Presentation on theme: "The Earth in Space. Day and Night The Earth is a sphere (actually, it’s an oblate spheroid – a very slight rugby ball shape) The Earth orbits the Sun."— Presentation transcript:
The Earth in Space
Day and Night The Earth is a sphere (actually, it’s an oblate spheroid – a very slight rugby ball shape) The Earth orbits the Sun in a path that is egg- shaped – an ellipse. It takes / 4 days to orbit the Earth – every 4 years we have an extra day – a leap year. The Earth rotates once in 24 hours. The side of the Earth facing the Sun experiences daylight; facing away from the Sun it is night.
Seasons If the Earth’s axis was exactly at 90 o to the plane of the orbit round the Sun, day and night would last the same time all year round – 12 hours. However, the axis is tilted so we have seasons. If the axis is tilted towards the Sun, day lasts longer – it is Summer. If the axis is tilted away, day is shorter – it is winter. In spring and autumn, the axis is neither towards nor away from the Sun. This is when day and night are the same length; the spring (vernal) and autumn (autumnal) equinoxes.