Origin & Systems of Earth - Vocabulary Flashcards

A comprehensive set of vocabulary flashcards covering the major concepts from the lecture notes on the origin of the universe, formation of star systems, the solar system, Earth's subsystems, and Earth's history.

Big Bang Theory

The universe started from a very small, hot state and expanded over time; the best explanation for the origin of the universe.

Steady State Theory

The universe is always expanding and matter is continuously created to form celestial bodies; the universe has no beginning or end in time.

Cosmic Inflation Theory

Rapid expansion of space-time; the early universe was a rapidly expanding bubble of pure vacuum energy.

Nebular Hypothesis

A star system formed from a rotating, hot gas cloud (nebula) that cooled, shrank, and formed a disk whose rings condensed into planets and satellites.

Planetesimal Theory

Debris from interactions near the Sun coalesced into solid bodies that became planets as they cooled.

Solar System

The Sun and all objects bound to it by gravity, including planets, moons, asteroids, and comets.

Terrestrial Planets

Also called Telluric planets; have solid surfaces and are mainly composed of silicate rocks and metals.

Jovian Planets

Also called Gas giants; primarily made of hydrogen and helium and lack solid surfaces.

Goldilocks Zone

The region around a star where conditions allow liquid water to exist on a planet’s surface.

Ozone Layer

High-altitude layer of ozone that shields living organisms from harmful ultraviolet radiation.

Moon’s Stabilization of Axial Tilt

Earth’s Moon helps stabilize the planet’s axial wobble, contributing to climate stability.

Water

Key element with neutral pH, high specific heat, good heat/conductive properties, and universal solvent; essential for life.

Energy

Key element representing the capacity to do work and drive biological and geological processes.

Time

Key element representing the temporal dimension over which Earth’s history and processes unfold.

Cycle

Key element referring to repeating processes in Earth’s systems (e.g., water cycle, carbon cycle).

Atmosphere (ATMO)

The gaseous envelope surrounding Earth.

Biosphere (BIO)

All living components that allow energy to circulate through ecosystems.

Hydrosphere (HYDRO)

All water on Earth, including oceans, rivers, lakes, groundwater, ice, and glaciers.

Geosphere (GEO)

Earth’s solid portions, including crust, mantle, and core.

Troposphere

Densest atmospheric layer; weather occurs here.

Stratosphere

Layer with ozone and strong horizontal winds.

Mesosphere

Coldest atmospheric layer.

Thermosphere

Hottest atmospheric layer; contains auroras.

Exosphere

Outermost layer of the atmosphere, fading into space.

Lithosphere

Crust and the rigid, upper part of the mantle.

Asthenosphere

Layer between the crust and mantle that is partially molten and deformable.

Mantle

Thick layer between crust and core; includes upper and lower mantle.

Core

Earth’s center; outer core is liquid, inner core is solid.

Mohorovičić Discontinuity (Moho)

Boundary between the crust and the mantle.

Gutenberg Discontinuity

Boundary between the lower mantle and the outer core.

Lehmann Discontinuity

Boundary between the outer core and the inner core.

Primordial Soup

Idea that life began from nonliving matter through simple organic compounds.

Deep-Sea Vents

Hypothesized origin sites for life on Earth, near hydrothermal vents in the deep ocean.

Panspermia

Idea that life on Earth began somewhere in the universe and was carried here by cosmic bodies.

James Hutton

Founder of modern geology; proposed Uniformitarianism—the present process shapes Earth’s history.

Charles Darwin

Developed the theory of natural selection and evolution; studied variation and adaptation.

Andrija Mohorovičić

Seismologist who proposed the boundary between Earth’s crust and mantle (Moho).

Beno Gutenberg

Seismologist who identified the boundary between the lower mantle and outer core (Gutenberg discontinuity).

Inge Lehmann

Seismologist who proposed the existence of a solid inner core (Lehmann discontinuity).

Alexander Oparin

Proposed the primordial soup theory in 1924 to explain the origin of life on Earth.

Stanley Miller

Co-created an experiment (Miller–Urey, 1952) that produced amino acids, supporting Oparin’s theory.

Harold Urey

Co-researcher on the Miller–Urey experiment; helped simulate early Earth conditions.

Catastrophism

Theory that catastrophic events (volcanoes, floods, earthquakes) caused mass extinctions and landform formation.

Uniformitarianism

Geologic processes occurring today also operated in the past, shaping Earth over long times.

Gradualism

Idea that Earth’s changes occur by small steps over long periods of time.