An Introduction

SPACE

• Everything that exists, including stars and planets, as well as all the matter and empty space surrounding them

THE UNIVERSE

CELESTIAL OBJECTS• LUMINOUS: some objects produce and emit

their own light

• Example: Stars

• NON-LUMINOUS: some objects do not produce or emit their own light but reflect light

• Example: The moon

• A collection of many billion of stars, plus gas and dust held together by gravity

A GALAXY

GALAXIES• There are four types of galaxies

• ELLIPTICAL: shaped like spheres or ovals

• SPIRAL: flat and circular with curving arms

• LENTICULAR: disc shaped with a bulge in the middle

• IRREGULAR

• There are billions and billions of galaxies in the universe

• We live in the Milky Way galaxy

• It gets its name because it looks like a hazy or milky path across the night sky

THE MILKY WAY

• A shape or pattern of stars in the night sky make by imagining that starts are joined together by make believe lines

CONSTELLATIONS

• Massive balls of superheated gases that radiates heat and light

• Example: The Sun

STARS

CHARACTERISTICS OF STARSSIZE: 20 kilometres to millions of kilometres wide

COLOUR: red, orange, yellow, blue, bluish-white or white

TEMPERATURE: reddish stars are cooler (3000oC) while bluish starts are hotter (55 000oC)

DENSITY: some are less dense than water, will others are very dense

• The system of planets, including Earth, moons and other objects that orbit the Sun

• The Sun in the centre of our solar system

SOLAR SYSTEM

THE SUN• DISTANCE: 150 000 000 km from Earth

• SIZE: 14 000 000 km in diameter

• COMPOSISTION: 73% hydrogen, 25% helium and other gases

• TEMPERATURE: 6000oC at the surface, 15 000 000oC at the core

• GRAVITATIONAL PULL: All other objects in our solar system are kept in orbit due to the Sun’s gravity

THE SUN

CHARACTERISTICS OF THE SUN• CORE: location of nuclear reactions that cause the

release of energy

• SUN SPOT: a dark area on the Sun’s surface that is cooler than the area around it

• SOLAR FLARE: gases and charged particles that are blasted above an active region of the Sun’s photosphere

• PHOTOSPHERE: the Sun’s surface

• Coloured lights in the sky produced when the solar winds comes into contact with the Earth’s magnetic field and atmosphere

• Can be seen at the North and South Poles

• Example: Northern Lights

AURORA

• It takes 27 days for the Moon to orbit the Earth

• It takes 27 days for the Moon to make one rotation

• This why the same side of the moon faces the Earth at all times

THE MOON

• DISTANCE: 384 000 km from Earth

• SIZE: 3475 km wide

• TEMPERATURE:

-170oC to 100oC

THE MOON

THE MOON• LUNAR CYCLE: the sequence of phases made by the

Moon during one orbit around the Earth

• PHASES OF THE MOON: the changing amount of illuminated Moon surface visible from the Earth

• WAXING: a period during the visible surface of the Moon increases

• WANING: a period during the visible surface of the Moon decreases