Hin K LiK T E A s CiEn T isT HOW DOEs iT WORK CHAPTER 1 EUREKA MOMENTS Many consider physics to be the oldest subjects from the smallest atomic particle science physics covers a wide range of to enormous galaxies physicists scientists who study physics conduct research in subjects such as electricity astronomy forces light and sound objects on our planet and throughout our universe affect each other so it is the job of some physicists to study these interac tions Much of the technology we use today comes from discoveries physicists have made in the last few centuries since ancient times people have noticed and attempted to understand the extraordinary natural occur rences or events around them When they looked up at what was happening in the sky they tried to explain the concepts of night and day When they observed the seasons they invented reasons for those as well in 1400s europe explanations for the changing Observations of the universe led to theories of its physical makeup and workings seasons and how day turned into night involved the belief that earth was the 7
center of the entire universe and everything revolved around it Some even believed that stars were tiny glass-filled holes in the night sky Nicolaus Copernicus a Polish student of astronomy and mathemat ics found flaws in what he was taught and began to ask questions What if everything humans believed about how our universe worked was wrong Copernicus gained as much knowledge as he could even working as an assistant to an astronomer in 1496 In secret Copernicus worked on his hypothesis He believed Earth and the planets orbited the sun Known as heliocentric theory this was in direct opposition to what was taught at the time Some historians suggest Copernicus did not want to publish his find ings because of possible objections from scholars After nearly 30 years of study and observation Copernicus finally allowed his heliocentric theory to be published in a book titled On the Revolutions of the Heavenly Spheres In it he described the yearlong path of Earth around the sun and explained how the mo tions of the planets were elliptical rather than circular as the ancient Greeks had claimed He also discussed how Earth rotated on its axis causing the seasons and the positions in the universe of the five planets he could observe Copernicus estimated the distance from Earth to the sun was closer than the distance between Earth and what he called fixed stars Printed the year of his death a d 1543 Copernicus’s book influenced Galileo Galilei an Italian physicist mathematician and astronomer who faced opposition for his own research in the 1600s Galileo was particularly interested in the science of motion He hypothesized that if a heavy object and a lighter object were dropped from the same distance they both would land at the same time despite the weight of the heavier object According to an account by one of Galileo’s students to test his theory Galileo EUREKA MOMENTS Copernicus above may have erred in his ideas about fixed stars but his sun-centered model opposite was correct 9
