Test 1 Flashcards
what is geology? (4)
Geology is the study of Earth’s physical structure, history, substance and processes that have acted on it
what is comparative geology?
It is the study of how we compare different planets of the solar system and observe their similarities and differences that they have towards Earth.
Definition of a planet
A celestial body that
-orbits the Sun
-Has enough mass to maintain hydrostatic equilibrium
-must be able to clear it’s neighborhood
name the planets of our solar system in order
-Mercury
-Venus
-Earth + Moon
-Mars
-Astroid Belt
-Jupiter
-Saturn
-Uranus
-Neptune
what is a dwarf planet?
It is a body that doesn’t satisfy the rule that a planet needs to clear it’s neighborhood. Like Pluto, Pluto doesn’t have enough sufficient mass to clear it’s neighborhood.
Name 5 dwarf planets
-Pluto
-Eris
-Ceres
-Haumea
-Makemake
Definition of a moon
A natural satellite that orbits around a celestial body or a body that is not a star
Where are we in the universe?
The Milky Way Galaxy
What happened after the Big Bang?
The Dark Ages began. There was no light because there was no stars.
How did our S.S form?
The Nebular Hypothesis
What is the 4 main processes of the Nebular Hypothesis?
-A cloud of matter (nebula) began to contract at the center giving us our protosun
-at high temps, nebula flattens into disk by nuclear fusion (H fuses with He, light and energy)
-Dust and ice accumulate around it and clump together forming planetesimals. Protoplanetary disk is formed by cloud differentiation and accretion
-Planetesimals grew into planets. They cleared their orbit by gravitationally attracting or ejecting other planetesimals.
What is cloud differentiation?
-The heavier elements such as dense rocky elements would condense closer to the Sun
-The gaseous elements would condense in the outer part of the planetary disk.
What is accretion in terms of the nebular hypothesis? (Think of how the solar system is organized)
It’s when larger planetesimals would pull and attract smaller ones
Evidence for the Nebular Hypothesis?
The chemistry of the Sun and it’s elements
What are the main processes of the planetary evolution?
After Accreted, planets and moons evolved to…
-Melting and differentiation of elements
-volcanism
-planetary mass
-distance from the Sun
-Presence of biosphere
What is the formation of Terrestrial Planets? (3)
-Accretion: Planets bang into each other or other bodies and heat up
-Differentiation: The internal structure splits into categories. The metallic towards the core and the low-density magma towards the crust
-Stratification: Zones of different elements–> creating minerals—> creating rocks
Basic Internal structure of Earth?
-Crust (litho & asthenosphere)
-Mantle (solid)
-outer core (liquid)
-inner core (solid because of pressure)
Hubble space telescope’s goal
to measure the distance of our galaxy
OSIRIS-REx mission
To collect samples of asteroid Bennu and bring back to Earth (sample return mission)
Key observations of densities of planets: (4)
-They inform about composition
-Reflect rocks and metals
-Terrestrial = silicate planets
-Density increases as you move from crust –> inner core
What are the terrestrial planets made up of?
-Minerals, rocks, metals, volatiles
Which are denser? Volatiles, sillicates, metals?
1-metal
2-sillicate
3-volatile
What is the importance of
Si + O?
They make up the crust (rocks)
Why is there less iron in the crust?
Because due to differentiation, denser elements (like Fe) migrate towards the inner core
what is planetary differentiation?
the split of the planets structure
- the heavier elements will migrate towards the core and the loghter will migrate towards the crust through accretion
what are the planetary heat sources?
1-Accretion (planets bang into each other)
2-Differentiation and crystalization of metal core
3-Radioactive decay (isotopes supply heat)
how do planets cool down?
volcanoes
what does the cooling rate depend on for planets?
the size, smaller planets cool down faster
4 main processes affecting planetary surfaces?
-Impact cratering
-volcanism
-Tectonics
-Weathering erosion
What does impact cratering cause?
circular shock waves
What does impact cratering mean?
comets, asteroids, meteorites hit planets
Key features of Mercury
-closest to sun
-smallest
-heavily-cratered
-no tectonic plates
-no moons
-no liquid water
-no winds
-no atmosphere
Internal structure of Mercury?
-crust
-solid mantle
-central core
what is the main mission of Mercury?
-MESSENGER
They found water ice in shadowed-craters
What’s Mercury’s orbit and rotation type?
-excentric orbit and 1 rotation takes 59 days
