* Planets orbit around the sun. * In other solar systems in the universe, planets also orbit around a sun. * Our sun is a star. It seems enormous as it is close to us. * Other stars are as big, but seem small because they are very far away.
The sun is the star at the centre of our solar system. It is almost perfectly spherical. It consist mostly of plasma interwoven with magnetic fields
This solar flare illustrates the filamentous nature of the sun’s plasma
* Mostly gaseous * Set position * Shines with flickering glow (has own light) * Solid rock, or mixtures of gas and rocks * Orbit - „wanderers” of galaxies * Shines with steady glow (reflects light from sun)
* Mercury as seen from the space craft Mariner. * Closest planet to the sun. * It is the smallest planet. * Mercury’s surface looks a lot like the moon – plains and craters. * The core consist of iron. * There is no atmosphere. * Surface temperatures are extremely low (-450 0 C!)
* Venus second planet from sun. * Almost same size as earth. * Dense atmosphere of carbon dioxide and sulphuric acid clouds. * Greenhouse effect enormous – temperatures up to 482 ◦ C. * Little water on planet, occurs as water vapour. * Air pressure 90 times stronger than on earth. * Takes 243 earth days to rotate around own axis. * Takes 225 earth days to orbit around sun.
* Earth as seen from Apollo 17. * Nucleus of the earth consists of metals such as nickel and iron. Nucleus has temperature of up to 7000 ◦ C. * Shape of earth not totally spheric – earth is a geoid.
* WHY IS LIFE ON EARTH POSSIBLE? * 1. We are at the correct distance from the sun – not too close to be too hot, and not too far away to be too cold. * 2.This means that water can be available in a liquid form.
Mars is the fourth planet from the sun. It is known as the red planet because of the reddish colour it as. The red is the result of masses of iron oxide in the soil of Mars. https://www.youtube.com/wa tch?feature=player_detailpage &v=IWPO-VViwx4
The atmosphere on Mars is almost 100% carbon dioxide. Mars has water, but all in a frozen form.