Life cycle of a star 5.0 / 5 based on 2 ratings ? PhysicsStarsGCSEAQA Created by: asho glenoCreated on: 10-04-15 13:28 1. Stars initially form from clouds of... dust and gas 1 of 20 The force of gravity makes the gas and dust... spiral together to form a PROSTAR 2 of 20 2. Gravitational energy is converted into... heat energy, so the temperature rises 3 of 20 When the temperature gets high enough... hydrogen nuclei undergo nuclear fusion to form helium nuclei 4 of 20 This gives out huge amounts of... heat and light 5 of 20 A STAR is created and also, smaller masses of gas and dust may pull together to make... planets to orbit the star 6 of 20 3. The star enters a long stable period, where the heat creted by the nuclear fusion provides... an outward pressure to balance the force of gravity pulling everything inwards 7 of 20 The star maintains its energy output for millions of years due to the... massive amounts of hydrogen it consumes 8 of 20 In this stable period, it is called a... MAIN SEQUENCE STAR and it lasts several billions of years 9 of 20 4. Eventually the hydrogen... begins to run out 10 of 20 Heavier elements like iron are made by... nuclear fusion of hydrogen 11 of 20 The star then swells into a RED GIANT,if it is a smaller star, or a... RED SUPER GIANT, if it is bigger. 12 of 20 It becomes red because... the surface cools 13 of 20 5. For RG: A small to medium star like the sun then becomes... unstable and ejects its outer layer of dust and gas as a PLANETARY NEBULA 14 of 20 6. For RG: This leaves behind a hot solid core called a... WHITE DWARF, which cools down to a BLACK DWARF and eventually diasappears 15 of 20 7. For RSG: Big stars start to glow brightly again and undergo... more fusion and expand and contract several times 16 of 20 For RSG: This forms elements as heavy as iron in... various nuclear reactions 17 of 20 For RSG: Eventually they explode in a... SUPERNOVA, forming elements heavier than iron and ejecting them into te universe to form new plantes and stars 18 of 20 8. For RSG: The exploding supernova throws the outer layers into space, leaving a... very dense core called a NEUTRON STAR. 19 of 20 For RSG: If the star is big enough, it will form a... BLACK HOLE 20 of 20
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