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Download SNC 1D The Sun
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The Sun FORMATION OF THE SOLAR SYSTEM Solar Nebula Theory - states that stars and planets form together from contacting, spinning disks of gas and dust. Nebula - a cloud of gas and dust How did our solar system form? a) a supernova (big explosion where the entire outer part of a star is blown off) sends waves in space that triggered a nebula to start spinning b) as the nebula spins, it begins to collapse as gravity pulls the gas and dust together http://www.youtube.com/watch?v=tFLOsRSuW0E&feature=related c) the cloud spins faster and flattens the dust and gas into a disc d) the gas and dust collect in the centre forming a hot condensed lump of matter (protostar) which eventually becomes a star e) small amounts of matter in the disc collect and form bigger, rocky lumps called planetismals. f) those planetismals that survive collisions turn into planets OUR STAR – THE SUN - as the nebula contracts, the gases that collect in the centre compress increasing the temperature of the protostar - when temperatures reach 10 000 000oC we get: NUCLEAR FUSION! Nuclear Fusion -the process that produces energy in the Sun. -Hydrogen nuclei combine to form helium nuclei. -Takes a lot of pressure and temperature -Nuclear reaction http://www.youtube.com/watch?v=fSr3V498A3I&feature=related PARTS OF THE SUN CORE - gravity pulls all the mass inwards creating intense pressure forcing hydrogen atoms to come together (nuclear fusion) to make helium atoms - Energy is transferred from core to outer parts by RADIATION. - The outer layers transfer energy by CONVECTION CURRENTS. Structure of the Sun PHOTOSPHERE - called the surface of the Sun (not really a surface since the Sun is made up of gases) - 5500oC; thousands of km deep CHROMOSPHERE - the inner atmosphere Structure of the Sun CORONA - the hot outer part of the Sun (1 000 000 oC) A GROWING SUN - Helium is denser than hydrogen and settles in the Sun’s core - Helium core grows larger as well as the fusion area around it - Sun is getting larger; 30% larger than when it was born 5 billion years ago - Sun has enough hydrogen fuel (for fusion) for 10 billion years Our Sun has 5 billion more years left SUNSPOTS AND SOLAR FLARES - Sun spots are areas of strong magnetic fields (dark spots we see on the Sun; 4500oC) - - start off small, then get larger, form clusters and eventually fade and disappear. They occur in 22-year cycles and seem to move on the Sun’s surface, which we believe is actually the Sun rotating. When a magnetic field is so intense that the solar flare can eject intense streams of charged particles into space called solar wind. SOLAR WIND – How does it affect Earth? 1) Disrupt telecommunications and damage equipment aboard spacecrafts 2) Harmful to astronauts (like x-rays on humans) 3) Aurora Borealis (Northern Lights) - The Aurora Borealis are caused by the solar wind interacting with Earth’s magnetic field - the gases in Earth’s upper atmosphere become charged and produce light (strongest are the Earth’s poles) http://www.youtube.com/watch?v=xUYibQFIIVk&feature=PlayList&p=60FA28 55CF33865F&index=45 IMPORTANCE OF THE SUN 1. Provides radiant energy for all life on Earth 2. Keeps Earth in a steady orbit because of its gravitational pull. 3. Creates winds and ocean currents 4. Microwaves, radio waves, X-rays, gamma rays http://www.youtube.com/watch?v=gdLaPhNBOcU&feature=related
