AST101H1 Chapter 1: AST 101 Chapter 1 Notes

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST101H1
• Professor: Bryan Gaensler, C. Barth Netterfield, Ilana MacDonald

Document Summary

Earth is not the center of the universe but instead is a planet orbiting a rather ordinary star in the milky way galaxy. The milky way galaxy, in turn, is one of billions of galaxies in our observable universe. Cosmic distances are literally astronomical, but we can put them in perspective with the aid of scale models and other scaling techniques. When you think about these enormous scales, don"t forget that every star is a sun and every planet is a unique world. The atoms from which we are made began as hydrogen and helium in the big bang and were later fused into heavier elements by massive stars. Stellar deaths released these atoms into space, where our galaxy recycled them into new stars and planets. Our solar system formed from such recycled matter around 41 billion years ago. We are latecomers on the scale of cosmic time.