Proto - Planet or Nebular

Hypothesis• The origin of the universe and ultimately

our solar system!

-Big Bang Theory : 13-14 Billion Years Ago-

Huge Explosion Sends Materials Out into Space

*5-7 Billion Years Ago; Nebula- Dust

& Gas Cloud floated in space

-Accretion-(to grow by accumulation) due to the

pull of gravity nebula begins to come together

-Movement From Accretion Causes Swirling Motion In Cloud

-Swirling Materials Begin to Compress

& A Star Is Born @ Center

-Accretion forms Whirlpools (an eddy), continues

and later forms Planetesimals (baby planet)

-Planetesimals turn into

Protoplanets (teenager)

-Accretion continues and Planets

(adults) form

Our Solar System

-Remaining unaccreted materials

form comets, meteoroids,

& asteroids

-Entire process

goes from

disorganized gas

and dust material

to something

clear and

recognizable

• Crust- the outer solid layer. Under the

continents this layer is up to 45 mi. thick, while

under the oceans it may be as thin as 3 mi.

The average specific gravity here is between

2.7 and 3. The continents are mostly made of

the rock granite and the ocean floor is made of

the rock basalt.

• Mantle- the second layer, about 1800 mi. thick.

The top portion is solid, while the bottom is

more fluid, like ‘play-dough’. This layer’s

specific gravity is about 5 and it is made of iron,

magnesium, and silicon.

• Lithosphere- This is a further division made

up of the crust and upper mantle. From the

top of the tallest mountain to about 400 mi.

into the earth’s interior. This separation is due

to the fact that these two areas are made of

solid rocky material that seem to float on the

liquid lower mantle.

• Outer Core- Enormous pressure makes

this layer a liquid. It has a specific gravity

of 8 to 9, is made of iron and nickel, and is

1400 mi. thick.

• Inner Core- Extreme pressure makes

this layer a solid. It has a specific gravity

of 10 to 12, is 745 mi. thick and is made of

iron and nickel.

Earth Structure and Shape• Planet Earth is made of 4 different layers. Each

is separated from the other due to different

properties, like the material’s density, (amount

of material contained in a certain volume) or its

specific gravity.

• Oblate spheroid- The shape of earth is not a

perfect sphere. It is slightly flattened at the

poles and slightly bulging at the equator. Proof

exists in the fact that any object weighs

ALMOST the same anywhere on earth.

• Weight a measure of the amount of force of

gravity pulling an object toward the center of

earth. Weight will change if its distance from

the center of earth changes. Can be seen

using the unit of weight called a Newton. An

object that is 195 Newtons at the poles it will

be194 Newtons at the equator because it is

closer to the center of the earth at the poles and

farther at the equator.

194 N

195 N

7,900 mi

7,927 mi

24,860 mi

24,900 mi

DIAMETER - CIRCUMFERENCE -