Chapter 2: Journey to the center of the Earth
2.1 Introduction
Voyager 1 passed out of our Solar System.
2.2 Welcome to the neighborhood
A Journey through the Solar System
The exoprobe travels through interstellar space: the region between stars, it’s a vacuum (an absence
of mater, less than 1 atom per liter.. Atoms either parts of nublae or cosmic rays: high-energy
atomic nuclei ejected into space at extreme velocity by supernova explosions.
AU (Astronomical unit): distance from sun to earth 150 million kilometers.
Pull of gravity by sun felt at 50 000 AU form sun. contnues move toward sun -> detects specks, fakes
and balls of “ice”. Either lefovers of nublea that formed Solar System or fragments scatered into
space soon afer Solar System formaton. Together these objects make up the Oort Cloud, whose
inner edge lies 3,500 AU from the sun.
At 200 AU crosses bubble-like heliosphere (inner edge interstellar space. (‘edge’ of the Solar
System.. Inside contains predominantly solar wind partcles, electrons and protons ejected into space
from our sun.
30-55 AU = Kuiper Belt: a diffuse ring of icy objects lef over from the protoplanetary disk. Comets
originate from the Kuiper Belt, and to a lesser extent from the Oort Cloud. The orbit of Neptune
defnes the inner edge of the Kuiper Belt. Afer that you are traversing interplanetary space. Much
denser than interstellar space (between 5000 and 100 000 atoms per liter..
Ecliptc: the plane containing the orbits of all the planets
Asteroid belt: a diffuse band about 2.5 AU across that contains about 10 million small solid objects.
Earth’s magnetic feld
Magnetic feld: is the region measurably affected by the force emanatng from a magnet. Grows
when you come closer, can atract or repel another magnet and cause charged partcles to move.
Earth’s feld is a dipole, it has 2 ends (north and south pole.. Present the orientaton by an arrow that
points from south to north. Depict the magnetc feld of a magnet by a set of invisible magnetic feld
lines that curve through the space around the magnet. Arrowheads along these lines point in a
directon to complete a loop.
We can represent the feld by a bar magnet. North pole of this bar lies near the south geographic
pole. Geographic poles: the place where the spin axis of the Earth intersects the planet’s surface.
The magnetc pole closer to the north geographical pole is called north magneti ooee North seeking
end of the compass points toward the noth geographic pole. Magnetc poles move at an observable
rate. Magnetc feld surves as a shield against solar-wind partcles. This partcles can be dangerous for
life forms. Magnetosphere: region inside this magnetc shield.
3000 – 10 500 km from the Earth -> van Aooen Radiaton eots region in which magnetc feld starts to
strengthen, trap cosmic rays and solar wind partcles. Serves as second line of defends. Don’t trap
everything, some make it past it and follow the magnetc feld lines to the polar regions of Earth.
Interactng with gas atoms, they can cause gases to glow creatng spectacular aurorae. Aurora
boreaois -> north ooee Aurora austraois -> south- ooee
, A plunge through the atmosphere
Atmosphere: the gaseous cloak that envelops the planet. Contains a mixture of gasses, which we
refer to as air. 78% Nitrogen (N2., 21% Oxygen (O2., minor amounts or other gasses ( argon, CO 2,
neon, methane, ozone, CO, Sulfur dioxide. Also contains water gas, clouds.
Density of the atmosphere increases closer to the earth, for the weight of overlying air squeezes on
the air below, pushing gas molecules in the air closer togheter. At the surface 1,2 g/L. 12% that of
water. Air pressure: the amount of push that the air exerts on material surrounding it, also increases.
Because of the weight of the overlying atmosphere. 1,04 kg/cm2 = 1 atm = 1.01 bars (pressure above
ocean..
Air pressure decreases with height. People can live long under low pressure. Top of the atmosphere
is 600 km. devision in the atmosphere: troposphere: winds and clouds only in the lowest layer.
Stratosphere, mesosphere, thermosphere. The boundaries between layers are defned as elevatons
where temperature stops decreasing and starts increasing. Boundaries are named for the underlying
layer. Tropopause, stratopause, mesopause.
2.3 Basic characteristics of the Earth
The Earth system
Atmosphere -> the gaseous envelope
Hydrosphere -> surface and near-surface liquid water
Cryosphere -> surface and near-surface ice and snow
Biosphere -> the great variety of living organisms
Solid Earth
Combinaton and complex interactons among them are referred to as the Earth System. Earth lies in
the habitable zone: the distance from the sun in which temperatures are in the range that liquid
water exists. Venus is too hot, mars is too cold -> respectve abilites of their atmospheres to trap
heat.
Land and sea
30 % is dry land (contnents and islands.. 70% surface water. Most of it is salty and makes up oceans.
Some is fresh and flls lakes and rivers. Also detects groundwater: the water that flls cracks and
holes beneath the land surface. Ice covers signifcant areas of land and sea. Living organisms
populate the land, sea, air and even the upper few kilometers of the subsurface.
Surface has topography: variatons in the elevaton of the surface land, and distnguishes plains,
mountains and valleys. Bathymetry: variatons in elevatons of the ocean foor. Most of the sea foor
comprises broad abyssal plains: where the fat seafoor lies at a depth of 4 to 5 km below sea level.
Rises to shallower depths along mid-ocean ridges: elongate submarine mountains that rise as much
as 2,5 km above the abyssal plains. They descends to greater depths: deep-ocean trenches: elongate
troughs in which the sea foor reaches 10,9 km below. Very small changes.
Hypsometric curve: plotting surface elevaton on the vertcal axis and the percentage of the Earth’s
surface on the horizontal axis, shows that a relatvely small porton of the Earth’s surface occurs at
very high elevatons or great depths. Land just within a kilometer of the sea level, great change in sea
level would have huge consequences.
What is the solid earth made of?
Analyzing the Earth materials that make up the solid planet. 91,2 % consists of iron oxygen, silicon
and magnesium. They bond together to form materials. Several categories
2.1 Introduction
Voyager 1 passed out of our Solar System.
2.2 Welcome to the neighborhood
A Journey through the Solar System
The exoprobe travels through interstellar space: the region between stars, it’s a vacuum (an absence
of mater, less than 1 atom per liter.. Atoms either parts of nublae or cosmic rays: high-energy
atomic nuclei ejected into space at extreme velocity by supernova explosions.
AU (Astronomical unit): distance from sun to earth 150 million kilometers.
Pull of gravity by sun felt at 50 000 AU form sun. contnues move toward sun -> detects specks, fakes
and balls of “ice”. Either lefovers of nublea that formed Solar System or fragments scatered into
space soon afer Solar System formaton. Together these objects make up the Oort Cloud, whose
inner edge lies 3,500 AU from the sun.
At 200 AU crosses bubble-like heliosphere (inner edge interstellar space. (‘edge’ of the Solar
System.. Inside contains predominantly solar wind partcles, electrons and protons ejected into space
from our sun.
30-55 AU = Kuiper Belt: a diffuse ring of icy objects lef over from the protoplanetary disk. Comets
originate from the Kuiper Belt, and to a lesser extent from the Oort Cloud. The orbit of Neptune
defnes the inner edge of the Kuiper Belt. Afer that you are traversing interplanetary space. Much
denser than interstellar space (between 5000 and 100 000 atoms per liter..
Ecliptc: the plane containing the orbits of all the planets
Asteroid belt: a diffuse band about 2.5 AU across that contains about 10 million small solid objects.
Earth’s magnetic feld
Magnetic feld: is the region measurably affected by the force emanatng from a magnet. Grows
when you come closer, can atract or repel another magnet and cause charged partcles to move.
Earth’s feld is a dipole, it has 2 ends (north and south pole.. Present the orientaton by an arrow that
points from south to north. Depict the magnetc feld of a magnet by a set of invisible magnetic feld
lines that curve through the space around the magnet. Arrowheads along these lines point in a
directon to complete a loop.
We can represent the feld by a bar magnet. North pole of this bar lies near the south geographic
pole. Geographic poles: the place where the spin axis of the Earth intersects the planet’s surface.
The magnetc pole closer to the north geographical pole is called north magneti ooee North seeking
end of the compass points toward the noth geographic pole. Magnetc poles move at an observable
rate. Magnetc feld surves as a shield against solar-wind partcles. This partcles can be dangerous for
life forms. Magnetosphere: region inside this magnetc shield.
3000 – 10 500 km from the Earth -> van Aooen Radiaton eots region in which magnetc feld starts to
strengthen, trap cosmic rays and solar wind partcles. Serves as second line of defends. Don’t trap
everything, some make it past it and follow the magnetc feld lines to the polar regions of Earth.
Interactng with gas atoms, they can cause gases to glow creatng spectacular aurorae. Aurora
boreaois -> north ooee Aurora austraois -> south- ooee
, A plunge through the atmosphere
Atmosphere: the gaseous cloak that envelops the planet. Contains a mixture of gasses, which we
refer to as air. 78% Nitrogen (N2., 21% Oxygen (O2., minor amounts or other gasses ( argon, CO 2,
neon, methane, ozone, CO, Sulfur dioxide. Also contains water gas, clouds.
Density of the atmosphere increases closer to the earth, for the weight of overlying air squeezes on
the air below, pushing gas molecules in the air closer togheter. At the surface 1,2 g/L. 12% that of
water. Air pressure: the amount of push that the air exerts on material surrounding it, also increases.
Because of the weight of the overlying atmosphere. 1,04 kg/cm2 = 1 atm = 1.01 bars (pressure above
ocean..
Air pressure decreases with height. People can live long under low pressure. Top of the atmosphere
is 600 km. devision in the atmosphere: troposphere: winds and clouds only in the lowest layer.
Stratosphere, mesosphere, thermosphere. The boundaries between layers are defned as elevatons
where temperature stops decreasing and starts increasing. Boundaries are named for the underlying
layer. Tropopause, stratopause, mesopause.
2.3 Basic characteristics of the Earth
The Earth system
Atmosphere -> the gaseous envelope
Hydrosphere -> surface and near-surface liquid water
Cryosphere -> surface and near-surface ice and snow
Biosphere -> the great variety of living organisms
Solid Earth
Combinaton and complex interactons among them are referred to as the Earth System. Earth lies in
the habitable zone: the distance from the sun in which temperatures are in the range that liquid
water exists. Venus is too hot, mars is too cold -> respectve abilites of their atmospheres to trap
heat.
Land and sea
30 % is dry land (contnents and islands.. 70% surface water. Most of it is salty and makes up oceans.
Some is fresh and flls lakes and rivers. Also detects groundwater: the water that flls cracks and
holes beneath the land surface. Ice covers signifcant areas of land and sea. Living organisms
populate the land, sea, air and even the upper few kilometers of the subsurface.
Surface has topography: variatons in the elevaton of the surface land, and distnguishes plains,
mountains and valleys. Bathymetry: variatons in elevatons of the ocean foor. Most of the sea foor
comprises broad abyssal plains: where the fat seafoor lies at a depth of 4 to 5 km below sea level.
Rises to shallower depths along mid-ocean ridges: elongate submarine mountains that rise as much
as 2,5 km above the abyssal plains. They descends to greater depths: deep-ocean trenches: elongate
troughs in which the sea foor reaches 10,9 km below. Very small changes.
Hypsometric curve: plotting surface elevaton on the vertcal axis and the percentage of the Earth’s
surface on the horizontal axis, shows that a relatvely small porton of the Earth’s surface occurs at
very high elevatons or great depths. Land just within a kilometer of the sea level, great change in sea
level would have huge consequences.
What is the solid earth made of?
Analyzing the Earth materials that make up the solid planet. 91,2 % consists of iron oxygen, silicon
and magnesium. They bond together to form materials. Several categories
