Formation of Solar System, Earth, Moon Flashcards
(24 cards)
Equilibrium Condensation Theory
a model that predicts the chemical composition of planets in a solar system by using the temperature and pressure conditions of the solar nebula
Why is the dust near a “newly formed” star hotter than further out?
Friction and solar wind
What phase change is seen as particles move apart in a pre-solar nebula?
gas to solid
What phase is not found in space?
liquid - pressures are too low for them to be stable
Refractory (definition)
materials that are stable in high temperatures
What materials are refractory?
metals, some oxides like alumina
What order do solids condense out as a solar system forms?
Most refractory to least refractory
metals -> oxides and silicates -> ices (including ammonia and methane)
What is Mercury made out of?
metals
What are Venus, Earth, Mars made out of? What are they called?
Metals, silicates, oxides
Rocky planets
What are the outer planets made out of? What are they called?
water, ammonia, methane
Gas and Ice planets
Density of Earth
5.5g/cm^3
Kuiper Belt theory
Gas giants migrated out of orbit, causing Kuiper Belt (ring in outer parts of the solar system) to move inwards enough to deliver volatiles after accretion
chondrites
stony meteorites from astroids formed from dust of early solar system that did not accrete
give us a clue to original composition of Earth
CAIs
Calcium-Aluminum Inclusions
whitish spots seen in chondrites
oldest, non-recylced, materials in our solar system
used to date solar system
How old is the solar system?
4.566 billion years
Three earlier hypotheses of moon formation
Wife: formed somewhere else and later captured by the Earth’s orbit
Sister: formed near Earth, but didn’t accrete with it
Daughter: material from Earth torn away due to a more rapid rotation earlier on
Current moon formation theory
Moon Forming Impact: giant impact (of about same size as Earth) causing material to separate and reform in Earth orbit
When did moon forming impact happen
after majority of earth was accreted, but not yet differentiated
estimated between 30my and 100my after CAI formation
original earth atmosphere (prior to differentiation): composition and origination
volatiles could come from heated up basic stony chondrites - H2, CO, H2O
very reducing environment
how did differentiation begin within earth
-carbonmonoxide (CO) and protons (H+) released from the reducing mantle and crust.
-H2 would be lost to space, because it is light
- heavier oxygen would increase through subduction, oxidizing mantle/crust
atmosphere of early earth (Archean)
more neutral (CO2), rather than reducing (H2, CO) like that of original atmosphere
When did Earth begin to form?
4.54 Billion years ago (Gya)
When did the moon form?
~4 Gya (billion)
What does Equilibrium Condensation Theory NOT tell us?
Why we have liquid water and volatiles on Earth
