Physics Colloquia

Kristy McQuinn, Rutgers University

The Baryon Cycle in the Smallest of Star-Forming Galaxies

Our view of galaxy evolution has expanded to include not just the evolution of individual galaxy components (gas, stars, chemical elements), but the cyclical interplay of a galaxy with its surroundings. Frequently termed the 'baryon cycle', the galaxy evolution framework now includes: how gas is accreted onto galaxies, turned in stars, ejected out of galaxies via energetic feedback processes, and potentially re-accreted.

Dr. Chris Williams, Brigham & Women's Hospital

MRI-Guided Adaptive Radiation Therapy: Improving Precision in Cancer Therapy

Radiation therapy treatments have traditionally used x-ray imaging to ensure that a patient is accurately positioned before treating them with a beam of ionizing radiation. In the past several years, new treatment machines have been developed that combine magnetic resonance imaging (MRI) systems with linear accelerators, enabling MRI-guidance before and during treatment delivery. These devices have the potential to improve our ability to visualize and treat soft-tissue tumors as well as to compensate for motion and changes in a patient’s anatomy.

Dr. Neil Turok, Director Emeritus; Perimeter Institute

Quantum Universe

Observations show the cosmos to be astonishingly simple, and yet deeply puzzling, on the largest accessible scales. How did everything we see emerge from a singular “point” in the past? Why is there a cosmological constant (or dark energy) and what fixes its value? What caused the density variations which seeded the formation of galaxies? All these questions involve the interplay between quantum mechanics and spacetime.