EAPS 105 Homework 4

4.19. In Wikipedia, look up "Aurora", scroll down to "Atmosphere", and answer this question: True or false: The northern and southern lights are caused by emission of photons in Earth's upper atmosphere from ionized (excited) nitrogen and oxygen atoms caused by the solar wind.

True

4.8. In Wikipedia, look up "Mantle (geology)" and answer this question: What is a mantle?

a. A layer inside a planetary body bounded below by a core and above by a crust.

4.2. In Wikipedia, look up "Earth's internal heat budget", scroll down to "Primordial heat", and answer this question: What is primordial heat?

a. Heat from the original formation of planet.

4.13. In Wikipedia, look up "Mid-ocean ridge" and answer this question: What is a mid-ocean ridge?

a. It is where seafloor spreading takes place along a divergent plate boundary.

4.12. In Wikipedia, look up "Earth's internal heat budget", scroll down to "Heat flow and tectonic plates", and answer this question: What is the primary means with which bodies with intermediate internal heat, such as the Earth, get rid of their internal heat (don't concern yourself with a very young Earth)?

a. Plate tectonics

4.1. In Wikipedia, look up "Kelvin" and answer this question: The Kelvin scale is a temperature scale like the Celsius temperature scale (1 deg C = 1 deg K), but they are shifted from each other. Kelvin is the predominantly used for scientific purposes. What is the lowest theoretical temperature that can exist in the universe on the Kelvin scale?

b. 0 K

4.18. In Wikipedia, look up "Magnetosphere" and answer this question: What is a magnetosphere?

b. A region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field.

4.4. In Wikipedia, look up "Tidal heating" and answer this question: Tidal heating occurs when gravitational forces cause a body like a moon to deform, which creates heat. This happens whenever something is deformed due to internal friction. However, for heat to be sustained, the moon must continually deform, like an accordion being played. What kind of orbit is required in order to induce sustained tidal heating?

b. An elliptical orbit

4.7. In Wikipedia, look up "Convection (heat transfer)" and answer this question: How is heat transferred through convection?

b. By movement of fluids

4.15. In Wikipedia, look up "Earth's internal heat budget", scroll down to "Heat flow and tectonic plates", and answer this question: What is the primary means with which bodies with lower internal heat, such as the Moon and Mars, get rid of their internal heat?

b. Conduction through a single lithospheric plate

4.20. In Wikipedia, look up "Jupiter", scroll down to "magnetosphere", and answer this question: What layer in Jupiter does its magnetic field arise from?

b. Its liquid metallic hydrogen layer

4.9. In Wikipedia, look up "Lithosphere" and answer this question: What is lithosphere?

b. The rigid, outermost shell of a terrestrial-type planet or natural satellite

4.11. In Wikipedia, look up "Mantle convection" and answer this question: What is a mantle convection?

b. The very slow creeping motion of mantle caused by convection currents carrying heat from the interior to the planet's surface.

4.3. In Wikipedia, look up "Earth's internal heat budget", scroll down to "Radiogenic heat", and answer this question: What percent of the Earth's internal heat originates from radioactive decay?

c. 50%

4.6. In Wikipedia, look up "Thermal conduction" and answer this question: How is heat transferred though conduction?

c. By microscopic collisions of particles within the body.

4.14. In Wikipedia, look up "Subduction" and answer this question: What is a subduction?

c. It is where oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries.

4.17. In Wikipedia, look up "Earth's magnetic field" and answer this question: In what layer is Earth's magnetic field generated?

c. The liquid outer core

4.10. In Wikipedia, look up "Asthenosphere" and answer this question: What is asthenosphere?

c. The viscous, mechanically weak, and ductile region of the upper mantle.

4.5. In Wikipedia, look up "Earth's internal heat budget", scroll down to "Heat flow and tectonic plates", and answer this question: What is the primary means with which bodies with high internal heat, such as Io, get rid of their internal heat?

c. Volcanism

4.16. In Wikipedia, look up "Dynamo theory" and answer this question: What is a dynamo?

d. The process through which a rotating, convecting, and electrically conducting fluid can maintain a magnetic field over astronomical time scales.