OUR PRETTY PLANET

THE EARTH

THE SUN IS THE STAR AT THE CENTRE OF OUR SOLAR

SYSTEM

The nine planets orbit the sun.

Here is a useful mnemonic to help remember their order:My Very Easy Method Just Shows Us the Names of Planets.

ABOUT THE SUN

The Sun is 150 million kilometres away from us.

It has a massive diameter of 1,393,000 km.

Our Sun was probably formed from a large cloud of gas about 5,000 million years ago.

HOW OLD IS THE EARTH?

• 4.5 to 4.56 Billion years, based on current scientific estimates.

• Surface constantly changes, due to Plate Tectonics

A BILLION YEAR OLD EARTH

The Earth is about 7,926 miles (12,756 km) in diameter

The Earth is the fifth-largest planet in our Solar System (after Jupiter, Saturn, Uranus, and Neptune)

THE EARTH SHAPE

• The Earth is not round. It is now known

that the Earth is not a perfect sphere.

The Earth is actually oblate.- Flattened at the poles.- Has an equatorial bulge.

EARTH IS UNIQUE IN MANY RESPECTS

• Water on its surface.

• Oxygen.

• The only planet in the solar system having living organisms.

• Earth is the only terrestrial planet having a moderately strong magnetic field.

• Earth is the only terrestrial planet having a large satellite.

THE MOON ORBITS THE EARTH...

Sun

Earth

moon

...as the Earth orbits the Sun.

The Earth rotates on its axis at 1670 km/hr! As it rotates, the Earth is also orbiting the Sun at a speed of 1,08,000 km/hr!

But, don’t worry! Thanks to the Earth’s gravity and atmosphere, we won’t fall off.

It takes 24 hours.

It turns anti-clockwise.

Do you know...

It takes 365¼ days.

It turns anti-clockwise.

How long it takes the Earth to spin round once?

Which direction the Earth turns?

How long it takes the Earth to orbit the Sun once?

Which direction the Earth orbits the sun?

Did you know?

One day on Venus lasts 117 Earth days.

Jupiter whips around in just 9 hours and 57 minutes.

One day on Mars is about the same as one day on Earth.

TEMPERATURE ON EARTH

• The temperature on Earth ranges from between -127°F to 136°F (-88°C to 58°C).

• The coldest recorded temperature was on the continent of Antarctica (Vostok in July, 1983).

• The hottest recorded temperature was on the continent of Africa (Libya in September, 1922)

LAYERS OF THE EARTH’S INTERIOR

• Crust

• Mantle

• Core

WHAT IS THE CRUST?

• Thin layer of rock at the earth’s surface

• Two types of crust layers

• Both the continental and oceanic crust float on the Mantle

• 5-50 km deep

WHAT IS THE MANTLE?

• Surrounds the core

• Soft layer of molten (melted) rock called magma.

• Once magma reaches the surface, it is called lava.

• About 1,790 miles (2,900 km) deep

WHAT IS THE EARTH’S CORE?

• Types core

• Together, they generate the Earth’s magnetic field.

• Outer Core: about 1,400 miles ( 2300 km) deep

• Inner Core: about 750 miles (1300 km) deep

EARTH'S MAGNETIC

• The Earth's magnetic field is created by the rotation of its molten core

THE CONTINENTS

2.5 billion years ago, the continents had been formed

The density of the continental crust is lighter that the crust found on ocean bottoms, so the continents rise above the ocean floor

WHAT ARE PLATES?

• Continent-sized slabs that make up the crust and the mantle

• Plates are constantly moving, very slowly

PLATES MOVE

• Away from each other

• Toward each other

• Past each other

WHEN PLATES MOVE

• Mountains or Volcanoes are formed

WHEN PLATES MOVE

• Earthquakes occur

Earth’s Four Spheres

ATMOSPHERE(MIXTURE OF GASES, SOLIDS, AND LIQUIDS)

• Early atmosphere was much different than today

• Volcanoes produced nitrogen and carbon dioxide, but little oxygen

• More than 2 billion years ago, early organisms began producing oxygen

• Eventually, oxygen formed an ozone layer that protected Earth from harmful rays

• Green plants and diverse life forms developed

ATMOSPHERIC GASES(MIXTURE OF GASES, SOLIDS, AND LIQUIDS)

• Nitrogen - 78%

• Oxygen - 21%

• Water Vapor – 0 to 4%

• Used for clouds and precipitation

• Carbon Dioxide - .037%

• Keeps Earth warm and is used by plants to make food

• Argon - .93%

• Traces of neon, helium, methane, krypton, xenon, hydrogen, and ozone

ATMOSPHERIC GASES(MIXTURE OF GASES, SOLIDS, AND LIQUIDS)

• Atmosphere is changing with the introduction of pollutants; increasing human energy use is increasing the amount of carbon dioxide

• Pollutants mix with oxygen and other chemicals to form smog

LOWER LAYERS OF ATMOSPHERE

• Troposphere: lowest layer – extends up to 10km; contains 99% of the water vapor and 75% of the atmospheric gases

• The troposphere is the first layer above the surface and contains most clouds and half of the Earth's atmosphere.

• Weather occurs in this layer.

• Most of the layer’s heat is from Earth

LOWER LAYERS OF ATMOSPHERE• Stratosphere – directly above troposphere,

extending from 10 km to about 50 km above Earth’s surface

• Portion of the upper layer contains high levels of a gas called ozone

• Many jet aircrafts fly in the stratosphere because it is very stable. Also, the ozone layer absorbs harmful rays from the Sun.

THE OZONE LAYER• About 19 km to 48 km above Earth in the stratosphere

(90%) and mesosphere (10%).

• Layer that protects the Earth from the Sun’s harmful ultraviolet radiation

• Ozone layers has a large hole over Antarctica and a smaller one over the North Pole

UPPER LAYERS OF ATMOSPHERE

• Mesosphere – extends from the top of the stratosphere to about 85 km above Earth

• Coldest layer with little ozone

• Rock fragments burn up in the mesosphere.

UPPER LAYERS OF ATMOSPHERE

• Thermosphere – thickest atmospheric layer found between 85 km and 500 km above Earth’s surface

• The thermosphere is a layer with auroras, known for its high temperatures.

• Warms as it filters out X-rays and gamma rays from the Sun

UPPER LAYERS OF ATMOSPHERE

• Exosphere - The atmosphere merges into space in the extremely thin exosphere. This is the upper limit of our atmosphere.

• Outer layer where space shuttle orbits.

EARTH COLLAPSE?

• Earth is going to be collapse?

• When ?

• How?

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