H U M S S 1 1 - C

JUSTINE JOHN REGALADO

EARTH.

Earth, otherwise known as the world,

is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets.

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*EARTH FACTS The Earth formed 4570 million years ago (mya) but the first

animals with shells and bones appeared less than 600 mya. It is mainly with the help of their fossils that geologists have learned about the Earth’s history since then. We know very little about the 4000 million years before, known as Precambrian Time.

Hot material from the Earth’s interior often bursts on to the surface from volcanoes. 216

The Earth probably began when tiny pieces of space debris (called planetesimals) began to clump together, pulled together by each other’s gravity.

* F O U R ( 4 ) L AY E R S OF THE E A RT H

CrustMantleOuter CoreInner Core

• Earth's crust. The crust of the Earth is composed of a great variety of igneous, metamorphic, and sedimentary rocks. The crust is underlain by the mantle. The upper part of the mantle is composed mostly of peridotite, a rock denser than rocks common in the overlying crust.

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- C R U S T-

* FACTS ABOUT THE EARTH’S CRUST The crust is deepest in mountainous areas. It can be up to 70km

thick here.

The continental and oceanic crusts are bonded to the mantle, and this forms a layer called the lithosphere. This layer is cool and rock solid.

The continental crust is solid and the temperature overall is about 22⁰C.

• The mantle is the mostly-solid bulk of Earth's interior. The mantle lies between Earth's dense, super-heated core and its thin outer layer, the crust. The mantle is about 2,900 kilometers (1,802 miles) thick, and makes up a whopping 84% of Earth's total volume.

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- M A N T L E -

* FACTS ABOUT THE EARTH’S MANTLE The mantle of the earth is solid rock, but amazingly it can

be moulded, just like play dough. This certainly isn’t the type of play dough you’d want to play with; your fingers would burn as it’s so crazy, mad hot!

It is made of molten (melted) iron, minerals and other semi-solid rocks that can flow under pressure.

thought that when the rocks rise due to the very intense heat and then cool, this means that they sink back to the core and this movement causes the crust to break into sections, or plates.

• The outer core of the Earth is a fluid layer about 2,300 km (1,400 mi) thick and composed of mostly iron and nickel that lies above Earth's solid inner coreand below its mantle. Its outer boundary lies 2,890 km (1,800 mi) beneath Earth's surface.

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- O U T E R C O R E -

* FACTS ABOUT THE EARTH’S OUTER CORE

Did you know that the inner core and the outer core of the Earth are as big as Mars?

 The outer core moves around the inner core, Earth's magnetism is created.

 The Outer Core is about 4000-5000 degrees celsius. The Inner Core is so hot it causes all the metal in the Outer Core to melt into liquid magma.

• The Earth's inner core is the Earth's innermost part and according to seismological studies, it has been believed to be primarily a solid ball with a radius of about 1,220 kilometres (760 miles), which is about 70% of the Moon's radius. It is composed of an iron–nickel alloy and some light elements.

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- I N N E R C O R E -

* FACTS ABOUT THE EARTH’S INNER CORE Some scientists believe that the earth's inner core spins at a

faster speed than the rest of it - at a rate of 2/3rds of a second faster.

 The Inner Core is a solid ball composed of an element named NiFe.  Ni for Nickel and Fe for Ferrum also known as Iron.

The Inner Core is about 5000-6000 degrees celsius.  It melts all metal ores in the Outer Core causing it to turn into liquid magma.

EARTH’S ATMOSPHERIC LAYERS

T R O P O S P H E R E

o The troposphere starts at the Earth's surface and extends 8 to 14.5 kilometers high (5 to 9 miles). This part of the atmosphere is the most dense. Almost all weather is in this region.

S T R AT O S P H E R E

o The stratosphere starts just above the troposphere and extends to 50 kilometers (31 miles) high. The ozone layer, which absorbs and scatters the solar ultraviolet radiation, is in this layer.

M E S O S P H E R E

o The mesosphere starts just above the stratosphere and extends to 85 kilometers (53 miles) high. Meteors burn up in this layer

T H E R M O S P H E R E

o The thermosphere starts just above the mesosphere and extends to 600 kilometers (372 miles) high. Aurora and satellites occur in this layer.

E XO S P H E R E

o This is the upper limit of our atmosphere. It extends from the top of the thermosphere up to 10,000 km (6,200 mi).

God bless

Maam Tanawan ;)