centre of the earth Flashcards
4 things Earth is characterized by
- A layered interior
- An internally generated magnetic field
- Solid and liquid surfaces
- A gaseous envelope
solar system characteristics
= Magnetic field
= Atmosphere
= Surface features
what is Interstellar space
a vacuum with a virtual absence of matter
hoe does matter density change the closer you get to the sun
The closer to the Sun, the more matter is present
what does the sun do with matter
ejects it outward into space - consists of protons and electrons
explain the Earth’s Dipolar Magnetic Field and what it does
- has A north pole and a south pole end
- Magnetic Field Lines
- Extend into space
- Weaken with distance from Earth
- Create the magnetosphere
what does the magnetosphere do
- ## deflects the solar wind, preventing most charged particles from reaching Earth
what are Van Allen belts
form due to the magnetic field strengthening near the earth
- trap and arrest harmful solar and cosmic radiation, providing partial protection for life on Earth
what happens if Some ions escape Van Allen belts
- pulled to the magnetic poles
- create light in the upper atmosphere
- Aurora borealis – Northern lights
- Aurora australis – Southern lights
how does atmospheric density change with height
Densest at sea-level, the atmosphere thins upward
what gas is the atmosphere primarily made of
nitrogen
- Oxygen was absent from the atmosphere before ~2.5 Ga
- All other gases make up >1% of atmosphere
what 4 elements is 90% of the earth comprised from
= Iron (Fe) ~35%
= Oxygen (O) ~30%
= Silicon (Si) ~15%
= Magnesium (Mg) ~13%
where do organic compounds residue from
- once-living creatures
- wood, peat, lignite, coal, and oil
- Geologically rare (decomposes in contact with oxygen)
what are Volatiles and where to they come from
Materials that turn into gas at the surface
- H2O, CO2, and SO2…
- released from volcanic eruption
what are minerals
Inorganic crystalline solids
- Comprise rocks and, hence, most of the Earth
what are glasses
Non-crystalline solids
what are rocks and its 3 types
Aggregates of minerals
- Igneous – Cooled from a melt
- Sedimentary – Debris from pre-existing rock or minerals precipitated out of a water solution
- Metamorphic – Rock altered by pressure and heat
3 layers of the earth
= The Crust (Continental + Oceanic)
= The Mantle (Upper + Lower)
= The Core (outer and inner)
4 Clues that we have a layered earth
Density
Shape
Earthquake clues
Changes with depth
how is density a clue that we have a layered earth
- Average density greater than surface density
- Density must increase with depth
how is shape a clue that we have a layered earth
- A rotating sphere requires centered mass (i.e., Mass away from center would result in a flattened disk) –> The Core
- Solid interior - Surface doesn’t undulate from tidal forces
how are earthquakes a clue that we have a layered earth
- Earthquake energy transmitted as seismic waves
- Seismic waves have been used to probe the interior
- Velocity changes give depth of layer changes
how are changes with depth a clue that we have a layered earth
temp and pressure change with depth
earths crust characteristics
- The outermost “skin” of Earth with variable thickness
= Thickest under mountain ranges
= Thinnest under mid-ocean ridges - continental + oceanic crusts
- 98.5% of the crust is comprised of 8 elements - oxygen is the most abundant
= silicate (SiO4-based) minerals
