Preface to Chapter 1: “Artistic Qualities of the Universe”

“Artistic Qualities of the Universe” Order ….. Symmetry ….. Beauty

Artistic Qualities of the Universe Order: We live in a hierarchical Universe

Artistic Qualities of the Universe Symmetry: The Universe exhibits repetitive patterns

Artistic Qualities of the Universe Beauty: The Universe is beautiful

Chapter 1: “Where are We?: Our Cosmic Address” Chapter 1 “The Scale of the Cosmos” Astronomy 10 The Solar System

How Big is BIG? Chapter 1 “The Scale of the Cosmos” Astronomy 10 The Solar System

Earth, the Terrestrial Planets & Pluto

The Planets of the Solar System

The Sun and Planets

Red Giant & Supergiant Stars

Scales of Size and Time Astronomy deals with objects on a vast range of size scales and time scales. Most of these size and time scales are way beyond our every-day experience. Astronomers use numbers that are so big that it is convenient to write them using scientific notation.

Scientific Notation: is an easy way to write very big or very small numbers. 6 10 = 10 X 10 X 10 X 10 X 10 X 10 = 1,000,000 6 X 10 = 6 X 1,000,000 = 6 million

What is your “cosmic address” What is your “cosmic address”? John Doe Earth Solar System Milky Way Galaxy Local Group Virgo Supercluster Universe

Moons (Satellites of the planets) The Earth is one of eight planets which travel around a star we call the Sun. The Sun and eight planets form the Solar System. Other types of objects orbit the Sun and are part of the Solar System: Kuiper Belt Objects (Pluto) Moons (Satellites of the planets) Asteroids Comets Meteoroids

Figure 1.8 Our Solar Family. The Sun, the planets, and some dwarf planets are shown with their sizes drawn to scale. The orbits of the planets are much more widely separated than shown in this drawing. Notice the size of Earth compared to the giant planets. (credit: modification of work by NASA)

Chapter 1: “The Scale of the Cosmos” In the Solar System distances are usually measured in miles, kilometers or astronomical units. One astronomical unit (A.U.) is 93,000,000 miles or the average distance from Earth to the Sun.

Chapter 1: “The Scale of the Cosmos” The largest object in the Solar System is the Sun. Our Sun is an average star. Our Sun and all of the stars we see in the night sky and many more we can’t see form a huge, spiral, disk-shaped object we call the Milky Way Galaxy. This is a Hubble Space Telescope picture of a distant galaxy that resembles the Milky Way Galaxy.

Chapter 1: “The Scale of the Cosmos” The Milky Way galaxy is about 75,000 light-years in diameter and may contain 100 billion stars. Galaxies range from 1,500 to over 300,000 light-years in diameter.

Figure 1.9 Spiral Galaxy. This galaxy of billions of stars, called by its catalog number NGC 1073, is thought to be similar to our own Milky Way Galaxy. Here we see the giant wheel-shaped system with a bar of stars across its middle. (credit: NASA, ESA)

Figure 1.13 Closest Spiral Galaxy. The Andromeda galaxy (M31) is a spiral-shaped collection of stars similar to our own Milky Way. (credit: Adam Evans)

Chapter 1: “The Scale of the Cosmos” When we talk about distances in our galaxy we use a new unit called the light-year. One light-year is the distance light, traveling at a speed of 186,000 miles per second, travels in a year – 6 trillion miles. (63,000 A.U.) The nearest star -Proxima Centauri- is 4.2 light-years away.

Chapter 1: “The Scale of the Cosmos” Galaxies are organized into clusters of galaxies. The Milky Way Galaxy belongs to the Local Group.

Figure 1.14 Fornax Cluster of Galaxies. In this image, you can see part of a cluster of galaxies located about 60 million light-years away in the constellation of Fornax. All the objects that are not pinpoints of light in the picture are galaxies of billions of stars. (credit: ESO, J. Emerson, VISTA. Acknowledgment: Cambridge Astronomical Survey Unit)

Local Group The Local Group

Chapter 1: “The Scale of the Cosmos” Clusters of galaxies are organized into superclusters of galaxies. The Local Group of galaxies is a member of the Virgo Supercluster

The Virgo Supercluster

Galaxies, galaxies everywhere - as far as the Hubble Space Telescope can see. This view of nearly 10,000 galaxies is the deepest visible-light image of the cosmos.

3-D Large Scale Structure of the Universe