On May 22, the Faculty of Science offered students and community members their widely popular Soup and Science presentation series, where professors from various departments deliver short talks on their research. For the first time in its history, lectures were offered in the spring and online, prompting organizers to aptly rebrand the event as “Sun and Science.” The McGill Tribune brings you the highlights of the afternoon: 

Life at the edge: Understanding species geographic distributions

Anna Hargreaves, Assistant Professor in the Department of Biology, is a trained evolutionary ecologist. Her work centres around how species change over time in response to their environment. Yet, Hargreaves’ research takes these questions one step further, addressing how interactions between species—and with them, emergent patterns of global biodiversity—have changed over the course of Earth’s history. 

“My lab thinks a lot about species distributions and why species occur where they do,” Hargreaves said. “Not only because they combine to shape global patterns of biodiversity but also because they are really fundamental to many pressing conservation issues.”

Hargreaves spoke about the different types of experiments her lab conducts in order to address some fundamental questions of evolutionary ecology. Their methods range from traditional field experiments to new and exciting work that models species interactions at large scales. 

“When we, as biologists, try to model [species distributions], where species occur now and where they will go in the future, we often treat species as though they exist in isolation,” Hargreaves said. “Of course, we know this is not true. Every species exists in a web of interactions with the species around it.” 

Presently, the Hargreaves lab is exploring new experimental methods that allow researchers to test hypotheses that are nearly impossible to assess in natural systems. One method, known as “micro landscapes,” involves the creation of habitats in miniature, allowing microorganisms to evolve, and tracking population level genetic and ecological changes over time. Hargreaves also noted that it is much easier to manipulate populations using the micro landscapes approach, making it possible to induce rapid changes in the environment, an important factor in addressing pressing conservation such as climate change.

Neutrinos: The universe’s most mysterious particle

Thomas Brunner, a professor in the Department of Physics, dove down to the smallest of scales in his talk titled “Understanding our Universe through neutrinos.”

Neutrinos are subatomic particles very similar to electrons, but have no charge. Though they are one of the most abundant particles in the universe, neutrinos are incredibly difficult to detect, due to their neutral charge, near-zero mass, and low probability of interacting with other matter. 

“Every second, you have about 50 billion neutrinos passing through [an area of one square centimeter],” Brunner said. “They pass through the body and through the earth.” 

However, Brunner emphasized that, though abundant, very little is known about the nature of neutrinos and their antimatter counterparts, antineutrinos.

In particle physics, antiparticles have opposite electric charges and magnetic movements when compared to regular particles. The positron, for example, has a positive charge, making it the antiparticle to an electron, which is negatively charged. Particles and antiparticles interact to produce energy through annihilation, the process by which particles collide and disappear, effectively cancelling out one another.

“Neutrinos are electrically neutral,” Brunner said. “This, however, now opens the possibility in quantum mechanics that neutrinos and antineutrinos may be the same particle.” 

Brunner went on to mention that some of the fundamental differences between particles and antiparticles may not exist between neutrinos and antineutrinos.

“To figure out if this is indeed the case, we are searching for a type of radioactive decay called neutrinoless double beta decay,” Brunner said. “This decay can only happen if neutrinos and antineutrinos are the same particle.”

If this decay were to be observed, it would classify neutrinos as a Majorana particle: A particle that is its own antiparticle.

According to Brunner, the discovery of this kind of decay could explain why our universe is matter-dominated, instead of antimatter-dominated, forcing physicists to rethink the standard model of particle physics.