speak with politicians and organize rallies and workshops to ensure Afghanistan and its people remain in the public consciousness.

“Despite all the difficulties, I’m an optimist because when I call someone in Afghanistan – even in a remote area and even though young women and girls are not allowed to go to school – they still have drive and hope,” he says. “Many people send me emails or texts saying they are looking for online education as they want to learn.

“Those small things give me a lot of hope.”

Physicists create 'quasicrystals' that exhibit superconductive properties

Christopher.Sorensen — Wed, 18 Oct 2023 18:11:09 +0000

Physicists create 'quasicrystals' that exhibit superconductive properties

Christopher.Sorensen Wed, 10/18/2023 - 14:11

Cutline

MIT’s Aviram Uri, left, and ��˾��ֱ��’s Sergio C. de la Barrera are part of a team that coaxed superconductivity from an enigmatic class of materials known as quasicrystals (photo by Eva Cheung)

Topic

Breaking Research

Subheadline

“We don’t yet fully understand the system. There are still quite a few mysteries.”

Researchers at the University of Toronto and the Massachusetts Institute of Technology have discovered a way to create new atomically thin versions of quasicrystals – an enigmatic class of materials – that exhibit superconductivity.

The work by Sergio C. de la Barrera, an assistant professor in ��˾��ֱ��’s department of physics, and his MIT colleagues promises to jumpstart interest in quasicrystals by creating a new platform for further research. That, in turn, could lead to new physics insights and important applications such as more efficient electronic devices.

Recently published in Nature, the research and brings together two previously unconnected fields: “quasicrystals” and “twistronics.”

“It's really extraordinary that the field of twistronics keeps making unexpected connections to other areas of physics and chemistry – in this case the beautiful and exotic world of quasiperiodic crystals,” says Pablo Jarillo-Herrero, the Cecil and Ida Green Professor of Physics at MIT who pioneered the field of twistronics only five years ago.

Twistronics involves placing atomically thin layers of materials on top of one another. Rotating, or twisting, one or more of the layers at a slight angle creates a unique pattern called a moiré superlattice. And a moiré pattern, in turn, has an impact on the behaviour of electrons.

“It changes the spectrum of energy levels available to the electrons and can provide the conditions for interesting phenomena to arise,” says de la Barrera, one of four co-first authors of the recent paper who conducted the work while a postdoctoral associate at MIT.

A moiré system can also be tailored for different behaviors by changing the number of electrons added to the system. As a result, the field of twistronics has exploded over the last five years as researchers around the world have applied it to creating new atomically thin quantum materials.

Image of a moiré quasicrystal, center column, created by three overlapping sheets of atomically thin graphene (photo credit: Sergio C. de la Barrera)

In the current work, the researchers were tinkering with a moiré system made of three sheets of graphene. Graphene is composed of a single layer of carbon atoms arranged in hexagons resembling a honeycomb structure. In this case, the team layered three sheets of graphene, but twisted two of the sheets at slightly different angles.

To their surprise, the system created a quasicrystal, an unusual class of material discovered in the 1980s. As the name implies, quasicrystals are somewhere between a crystal such as a diamond, which has a regular repeating structure, and an amorphous material like glass, “where the atoms are all jumbled, or randomly arranged,” says de la Barrera.

In a nutshell, quasicrystals “have really strange patterns,” de la Barrera says.

Compared to crystals and amorphous materials, however, relatively little is known about quasicrystals. That’s in part because they’re hard to make. “That doesn’t mean they’re not interesting; it just means that we haven’t paid as much attention to them, particularly to their electronic properties,” says de la Barrera, adding that the relatively simple quasicrystal created by the study’s authors could be used by other researchers as a platform to advance the field.

Because the original researchers weren’t experts in quasicrystals, they reached out to Professor Ron Lifshitz of Tel Aviv University, a co-author who helped the team to better understand what they were looking at, which they call a moiré quasicrystal.

The physicists then tuned a moiré quasicrystal to make it superconducting, or transmit current with no resistance at all below a certain low temperature. That’s important because superconducting devices could transfer current through electronic devices much more efficiently than is possible today, but the phenomenon is still not fully understood in all cases.

The team also found evidence of symmetry breaking – a phenomenon that “tells us that the electrons are interacting with one another very strongly,” de la Barrera says. “And as physicists and quantum material scientists, we want our electrons interacting with each other because that’s where the exotic physics happens.”

In the end, “through discussions across continents we were able to decipher this thing, and now we believe we have a good handle on what’s going on,” says Aviram Uri, a co-first author of the paper and an MIT Pappalardo and VATAT postdoctoral fellow, although he notes that “we don’t yet fully understand the system. There are still quite a few mysteries.”

The best part of the research was “solving the puzzle of what it was we had actually created,” de la Barrera says. “We were expecting [something else], so it was a very pleasant surprise when we realized we were actually looking at something very new and different.”

With files from Elizabeth A. Thomson, MIT

��˾��ֱ�� undergrad student takes the fight against climate change to the streets

Christopher.Sorensen — Wed, 30 Aug 2023 17:59:37 +0000

��˾��ֱ�� undergrad student takes the fight against climate change to the streets

Christopher.Sorensen Wed, 08/30/2023 - 13:59

Cutline

Sebastian Ibarra Mendez, pictured here towing a gas analyzer behind his bike, is a summer researcher with Climate Positive Energy, a ��˾��ֱ�� institutional strategic initiative (photo by Chris Sasaki)

Topic

Institutional Strategic Initiatives

Climate Positive Energy

Undergraduate Students

Subheadline

Sebastian Ibarra Mendez cycles around the Toronto region towing a unit that measures methane leaks

As a high school student in Cajicá, Colombia, Sebastian Ibarra Mendez developed a methane detector for homes that was designed to alert users of harmful levels of the gas leaking from domestic stoves – not unlike a smoke or carbon monoxide alarm.

He won a national competition with the idea, which he dubbed the Air Keeper.

Now entering his fourth year in the University of Toronto’s Faculty of Arts & Science, Ibarra Mendez is continuing his focus on measuring methane leaks as a summer undergraduate researcher with Climate Positive Energy, a ��˾��ֱ�� institutional strategic initiative.

He and Mishaal Kandapath – a former CPE summer researcher – have been monitoring levels of methane throughout the Toronto region by towing a gas analyzer behind a bicycle. The mobile device measures the concentration of methane along different routes, revealing plumes or hotspots with higher-than-normal emission levels.

“Kilogram for kilogram, methane traps over 20 times more heat in the atmosphere than carbon dioxide so it’s very important to track,” says Ibarra Mendez, who is a physics and statistics major with a minor in computer science.

“Measuring levels in different locations helps identify methane emitters. It allows the City of Toronto to better focus its efforts on methane emission reduction and it can be used to test existing policies designed to tackle the problem.”

Water treatment plants are one place where the breakdown of biodegradable materials creates plumes of methane in Toronto, the researchers found. The data collected by the students can be used to identify excessive emissions and help plant operators to mitigate the problem.

Active landfill sites also emit methane and plumes from these locations similarly show up in the maps.

The researchers also discovered that landfill sites no longer in use continue to outgas at significant levels.

“It made me realize that you can close a landfill site, but it’s still going to be a source of methane,” Ibarra Mendez says.

Sebastian Ibarra Mendez, right, and Mishaal Kandapath, left, prepare for another ride (photo by Chris Sasaki)

Recently, the team even detected a major leak from a Toronto hospital that resulted in measurements of 300 parts-per-million. “The concentration of methane in your home is about 2 parts-per-million – so 300 is a lot of methane,” Ibarra Mendez says.

The research is part of the ongoing GTA Urban Emissions project headed by Debra Wunch, an associate professor in the Faculty of Arts & Science’s department of physics and the School of the Environment.

The project is just part of Wunch’s overall research as a member of the department’s Earth, atmospheric, and planetary physics group. Throughout her career, she has focused on measuring atmospheric greenhouse gases to gain a better understanding of the flow of carbon within the Earth’s land, oceans and atmosphere.

“With the bike measurements, we can identify facilities in the city that emit methane,” she says. “And then, with five remote sensing instruments in permanent locations, we get the bigger picture of city-scale emissions – I can't tell you if it's a particular building or road, but we can see the amount of methane being put into the atmosphere by the city as a whole. And then, we also get measurements from satellites, which show us how much Toronto is producing relative to other cities around the world.”

Among other criteria, the Climate Positive Energy (CPE) summer undergraduate research program provides funding for undergraduate students conducting research in climate and sustainability topics that are “focused on achieving a just and equitable net-zero future.”

“With this in mind, we planned our routes so they covered neighbourhoods that varied by household income,” says Ibarra Mendez. “By using this methodology, we ensure that the data being collected doesn’t benefit just specific target areas or groups, but rather supports everyone across the GTA.”

Not only has the research been a natural extension of the methane alarm he began working on in high school, it also lets Ibarra Mendez enjoy another of his interests: cycling.

“Yes, I really like cycling,” he says. “And we’ve covered over 160 kilometres so far. So, for me, it’s the perfect job.”

‘Something out there’: How a ��˾��ֱ�� undergrad uses AI to search for aliens

siddiq22 — Mon, 31 Jul 2023 13:15:42 +0000

‘Something out there’: How a ��˾��ֱ�� undergrad uses AI to search for aliens

siddiq22 Mon, 07/31/2023 - 09:15

Cutline

Peter Ma, who is entering his fourth year of study in ��˾��ֱ��’s Faculty of Arts & Science, was the lead author on a paper published in Nature Astronomy earlier this year (photo by Johnny Guatto)

Tabassum Siddiqui

Topic

Dunlap Institute for Astronomy & Astrophysics

Artificial Intelligence

Mathematics

Space

Undergraduate Students

Victoria College

Subheadline

Peter Ma wrote an algorithm to detect signs of extraterrestrial life while still in high school

Is there life beyond our planet? It’s a question that third-year University of Toronto undergraduate student Peter Ma began thinking about when he was still in high school.

A math and physics student entering his fourth year in the Faculty of Arts & Science, Ma is dedicated to searching for aliens – and while that may sound like something out of science fiction, he isn’t exactly chasing down little green men. Instead, he’s drawing on his passion for science to find the data that could prove we’re not alone in the universe.

Ma was in Grade 12 when he wrote an algorithm to look for signs of intelligent life using open-source data from the University of California, Berkeley and its Breakthrough Listen research program.

After cold-emailing researchers at the SETI Institute, he became the youngest member of the team of international researchers at UC Berkeley dedicated to the search for extraterrestrial intelligence, and was lead author on a paper published earlier this year in the journal Nature Astronomy.

“I was super-curious even as a really young kid,” says Ma, who grew up in a Chinese-speaking household and learned English by reading books borrowed during visits to the local library.

“I remember asking my parents questions about everything as early as age four – and they didn’t really know how to answer most of them.”

Ma recalls getting a telescope at age six, and frequent trips to Home Depot and Walmart to buy supplies for his many “on steroids” science projects. One such challenge to build a working chair for the school principal out of recycled materials found Ma toying with the idea of melting aluminum cans – until he realized it was “probably not a good idea to build a furnace in the backyard.”

In high school, he taught himself Grade 11 computer science in three weeks, spending the remainder of the semester devouring videos on machine learning and deep learning – eventually developing his space-scanning algorithm using Breakthrough Listen’s open-source data.

“I was looking for interesting problems to solve,” he says, recalling how his high school teachers were more perplexed than impressed with his AI exploits.

Even while stuck at home during the pandemic, Ma managed to maintain that momentum, working with SETI in the summer before starting university as a member of Victoria College. Once his classes were underway, he continued the collaboration with the support of the Laidlaw Scholars Program.

Using his algorithm, Ma and the SETI team detected eight radio signals that may have originated from life on another planet – when he relayed the findings to his ��˾��ֱ�� supervisors, he was surprised to hear them suggest the study could be published.

“When they said, ‘We’re going to send this to Nature Astronomy,’ I thought, ‘Wow, hold on – I’m not ready for papers.’ Usually those are done by actual researchers – in comparison to them, I’m still learning my ABCs.”

Ma stresses that when SETI refers to signals coming from an alien civilization, they aren’t necessarily talking about the big-eyed creatures we see in movies – but rather signs that point to some kind of life well beyond our own planet.

“We obviously can't search for intelligence per se – we search for proxies of the targets. So, we search for signs of engineering – in this case, engineering of radio technosignatures, or radio emissions. We believe that intelligent species can produce technology – a phone or a telescope or something like that – and we detect those kinds of signals.”

Ma credits his ��˾��ֱ�� supervisors and collaborators – in particular study co-author Cherry Ng, a former research associate at the Dunlap Institute for Astronomy and Astrophysics, jointly affiliated with SETI, who is now an astronomer at the Centre National de la Recherche Scientifique in France; and Bryan Gaensler, director of the Dunlap Institute and professor in the David A. Dunlap department of astronomy – for preparing him to work alongside veteran researchers in the field.

“Peter is self-motivated and not afraid of challenges,” says Ng, who began working with Ma in the summer of 2020 to search for technosignatures using the Green Bank Telescope based in West Virginia.

“When we get stuck on the analysis, instead of giving up, Peter would always come up with new ideas to try again. It’s his determination that sets him apart.”

Ma and the SETI team plan to continue their work with a two-year project that will scan up to one million stars (Ma’s paper, by contrast, looked at just 820 stars) using a set of 64 telescopes in South Africa.

Ma will have graduated from ��˾��ֱ�� by the time the project wraps up, but unsurprisingly plans to continue his scientific exploration as a graduate student.

“There has never been a better time in history to find extraterrestrial life now and in the future – our probability of actually finding them only goes up from here,” says Ma, who is spending his summer working with the experimental particle physics group at McGill University on a joint project with CERN, the Swiss-based organization that developed the Large Hadron Collider.

“If you truly believe that we’re alone here [in the universe], then that’s a different story. But if you believe that there’s something out there, then it’s only a matter of time until we actually find it.”

For a billion years, Earth's day lasted just 19.5 hours – a new study reveals why

siddiq22 — Thu, 13 Jul 2023 16:54:12 +0000

For a billion years, Earth's day lasted just 19.5 hours – a new study reveals why

siddiq22 Thu, 07/13/2023 - 12:54

Cutline

Without the sun’s pull on the Earth’s atmosphere, our day would be 60 hours long (photo by dima_zel/Getty images)

Physical and Environmental Sciences

Topic

Breaking Research

Astronomy

Astrophysics

Canadian Institute for Theoretical Astrophysics

Climate Change

��˾��ֱ�� Scarborough

Subheadline

An atmospheric tide driven by the sun countered the effect of the moon, astrophysicists say

A team of astrophysicists from the University of Toronto has revealed how the slow and steady lengthening of Earth’s day caused by the tidal pull of the moon was halted for over a billion years.

They show that from approximately two billion years ago until 600 million years ago, an atmospheric tide driven by the sun countered the effect of the moon, keeping Earth’s rotational rate steady and the length of day at a constant 19.5 hours.

Without this billion-year pause in the slowing of our planet’s rotation, our current 24-hour day would stretch to over 60 hours.

Drawing on geological evidence and using atmospheric research tools, the scientists show that the tidal stalemate between the sun and moon resulted from the incidental but consequential link between the atmosphere’s temperature and Earth’s rotational rate.

The study was published in the journal Science Advances.

The paper’s authors include Professor Norman Murray, a theoretical astrophysicist with the Faculty of Arts & Science’s Canadian Institute for Theoretical Astrophysics (CITA); graduate student Hanbo Wu, with CITA and the department of physics; Kristen Menou, associate professor in the David A. Dunlap department of astronomy and astrophysics and the department of physical and environmental sciences at ��˾��ֱ�� Scarborough; Jeremy Leconte, a CNRS researcher at the Laboratoire d’astrophysique de Bordeaux and a former CITA postdoctoral fellow; and Christopher Lee, assistant professor in the department of physics.

Murray and his collaborators relied on geologic evidence in their study, like these samples from a tidal estuary that reveal the cycle of spring and neap tides. Thick bands correspond to spring tides, and thin bands to neap tides (image by G.E. Williams)

When the moon first formed some 4.5 billion years ago, the day was less than 10 hours long. But since then, the moon’s gravitational pull on the Earth has been slowing our planet’s rotation, resulting in an increasingly longer day. Today, it continues to lengthen at a rate of some 1.7 milliseconds every century.

The moon slows the planet’s rotation by pulling on Earth’s oceans, creating tidal bulges on opposite sides of the planet that we experience as high and low tides. The gravitational pull of the moon on those bulges, plus the friction between the tides and the ocean floor, acts like a brake on our spinning planet.

“Sunlight also produces an atmospheric tide with the same type of bulges,” says Murray. “The sun's gravity pulls on these atmospheric bulges, producing a torque on the Earth. But instead of slowing down Earth’s rotation like the moon, it speeds it up.”

For most of Earth’s geological history, the lunar tides have overpowered the solar tides by about a factor of ten – hence the Earth’s slowing rotational speed and lengthening days.

But some two billion years ago, the atmospheric bulges were larger because the atmosphere was warmer and because its natural resonance – the frequency at which waves move through it – matched the length of day.

The atmosphere, like a bell, resonates at a frequency determined by various factors, including temperature. In other words, waves – like those generated by the enormous eruption of the volcano Krakatoa in Indonesia in 1883 – travel through it at a velocity determined by its temperature. The same principle explains why a bell always produces the same note if its temperature is constant.

Throughout most of Earth’s history that atmospheric resonance has been out of sync with the planet’s rotational rate. Today, each of the two atmospheric “high tides” take 22.8 hours to travel around the world. Since that resonance and Earth’s 24-hour rotational period are out of sync, the atmospheric tide is relatively small.

But during the billion-year period under study, the atmosphere was warmer and resonated with a period of about 10 hours. Also, at the advent of that epoch, Earth’s rotation – slowed by the moon – reached 20 hours.

When the atmospheric resonance and length of day became even factors (ten and 20), the atmospheric tide was reinforced, the bulges became larger and the sun’s tidal pull became strong enough to counter the lunar tide.

“It’s like pushing a child on a swing,” Murray says.

“If your push and the period of the swing are out of sync, it’s not going to go very high. But, if they’re in sync and you’re pushing just as the swing stops at one end of its travel, the push will add to the momentum of the swing and it will go further and higher. That’s what happened with the atmospheric resonance and tide.”

Along with geological evidence, Murray and his colleagues achieved their result using global atmospheric circulation models (GCMs) to predict the atmosphere’s temperature during this period. The GCMs are the same models used by climatologists to study global warming. Murray says the fact they worked so well in the team’s research is a timely lesson.

“I've talked to people who are climate-change skeptics who don't believe in the global circulation models that are telling us we’re in a climate crisis,” he says. “And I tell them: We used these global circulation models in our research, and they got it right. They work.”

Despite its remoteness in geological history, the result adds additional perspective to the climate crisis. Because the atmospheric resonance changes with temperature, Murray points out that our current warming atmosphere could have consequences in this tidal imbalance.

“As we increase Earth's temperature with global warming, we’re also making the resonant frequency move higher – we’re moving our atmosphere farther away from resonance. As a result, there's less torque from the sun and therefore the length the day is going to get longer – sooner than it would otherwise.”

Shifting gears: How data science led Madeleine Bonsma-Fisher from studying germ models to bike lanes

Christopher.Sorensen — Tue, 09 May 2023 20:03:34 +0000

Shifting gears: How data science led Madeleine Bonsma-Fisher from studying germ models to bike lanes

Christopher.Sorensen Tue, 05/09/2023 - 16:03

Cutline

Madeleine Bonsma-Fisher, a post-doctoral researcher at ��˾��ֱ��'s Data Sciences Institute, is studying traffic "stress" in Toronto in order to pinpoint where more cycling infrastructure is needed (photo by Johnny Guatto)

Adina Bresge

Topic

Institutional Strategic Initiatives

Cycling

Data Sciences Institute

Cities

Faculty of Applied Science & Engineering