Formation of the Earth + magnetic fields Flashcards
When was the formation of the Universe?
about 14 billion years ago. big bang then giant stars then galaxies
characteristics of the solar system
- part of milky way galaxy
- sun is medium-seized star
- 8 plants (rip pluto)
- sun is 99.8% of solar system’s mass
what is a planet? what is a moon?
planet: nearly spherical in shape, cleared their neighbourhood of other objects (by gravity)
moon: a body gravitationally locked in orbit around a planet
what are the two main groups of planets?
terrestrial: small, dense, rocky (MMEV)
giant: large, low density, gas giant (JS) ice giant (UN)
describe the formation of the solar system
concentration of gas and dusts released by stars and supernova.
region of concentrated mass began to pull in gas.
region gained mass and density.
mass compacted and began to rotate.
rotation rate increased developing a disk shape.
central ball of disk became hot enough to glow.
sun, a protostar, was born 4.6 Ga.
planets formed within rotating nebula by condensation of minerals and dust
where do the elements come from?
big bang formed the lightest elements (H, He, Li, Be, and B)
heavier elements formed by fusion w/in subsequent stars
heaviest elements (above #26) form during fast neutron capture processes in supernovae
describe the formation of the earth
Planetesimals grow bigger and bigger to form protoplanet
Gravity becomes more important as planet grows bigger and forms into more spherical shape
Lighter elements at center and iron (denser) at core with stony outer shell (the mantle)
describe the formation of the moon
4.53 Ga, mars-sized protoplanet collides with earth. planet and part of earth’s mantle are disintegrated, collision debris forms ring around earth and debris coalesces to form the moon.
how did earth’s atmosphere form?
developed from volcanic gases. After about half a billion years, Earth’s surface cooled and solidified enough for water to collect on it.
how did oceans form?
moisture condenses and accumulates and form oceans (from condensation of atmosphere)
what is the earth system?
interactions between atmosphere, hydrosphere, biosphere, and lithosphere. sunlight powers all of them except for lithosphere
what generates the earth’s magnetic field
fluid circulation in the liquid outer layer of the core
explain the relationship between geographic poles and magnetic poles
N pole of field in Earth’s geographic S pole but shifted by 11 degrees (DECLINATION). N compass arrow points to geomagnetic S pole (so the geographic N which is what we would want)
name characteristics of magnetic field
extend into space, weaken with distance, form a shield around earth (magnetosphere), protection from cosmic radiation and solar wind
solar wind distorts magnetosphere (teardrop shape)
what are the van allen belts and what do they do?
they are stronger magnetic fields that most protect us from dangerous cosmic radiation.
how are northern/southern lights made
some charged particles from solar radiation make it past van allen belts and are channeled along magnetic field lines. cause atmospheric gases in polar regions to glow
describe the atmosphere
thins and dries away from surface
pressure at seal-level: 101.3 kpa
78% N2, 21% O2, a bit less than 1% of argon from radioactive decay of potassium
what happens in the atmosphere with increasing elevation
pressure decreases
density decreases
oxygen content decreases
what are the four elements that makes up 91% of earth’s mass?
iron (32.1)
oxygen (30.1)
silicon (15.1)
magnesium (13.9)
what is the combination of iron, oxygen, silicon, and magnesium called and what is its chemical composition?
olivine: (Mg,Fe)2SiO4
a silicate mineral. varied amounts of magnesium based on surroundings
CHECK SLIDES FROM EARTH MATERIALS TO THE WAY THE EARTH WORKS IF NEED BE
Who hypothesized plate tectonics and what was his evidence?
suggested a former supercontinent and that land masses slowly move. based off fit of the continents, glacial evidence, paleoclimatic evidence, and fossil evidence
describe glacial, paleoclimatic, and fossil evidences
glacial: late paleozoic glaciers found on five continents
paleoclimatic: rocks defining Pangea climate belts
fossil: Ancient fossils of the same species of extinct plants and animals are found in rocks of the same age but are on continents that are now widely separated
what is inclination?
angle between magnetic field line and surface of the earth. depends on geo-magnetic latitude
