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Ch15 SS Formation P1
Vocabulary
Term | Definition |
---|---|
Planet | major body that primarily orbits a star |
Moon | small body that primarily orbits something other than a star |
Differentiation | variation in the composition/density of an object |
Nebular Theory | original SS model where a large gas cloud contracted under its own gravity to form the Sun & planets |
Condensation Theory | builds on the nebular theory with interstellar dust grains that act as condensation nuclei |
Conservation of Angular Momentum | law explaining how an object spins faster as it contracts |
Axial Tilt | rotation angle of an object relative to the ecliptic |
Ecliptic | orbital plane of the planets, most asteroids, and Kuiper Belt Objects about the Sun |
Retrograde Rotation | backward, clockwise spin of a body |
Resonance | when two characteristic times are related in some simple way |
Interstellar Cloud | large cloud of gas found in the space among stars |
Solar Nebula | swirling gas cloud surrounding the early Sun during the solar system's formation |
Condensation Nuclei | dust grains in the interstellar medium that caused matter to clump together |
Planetesimal | object in the early solar system that had reached the size of a small moon |
Accretion Disk | rotating disk of matter formed by accretion around a massive body under the influence of gravity |
T Tauri Star | protostar in the late stages of formation exhibiting strong solar winds |
Solar Wind | outward flow of fast-moving charged particles from the Sun |
Protoplanet | planet forerunner that is formed in the early stages of solar system formation |
Core-Accretion Theory | says the Jovians formed when icy protoplanetary cores became massive enough to capture gas |
Gravitational Instability Theory | says the Jovians formed directly from the solar nebula via instabilities in the gas |