Presentation on theme: "8.2 Exploring the Sun Homework: page 340 # 2, 3, 5, 7, 9"— Presentation transcript:
18.2 Exploring the Sun Homework: page 340 # 2, 3, 5, 7, 9
2Key Concepts:The solar nebula theory says that the Sun and the solar system formed from a spinning, contracting disk of gas and dust particles.Evidence supporting the solar nebula theory consists of heavily cratered objects, most planets rotating about in the same direction, most planets revolving in the same direction and in about the same plane and the existence of other planets around the Sun.
3Key Concepts:The Sun’s energy source is hydrogen. It converts matter into energy through nuclear fusion.Sunspots can produce solar flares, which send gigantic beams of charged particles into space.Charged particles from the Sun that enter Earth’s atmosphere produce auroras, but the charged particles can also damage electronic equipment, cause large scale power blackouts and pose a danger to astronauts.Energy absorbed and emitted by Earth’s surface heats Earth and keeps it warm.
4FORMATION OF THE SOLAR SYSTEM Solar Nebula Theory- states that stars and planets formtogether from contacting, spinning disksof gas and dust.Nebula- a cloud of gas and dust
5How did our solar system form? A supernova (big explosion where the entire outerpart of a star is blown off) sends waves in spacethat triggered a nebula to start spinningb) As the nebula spins, it begins to collapse as gravitypulls the gas and dust togetherc) The cloud spins faster and flattens the dust and gasinto a discd) The gas and dust collect in the center forming a hotcondensed lump of matter (protostar) whicheventually becomes a stare) Small amounts of matter in the disc collect and formbigger, rocky lumps called planetismals.f) Those planetismals that survive collisions turn intoplanets
6NUCLEAR FUSION! OUR STAR – THE SUN As the nebula contracts, the gases that collect in the centercompress increasing the temperature of the protostarWhen temperatures reach oC we get:NUCLEARFUSION!
7Nuclear Fusion the process that produces energy in the Sun. Hydrogen nuclei combine to form helium nuclei.Takes a lot of pressure and temperatureNuclear reaction
8PARTS OF THE SUNCORE- gravity pulls all the mass inwards creating intensepressure 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.
9Structure of the Sun PHOTOSPHERE - called the surface of the Sun (not really asurface since the Sun is made up of gases)oC; thousands of km deepCHROMOSPHERE- the inner atmosphere
10Structure of the Sun CORONA - the hot outer part of the Sun ( oC)
11A 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 born5 billion years agoSun has enough hydrogen fuel (for fusion) for 10 billion yearsOur Sun has 5 billion more years left
12SUNSPOTS AND SOLAR FLARES - Sun spots are areas of strong magnetic fields (dark spots wesee on the Sun; 4500oC)start off small, then get larger, form clusters and eventuallyfade 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 calledsolar wind.
13SOLAR WIND – How does it affect Earth? Disrupt telecommunicationsand damage equipmentaboard spacecraftsHarmful to astronauts(like x-rays on humans)
143) Aurora Borealis (Northern Lights) - The Aurora Borealis are caused by the solar wind interactingwith Earth’s magnetic field- the gases in Earth’s upper atmosphere become chargedand produce light (strongest are the Earth’s poles)
16IMPORTANCE OF THE SUN Provides radiant energy for all life on Earth Keeps Earth in a steadyorbit because of itsgravitational pull.3. Creates winds and ocean currents4. Microwaves, radio waves, X-rays, gamma rays