Cosmologists are scientists who study the universe's origins, structure, and evolution. They explore fundamental questions about how the universe began, its current state, and its ultimate fate. Using tools like telescopes and computer simulations, they analyze cosmic phenomena such as galaxies, stars, and cosmic background radiation. Their work often involves theories from physics, particularly general relativity and quantum mechanics. Cosmologists also investigate concepts like dark matter and dark energy, which are believed to make up most of the universe. By understanding these elements, they aim to create a comprehensive picture of the cosmos and its workings.