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Transcript
Earth’s Spheres
Atmosphere: the envelope of
gases that surrounds the
Earth.
Earth’s Spheres
 Hydrosphere:
water part of the
Earth, including surface and
subsurface water.
Hydrosphere
 Refers
to the watery part of the
Earth.
 Most
of the Earth’s water is in
oceans but also in lakes, streams
rivers, groundwater and glaciers.
Hydrosphere
97%
is salt water
The remaining 3% is fresh
water, 2/3 of the total
freshwater is frozen in the ice
caps of the North and South
Poles.
Hydrosphere
The
hydrosphere also includes
water found in the atmosphere
and the amount tied up in the
cycle.
Earth’s Spheres
 Biosphere-Includes
things on Earth
all living
Earth’s Spheres
 Lithosphere:
outer solid shell of the Earth
that extends 70 km or more from the crust
and part of the Asthenoshere
Lithosphere
 Includes
the earth’s crust and the
upper mantle.
 It is 100 km thick
 The lithosphere is broken up into
plates. They can move around
independently of each other.
 The plates float around on the
asthenosphere, the liquid portion
of the mantle.
Earth’s Spheres
 Asthenosphere:
partially melted layer of
mantle below the lithosphere. This is
responsible for plate tectonic movement.
1. Crust: 10-65km thick
 A)
Thickest under the
continents.

B) Low density.

C) Lighter rock.

D) Solid.
2. Mantle: The upper mantle
contains magnesium, silicon, and
iron.
 A)
2900km ~ the
thickest layer.
 B) Made up of
heavier rocks.
 C) The upper
mantle contains
the Asthenoshere
which is soft and
flowing.
3. Outer Core: the base of the
mantle
 A)
Liquid iron
and nickel.
 B)
2175 km
4. Inner Core: solid iron and
nickel.
 A)
Spherical in
shape.
 B)
2575 km in
diameter.
Atmosphere
 The
gaseous layer, extending from the
surface of the earth to outer space.
 It is made up of a mixture of gases with
some suspended solids and liquids.
The most common gases are
 Nitrogen 78%
 Oxygen 21%
 1% water vapor and others
- The earth was NOT structured
like this 4 billion years ago.
- According to the Protoplanet
Hypothesis, the surface of the earth
looked like the moon does.
- The rock throughout the earth
was same all the way through.
- As the earth heated, iron and
nickel melted, flowed downward
toward the center. On the way it
melted lighter materials and forced
them upward to the surface.
- The lighter rock became solid
and formed the crust.
Layers of the Atmosphere
The
atmosphere filters
ultraviolet rays and protects
living things from the sun’s
harmful UV rays.
5 Layers of the Atmosphere
The
layers become less dense
(thick), the farther away from
the Earth’s surface you go.
Troposphere
Troposphere – surface to 10 km
(~6 miles) above.
 Contains most of the gases
 The air we breathe is here
 Most weather occurs here.
 1.
Stratosphere
Stratosphere – 10km-45km (6-28
miles) above
 The air is very thin here, but wind
still blows.
 Airplanes fly in the lowest parts
 Contains the ozone layer, which
protects us from the Sun’s UV rays.
 2.
Merge with Outer Space
3.
Mesosphere
4.
Thermosphere
5.
Exosphere
 “It’s
often said that you cannot get
something for nothing, but the
universe may be the ultimate free
lunch.” Alan Guth---physicist
How did the Earth Begin?
 meteroids,asteroids,comets
 No
scientist knows for certain how Earth
was formed or from what it came.
 There are a number of theories on the
origin of earth.
 All of these theories must consider the
following scientific facts:
How did the Earth Begin?
 A.
All planets revolve around the sun in
the same direction (counter clockwise)
 B. The paths or orbits of planets are all
nearly circular.
 C. Orbits of planets are in nearly the
same plane.
 D. The sun rotates on its axis in almost
the same plane as the planets
How did Earth Begin?
 E.
Most planets rotate in the same
direction as the sun.
 F. 6 planets have moons and most
revolve around the planet as the planet
does the sun.
 G. The sun’s rate of rotation is slower
than expected by scientists.
The Big 3
 1.


ENCOUNTER HYPOTHESIS
The Solar system began approximately 5
billion years ago with our sun already in
existence.
The sun is hanging out when a star or
perhaps a comet passes very close to the
sun.
ENCOUNTER HYPOTHESIS




A collision happens and HUGE amounts of
gas from the sun explode out of it but move in
the same direction around the sun.
After a million years, the gases shrink into ball
shaped bodies.
The larger ones become planets and the
smaller ones become moons.
The ones that never shrank became comets.
NEBULAR HYPOTHESIS




A HUGE cloud of gas rotates through space,
this cloud is called a nebular.
The nebula cools and shrinks, making it spin
faster.
The spinning increases causing it to throw off
a ring, then another until it has thrown off nine
rings.
Each thrown ring becomes a planet.
NEBULAR HYPOTHESIS


The cloud at the center shrinks A LOT more.
The shrinking causes compression which
causes heating and it becomes a fiery HOT
star.
The sun, planets and moons are all spinning
in the same direction as the original nebula
that they came from.
PROTOPLANET HYPOTHESIS




This is the theory most in favor right now.
The solar system began with a great cloud of
gas and dust.
The cloud shrinks under the pull of its own
gravitational force.
The material concentrates in the center where
compression causes it to get really hot and it
forms the sun.
PROTOPLANET HYPOTHESIS



Unlike the Nebular hypothesis, there are no
rings.
10% of the cloud’s matter forms a single disk
around the sun.
Both the disk and the sun rotate slowly.
PROTOPLANET HYPOTHESIS





Gravity within the disk causes material to
collect in several huge whirlpools called
eddies.
Write this on bottom of notes!
Eddies_beginning of sun
formationplanetesimalsprotoplanetssun
ignitesplanets and moons
There are some leftoverscomets, meteors
asteroids, planetoids(large asteroids)
Link
How does the Earth evolve over
time?
 There
are 3 theories on the evolution of
the universe:
 1. The Big Bang Theory




Proposed by Le Maitre and Gamnlow
In the beginning…
All matter in the universe was concentrated in
an EXTREMELY dense and hot fireball.
20 billion years ago: a HUGE explosion
occurred
The Big Bang Theory
 All
that matter was broken into pieces and
thrown with high speed in all directions.
 Eventually this formed stars and galaxies
and these bodies are STILL moving away
from each other.
 As the matter cooled from the explosion,
Hydrogen and Helium gas formed.
 1 billion years later, the first stars were
born.
2. Steady State Theory




Proposed by Bondi, Gold and Hoyle
The theory:
The number of galaxies in the universe is
constant and new galaxies are continuously
created out of empty space when galaxies
leave our universe.
The mass of the universe remains the same.
3. Pulsating Theory




The universe is supposed to be expanding
and contracting alternately…in other words
pulsating
Right now it’s expanding.
The expansion is stopped by the pull of
gravity and begins to contract again.
Once it reaches a certain size, an explosion
would occur and the universe starts to expand
again.