Transcript Space Part1
Introducing the Solar System The Solar System is made up of various celestial objects: the Sun the planets moons asteroids comets. How do these objects interact? The Sun is a star – a massive ball of hot glowing gas. It has the strongest gravitational field in the Solar System. All the other celestial bodies orbit around it. 1 of 48 © Boardworks Ltd 2008 The rotation of the Earth 2 of 48 © Boardworks Ltd 2008 The path of the sun in the sky 3 of 48 © Boardworks Ltd 2008 What are hemispheres? The Earth is divided into two hemispheres, separated by the equator. northern hemisphere equator southern hemisphere Why do the hemispheres have different seasons at different times of the year? 4 of 48 © Boardworks Ltd 2008 The seasons 5 of 48 © Boardworks Ltd 2008 What is the season? 6 of 48 © Boardworks Ltd 2008 The Moon The Sun and the Moon look about the same size from Earth, but they are not. The Sun is about 400 times wider than the Moon but is 400 times further away! sunlight The Moon takes just over 27 days to orbit the Earth. 7 of 48 © Boardworks Ltd 2008 The phases of the Moon 8 of 48 © Boardworks Ltd 2008 Phases of the Moon activity 9 of 48 © Boardworks Ltd 2008 Questions about the Moon 10 of 48 © Boardworks Ltd 2008 Eclipses A solar eclipse happens when the Moon passes between the Sun and the Earth, casting a shadow over the Earth. The last solar eclipse over the UK was on 11th August 1999. They are rare in the UK. A lunar eclipse happens when the Earth passes between the Sun and the Moon, casting a shadow over the Moon. Lunar eclipses happen in most years. 11 of 48 © Boardworks Ltd 2008 What happens during a solar eclipse? Where must the Moon be for a solar eclipse to take place? During a solar eclipse the Moon moves directly between the Sun and the Earth, blocking the Sun’s rays from reaching part of the Earth. 12 of 48 © Boardworks Ltd 2008 What happens during a lunar eclipse? Where must the Moon be for a lunar eclipse to take place? During a lunar eclipse the Moon is on the opposite side of the Earth to the Sun, blocking the Sun’s light from reaching the Moon. 13 of 48 © Boardworks Ltd 2008 Questions about eclipses 14 of 48 © Boardworks Ltd 2008 Gravity and satellites A satellite is any object that orbits another object. The Moon is a natural satellite of the Earth and is kept in orbit by the attraction of the Earth’s gravity and by its motion. An artificial satellite is an object made by, and put into orbit by, humans. Why do you think satellites stay in orbit, instead of falling back onto the surface of the Earth or drifting off into space? 15 of 48 © Boardworks Ltd 2008 Newton’s thought experiment 16 of 48 © Boardworks Ltd 2008