The first-ever Soup & Science event, held in 2006, was hardly an extravagant affair. Professors and students gathered together in the second-floor lobby of the Trottier building to talk science, pass along research developments, and, of course, share in the event’s eponymous light refreshments. Thirty editions and a venue change later, the Soup & Science lecture series has become a mainstay of McGill’s academic calendar, having hosted over 400 speakers and 10,000 attendees since its inception.
The McGill Tribune covered highlights from the five-day virtual event.
Satellite imaging Panama’s tropical forests to find “carbon refuges”
Because most forest trees tower into dense foliage, their heights are often impossible to measure accurately from the ground. In 2018, a team led by Dr. Catherine Potvin, professor in the Department of Biology, discovered a fallen tree in Panama’s tropical forests. The tree proved to be a rare find, allowing the researchers to obtain an exact measurement of its height.
“[The tree] measured 71 meters in height, which is amazing because it’s about twice the height of the reported forests of Panama,” Potvin said.
Trees are essential for naturally reducing the amount of greenhouse gases in the atmosphere. Through photosynthesis, they can store large amounts of carbon dioxide in their trunks for extended periods of time—a process known as carbon sequestration.
“Now that we were able to measure it, we know it contained 50 [tonnes] of carbon,” Potvin said.
That’s [in] a single tree. In the temperate forests [of Quebec], there are 40 tonnes of carbon […] in one hectare of forest.”
Potvin stressed the importance of developing novel methods, such as satellite imagery, for measuring these abnormally tall trees, and mapping areas where they grow en masse. Dubbed “carbon refuges,” their preservation would help to maintain stable levels of carbon in the atmosphere.
Applying a niche mathematical concept to calculate infinite values from finite points
Dr. Anush Tserunyan, assistant professor in the Department of Mathematics and Statistics, is a mathematician with a keen eye for deducing the logic behind complex systems. Ergodicity, the focus of Tserunyan’s research, is a branch of mathematics that studies the statistical properties of dynamic systems.
Tserunyan compared ergodicity to a well-mixed cup of milk and coffee. In this example, the movement of any given drop of milk in the coffee—here, an individual “point”—can be used to model the mixture’s movement over time.
The ergodic theory stipulates that studying an individual’s trajectory across time is the same as observing a collection of individual trajectories at a single time point.
“[Finding the] averages over infinitely many points is impossible to compute, and pointwise ergodic theorem gives you a way to measure it at finite points,” Tserunyan said. “The average you compute will be very close to the actual average.”
Although it can be hard to imagine ergodicity’s real-world applications, Tserunyan commented that ergodic theory is foundational to other branches of mathematics, including those used to conceive climate models.
McGill physicists are escaping radio frequency interference at the world’s northernmost research station
In a talk titled “Radio frequency interference at the McGill Arctic Research Centre,” Taj Dyson spoke about imaging the Universe during the Cosmic Dark Ages, just before the formation of the first stars. Dyson, U2 Science, explained his work with Doctors Cynthia Chiang and Jonathan Sievers to detect neutral hydrogen signals from one of the oldest but least-studied eras of the Universe.
“The only signal that comes from the Dark Ages comes from neutral hydrogen, which faintly glows at around 1.4 gigahertz,” Dyson said. “But, by the time that signal reaches us on Earth, it has been red-shifted down to 100 megahertz, which is pretty much exactly the frequency of FM radio broadcasts.”
This, Dyson explained, results in significant interference and becomes a serious problem when trying to image hydrogen signals.
The simplest solution is to position oneself as far away from radio signals as possible. Located at 80 degrees North, the McGill Arctic Research Centre is easily the best option.
After hunkering down in this small research facility, Dyson observed the data and determined the magnitude of interference still being received from Dark Age hydrogen molecules. With much significantly less radio frequency interference, Dyson concluded the Centre was a prime location for examining incoming signals.