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The Solar System. Our Solar Centre – the Sun. On the Sun, there are solar tornados which are tall funnel of twisting plasma with a temperature of several million degrees Celsius.
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Our Solar Centre – the Sun • On the Sun, there are solar tornados which are tall funnel of twisting plasma with a temperature of several million degrees Celsius. • Earth is the only planet in the solar system whose orbit is just the right distance away that a habitable environment for life is created.
The Nature of the Sun • Medium Size • It is composed mainly of hydrogen (73% by mass) and helium (25%) • 2% - carbon, oxygen, and iron. • Has shined for 5 billon years and is expected to continue shining for about another 5 billion years. • Emits radiations of almost all forms found in the electromagnetic spectrum. • Most obvious ones are visible light and ultraviolet (UV) radiation
The Nature of the Sun • How should we measure the mass of the Sun? • By observing the speed of the solar system’s planets and other celestial objects orbit around it. • Nuclear reactions are taking place in the Sun • converting hydrogen into helium and release tremendous amounts of energy • the nuclear reaction is as powerful as the atomic weapon, the hydrogen bomb.
THE Sun’s Layer • The Sun has 6 main layers (from the most inner layer): core, radiactive zone, convective zone, photoshpere, chromosphere, and corona.
Layer 1 - Core • High pressure and temperature (at least 15 million degrees Celcius) • Nuclear fusion takes place. • Nuclear fusion - a process in which light atoms fuse (combine) and become heavier ones. During fusion, a small amount of matter is turned into a huge amount of pure energy. • Fusion reaction creates helium. • Swelling outward :the large amount of energy is produced during fusion and cause the surface of the Sun to swell outward • Collapse inward : the Sun’s gravity pull the Sun’s mass inward.
Layer 2 • Radiative Zone: • Plasma is very dense • Thickest layer (3/4 of the way up to the surface of the Sun.) • Light and other forms of radiation are continuously absorbed and re-emitted in all directions. • Light takes 100, 000 years to pass through the layer and reach our eye -> the radiation we receive today was generated in the Sun’s core more than 100, 000 year ago.
Layer 3 – convective zone • Huge bubbles of hot plasma ooze up towards the surface and carrying energy. • Convection – constant circulation of plasma between hotter and cooler region.
Layer 4 - photosphere • The boundary between the inside and the outside of the Sun. • This is the part of the Sun we see from Earth. • Has the lowest temperature (around 5, 500 ˚ C) • The Sun’s yellow colour originates in this layer.
Layer 5 - chromosphere • Chromos mean coloured. • Has red cast – only can be seen during a total solar eclipse.
Layer 6 - corona • Outermost layer of the Sun • Extends beyond the chromosphere for millions of kilometres. • Most visible during a solar eclipse.
Surface features of the Sun • The Sun’s magnetic field is generated by movement of the plasma deep in the Sun’s interior. • The 4 main features on the surface of the sun are sunspots, prominences, flares, and coronal mass ejections.
Feature 1 – Sun Spot • A region on the Sun’s surface that is cooler than the surrounding areas. • Darker than the surrounding areas. • Magnetic field is extremely strong that the convection is slowing down. • The spot never stays at the same place. • The number of them reaches a maximum every 11 years, increasing when the magnetic field strength of the Sun also reaches a maximum level.
Feature 2 - Prominence • A large, often curved, bright stream of particles extending outward from the photosphere into the corona. • Often forms a complete loop. • There are electrically charged plasma in the prominence • Can be shaped by the magnetic field. • Many last for many hours.
Feature 3 – Solar Flares • A massive explosion at the surface of the Sun. • It usually originates where the magnetic field breaks out of the Sun’s surface and interacts with the chromosphere and corona. • The sudden release of magnetic energy flings hot plasma out into space.
Feature 4 – coronal mass ejection • Extremely powerful kind of flare • Thrown out through the corona and into space at a speed of more than 1000 km/s. • If it reaches Earth, the Earth’s magnetic field divert the plasma away from the planet’s surface and this causes aurora. • It can damage orbiting satellites and electrical transmission lines on the ground.
The Sun’s Effects on Earth • Warms Earth • Support every form of life on the planet. • Solar wind • Aurora borealis/
Solar Wind • The heat at the surface of the Sun produces a thin but steady stream of subatomic particles; the constant flow of particles is called Solar wind. • Blow away some gas and dust-> the ones that stayed formed solar system.
Aurora Borealis • Green, yellow, and red light in the skies near Earth’s Northern (aurora borealis) and Southern regions (aurora australis). • Occurs when the charged particles of the solar wind collide with the atoms and molecules in Earth’s atmosphere. • Trapped by Earth’s magnetic field and are swept toward the North and South Poles.