For thousands of years, humanity has gazed up at the stars in fascination, using them to navigate vast oceans, mark the passage of seasons, and inspire myths, art, and poetry. These celestial lights, scattered across the night sky, seemed mysterious yet constant, their true nature beyond comprehension. Many scientists and astronomers spent much time theorizing about the nature of these far-flung objects, and the early 1900s saw many of these theories debunked by a brilliant young graduate student.
What beliefs did scientists have about the stars a century ago? What are these celestial objects truly made of? And how did a 24-year-old would-be astronomer reveal the secrets of starlight? Click through this gallery to find out.