ESS 101 COMPREHENSIVE EXAM STUDY
GUIDE COMPLETE QUESTIONS AND
SOLUTIONS
●● Evidence of nebular hypotheses
Answer: 1. Planets and moons revolve in a counter-clockwise direction
(not random)
2. almost all planets and moons rotate on their axis in a counter-
clockwise direction.
3. planetary orbits are aligned along the suns equatorial plane (not
randomly organized)
4. observations from Hubble telescope and radio astronomy indicate that
other planetary systems are forming from condensed nebular dust.
●● Terrestrial Planets
Answer: Close to the sun, dense, small/rocky, silicate minerals, metallic
cores
Twelve earths would fit across the diameter of Jupiter.
●● Jovian Planets
Answer: Far from the sun, low density, large, gaseous (hydrogen,
methane)
,●● Why does the earth and terrestrial planets have so little molecular
hydrogen comprising their respective atmosphere, yet the primordial
dust cloud was mostly comprised of hydrogen gas?
Answer: Hydrogen gas and helium gas escapes to space when put in our
atmosphere.
Jupiter, saturn, and neptune maintain molecular hydrogen gas in the
atmosphere because they have high density.
●● Differentiated Earth
Answer: 1. Iron Nickel Core (outer core liquid)
(inner core solid)
2. Fe-Mg silicate mantle
3. Fe-Mg-Al Silicate Crust (Ocean and Continental)
4. Oceans
5. atmosphere
●● How is the earth compositionally zoned?
Answer: Along a density gradient
●● How did the earth become compositionally zoned?
Answer: 1. Accretion of planetesimals
,2. initial heating due to kinetic energy of colliding planetesimals and
compressional heating.
3. additional heating from radioactive decay.
4. iron catastrophe: melting temp of iron reached and dense iron nickel
sink to core and lighter materials are displaced outwards (including
silicate rock of mantle and crust, ocean waters and atmospheric gases)
5. earth becomes compositionally zoned based on density (densest iron
nickel in core-least dense materials comprise the atmosphere) 500 mil
yrs after the initial accretion process.
6. convective overturn in asthenosphere, mantle and outer core still
occur today.
●● Why did the earth heat up and then rapidly cool during the
differentiation process?
Answer: When earth was solid-heat gain was greater than the heat lost to
space. This means that the internal temperature rises until it exceeded the
melting temp of oxygen and nitrogen until exceeded iron nickel
catastrophe. Earth is completely molten and then compositionally zoned.
When earth was liquid- convection-hot gas rises , after it became molten,
the earth rapidly cooled off and solidified.
●● Why does earth possess little evidence of its early accretion history?
Answer: Because of weathering, plate tectonics, moon has no
atmosphere and biosphere.
, ●● Emissions from degassing of the earth during its differentiation.
Answer: h2o, co2, h2, he, n2
●● Where did molecular H and He escape to?
Answer: space
●● When did oxygenation of the atmosphere occur?
Answer: later following evolution of marine algae and plants that use
photosynthesis to convert co2 to o2 as a part of their life processes.
●● What layers of the earth can be directly observed?
Answer: crust and uppermost mantle.
●● Evidence of initial composition of the solid earth based on meteorite
studies. There are two major classes of meteorites that dominate
collected samples. Carbon based meteorites are much rarer, but indicate
that the prescursor of life was present early on.
Answer: 1. Metallic meteorites (iron nickel density 9.0-10 gm/cm3)
2. chondritic meteorites: Fe-Mg silicate, rocky, density is 3.0-3.3)
3. carbonaceous chondrites (rare)
●● What is earths average density?
Answer: 5.5 g/cm3
GUIDE COMPLETE QUESTIONS AND
SOLUTIONS
●● Evidence of nebular hypotheses
Answer: 1. Planets and moons revolve in a counter-clockwise direction
(not random)
2. almost all planets and moons rotate on their axis in a counter-
clockwise direction.
3. planetary orbits are aligned along the suns equatorial plane (not
randomly organized)
4. observations from Hubble telescope and radio astronomy indicate that
other planetary systems are forming from condensed nebular dust.
●● Terrestrial Planets
Answer: Close to the sun, dense, small/rocky, silicate minerals, metallic
cores
Twelve earths would fit across the diameter of Jupiter.
●● Jovian Planets
Answer: Far from the sun, low density, large, gaseous (hydrogen,
methane)
,●● Why does the earth and terrestrial planets have so little molecular
hydrogen comprising their respective atmosphere, yet the primordial
dust cloud was mostly comprised of hydrogen gas?
Answer: Hydrogen gas and helium gas escapes to space when put in our
atmosphere.
Jupiter, saturn, and neptune maintain molecular hydrogen gas in the
atmosphere because they have high density.
●● Differentiated Earth
Answer: 1. Iron Nickel Core (outer core liquid)
(inner core solid)
2. Fe-Mg silicate mantle
3. Fe-Mg-Al Silicate Crust (Ocean and Continental)
4. Oceans
5. atmosphere
●● How is the earth compositionally zoned?
Answer: Along a density gradient
●● How did the earth become compositionally zoned?
Answer: 1. Accretion of planetesimals
,2. initial heating due to kinetic energy of colliding planetesimals and
compressional heating.
3. additional heating from radioactive decay.
4. iron catastrophe: melting temp of iron reached and dense iron nickel
sink to core and lighter materials are displaced outwards (including
silicate rock of mantle and crust, ocean waters and atmospheric gases)
5. earth becomes compositionally zoned based on density (densest iron
nickel in core-least dense materials comprise the atmosphere) 500 mil
yrs after the initial accretion process.
6. convective overturn in asthenosphere, mantle and outer core still
occur today.
●● Why did the earth heat up and then rapidly cool during the
differentiation process?
Answer: When earth was solid-heat gain was greater than the heat lost to
space. This means that the internal temperature rises until it exceeded the
melting temp of oxygen and nitrogen until exceeded iron nickel
catastrophe. Earth is completely molten and then compositionally zoned.
When earth was liquid- convection-hot gas rises , after it became molten,
the earth rapidly cooled off and solidified.
●● Why does earth possess little evidence of its early accretion history?
Answer: Because of weathering, plate tectonics, moon has no
atmosphere and biosphere.
, ●● Emissions from degassing of the earth during its differentiation.
Answer: h2o, co2, h2, he, n2
●● Where did molecular H and He escape to?
Answer: space
●● When did oxygenation of the atmosphere occur?
Answer: later following evolution of marine algae and plants that use
photosynthesis to convert co2 to o2 as a part of their life processes.
●● What layers of the earth can be directly observed?
Answer: crust and uppermost mantle.
●● Evidence of initial composition of the solid earth based on meteorite
studies. There are two major classes of meteorites that dominate
collected samples. Carbon based meteorites are much rarer, but indicate
that the prescursor of life was present early on.
Answer: 1. Metallic meteorites (iron nickel density 9.0-10 gm/cm3)
2. chondritic meteorites: Fe-Mg silicate, rocky, density is 3.0-3.3)
3. carbonaceous chondrites (rare)
●● What is earths average density?
Answer: 5.5 g/cm3
