9StarsAndGlaxies_F3

THE STRUCTURE OF THE SUN

4 layers from the inner core to the outer corona CORE:

Centre: gaseousSite where nuclear reaction occur Temperature: 150 000 000C

PHOTOSPHERE:The visible surface of the sunProduce the visible light that we seeOne of the coolest layers of the sun <6000CLarge magnetic disturbance causes sunspots

THE STRUCTURE OF THE SUN

CHROMOSPHERE:Red glowing region of the sun (part of solar atmosphere)Temperature about 15 000CActive with activities mainly due to various magnetic which cause sunspots, flares and prominence

CORONA:Outermost layerExtremely hot about 200000C

SUN/SOLAR FLARES: explosive event on solar surface (huge outburst of solar material from several thousands to million km long). It gives off UV light and X-rays that heats up the earth’s atmosphere.

SOLAR FLARES

SOLAR FLARES

PROMINENCE: masses of glowing gas above sun’s surface (visible during total eclipse- thosands to millions km wide and tall).

PROMINENCE

SUNSPOTS: cooler spots compared to surrounding region. Appear as darker patches. May last from a few hours to a few months.

SOLAR WIND: a flow of gases from the sun that disturbs and shakes the earth’s magnetic field.

GENERATION OF ENERGY BY THE SUN.

a.The sun generates its energy by nuclear reaction called nuclear fusion.b.Fusion at the centre of the sun.c.Hydrogen atoms bang on each other and fuse into atoms of Helium. (energy converts hydrogen into helium – small amount of mass is converted into a large amount of energy.

STARS AND GALAXIES

STAR

• self luminous gaseous body• eg the sun• come is different sizes• type of stars: supergiant, giant & white dwarf• vary in brightness and colour according to surface temperature

GALAXIES

• a system of stars• comes in various shapes: spiral, elliptical & irregular• solar system is located in milky way galaxy• milky way is a spiral galaxy (200 billion stars)

ELLIPTICAL GALAXY

SPIRAL GALAXY

IRREGULAR GALAXY

FORMATION OF A STAR.

• stars are formed from nebulae• nebulae are clouds of gas or dust.• a star is born when enormous clouds/gas collapse under the force of gravity. It is condensed and compressed by gravitational force which later causes a rise in temperature at its centre.• later nuclear fusion occurs in the core and glows and turn into a star.

DEATH OF STARS.

• occurs when it has used up its core of hydrogen fuels.• the core shrink and heat up, outer layer expands and cool – RED GIANT(RG).• medium sized starsRG white dwarf• giant starsRGRSGSN neutron star• very big starsRGRSGSN black hole

SUPERNOVA REMNANTS

A giant black hole rips a star apart. Credit: NASA

THE IMPORTANCE OF THE SUN AND MOON

THE SUN• SOURCE OF LIGHT AND HEAT.• IMPORTANT FOR PHOTOSYNTHESIS• SOLAR ENERGY IS USED AS ALTERNATIVE SOURE OF POWER.

THE MOON

• IMPORTANCE IN OCEAN TIDES• CREATE DEVELOPMENT IN INTELLIGENTS IN MATHS, SCIENCE AND ARTS• MOON PHASE – DEVELOP CALENDARS