Earth and Life Science – Origin of Universe, Solar System & Earth Systems

Vocabulary flashcards covering key terms in the lecture on the universe’s origin, solar-system formation, Earth’s uniqueness, Earth systems, rock cycle, minerals, and rock textures.

Cosmology

The branch of science that studies the origin, evolution, structure, and fate of the universe.

Geology

The science that examines Earth’s materials, structures, processes, and the organisms that have inhabited the planet.

Terrestrial Planets

Inner planets (Mercury, Venus, Earth, Mars) made mostly of dense metals, lacking rings and having few or no moons.

Jovian Planets

Outer gas giants (Jupiter, Saturn, Uranus, Neptune) that are large, have rings, and possess many moons.

Goldilocks Zone

Habitable region around a star where conditions are ‘just right’ for liquid water to exist on a planet’s surface.

Plate Tectonics

Theory describing the movement of Earth’s lithospheric plates and the processes that shape the planet’s surface.

Jupiter Shield Effect

The role of Jupiter in gravitationally deflecting or capturing debris, reducing impacts on Earth.

Friendly Moon Hypothesis

Concept that Earth’s large moon stabilizes the planet’s axial tilt and drives tides conducive to life.

Closed System (Earth)

System that exchanges energy but not significant matter with its surroundings; applies to the whole Earth system.

Hydrosphere

All liquid, solid, and gaseous water on or near Earth’s surface.

Atmosphere

Thin layer of gases (78 % N₂, 21 % O₂, trace gases) surrounding Earth.

Lithosphere

Rigid outer layer consisting of the crust and uppermost solid mantle; broken into tectonic plates.

Asthenosphere

Weak, semi-molten upper mantle layer on which lithospheric plates float.

Biosphere

All living organisms on Earth and the ecosystems they inhabit.

Geosphere

Solid Earth, including crust, mantle, and core.

Crust

Earth’s outermost solid layer; varies as dense oceanic basaltic crust (~5–10 km) or less dense continental granitic crust (~30–50 km).

Mantle

Thick, mostly solid layer between crust and core; exhibits convection that drives plate motion.

Core

Central Earth layer composed mainly of iron-nickel; liquid outer core and solid inner core.

Mohorovičić Discontinuity (Moho)

Boundary between Earth’s crust and upper mantle characterized by a sudden seismic velocity change.

Continental Crust

Thicker, felsic, less-dense crust forming landmasses; average density ~2.7 g/cm³.

Oceanic Crust

Thinner, mafic, more-dense crust beneath oceans; density ~3.0 g/cm³.

Mineral

Naturally occurring, inorganic solid with definite chemical composition and ordered crystalline structure.

Ore

Rock or mineral deposit containing valuable metal or minerals that can be mined profitably.

Streak

Color of a mineral’s powdered form when rubbed on unglazed porcelain.

Luster

The way a mineral’s surface reflects light (e.g., metallic, vitreous, pearly).

Cleavage

Tendency of a mineral to break along flat planes of weakness.

Fracture

Irregular or curved breakage in a mineral lacking cleavage (e.g., conchoidal in quartz).

Specific Gravity

Ratio of a mineral’s density to the density of water (1 g/cm³).

Mohs Hardness Scale

Relative scale (1–10) ranking minerals’ resistance to scratching, from talc (1) to diamond (10).

Igneous Rock

Rock formed by solidification of magma or lava; classified by texture and composition.

Sedimentary Rock

Rock formed from accumulation, compaction, and cementation of sediments or precipitation from solution.

Metamorphic Rock

Rock altered by heat, pressure, and/or chemically active fluids without melting.

Rock Cycle

Model describing the transitions among igneous, sedimentary, and metamorphic rocks through Earth processes.

Bowen’s Reaction Series

Sequence describing the order in which minerals crystallize from cooling magma based on temperature.

Phaneritic Texture

Coarse-grained igneous texture with interlocking crystals visible to the naked eye, typical of intrusive rocks.

Aphanitic Texture

Fine-grained igneous texture where crystals are too small to see unaided; typical of extrusive rocks.

Porphyritic Texture

Igneous texture with large crystals (phenocrysts) embedded in a finer groundmass, indicating two stages of cooling.

Glassy Texture

Amorphous igneous texture formed by extremely rapid cooling, producing natural glass (e.g., obsidian).

Vesicular Texture

Igneous texture containing gas bubble cavities (vesicles), common in pumice and scoria.

Pyroclastic Texture

Fragmental texture formed from explosive volcanic ejecta consolidated into rock (e.g., tuff).

Foliation

Planar alignment of minerals in metamorphic rocks produced by directed pressure (e.g., slate, schist, gneiss).

Non-foliated Rock

Metamorphic rock lacking planar fabric, often composed of one dominant mineral (e.g., marble, quartzite).

Clastic Texture

Sedimentary texture where detrital grains are cemented but not interlocking; porous structure.

Bioclastic Texture

Sedimentary rock texture composed chiefly of fossil fragments (e.g., fossiliferous limestone).

Crystalline Texture (Sedimentary)

Interlocking crystals of mostly one mineral precipitated from solution, as in rock salt or gypsum.

Microcrystalline

Texture with crystals too small to see but forming an interlocking network; typical of chert.

Weathering

Physical and chemical breakdown of rocks at Earth’s surface.

Lithification

Processes (compaction and cementation) that convert sediments into solid sedimentary rock.

Magma

Molten or partially molten rock beneath Earth’s surface containing dissolved gases and crystals.

Protolith

Original, unmetamorphosed rock from which a metamorphic rock forms.

Water Planet

Descriptor for Earth highlighting the presence of abundant surface liquid water (~70 % coverage).

Closed vs. Open System

Closed exchanges energy but not matter (Earth); open exchanges both (individual spheres or subsystems).