Introduction to Earth Science and Solar System Formation

Vocabulary flashcards covering the key concepts of early Earth history, astronomical observations, solar system formation, and planetary differentiation from Chapter 1 to Chapter 7.

Pale Blue Dot

An essay and philosophical perspective by Carl Sagan based on a photograph of Earth taken from space by the Voyager probe, highlighting Earth's small place in the cosmos.

Universe

The totality of all existing space, time, matter, and energy, containing billions of galaxies and estimated to be approximately $13.8\text{ billion years}$ old.

Galaxy

An organized, disk-like rotating cloud of stars, planetary bodies, gas, and dust held together by gravity.

Milky Way Galaxy

The specific galaxy that contains our solar system, visible in low light-pollution areas as a dense band of stars across the sky.

Interior Planets

The planets closest to the Sun characterized by dense, rocky cores and relatively thin atmospheres.

Outer Planets

The massive planets farther from the Sun that feature rocky cores covered with ice, frozen gases, and thick, massive atmospheres.

Chondritic Meteorite

A type of meteorite formed from the accretion of primordial space dust, representing the original composition of the early solar system.

Iron Meteorite

A metallic meteorite composed of an iron-nickel alloy originating from the core of a destroyed planetesimal.

Widmanstätten Pattern

A crystalline pattern unique to iron-nickel alloys in iron meteorites that forms only when metal cools extremely slowly over tens to hundreds of millions of years.

Carbon-14 Dating

A radiometric dating method based on the decay of carbon-14 (half-life of about $5,000\text{ years}$), useful for dating materials up to around $30,000\text{ to }50,000\text{ years}$ old.

Zircon

A resilient mineral found in continental rocks; the oldest known zircon grains in Australia have been dated to approximately $4.4\text{ billion years}$ old.

Doppler Effect

The alteration of observed wave frequency or wavelength resulting from relative motion between a wave source and an observer.

Redshift

The stretching of light to longer, redder wavelengths observed from distant galaxies, indicating that objects are moving away from the observer as the universe expands.

Big Bang Theory

The cosmological model stating that the universe originated from a single point approximately $13.8\text{ billion years}$ ago and was initially composed mostly of hydrogen and helium.

Nuclear Fusion

The process inside stars where smaller elements combine under high heat and pressure to form heavier elements up to iron.

Supernova

A highly energetic stellar explosion capable of generating the extreme energy required to create elements heavier than iron.

Nebular Theory

The model describing how a solar system forms through the gravitational collapse, contraction, spinning, and flattening of a rotating disk of gas and dust.

Planetary Accretion

The process by which colliding dust particles, rocks, and planetesimals stick together through kinetic energy and gravitational attraction to build planets.

Homogeneous Accretion

The initial stage of planet formation where the material accumulating to form a body is uniformly distributed and identical in composition throughout.

Planetary Differentiation

The process in a molten planet where gravity pulls dense elements (iron and nickel) toward the center to form a core, while lighter silicate materials float upward to form the mantle and crust.

Volcanic Outgassing

The release of gases (such as carbon dioxide, methane, and water vapor) from Earth's interior during volcanic eruptions, contributing to the formation of the secondary atmosphere.