Imaads Flashcards
What is a planet?
Cold object that orbita around a central luminous start
What is a Planetary body?
General term for any body orbiting a star includes planets and their natural satellites/moons
Terrestrial (Inner) planets
Relatively small, rocky (“Earth-like”) bodies closest to the sun
↳ moon is studied as a terrestrial planet
General planet info
- Mercury
↳ larger than earths moon & closes to sun - Venus
↳ 2nd closest planet & shrouded by clouds
↳ lots of craters and mountain belts - Earth
↳ lots of plate tectonics, erosion, has life along with atmosphere - Moon
↳ orbits earth - Mars
↳ very thin atmosphere
↳ erosion by water, lots of volcanoes & valleys
Asteroid
small rocky or metal-rich planetary body orbiting the sun
Asteroid belt
- region between the orbits of Mars and Jupiter where most asteroids are found
- asteroids range from 1 - 1000km in diamerter
Gas Giants (outer Planets)
Large planets that have a deep atmosphere and no solid surfaces
↳ icy/rocky
Comets
small, ice rich bodies which formed at the outer edges of the solar system
Neptune & Uranus
- Both are gas and ice rich
- Have icy moons
The three main tock types
Igneous, Sedimentary, and Metamorphic
Law of Superposition?
Each layer of sediment is older than the layer above it and younger than the layer below it
Law of Cross-cutting Relationships?
If a fault or other body of rock cuts through another body of rock then it must be younger in age than the rock through which it cuts
Law of Inclusions?
One rock included in another is older than the rock that includes it
Law of original horizontality
Sedimentary layers are deposited horizontally
Crust
The outermost layer, on top of the mantle
Mantle
It has upper and lower sections and includes the asthenosphere, iron, and magnesium-rich silicate minerals
Asthenosphere
The top part of the upper mantle where it is plastic, and partly molten
Lithosphere
includes the rigid part of the mantle and the overlying crust, rides on the plastic asthenosphere
The three ways we know what the interior of the Earth looks like
Density, Seismic data, Meteorites
Main geologic processes active on Earth today
Tectonics, volcanic activity, mass wasting, water, wind, ice -> erosion and deposition of sediment, impact crater, life
Fusion
The combination of two or more nuclei to form a different, heavier, element; the by-product is radiation
What Keeps a Star together?
- Gravity attempts to make the star collapse
- High gas pressure opposes gravity
Supernova
The cataclysmic explosion of a star, as a result of internal nuclear reactions
Nebula
Dust in space with a density of 1,000 gas molecules/10cm^3
Gravitational Collapse
When molecules are concentrated, attracted to each other; may be triggered by a nearby supernova
T Tauri stars
stars that are similar in mass to the
Sun, but only about 1 million years old
Proplyds
disks of dust and gas around young
stars; contraction of “protoplanetary disks”
Meteorites
extraterrestrial rock that’s fallen through our atmosphere
Refractory
materials that form solids at
very high temperatures
Volatile
materials that condense/solidify
at very low temperatures
Planetesimal
Small solid bodies, ~100km across, that formed from grain-to-grain accretion of dust
Accretion
Solids come together to form larger objects through gravitational attraction and collisions
Differentiation
The separation of materials in a planetary body according to density and chemical affinity
Conduction
The vibrational energy of an atom is transferred to adjacent atoms
Convection
Warm material expands and moves upwards, displacing cooler, denser materials downwards
Radiation
The emission of electromagnetic waves from a hot body’s surface to its surroundings
Law of Cross-cutting Relationships for impact cratering
If an impact crater, fault, or body of rock cuts through another body of rock then it must be younger than the rock through which it cuts
Three things that must be explained by any model for how the solar system was formed
- The planets orbit in the same plane
- They orbit the Sun in the same direction
- The Solar System is zoned from rocky inner planets to gas-rich outer planets to ice-rich comets
Why the Moon always shows the same side to the Earth
The period of rotation and period of revolution are exactly the same
Two surfaces on the Moon that can be easily seen from Earth
- Maria (smooth surfaces)
- Terrae (cratered highland)
Crater sizes on the moon
- 20 to 200km diam
↳ have central peaks - crater > 300km diam
↳ called multi ring basins & spacing of rings increases outward
What is KREEP
KREEP is a component found in soils, breccias and impact melts
Fire fountaining
Volcanic activity on the Moon, it creates Lunar Glass Beads
Anorthosite
Most abundant and
oldest rock type
Breccia
A rock made up of
angular fragments of
other rocks
↳ more basalts
Regolith
- Mixture of rock fragments
- Formed during micrometeorite impacts;
Explain why mare basalts can flow such great distances on the Moon
They contain more iron and less silicate and aluminum, which causes lunar basalts to have a lower viscosity
List the main observations that any model for the formation of the Moon must explain
- size of the moon relative to earth
- The low bulk density/size of its iron core and its composition
- Moon has little water and is depleted in other elements
- it’s orbit
Giant Impact Hypothesis
- The giant impact hypothesis proposes that the Moon formed from debris ejected during a collision between the early Earth and a Mars-sized protoplanet around 4.5 billion years ago.
The major discoveries made by the Lunar Reconnaissance Orbiter mission
evidence of water on the Moon, Moon caves, map of the lunar south poles, more topography, temperature map
Describe how the crystallization of a magma ocean explains the anorthosite composition of the Moon’s crust
- pyroxene and olivine in the magma sink and the anorthosite (lighter mineral) floats
Explain how the lunar cratering record is used to date the surfaces of other planets
- the number of craters on a part of a planetary surface can be used to estimate its age; the more craters, the older the age
Explain how it is possible that water ice could be present on Mercury’s surface
There are some deep craters at the poles of Mercury that are permanently shadowed which protect/preserve any volatiles present in the craters
Describe Mercury in terms of its orbit, length of the day, and length of the year
Orbit: ~1/3 of the distance from the Sun to Earth
Length of the Day: 59 earth days
Length of the Year: 88 Earth Days
Describe the surface of Venus as seen from landersDescribe the surface of Venus as seen from landers
It has a very rough, rocky surface and due to the atmosphere, everything has a yellow tintIt has a very rough, rocky surface and due to the atmosphere, everything has a yellow tint
Mercury’s unique tectonic features
Compressional stresses are dominant. Mercury has contracted 7 km in radius
What are Lowlands, Uplands and Highlands
- Lowland: below 0km of elevation
- Uplands: around 0-2km of elevation (isolated domes)
- Highlands: areas that are > 2km (mountain regions)
Tectonic features of Venus:
What do fracture belts, domes and rifts represent on Venus
Extension
Tectonic features of Venus:
What do mountain and ridge belts represent on Venus
Compression
What are Coronae?
- Volcano-tectonic features that unique to Venus
- Corona: system of concentric fractures and ridges surrounding a central plain
(STAGES ARE NOT IMPORTANT WE WERE TESTED ALR)
Atmosphere of Venus
Effects:
- High surface temps (greenhouse effect)
- Wind erosion and deposition
How does the greenhouse effect affect venus?
- It is too hot for liquid water to condense, water stays as a gas, CO2 stays as a gas
- TLDR for “runaway greenhouse effect”: it’s super hot because of all the CO2 and you need to cool the atmosphere a bunch to stabilize all the carbonate
Geologic History of Mars: Pre-Noachian
- Pre-Noachian
↳ Magma formation
↳ large basin formation from impacts
Geologic History of Mars: Noachian
- Noachian
↳ Early volcanism
↳ Tectonism begins
Geologic History of Mars: Herperian
- Herperian
↳ Valles Mariuneris forms
↳ Elysium volcanoes form
Geologic History of Mars: Amazonian
- Amazonian
↳ Ongoing volcanism
↳ Polar Icy deposits
↳ mass movement
Mars Hydrological Cycle
The current hydrologic cycle on Mars involves the periodic release of ground ice into the atmosphere as vapour, which travels to and freezes at the poles, with pole ice sublimating in summer and travelling to the colder pole, and surface frost precipitating and sublimating due to daily temperature changes.
Ground Ice in Mars
- Right now liquid water is NOT stable at the surface of present day mars
- Water ice is present
Mass movement in Mars
- Mass movement: gravity-driven downhill
movement of unconsolidated material
Slope Streak characterization
Slope Streak: start in a point upslope, widen downslope
- Wet (liquid water)
↳ melting of frost/ice
↳ groundwater spring
- Dry
↳ Dust avalanching
Where do Humans appear on the tree of life?
Eukaryota, under Animals
Earliest forms of life
- Stromatolites: formed by filamentous bacteria mats that trap sediment as bacteria grows
What is a Gas Giants
Relatively large planets that have deep atmospheres and have NO solid surfaces; have rings of particles around them, and many icy/rocky satellites
What is Jupiter’s atmosphere made of
- 90% H2 and 10% He
- little amounts of water,methane and ammonia
- Clouds in jupiter are made of ammonia ice
Difference between Earth and Jupiter
- Earth is composed of dense silicates while Jupiter is made up mostly of hydrogen and helium
- Jupiters magnetic field is 20,000 times that of earth
- Jupiter has a quicker period of rotation (9.9 hours)
- Jupiter is also much colder than earth
Jupiter internal structure
- Atmosphere and Molecular Hydrogen Layer - beneath the atmosphere, there is a molecular hydrogen layer that extends to about 20,000 km.
- Metallic Hydrogen Layer
- Core - Jupiter has a volatile-rich core estimated to be 10-15 times the mass of Earth
Differences between Jupiter and Saturn
- Jupiters magnetic field is significantly stronger than Saturn (20,000 vs 0.4)
- They are composed of the same things in the atmosphere
- Jupiter is slightly warmer than Saturn
Saturns Atmosphere
- 96% H2, 3% He, small amounts of Methane & Ammonia Clouds
Saturns internal structure
- eddies and cyclones cause by heat released from the planets interior
1. Atmosphere consists of H2 and He
2. Molecular Hydrogen Layer: 30,000km thick composed of H2
3. Metallic Hydrogen Layer: contains metallic H+
4. Core: volatiles and silicates
Uranus compared to Jupiter
- Uranus has a more complex composition than jupiter
- Significantly weaker magnetic field than jupiter
- Almost double the period of rotation of jupiter (uranus 17.2hr)
Uranus – Atmosphere & internal structure
Composition:
– 83% H2, 15% He, 2% CH4
- Internal Structure:
- rich in ice and silicates
- Core of volatiles and silicate rock
Uranus compared to Neptune
- Both have a complex bulk composition
- Same things make up the atmosphere
- similar magnetic fields & temps
Neptune – Atmosphere & Internal Structure
Composition:
– 80% H2
– 18% He
– 1.5% CH4
- Internal Struc: Higher density
- Core of ice and silicate rock
How each planet gets their heat
- Jupiter, Saturn have a greater internal heat than what they get from the sun
- Uranus receives less heat from the Sun and its heat is not solar; it has more rocky components.
- Neptune, despite being further from the Sun, generates more heat than it receives from the Sun. This heat is not solar and Neptune has the most rocky components among these planets.
Origins of gas Giants: Core Accretion Model
- This model involves the accretion of rock-ice planetesimals to form a core that is 10 to 20 Earth masses, which takes about 1 million years (Ma).
- The next step is the accretion of a massive gaseous envelope, which takes between 1 to 10 Ma.
- The problem with this model is that the nebula was all gone by 10 Ma after the start of the solar system.
Origins of gas Giants: Disk Instability Model: (MORE LIKELY ONE)
- This model involves the clumping of gas and dust in the disk.
- There is a sudden gravitational collapse to form the planet, which takes only a few hundred or thousand years (within the first 1 Ma).
- This model solves the problem of the nebula disappearing too quickly and is considered the most likely model for the formation of gas giants like Jupiter and Saturn
What are the four moons of Jupiter?
– Io
– Europa
– Ganymede
– Callisto
Io Volcanic features
- Io is the most volcanically active body in the solar system
- Volcanic pit craters, calderas, shield volcanoes and so on
- there are umbrella shaped eruption Plumes
Tidal heating in Io
- Caused by gravitational interaction btw Jupiter and Io
- Volcanic Activities: The heat generated from this frictional movement drives strong volcanic activities on Io’s surface
Europa compared to Io
- Io is closer to Jupiter, larger and denser
↳ Composed of silicates and sulfur - Europa is smaller, less dense and composed of silicates and water ice
- Io has a slightly higher temp (118k vs 103k)
Europa features
- surface is characterized by fractured water ice with few craters
Europa compared to ganymede
- Ganymede is further from Jupiter & larger
- Composition is the same but it has a higher temperature
Ganymede Features
- The surface of Ganymede is characterized by a
dark, cratered terrain and a light, grooved terrain
↳ Dark cratered terrain is darkened by silicate
↳ Light grooved terrain is shallow but long
Ganymede compared to Callisto
- Callisto is a lot further away from jupiter
- It is smaller with a similar denisty and same composition
- Temp is very similar
Callisto Features
- The surface of Callisto is dominated by impact structures
- Impacts onto an icy surface
What causes the differences in the Galilean Satellites
- The differences come with distance from jupiter
↳ Increase in surface ages
↳ Decreases in density
