Unit 8 The Earth in Space

Axis

A real or imaginary line that a spinning object turns around.

Rotation

The act of spinning around an axis. Earth spins once on its axis every 24 hours.

Revolution

One complete trip around an object in a circular or nearly circular path. Earth takes 365 days (1 year) to revolve around the sun.

Orbit

The path an object takes as it travels around another object.

Phases

A temporary state of being, often used to describe a change in the appearance of the Moon.

Solar system

The Sun and all the objects that orbit around it.

Planets

A large sphere in space that orbits a star.

Gravity

A force of attraction, or pull, between objects.

Seasons

The seasons on Earth are caused by the tilt of the earth combined with it's rotation around the sun.

Moon

A natural satellite that orbits a planet

Sun

The star at the center of our solar system that supplies heat and light to Earth

Earth

The planet that all known life exists on

Day length is caused by

how long it takes earth to rotate once on its axis

Year length is caused by

how long it takes the earth to revolve once around the sun

Winter is colder because

the earth's axis is tilted on an angle that means the sun's warmth and rays are more spread out when our hemisphere is tilted away from the sun.

Summer is hotter because

the earth's axis is tilted on an angle that means the sun's warmth and rays are more focused or more direct when our hemisphere is tilted towards the sun.

Solstice

two times in the year, marked by the longest and shortest days

Tides

Rising and falling of the sea, usually twice in each day at a particular place, due to the attraction of the moon and sun.

Solar Eclypse

When the moon moves between the Sun and the Earth blocking out the light

Lunar Eclypse

When the Earth moves between the Sun and the moon preventing light from being reflected

Planets in our solar system

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

Pluto

A dwarf planet in our solar system

Atmosphere

The layer of gases surrounding the earth, held in place by the force of gravity

Climate change

the changes in climate due to the greenhouse effect

The green house effect

the warming of the planet by the action of green house gases

Greenhouse gas

A gas that traps heat energy in the atmosphere e.g. carbon dioxide