What is Astronomy? Astronomy is an ancient science that studies all objects in the universe beyond the Earth’s atmosphere. The sun & other stars The planets The galaxies (our own being the milky way) Much more

The Importance of The Sky Our ancestors watched the sky and the celestial bodies (anything outside the Earth’s atmosphere) constantly for a variety of reasons. To tell the time of day To tell the date To tell the weather To determine when to plant/ harvest crops To navigate

Hierarchy of Objects The moon orbits the Earth. The Earth and all of the other planets orbit the Sun. The Sun and all the other stars in our galaxy (the Milky Way) orbit the centre of the galaxy. There are over 400 billion stars in our galaxy. There are about 100 billion galaxies in our universe. The Earth and Sun are about 5 billion years old. The universe is thought to be about 13 billion years old. - The Romans got the name from the Greeks, who called it galaxias kyklos, which translates into “milky circle”

Universe Hierarchy – How Does Everything Fit Together? The Earth (among other planets) are part of our solar system Our solar system, and many others, are part of our galaxy (the Milky way) The Milky way galaxy, and many others, are part of the “Local Group” of galaxies The Local Group and many others like it, make up the “Local Supercluster” of galaxies Many superclusters of galaxies make up the known universe.

Homework Read page: 305 – 307 . Summarize: Questions: 3 – 9. Stars The Sun Planets Moons Earth’s Companion Galaxies (Milky Way) Questions: 3 – 9.