An astronomer is a scientist who studies celestial objects, such as stars, planets, and galaxies. They use telescopes and other tools to observe the universe and gather data about its structure, origins, and evolution. Astronomers often work in research institutions or universities, contributing to our understanding of phenomena like black holes and the expansion of the universe. Astronomy is a broad field that includes various sub-disciplines, such as astrophysics, which focuses on the physical properties of celestial bodies, and planetary science, which studies planets and their atmospheres. Astronomers may also engage in public outreach, sharing their findings with the community and inspiring interest in space exploration.