Formation of the Earth + magnetic fields

Question 1

When was the formation of the Universe?

Answer 1

about 14 billion years ago. big bang then giant stars then galaxies

Question 2

characteristics of the solar system

Answer 2

• part of milky way galaxy
• sun is medium-seized star
• 8 plants (rip pluto)
• sun is 99.8% of solar system’s mass

Question 3

what is a planet? what is a moon?

Answer 3

planet: nearly spherical in shape, cleared their neighbourhood of other objects (by gravity)
moon: a body gravitationally locked in orbit around a planet

Question 4

what are the two main groups of planets?

Answer 4

terrestrial: small, dense, rocky (MMEV)
giant: large, low density, gas giant (JS) ice giant (UN)

Question 5

describe the formation of the solar system

Answer 5

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

Question 6

where do the elements come from?

Answer 6

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

Question 7

describe the formation of the earth

Answer 7

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)

Question 8

describe the formation of the moon

Answer 8

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.

Question 9

how did earth’s atmosphere form?

Answer 9

developed from volcanic gases. After about half a billion years, Earth’s surface cooled and solidified enough for water to collect on it.

Question 10

how did oceans form?

Answer 10

moisture condenses and accumulates and form oceans (from condensation of atmosphere)

Question 11

what is the earth system?

Answer 11

interactions between atmosphere, hydrosphere, biosphere, and lithosphere. sunlight powers all of them except for lithosphere

Question 12

what generates the earth’s magnetic field

Answer 12

fluid circulation in the liquid outer layer of the core

Question 13

explain the relationship between geographic poles and magnetic poles

Answer 13

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)

Question 14

name characteristics of magnetic field

Answer 14

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)

Question 15

what are the van allen belts and what do they do?

Answer 15

they are stronger magnetic fields that most protect us from dangerous cosmic radiation.

Question 16

how are northern/southern lights made

Answer 16

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

Question 17

describe the atmosphere

Answer 17

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

Question 18

what happens in the atmosphere with increasing elevation

Answer 18

pressure decreases
density decreases
oxygen content decreases

Question 19

what are the four elements that makes up 91% of earth’s mass?

Answer 19

iron (32.1)
oxygen (30.1)
silicon (15.1)
magnesium (13.9)

Question 20

what is the combination of iron, oxygen, silicon, and magnesium called and what is its chemical composition?

Answer 20

olivine: (Mg,Fe)2SiO4
a silicate mineral. varied amounts of magnesium based on surroundings

Question 21

CHECK SLIDES FROM EARTH MATERIALS TO THE WAY THE EARTH WORKS IF NEED BE

Question 22

Who hypothesized plate tectonics and what was his evidence?

Answer 22

suggested a former supercontinent and that land masses slowly move. based off fit of the continents, glacial evidence, paleoclimatic evidence, and fossil evidence

Question 23

describe glacial, paleoclimatic, and fossil evidences

Answer 23

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

Question 24

what is inclination?

Answer 24

angle between magnetic field line and surface of the earth. depends on geo-magnetic latitude

Question 25

what is paleomagnetism?

Answer 25

magnetism in rocks that was induced by the earth’s magnetic field at the time of their formation. iron minerals in rock preserve information about the magnetic field at the time the rocks formed. We can find the age of the rock based on its dipole that was locked in during its formation

Question 26

describe hot magma in terms of paleomagnetism

Answer 26

no magnetization, high thermal energy, magnetic dipoles randomly oriented

Question 27

describe cooled magma in terms of paleomagnetism

Answer 27

permanent magnetization
slow thermal energy of atoms
dipoles align earth’s magnetic field at the time of cooling
dipoles become frozen in alignment with field

Question 28

what is polar wandering

Answer 28

movement of the Earth’s magnetic or rotational poles over time. location of magnetic pole is fixed, continents have moved.