Earth Science Glossary

A

abrasion

scraping of rock by sand or other hard substances moving against it

absolute magnitude

how bright a star appears from a set distance

accelerating

increasing the speed of motion

acceleration

change in an object’s motion

agent of weathering

force or object that causes weathering

air mass

a large body of air with similar temperature and humidity

air pressure

the weight of a column of air above a certain spot

albedo

the amount of light reflected by a surface

anaerobic

requiring conditions without oxygen

anthropogenic climate disruption

disturbance of the climate caused by human activities

apparent magnitude

how bright a star appears from Earth

asteroid

small, rocky body orbiting the sun

astronomical unit

the average distance from the sun to Earth

atmosphere

the envelope of gases and small particles that surrounds Earth

auroras

lights caused by interaction between particles from the sun and Earth’s atmosphere

B

baryonic matter

matter that is made of atoms

big bang

theory that says the universe began with a massive explosion of very dense matter

big bang theory

an explanation of how the universe began from a small point and expanded

biosphere

all living organisms on Earth

black hole

an entity with gravity so strong that no light can escape it

blueshift

the change to higher frequencies in the light coming from distant celestial objects moving toward the observer

C

calyx

the calcium carbonate cup that a coral polyp sits in

carbon load

the amount of carbon stored within a living or nonliving reservoir of the carbon cycle

carbonation

the chemical reaction of carbon dioxide and water

chemical decomposition

changing a compound into simpler compounds or elements

climate

a pattern of atmospheric conditions over a long period of time

climate change

the long-term change of temperature and normal weather patterns in a place

constellation

a group of stars forming a recognizable pattern

convection

energy transfer by particle movement within a fluid

cosmic microwave background

electromagnetic radiation that is a remnant of the big bang

D

dark energy

energy that humans cannot observe directly

dark matter

matter that humans cannot see

data assimilation

incorporating and absorbing data

deep current

ocean current caused by differences in density that moves vertically and horizontally

deforestation

the removal of large areas of forest

delta

land made of sediment dropped by a river at its mouth

deposition

release of sediments from a flow of air or water so that they come to rest in place

dissolution

a reaction in which substances disintegrate in water

dwarf galaxy

small, dim galaxy of a few billion stars

E

eccentricity

measure of how elliptical an orbit is

electric currents

movement of positive or negative electric particles

electromagnetic radiation

energy carried by oscillating magnetic and electrical fields

elliptical

oval or egg-shaped

ensemble forecast

a forecast made up of several separate forecasts

equilibrium

a state of balance between opposing processes

erosion

gradual wearing away or destruction of a material by moving air or water

evaporation

the phase change from liquid to gas when a substance absorbs enough energy

event horizon

a theoretical boundary around a black hole that blocks the exit of light and matter

evolution

gradual development, usually from simple to more complex

exoplanets

planet in a solar system other than ours

exosphere

the outermost layer of Earth’s atmosphere

F

feedback

ability of change in a system to lead to further changes

fossil fuel

a substance formed from the remains of once-living organisms used by people for energy

frequency

the number of waves that pass a point in a set amount of time

front

the place where two unlike air masses meet

frost wedging

the breakdown of rock due to the expansion of ice in cracks

G

galaxy

a large group of stars, dust, dark matter, and gas

geocentric

centered on Earth

geologic time scale

a chart of Earth's history from its formation to the present

geosphere

the atmosphere, hydrosphere, and lithosphere

glacial period

a period in Earth’s history marked by prolonged low global temperature

glacial retreat

the moving up of the end of a glacier so that it does not extend as far downvalley as it once did

global conveyer belt

a system of currents that transfers heat between the poles and the equator

global positioning system

a system utilizing satellites that provides users with positioning, navigating, and timing

global warming

the gradual increase in the overall temperature of Earth’s atmosphere

gravitational force

attractive force between two objects due to their mass

gravity

force of attraction between two objects due to their masses

greenhouse effect

gases near Earth’s surface absorbing and reemitting heat / the trapping of heat by certain gases in Earth’s atmosphere

greenhouse gas

a gas in the atmosphere that traps Earth’s heat / a gas that absorbs and reradiates infrared radiation / atmospheric gas that absorbs and reradiates the sun's energy

gyre

a system of rotating ocean currents

H

heavy element

an atom with four or more protons, up to the number of protons in iron

heliocentric

centered on the sun

high frequency radio waves

radio waves used to transmit radio and other sound signals

hydrolysis

the breaking apart of molecules by water

hydrosphere

Earth's water and its cycling

I

inertia

the tendency of an object to move along a straight path at a constant speed

inside-out model

theory of galaxy formation in which small structures join to become large structures

interglacial period

a period in Earth’s history marked by prolonged high global temperature

ionosphere

the layer of Earth’s atmosphere that has a high concentration of ions and free electrons and is able to reflect radio waves

J

jet stream

a band of strong winds high in the atmosphere

L

light element

an atom with one, two, or three protons in its nucleus

light spectrum

the colors of light that are coming from a star

lithosphere

Earth's crust and upper mantle

luminosity

brightness

M

main sequence

the most stable stage in the life of a star

mesosphere

middle layer of the atmosphere

meteorologist

a person who studies weather and weather patterns

microbe

an organism too small to view without magnification

mutualistic

a close, long-term relationship in which both organisms benefit

N

near infrared

wavelengths of electromagnetic energy just outside the visible light wavelengths

nebulae

clouds of interstellar gas and dust

neutron star

structure that forms when the mass of the remaining core after a supernova is between 1.4 and 3.0 times the mass of the sun

non-visible light

electromagnetic radiation that cannot be seen by the unaided human eye

nuclear fission

nuclear reaction that occurs when a larger atom splits into two or more smaller atoms

nuclear fusion

nuclear reaction that occurs when two atoms fuse to form one atom

nucleus

the center of an atom, which contains protons and neutrons

O

obliquity

tilt of an axis

ocean acidification

the increase in acidity of the ocean due to added CO2

opaque

absorbing or reflecting all of the incident electromagnetic energy

orbit

path of an object moving around a central attractive mass

orbital period

time to complete one orbit

outside-in model

theory of galaxy formation in which a large gas cloud collapses, forming many stars

oxidation

the gaining of oxygen electrons to form new substances

ozone hole

decrease in ozone over Antarctica

P

paleoclimatology

the study of ancient climates

photon

particle of electromagnetic radiation

planetary nebula

structure that forms when the carbon core of an average star collapses, expelling the outer layers

plasma

a state of matter in which electrons separate from atomic nuclei, but remain balanced in number

precession

rotation of an axis

protostar

structure that forms as hydrogen in a nebula spins faster and the temperature increases

R

radio telescope

an instrument that gathers radio waves from objects in space

red giant

structure that forms when stars run out of hydrogen and their outer layers expand and cool

red supergiant

a massive star appearing yellow or red and in the process of dying

redshift

the change to lower frequencies in the light coming from distant celestial objects moving away from the observer

respiration

the process by which organisms obtain energy by taking in oxygen and releasing carbon dioxide

retrograde

the apparent backward motion of an object resulting from the circular motions of the viewer and the object

S

salinity

the amount of salt dissolved in a body of water

salt wedging

the breakdown of rock due to the expansion of salt crystals in cracks

satellite

an artificial body placed in orbit around Earth, the moon, or another planet to collect data or communicate

scale

a system of measuring and describing quantities

singularity

a mathematical point with essentially zero volume and infinite density

solar maximum

the period of the solar cycle when the sun’s emissions are at their highest level

solar minimum

the period of the solar cycle when the sun’s emissions are at their lowest ebb

solar wind

plasma from the sun that spreads outwards through the solar system

source region

an area where an air mass forms

spectral lines

pattern of dark lines and colors representing emitted energy

spectrograph

a tool that astronomers can use to see the light spectrum of a star

spectroscopy

study of spectra produced by matter emitting radiation

stellar parallax

the appearance of movement of a star as a result of the Earth moving around the sun

stratosphere

the layer of Earth’s atmosphere above the troposphere

stream capacity

the maximum amount of solid a stream can carry at one time

stream competence

the heaviest particles a stream can carry

stream transportation

movement of silt, sand, gravel, or rocks by a flowing body of water

supernova

explosion in which a super red giant expels heavy elements into space

surface current

ocean current caused by wind that moves horizontally near the surface

T

thermosphere

the hottest and most ionized layer of Earth’s atmosphere

Total Solar Irradiance

a measure of the radiant energy emitted from the sun

troposphere

the layer of the atmosphere closest to Earth’s surface

U

universal

applying to all objects

upwelling

ocean current in which cold water moves up toward the surface from deeper areas

V

vacuum

area with no matter

visible light

electromagnetic radiation with wavelengths between 380 nm and 700 nm

W

wavelength

the distance from crest to crest of a wave pattern

weather

atmospheric conditions at a specific time and place

white dwarf

structure that forms as the remaining core of a red giant

wind

the movement of air from higher to lower pressure

Climate and Weather

air mass

a large body of air with similar temperature and humidity

air pressure

the weight of a column of air above a certain spot

albedo

the amount of light reflected by a surface

atmosphere

the envelope of gases and small particles that surrounds Earth

climate

a pattern of atmospheric conditions over a long period of time

convection

energy transfer by particle movement within a fluid

data assimilation

incorporating and absorbing data

deep current

ocean current caused by differences in density that moves vertically and horizontally

eccentricity

measure of how elliptical an orbit is

ensemble forecast

a forecast made up of several separate forecasts

evaporation

the phase change from liquid to gas when a substance absorbs enough energy

exosphere

the outermost layer of Earth’s atmosphere

front

the place where two unlike air masses meet

gyre

system of currents in an ocean basin

mesosphere

middle layer of the atmosphere

meteorologist

a person who studies weather and weather patterns

near infrared

wavelengths of electromagnetic energy just outside the visible light wavelengths

obliquity

tilt of an axis

opaque

absorbing or reflecting all of the incident electromagnetic energy

precession

rotation of an axis

source region

an area where an air mass forms

stratosphere

the layer of Earth’s atmosphere above the troposphere

surface current

ocean current caused by wind that moves horizontally near the surface

thermosphere

the hottest and most ionized layer of Earth’s atmosphere

troposphere

the layer of the atmosphere closest to Earth’s surface

upwelling

ocean current in which cold water moves up toward the surface from deeper areas

weather

atmospheric conditions at a specific time and place

wind

the movement of air from higher to lower pressure

Climate Change

anthropogenic climate disruption

disturbance of the climate caused by human activities

carbon load

the amount of carbon stored within a living or nonliving reservoir of the carbon cycle

climate change

the long-term change of temperature and normal weather patterns in a place

deforestation

the removal of large areas of forest

equilibrium

a state of balance between opposing processes

feedback

ability of change in a system to lead to further changes

fossil fuel

a substance formed from the remains of once-living organisms used by people for energy

glacial period

a period in Earth’s history marked by prolonged low global temperature

glacial retreat

the moving up of the end of a glacier so that it does not extend as far downvalley as it once did

global conveyer belt

a system of currents that transfers heat between the poles and the equator

global warming

the gradual increase in the overall temperature of Earth’s atmosphere

greenhouse effect

gases near Earth’s surface absorbing and reemitting heat / the trapping of heat by certain gases in Earth’s atmosphere

greenhouse gas

a gas in the atmosphere that traps Earth’s heat / a gas that absorbs and reradiates infrared radiation / atmospheric gas that absorbs and reradiates the sun's energy

gyre

a system of rotating ocean currents

interglacial period

a period in Earth’s history marked by prolonged high global temperature

jet stream

a band of strong winds high in the atmosphere

ocean acidification

the increase in acidity of the ocean due to added CO2

ozone hole

decrease in ozone over Antarctica

paleoclimatology

the study of ancient climates

respiration

the process by which organisms obtain energy by taking in oxygen and releasing carbon dioxide

salinity

the amount of salt dissolved in a body of water

scale

a system of measuring and describing quantities

Rocks & Minerals

alluvial deposit

gravel and sediment deposited where flowing water slows down

artisanal and small-scale mining

resource extraction by individuals not working at regulated mine sites

cleavage

the tendency of a mineral to break along smooth planes

conflict minerals

minerals mined in areas of violent conflict and sold to fund the activities of violent groups

corrosion

the destruction of a material by a chemical action

density

how tightly an object's atoms are packed together

depleted

when the supply or resource is all used up

dredge

a machine that lifts sediment from the bottom of a body of water

effluent

liquid waste

e-waste

electronics that have been discarded or are near the end of their useful life

fracture

the tendency of a mineral to break along surfaces that are not smooth

hardness

a mineral's ability to resist scratching

land reclamation

to restore land degraded from mining operations

luster

the way light interacts with the surface of a rock or mineral

magnetism

how a mineral reacts when placed within a magnetic field

mitigate

to offset, make less severe, or alleviate

ores

naturally occurring rocks that contains useful metals and minerals mixed with large amounts of earth

overburden

the rock or soil that needs to be removed to expose seams of ore

rare-earth elements

a group of metallic elements in the lanthanide series that are not actually rare but difficult and dangerous to extract

reduction

removal of oxygen from a substance

smelting

to extract metal from an ore by heating and melting it

solvent

a chemical that can dissolve other substances

surface mining

the practice of stripping layers of the earth to reach ore deposits underneath

sustainable

able to continue over a period of time

tailings

material left over after the valuable resources have been removed from ore

tailings dams

structures used to hold the chemicals and dust particles left over from extracting valuable minerals from mined ore

trommel

a rotating cylindrical screen used for washing and sorting ore

underground mining

the practice of drilling deep below Earth's surface to extract ores

vitreous

glassy

Land Resources

agroforestry

the intentional use of trees and shrubs in farming

alley cropping

a type of agroforestry in which rows of trees are planted in between rows of crops

aquifer

an area of rock that absorbs and holds water that exists below the water table

beach erosion

the movement of sand and sediment from off the shore to deeper waters

beach nourishment

act of adding sediment and sand to a beach to elevate and extend the shoreline into the water

carbon sequestration

the process by which carbon dioxide is removed from the atmosphere and stored

crop rotation

planting a different crop each year

dredge

to dig or pull up

eutrophication

excessive nutrients in a water body causing overgrowth of algae, plankton, and other microorganisms

flood mitigation techniques

strategies to manage and control the movement of floodwaters

greenhouse gases

gases that absorb infrared radiation and trap heat in the atmosphere

intercropping

growing multiple crops on the same plot of land

loam

soil that is a balanced mix of sand, clay, and silt

ocean current

continuous movement of seawater

pH

a measure of how acidic or basic a substance is

shoreline

where a body of water meets the land

socioeconomic

relating to a combination of social and economic factors

sustainability

the ability to use a resource so that it is not depleted or permanently damaged

sustainable agriculture

farming that meets current needs while preserving and protecting resources for the future

terrace farming

creating flat steps for farming on slopes of hills or mountains

urban

having to do with a town or city

water table

the boundary between unsaturated ground and saturated ground

Energy Resources

albedo

the amount of radiation reflected from a surface

biosphere

the parts of Earth that serve as habitats for living things

cryosphere

areas of snow or ice on Earth

emissions

gases that are released when fossil fuels are burned

fossil fuel

a fuel (such as coal, crude oil, or natural gas) that is formed in the earth from dead plants or animals

greenhouse gases

gases that trap heat from the sun in Earth's atmosphere

hydrosphere

water that is on or under Earth's surface

nacelle

the cover of a wind turbine that houses the generator, gears, shafts, and controllers

nonrenewable resource

a resource that cannot be renewed or replaced

particulate matter

a form of pollution consisting of solid or liquid particles in the air

smog

a severe type of air pollution, originally named for a mixture of smoke and fog

Water as a Resource

agricultural runoff

precipitation or irrigation water from farm fields that reaches streams, rivers, lakes, or the ocean, often carrying pollutants

agricultural water

water used to grow fresh produce and raise livestock

algal bloom

rapid growth in the algae population in a body of water

aquifer

an area of rock that absorbs and holds water that exists below the water table

aquitard

a layer of rock that allows a small amount of liquid to pass through

artesian well

a well under sufficient pressure such that water flows upward to the surface

climate change

changes in regional and global climate patterns, particularly marked by a warming of average global temperatures caused by the release of greenhouse gases due to the burning of fossil fuels

coastal erosion

the loss of coastal lands due to the net removal of sediments or bedrock from the shoreline

demand

the amount of a resource that is desired by consumers

direct water

water that is used or consumed by an individual or group of individuals

drought

a period of drier-than-normal conditions resulting from a decrease in precipitation levels over weeks, months, or years

economic water scarcity

when there is a lack of money and resources to utilize adequate sources of water

fall line

a narrow zone between an elevated region and a plain where rivers form falls and rapids

flood

an event where land is covered with more water than it can soak up

global average temperature

the average of thousands of temperature measurements in the atmosphere, oceans, and on land over a specific time period

hydraulic fracturing (fracking)

a process of fracturing rocks by injecting liquid at high pressure to extract oil or gas

hydropower

power produced by capturing the energy of flowing water

land subsidence

sinking of land

permeability of rocks

the ease with which rocks allow liquids to pass through

physical water scarcity

when there is limited access to water supply

recharge

restore or refill

resource

a source or supply that a country has and can use to increase its wealth

saltwater intrusion

the movement of saline water into freshwater aquifers

sanitation

systems to treat and dispose of waste to prevent the spread of disease

sea level

the average altitude of the surface of one or more of the world's oceans

supply

the amount of a resource that is available to consumers

turbidity

cloudiness in water caused by stirred up sediments or by algae or other microscopic organisms

virtual water

water used in production of services and goods that consumers need and enjoy

wastewater

water than has been used for household or industrial purposes

water privatization

when private companies buy or operate public water utilities

water table

a boundary between unsaturated ground and saturated ground

Water Quality and Conservation

aquaponics

the farming of plants and aquatic animals in a recirculating environment

biodiesel

a fuel similar to fossil diesel fuel that is derived from organic sources such as plant or animal oils

biodiversity

the variety of life within an ecosystem, including all plants and animals

Clean Water Act (CWA)

law that regulates discharges of pollutants into U.S. waters and regulates the quality standards for surface water

Environmental Protection Agency (EPA)

a federal agency of the United States government that sets and enforces guidelines that protect the environment

eutrophication

excessive nutrients in a water body causing overgrowth of algae, plankton, and other microorganisms

ground water

water stored in the cracks and spaces of underground rock

hydrologic cycle (water cycle)

the continual movement of water throughout Earth's atmosphere, oceans, and land surface by evaporation, transpiration, condensation, and precipitation

hydrologist

a scientist who studies how water interacts with Earth's systems and helps manage water resources

hydrology

the study of the occurrence, movement, distribution, and quality of water throughout Earth

nonpoint source pollution

pollution that does not come from a single, identifiable point

term

definition

nonpotable

not safe for drinking

point source pollution

pollution that comes from an identifiable confined source such as a smokestack or wastewater treatment plant

runoff

precipitation or irrigation water that reaches streams, rivers, lakes, or the ocean, often carrying pollutants

Safe Drinking Water Act (SDWA)

an act passed in 1974 that ensures drinking water is safe by requiring drinking water to be monitored for microorganisms, disinfectants, disinfectant by-products, inorganic and organic chemicals, and radionuclides

surface water

bodies of water on the surface of Earth such as oceans, rivers, and lakes

wastewater

water that has been used for household or industrial purposes

water pollution

harmful substances contaminating a stream, river, lake, ocean, aquifer, or other body of water, lowering water quality and making the water toxic

water treatment

the process of removing physical, biological, and chemical contaminants from wastewater and household water

water-saving technologies

the application of scientific knowledge to save water