Earth's Composition Flashcards
Density equation
mass / volume
Density of water
1 g/cm^3
Average density of earth
5.52 g/cm^3
Earth’s Atmosphere
Extends 100km above surface, 77% nitrogen, 21% oxygen, 2% argon, water, carbon dioxide
Oblate Spheroid
Earth bulges around equator, slightly squashed sphere, makes gravity weaker at the equator
Crust
Outermost layer of earth, DENSITY 3 g/cm^3, 100km thick, continental crust is thick and less dense, and oceanic crust is thin but more dense,
Mantle
Majority of earth, hot moving rock in upper mantle (taffy like), moves continents, crust to 2900 km, density 3 g/cm^3 at top and 9 g/cm^3 at bottom
Core
Mantle to center of earth, outer core is molten, inner core is solid, creates earth’s magnetic field, density 9 g/cm^3 at top and 13 g/cm^3 at center
Order of Earth’s interior
crust - mantle- liquid core - solid core (will need to be able to draw)
Seismic Waves
earthquakes, helps us understand the internal structure of earth
P waves
Travel through liquid and solids, straight line
S Waves
Can only travel through solids, shows us the upper mantle is molted, bounces, important for understanding interior
Plate Tectonics
Multiple plates make up earth, move over the mantle to form crevasses, faults, or mountains and volcanoes, driven by CONVECTION CURRENT
Pangea
Ancient super continent, we know because continents fit together like a puzzle, fossils match on far away continents, rocks of same ancient types
Earthquake Epicenters
Earthquakes are when stress builds up between plates, this energy is concentrated at the epicenter
Divergent Boundaries
Plates move away from each other, small earthquakes
Convergent Boundaries
Plates move towards each other, large earthquakes with volcanic activity
Transform Boundaries
Plates slide past each other, shallow but destructive earthquakes, San Andreas Fault
Ring of Fire
High are of tectonic activity, 75% of all earthquakes occur here, where tectonic plates meet, all coastline surrounding pacific ocean
Earth’s Magnetic Field
generated by movement of molten metal in the outer core (swirls since inner core is warmer), geodynamo (cycle between changing electric and magnetic fields), poles move over time and reverse every 100,000 years
Magnetosphere of Earth
Magnetic field protects us from solar winds, charged particles circle back to poles, when they hit the atmosphere at the poles aurora occurs
Solar Wind
Harmful, destroys our atmosphere
Color of Aurora
Depends on what type of molecules are struck by the charged particles and atmospheric level,
green = oxygen 60 miles up
red = oxygen 300 km up
purple and pink = neutral nitrogen
blue = ionized nitrogen at 100km
(colors is from particles dropping in energy)
Aurora Ring
Where aurora occurs, circle around poles
Earth’s Atmosphere Levels
Troposphere - Stratosphere - Mesosphere - Thermosphere
Troposphere
0-12km, contains 75% of the gases in the atmosphere, where we live and where pretty much all weather occurs, thicker at equator and thinner at poles, temp decreases with altitude
Tropopause
Layer between troposphere and stratosphere, jet stream is here
Stratosphere
12-50km, contains ozone layer 15-35km (absorbs and scatters suns harmful UV rays), temp increases with altitude due to absorption of UV radiation
Mesosphere
50-80km, temp decreases with alt., coldest layer, where meteors burn up due to dense friction
Mesopause
Coldest part of earth’s atmosphere
Thermosphere
80-100km, Air is very thin and hot, can reach temps of 2000 degrees C from UV radiation, ISS and auroras are found here
Ionosphere
Contains charged particles that reflect radio waves, enabling long-distance communication
Age of Earth
4.55 billion years, we know from radiometric dating (measuring decay of radioactive material, half-life)
Carbon Dioxide levels in the atmosphere due to fossil fuel usage
Shot WAY up
What carbon dioxide does to earth
raises earth’s temp, traps heat
Representative Concentration Pathway (RCP)
Predictor of how CO2 levels will affect earth depending on their levels
Effects of Climate Change
higher storm surges, rising sea levels, thermal expansion (water molecules spreading out as they get warmer), stronger storms, heatwaves, melting glaciers, acidic ocean, food insecurity, climate refugees, loss of biodiversity
