Heinrich Wilhelm Olbers was born on October 11, 1758. An amateur astronomer, he discovered the asteroids Pallas and Vesta in the early 1800’s, and suggested that the asteroid belt was the remnants of a destroyed planet (today we think it’s material that was never able to build itself into a planet, thanks to the gravitational effects of Jupiter.) But he is best known for Olber’s Paradox. He asked a simple question: "why is the sky dark at night?" Now that seems a bit silly - after all, the sky is dark at night because the earth rotates into its own shadow, what we call night. ”I know that,” he said. But if the universe is infinite in size, then that means there's an infinite number of stars out there. So no matter where you look, you'll eventually find a star - the sky should be ablaze with light! But it's not. This suggests that the Universe is perhaps not infinite, and that there was a definitive point in time in which everything began, and also that our Universe is expanding!