1. Solar System D. Crowley, 2008

2. Solar System To understand how ideas of the solar system have changed Monday, August 10, 2015

3. Solar System What do you know about our solar system? What planets are there? Are they ordered? Do they have life on them? How big is our solar system? Is it bigger than a galaxy? Bigger than the Universe? Discuss with your partner anything you know about the solar system and beyond…

4. Big The universe contains over 100 billion galaxies A galaxy is a group of billions of stars. Our own galaxy is called the Milky Way, containing ~100 billion stars (including our Sun) The Sun is at the centre of our solar system, which contains many different types of objects including: - A star (the Sun) Planets, orbiting the Sun Satellites, orbiting planets Smaller objects such as asteroids and comets

5. Stars & Galaxies Our Sun is a star - it seems much bigger than other stars, but this is because it is so much closer than the others Most stars have planets orbiting them Galaxies contain many millions of stars (our galaxy is the Milky Way) The universe contains everything - billions of galaxies, each with millions of stars (which usually have planets orbiting them) With billions of galaxies, each with millions of stars and planets orbiting them, chances are we are not alone!

6. The idea that fits scientific observations, allowing us to predict the movement of the planets is called the heliocentric model The Sun is at the centre of the solar system, and the Earth and other planets orbit the Sun in ellipses Solar System

7. Planets Scientists have discovered some extra objects orbiting the Sun that may be planets, but normally we assume that there are nine planets in the solar system The planets in our solar system are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto The order of the planets can be remembered by the phrase: “my very efficient memory just stores up nine planets”

8. Size Planet Star Solar System Galaxy Universe Not to scale!

9. The heliocentric model which says the planets orbit the Sun fits our observations, however we did not always believe this People used to think that the Earth was at the centre of the universe, with everything going around it Your task (in groups of 4) is to research what the following scientists thought about the solar system (each group member researchers one scientist): - Aristotle Ptolemy Copernicus Johannes Kepler Then as a group come up with a time line about how the key ideas of the solar system have changed Solar System

10. Solar System Ideas Aristotle (~300BC) was a supporter of the geocentric model - he believed the Sun and other planets orbited around the Earth. Ptolemy (83AD) refined this model slightly, suggesting that some planets moved in little circles, at the same time as rotating around the Earth (which was in the middle) Copernicus (1543) suggested the Earth and other planets orbited the Sun in circles which Galileo (1564) agreed with - the heliocentric model Kepler (1609) suggested the modern model, where the Earth and other planets orbit the Sun in ellipses

11. Solar System Using the materials for research, complete the solar system worksheet

12. Solar System