Olber's Paradox
If the universe is infinite, static, and filled with a endless number of stars, why is the night sky dark?
This simple question forms the core of Olber’s Paradox. In an infinite and unchanging cosmos, every line of sight from Earth should eventually land on the surface of a star—meaning the entire night sky should glow as brightly as the surface of the Sun. The fact that nighttime is dark reveals a fundamental truth about our cosmos: the universe is neither static nor infinitely old.
Watch the video to explore how resolving Olber's Paradox provided early compelling evidence that our universe had a beginning and is actively expanding.