Formation & Structure
Define "nebula."
A cloud of gas and dust in space.
What are the two classifications of planets in our solar system?
Terrestrial and Jovian planets
What is "regolith" on the Moon?
Loose surface dust and broken rock produced by impacts.
During which lunar phase can a solar eclipse occur?
New Moon
State the Nebular Hypothesis (briefly).
Solar systems form from collapsing rotating clouds of gas and dust (nebulae).
Put these in order from the center outward: Kuiper Belt, Jovian Planets, Sun, Asteroid Belt, Oort Cloud, Terrestrial Planets.
Sun → Terrestrial Planets → Asteroid Belt → Jovian Planets → Kuiper Belt → Oort Cloud.
What are "maria" and how did they form?
Dark basalt plains formed when large impacts exposed molten material that filled basins and solidified.
During which lunar phase can a eclipse occur?
Full moon
What random astronomical event commonly triggers a nebula to begin collapsing into a star system?
A nearby supernova or other shock wave that compresses the nebula.
Give two primary compositional differences between terrestrial and Jovian planets.
Terrestrial: rocky composition, metal cores, smaller, denser, closer to Sun. Jovian: gaseous/icy, larger, low density, farther out, thick atmospheres.
Where on the Moon would you find anorthosite and why is it important?
Anorthosite is abundant in the lunar highlands (light crustal rock), indicating an early differentiated crust rich in plagioclase.
Explain why the Moon can cover the Sun in a solar eclipse even though the Sun is vastly larger.
Because the Moon is much closer to Earth, its apparent angular size can match the Sun's, allowing it to cover the Sun from some locations.
Explain how conservation of angular momentum affects a collapsing nebula.
As radius decreases, rotation rate increases (angular momentum conservation), causing flattening of the cloud.
Explain why there were originally many more planetesimals than final planets.
Many planetesimals formed; through collisions and accretion some combined into protoplanets and then planets, while others were ejected or remained as small bodies.
How long is one complete cycle of Moon phases? Give the value in days
29.5 days
Why does the Moon appear red during a total lunar eclipse? Provide an atmospheric explanation.
Earth's atmosphere scatters shorter wavelengths; refracted sunlight through the atmosphere is reddened and illuminates the Moon with red light.
Describe what the accretion disk is and why most mass ends up near the center.
The accretion disk is the flattened rotating disk of gas and dust around the forming protostar; most mass concentrates near the center forming the star.
Describe the significance of the Asteroid Belt, Kuiper Belt, and Oort Cloud to understanding solar system formation
They are reservoirs of leftover formation material; studying them gives clues about early solar system composition and processes
Explain why, at any given phase, the Moon is always half lit even though we see varying amounts. Use geometry of Sun–Moon–Earth positions.
Half the Moon is lit by the Sun at all times; phase differences come from our changing viewpoint of how much of that lit half faces Earth.
Why are eclipses infrequent events?
The moon's orbit is not directly in line with the plane that the Earth orbits the Sun. Only when the two line up during Full moons or New moons will an eclipse occur.