Professor Chisholm observes how galaxies grow and influence their surroundings over time. In particular, he is interested in the first galaxies in the universe and how they shaped the universe by reionizing the entire cosmos. To do this, he studies the gas and stars of closer galaxies to develop a roadmap to interpret the first galaxies. This lays the foundation for upcoming telescopes, like the University of Texas' Giant Magellan Telescope, or the James Webb Space Telescope, to actually observe these young galaxies for the first time. These observations will be the first glimpse into how massive stars and galaxies reionized the entire universe.