Lecture 2: The Planet Earth Flashcards
Differentiate heliocentrism from geocentrism
Heliocentrism - Copernican Model
Geocentrism - Ptolemaic Model
Explain the Big Bang
“singularity” – explosion of space-time; extremely hot and dense state which expanded rapidly and then slowly (dark matter) while cooling
What were the pieces of evidence for the Big Bang?
- Hubble’s Law (red shift) – 1929; star moves away
- Cosmic Microwave Background Radiation – remnant/heat
- Abundance of H, He
What were the limitations of the big bang?
- Only explains the universe
- What was present before Big Bang?
- How will it end? Will it ever end?
Explain how the solar system forms
spins (contraction)
- conversion of Gravitational Energy to Thermal Energy
- cooling
- Temperature coalesce forming extraterrestrial bodies
Differentiate terrestrial planets and jovian planets in terms of:
*composition
Rocky composition
Gaseous liquid form composition
(denser materials go through the center of mass)
Differentiate terrestrial planets and jovian planets in terms of:
*elements
Si, Fe, O (Silicate rocks and metals) Light elements (H, He, Ar, C, O, Ni)
shape of earth
Oblate Spheroid
Describe Oblate Spheroid
*flattened at poles; bulging at the equator
Earth’s Axial Tilt
21.5 to 24.5 degrees
Obliquity
23.4 degrees
Orbital Speed
30 km/s
Nebula planetesimals protoplanets
accretion, differentiation
- accretion * differentiaion *
Nebula, planetesimals, protoplanets
*: the process of growth or increase, typically by the gradual accumulation of additional layers of material
Accretion
Accretion: the process of * or increase, typically by the gradual * of additional * of material
growth, accumulation, layers
*: random chunks of primordial matter were transformed into a body whose interior is divided into concentric layers that differ from one another both physically and chemically.
Differentiation
Differentiation: random * were transformed into a * whose interior is divided into * that * from one another both physically and chemically.
chunks of primordial matter, body, concentric layers, differ
In Stage 1 of the formation of earth:
Fe, O, Si, Mg
*no continents, oceans, atmospheres
*Temperature of the planet reached and surpassed the melting point of iron; denser elements sink to center and lighter elements float to top.
Iron Catastrophe
Chemically distinct layers
- Core:
- Mantle:
- Crust:
Fe, Ni
O, Si, Fe, Mg
O, Si
exposures on the surface of the Earth; large scale sequence of rocks
Ophiolites
foreign rock (rock from mantle)
Xenoliths
CO Age
4 Ga
160 Ma
CO Thickness
35-40 km, 7-10 km
CO Composition
Granitic (Si, O)
Basaltic (Mg, Fe)
CO Density
2.7 g/cc, 3.0 g/cc
- is the thickest layer
how thick?
Mantle
~2,900 km
Mantle is rich in the mineral
perovskite
uppermost mantle rock type:
peridotite
Core is ____ alloy
Fe-Ni
Crust * Mantle * Outer Core * Inner core
{Discontinuity}
Crust
Mantle
Outer Core
Layers of Earth according to Physical Properties:
Lithosphere,
Lithosphere is composed of:
It is ______
Crust + uppermost mantle
- solid but brittle
- ~100 km
contrary to lithosphere, asthenosphere is …
solid but plastic or mobile
*weak layer resulting from temperature/pressure conditions
asthenosphere
*solid, rocky layer
mesosphere
- 2,900 – 5,100 km in depth
* molten
outer core
- 5,100 – 6,370 km in depth
* solid
inner core
Differentiation of Earth’s Interior:
P-waves:
S-waves:
parehong solid and liquid
solid lang
