Earth & Space Science – Comprehensive Vocabulary

A set of vocabulary flashcards covering planets, Earth systems, rock science, geologic processes, dating methods, hazards, hydrometeorology, and coastal management for exam review.

Exoplanet

A planet that orbits a star outside our solar system.

Dwarf Planet

A nearly round body that orbits the Sun but has not cleared its orbital path of other debris.

Kuiper Belt

Distant, doughnut-shaped region beyond Neptune that hosts many dwarf planets and icy bodies.

Gas Giant

Large outer-solar-system planet composed mainly of hydrogen and helium (e.g., Jupiter, Saturn).

Ice Giant

Outer planet rich in water, ammonia and methane ices (Uranus and Neptune).

Great Red Spot

Centuries-old storm on Jupiter larger than Earth.

Runaway Greenhouse Effect

Process on Venus where thick CO₂ atmosphere traps extreme heat.

Great Dark Spot

Giant storm once observed on Neptune.

Hydrosphere

All Earth’s water in liquid, solid, and vapor forms, including oceans, lakes, ice, groundwater and moisture.

Geosphere

Solid Earth—crust, mantle, and core—composed of rock and minerals.

Biosphere

All living organisms and the environments they inhabit.

Atmosphere

Gaseous envelope surrounding Earth, ~78 % N₂ and 21 % O₂, regulating climate and supporting life.

Igneous Rock

Rock formed by cooling and crystallization of magma or lava.

Plutonic (Intrusive) Rock

Igneous rock that cools slowly beneath Earth’s surface (e.g., granite).

Volcanic (Extrusive) Rock

Igneous rock that cools quickly at or near the surface (e.g., basalt, pumice).

Sedimentary Rock

Rock formed by compaction and cementation of sediments.

Compaction

Weight of overlying layers squeezes sediments, reducing pore space.

Cementation

Minerals precipitate from groundwater and “glue” sediments together.

Metamorphic Rock

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

Rock Cycle

Continuous processes that transform rocks among igneous, sedimentary, and metamorphic types.

Mechanical Weathering

Physical breakup of rocks (e.g., frost wedging, root growth).

Chemical Weathering

Breakdown of rock through chemical reactions, such as oxidation or carbonation.

Erosion

Transport of weathered material by water, wind, ice, or gravity.

Deposition

Dropping of sediments when transporting agents lose energy.

Conduction (Earth)

Heat transfer through molecular contact, dominant in lithosphere.

Convection (Mantle)

Heat transfer by movement of molten or plastic material, driving plate tectonics.

Radiation (Heat)

Transfer of energy by electromagnetic waves; controls surface temperature exchange with space.

Crust

Earth’s outermost solid layer, 5–70 km thick, composed of continental and oceanic varieties.

Mantle

Layer from crust base to 2,900 km depth, behaving as viscous solid; 84 % of Earth’s volume.

Outer Core

Liquid iron-nickel layer that generates Earth’s magnetic field.

Inner Core

Solid iron-nickel sphere under immense pressure at Earth’s center.

Magma

Molten rock beneath Earth’s surface, containing minerals and volatiles.

Lava

Magma that reaches Earth’s surface.

Partial Melting

Process where only some minerals in a rock melt, generating magma of different composition.

Decompression Melting

Magma formation as hot mantle rock rises and pressure decreases (mid-ocean ridges).

Flux (Wet) Melting

Lowering of rock melting point by adding volatiles like water (subduction zones).

Folding

Plastic bending of layered rocks under compressive stress.

Anticline

Up-arched fold with oldest rocks at its core.

Syncline

Down-curved fold with youngest rocks at its center.

Monocline

Simple one-sided bend in otherwise horizontal strata.

Fault

Fracture where blocks of rock move relative to each other.

Normal Fault

Hanging wall moves down relative to footwall due to extension.

Reverse Fault

Hanging wall moves up relative to footwall due to compression.

Strike-Slip Fault

Blocks move horizontally past each other due to shear (e.g., San Andreas).

Law of Superposition

In undisturbed strata, oldest layers lie at the bottom and youngest at the top.

Law of Inclusions

Fragments enclosed in a rock must be older than the host rock.

Cross-Cutting Relationship

Geologic feature that cuts another is younger than what it cuts.

Original Horizontality

Sediments are initially deposited in nearly horizontal layers.

Unconformity

Surface representing a gap in the geologic record due to erosion or non-deposition.

Faunal Succession

Fossil assemblages succeed one another in a recognizable order through time.

Relative Dating

Placing rocks and events in sequence without assigning exact ages.

Absolute (Radiometric) Dating

Determining numerical ages using radioactive decay of isotopes.

Half-Life

Time required for half of a radioactive parent isotope to decay to daughter isotope.

Radiocarbon Dating

Method using decay of carbon-14 to date organic remains up to ~45,000 yrs old.

Potassium-Argon Dating

Radiometric technique for igneous rocks 100 kyr to billions of years old.

Uranium-Lead Dating

Radiometric method measuring lead-206 in zircon; dates rocks >100 Myr.

Rubidium-Strontium Dating

Technique using decay of 87Rb to 87Sr for rocks older than 10 Myr.

Hadean Eon

Oldest eon (4.6–4 Ga) marked by formation of Earth’s crust and oceans.

Archean Eon

3.8–2.5 Ga; early continents form; first life emerges in methane-rich atmosphere.

Proterozoic Eon

2.5 Ga–541 Ma; atmospheric oxygen rises, eukaryotes appear, supercontinents assemble.

Paleozoic Era

541–252 Ma; explosion of marine life, amphibians, reptiles, and formation of Pangaea.

Mesozoic Era

252–66 Ma; “Age of Dinosaurs” comprising Triassic, Jurassic, Cretaceous periods.

Cenozoic Era

66 Ma–present; mammals diversify, humans evolve, several ice ages occur.

Earthquake

Sudden release of energy along faults producing ground shaking.

Ground Shaking

Vibration of the ground during an earthquake; can trigger other hazards.

Liquefaction

Loss of soil strength during shaking when water-saturated sediments behave like liquid.

Landslide

Downslope movement of rock, earth, or debris; often earthquake-triggered.

Surface Faulting

Displacement that breaks through to Earth’s surface during fault slip.

Tsunami

Long-wavelength sea wave generated by seafloor disturbance such as an earthquake or landslide.

Tephra Fall

Volcanic ash and larger fragments ejected and deposited from eruption plume.

Pyroclastic Flow

Fast, dense avalanche of hot ash, lava fragments, and gases down volcano slopes.

Lahar

Volcanic mudflow of water and debris rushing down river valleys.

Lava Dome

Bulbous mound formed by viscous lava piling over a volcanic vent.

Hydrometeorology

Science of water in the atmosphere and its interaction with land and oceans.

Hydrometeorological Hazard

Atmospheric, hydrologic, or oceanographic process causing potential harm (e.g., typhoon, flood).

Tropical Cyclone

Warm-core, rotating low-pressure system forming over ≥26 °C oceans.

Typhoon

Tropical cyclone in the Northwest Pacific (Philippines, Japan, China).

Hurricane

Tropical cyclone in the North Atlantic or Eastern Pacific.

Cyclone (Indian Ocean)

Regional term for tropical cyclone over South Pacific or Indian Ocean.

Monsoon

Seasonal reversal of wind and rain pattern (e.g., Habagat and Amihan in Philippines).

Flood

Overflow of water onto normally dry land.

Tornado

Violently rotating column of air extending from a thunderstorm to the ground.

Hazard Map

Spatial representation identifying areas susceptible to specific natural hazards.

Wave (Ocean)

Rhythmic movement of water generated by wind friction on the surface.

Swash

Up-rush of water on a beach after a wave breaks, carrying sediment landward.

Backwash

Water flowing back to sea after swash, moving sediment seaward.

Longshore Drift

Zig-zag transport of sediment along coast by angled wave action.

Spring Tide

Large tidal range occurring at full and new moons when Sun, Earth, and Moon align.

Neap Tide

Small tidal range occurring at quarter moons when Sun and Moon forces act at right angles.

Sea Level Rise

Global or local increase in ocean height, currently ~2 mm/yr.

Storm Surge

Abnormal rise of sea level during a storm from wind and low pressure.

Coastal Erosion

Removal of shoreline material by wave action, currents, or sea level rise.

Saltwater Intrusion

Landward movement of seawater into freshwater aquifers.

Sea Wall

Concrete or stone barrier built parallel to shore to reflect wave energy.

Groynes

Structures built perpendicular to shoreline to trap sand and widen beaches.

Riprap (Rock Armour)

Large boulders placed at foot of cliffs or seawalls to absorb wave energy.

Beach Nourishment

Addition of sand to an eroding beach for protection and recreation.

Managed Retreat

Planned abandonment of low-value coastal land to allow natural processes.

Cliff Stabilization

Techniques (e.g., vegetation, netting) to reduce cliff erosion and slope failure.

Hard Engineering

Use of built structures to defend coasts against erosion and flooding.