Glossary

abscissa:

the x-coordinate of a point in a Cartesian coordinate plane

absolute:

standing alone, without reference to arbitrary standards of measurement

absolute dating:

determining the date of an artifact by measuring some physical parameter independent of context

absolute value:

the non-negative value of a number regardless of sign

absolute zero:

the coldest possible temperature on any temperature scale; −273° Celsius

abstract:

having only intrinsic form

abstract algebra:

the branch of algebra dealing with groups, rings, fields, Galois sets, and number theory

acceleration:

the rate of change of an object's velocity

accelerometer:

a device that measures acceleration

acute:

sharp, pointed; in geometry, an angle whose measure is less than 90 degrees

additive inverse:

any two numbers that add to equal 1

advection:

a local change in a property of a system

aerial photography:

photographs of the ground taken from an airplane or balloon; used in mapping and surveying

aerodynamics:

the study of what makes things fly; the engineering discipline specializing in aircraft design

aesthetic:

having to do with beauty or artistry

aesthetic value:

the value associated with beauty or attractiveness; distinct from monetary value

algebra:

the branch of mathematics that deals with variables or unknowns representing the arithmetic numbers

algorithm:

a rule or procedure used to solve a mathematical problem

algorithmic:

pertaining to an algorithm

ambiguity:

the quality of doubtfulness or uncertainty

analog encoding:

encoding information using continuous values of some physical quantity

analogy:

comparing two things similar in some respects and inferring they are also similar in other respects

analytical geometry:

describes the study of geometric properties by using algebraic operations

anergy:

spent energy transferred to the environment

angle of elevation:

the angle formed by a line of sight above the horizontal

angle of rotation:

the angle measured from an initial position a rotating object has moved through

anti-aliasing:

introducing shades of gray or other intermediate shades around an image to make the edge appear to be smoother

applications:

collections of general-purpose software such as word processors and database programs used on modern personal computers

arc:

a continuous portion of a circle; the portion of a circle between two line segments originating at the center of the circle

areagraph:

a fine-scale rectangular grid used for determining the area of irregular plots

artifact:

something made by a human and left in an archaeological context

artificial intelligence:

the field of research attempting the duplication of the human thought process with digital computers or similar devices; also includes expert systems research

ASCII:

an acronym that stands for American Standard Code for Information Interchange; assigns a unique 8-bit binary number to every letter of the alphabet, the digits, and most keyboard symbols

assets:

real, tangible property held by a business corporation including collectible debts to the corporation

asteroid:

a small object or "minor planet" orbiting the Sun, usually in the space between Mars and Jupiter

astigmatism:

a defect of a lens, such as within an eye, that prevents focusing on sharply defined objects

astrolabe:

a device used to measure the angle between an astronomical object and the horizon

astronomical unit (AU):

the average distance of Earth from the Sun; the semi-major axis of Earth's orbit

asymptote:

the line that a curve approaches but never reaches

asymptotic:

pertaining to an asymptote

atmosphere (unit):

a unit of pressure equal to 14.7 lbs/in², which is the air pressure at mean sea level

atomic weight:

the relative mass of an atom based on a scale in which a specific carbon atom (carbon-12) is assigned a mass value of 12

autogiro:

a rotating wing aircraft with a powered propellor to provide thrust and an unpowered rotor for lift; also spelled "autogyro"

avatar:

representation of user in virtual space (after the Hindu idea of an incarnation of a deity in human form)

average rate of change:

how one variable changes as the other variable increases by a single unit

axiom:

a statement regarded as self-evident; accepted without proof

axiomatic system:

a system of logic based on certain axioms and definitions that are accepted as true without proof

axis:

an imaginary line about which an object rotates

axon:

fiber of a nerve cell that carries action potentials (electrochemical impulses)

azimuth:

the angle, measured along the horizon, between north and the position of an object or direction of movement

azimuthal projections:

a projection of a curved surface onto a flat plane

bandwidth:

a range within a band of wavelengths or frequencies

base-10:

a number system in which each place represents a power of 10 larger than the place to its right

base-2:

a binary number system in which each place represents a power of 2 larger than the place to its right

base-20:

a number system in which each place represents a power of 20 larger than the place to the right

base-60:

a number system used by ancient Mesopotamian cultures for some calculations in which each place represents a power of 60 larger than the place to its right

baseline:

the distance between two points used in parallax measurements or other triangulation techniques

Bernoulli's Equation:

a first order, nonlinear differential equation with many applications in fluid dynamics

biased sampling:

obtaining a nonrandom sample; choosing a sample to represent a particular viewpoint instead of the whole population

bidirectional frame:

in compressed video, a frame between two other frames; the information is based on what changed from the previous frame as well as what will change in the next frame

bifurcation value:

the numerical value near which small changes in the initial value of a variable can cause a function to take on widely different values or even completely different behaviors after several iterations

Big Bang:

the singular event thought by most cosmologists to represent the beginning of our universe; at the moment of the big bang, all matter, energy, space, and time were concentrated into a single point

binary:

existing in only two states, such as "off" or "on," "one" or "zero"

binary arithmetic:

the arithmetic of binary numbers; base two arithmetic; internal arithmetic of electronic digital logic

binary number:

a base-2 number; a number that uses only the binary digits 1 and 0

binary signal:

a form of signal with only two states, such as two different values of voltage, or "on" and "off" states

binary system:

a system of two stars that orbit their common center of mass; any system of two things

binomial:

an expression with two terms

binomial coefficients:

coefficients in the expansion of (x + y)ⁿ, where n is a positive integer

binomial distribution:

the distribution of a binomial random variable

binomial theorem:

a theorem giving the procedure by which a binomial expression may be raised to any power without using successive multiplications

bioengineering:

the study of biological systems such as the human body using principles of engineering

biomechanics:

the study of biological systems using engineering principles

bioturbation:

disturbance of the strata in an archaeological site by biological factors such as rodent burrows, root action, or human activity

bit:

a single binary digit, 1 or 0

bitmap:

representing a graphic image in the memory of a computer by storing information about the color and shade of each individual picture element (or pixel)

Boolean algebra:

a logic system developed by George Boole that deals with the theorems of undefined symbols and axioms concerning those symbols

Boolean operators:

the set of operators used to perform operations on sets; includes the logical operators AND, OR, NOT

byte:

a group of eight binary digits; represents a single character of text

cadaver:

a corpse intended for medical research or training

caisson:

a large cylinder or box that allows workers to perform construction tasks below the water surface, may be open at the top or sealed and pressurized

calculus:

a method of dealing mathematically with variables that may be changing continuously with respect to each other

calibrate:

act of systematically adjusting, checking, or standardizing the graduation of a measuring instrument

carrying capacity:

in an ecosystem, the number of individuals of a species that can remain in a stable, sustainable relationship with the available resources

Cartesian coordinate system:

a way of measuring the positions of points in a plane using two perpendicular lines as axes

Cartesian plane:

a mathematical plane defined by the x and y axes or the ordinate and abscissa in a Cartesian coordinate system

cartographers:

persons who make maps

catenary curve:

the curve approximated by a free-hanging chain supported at each end; the curve generated by a point on a parabola rolling along a line

causal relations:

responses to input that do not depend on values of the input at later times

celestial:

relating to the stars, planets, and other heavenly bodies

celestial body:

any natural object in space, defined as above Earth's atmosphere; the Moon, the Sun, the planets, asteroids, stars, galaxies, nebulae

central processor:

the part of a computer that performs computations and controls and coordinates other parts of the computer

centrifugal:

the outwardly directed force a spinning object exerts on its restraint; also the perceived force felt by persons in a rotating frame of reference

cesium:

a chemical element, symbol Cs, atomic number 55

Chandrasekhar limit:

the 1.4 solar mass limit imposed on a white dwarf by quantum mechanics; a white dwarf with greater than 1.4 solar masses will collapse to a neutron star

chaos theory:

the qualitative study of unstable aperiodic behavior in deterministic nonlinear dynamical systems

chaotic attractor:

a set of points such that all nearby trajectories converge to it

chert:

material consisting of amorphous or cryptocrystalline silicon dioxide; fine-grained chert is indistinguishable from flint

chi-square test:

a generalization of a test for significant differences between a binomial population and a multinomial population

chlorofluorocarbons:

compounds similar to hydrocarbons in which one or more of the hydrogen atoms has been replaced by a chlorine or fluorine atom

chord:

a straight line connecting the end points of an arc of a circle

chromakey:

photographing an object shot against a known color, which can be replaced with an arbitrary background (like the weather maps on television newscasts)

chromosphere:

the transparent layer of gas that resides above the photosphere in the atmosphere of the Sun

chronometer:

an extremely precise timepiece

ciphered:

coded; encrypyted

circumference:

the distance around a circle

circumnavigation:

the act of sailing completely around the globe

circumscribed:

bounded, as by a circle

circumspheres:

spheres that touch all the "outside" faces of a regular polyhedron

client:

an individual, business, or agency for whom services are provided by another individual, business, or industry; a patron or customer

clones:

computers assembled of generic components designed to use a standard operation system

codomain:

for a given function f, the set of all possible values of the function; the range is a subset of the codomain

cold dark matter:

hypothetical form of matter proposed to explain the 90 percent of mass in most galaxies that cannot be detected because it does not emit or reflect radiation

coma:

the cloud of gas that first surrounds the nucleus of a comet as it begins to warm up

combinations:

a group of elements from a set in which order is not important

combustion:

chemical reaction combining fuel with oxygen accompanied by the release of light and heat

comet:

a lump of frozen gas and dust that approaches the Sun in a highly elliptical orbit forming a coma and one or two tails

command:

a particular instruction given to a computer, usually as part of a list of instructions comprising a program

commodities:

anything having economic value, such as agricultural products or valuable metals

compendium:

a summary of a larger work or collection of works

compiler:

a computer program that translates symbolic instructions into machine code

complex plane:

the mathematical abstraction on which complex numbers can be graphed; the x-axis is the real component and the y-axis is the imaginary component

composite number:

an integer that is not prime

compression:

reducing the size of a computer file by replacing long strings of identical bits with short instructions about the number of bits; the information is restored before the file is used

compression algorithm:

the procedure used, such as comparing one frame in a movie to the next, to compress and reduce the size of electronic files

concave:

hollowed out or curved inward

concentric:

sets of circles or other geometric objects sharing the same center

conductive:

having the ability to conduct or transmit

confidence interval:

a range of values having a predetermined probability that the value of some measurement of a population lies within it

congruent:

exactly the same everywhere; having exactly the same size and shape

conic:

of or relating to a cone, that surface generated by a straight line, passing through a fixed point, and moving along the intersection with a fixed curve

conic sections:

the curves generated by an imaginary plane slicing through an imaginary cone

continuous quantities:

amounts composed of continuous and undistinguishable parts

converge:

come together; to approach the same numerical value

convex:

curved outward, bulging

coordinate geometry:

the concept and use of a coordinate system with respect to the study of geometry

coordinate plane:

an imaginary two-dimensional plane defined as the plane containing the x-and y-axes; all points on the plane have coordinates that can be expressed as x, y

coordinates:

the set of n numbers that uniquely identifies the location of a point in n-dimensional space

corona:

the upper, very rarefied atmosphere of the Sun that becomes visible around the darkened Sun during a total solar eclipse

corpus:

Latin for "body"; used to describe a collection of artifacts

correlate:

to establish a mutual or reciprocal relation between two things or sets of things

correlation:

the process of establishing a mutual or reciprocal relation between two things or sets of things

cosine:

if a unit circle is drawn with its center at the origin and a line segment is drawn from the origin at angle theta so that the line segment intersects the circle at (x, y), then x is the cosine of theta

cosmological distance:

the distance a galaxy would have to have in order for its red shift to be due to Hubble expansion of the universe

cosmology:

the study of the origin and evolution of the universe

cosmonaut:

the term used by the Soviet Union and now used by the Russian Federation to refer to persons trained to go into space; synonomous with astronaut

cotton gin:

a machine that separates the seeds, hulls, and other undesired material from cotton

cowcatcher:

a plow-shaped device attached to the front of a train to quickly remove obstacles on railroad tracks

cryptography:

the science of encrypting information for secure transmission

cubit:

an ancient unit of length equal to the distance from the elbow to the tip of the middle finger; usually about 18 inches

culling:

removing inferior plants or animals while keeping the best; also known as "thinning"

curved space:

the notion suggested by Albert Einstein to explain the properties of space near a massive object, space acts as if it were curved in four dimensions

deduction:

a conclusion arrived at through reasoning, especially a conclusion about some particular instance derived from general principles

deductive reasoning:

a type of reasoning in which a conclusion necessarily follows from a set of axioms; reasoning from the general to the particular

degree:

1/360 of a circle or complete rotation

degree of significance:

a determination, usually in advance, of the importance of measured differences in statistical variables

demographics:

statistical data about people—including age, income, and gender—that are often used in marketing

dendrite:

branched and short fiber of a neuron that carries information to the neuron

dependent variable:

in the equation y = f(x), if the function f assigns a single value of y to each value of x, then y is the output variable (or the dependent variable)

depreciate:

to lessen in value

deregulation:

the process of removing legal restrictions on the behavior of individuals or corporations

derivative:

the derivative of a function is the limit of the ratio of the change in the function; the change is produced by a small variation in the variable as the change in the variable is allowed to approach zero; an inverse operation to calculating an integral

determinant:

a square matrix with a single numerical value determined by a unique set of mathematical operations performed on the entries

determinate algebra:

the study and analysis of equations that have one or a few well-defined solutions

deterministic:

mathematical or other problems that have a single, well-defined solution

diameter:

the chord formed by an arc of one-half of a circle

differential:

a mathematical quantity representing a small change in one variable as used in a differential equation

differential calculus:

the branch of mathematics primarily dealing with the solution of differential equations to find lengths, areas, and volumes of functions

differential equation:

an equation that expresses the relationship between two variables that change in respect to each other, expressed in terms of the rate of change

digit:

one of the symbols used in a number system to represent the multiplier of each place

digital:

describes information technology that uses discrete values of a physical quantity to transmit information

digital encoding:

encoding information by using discrete values of some physical quantity

digital logic:

rules of logic as applied to systems that can exist in only discrete states (usually two)

dihedral:

a geometric figure formed by two half-planes that are bounded by the same straight line

Diophantine equation:

polynomial equations of several variables, with integer coefficients, whose solutions are to be integers

diopter:

a measure of the power of a lens or a prism, equal to the reciprocal of its focal length in meters

directed distance:

the distance from the pole to a point in the polar coordinate plane

discrete:

composed of distinct elements

discrete quantities:

amounts composed of separate and distinct parts

distributive property:

property such that the result of an operation on the various parts collected into a whole is the same as the operation performed separately on the parts before collection into the whole

diverge:

to go in different directions from the same starting point

dividend:

the number to be divided; the numerator in a fraction

divisor:

the number by which a dividend is divided; the denominator of a fraction

DNA fingerprinting:

the process of isolating and amplifying segments of DNA in order to uniquely identify the source of the DNA

domain:

the set of all values of a variable used in a function

double star:

a binary star; two stars orbiting a common center of gravity

duodecimal:

a numbering system based on 12

dynamometer:

a device that measures mechanical or electrical power

eccentric:

having a center of motion different from the geometric center of a circle

eclipse:

occurrence when an object passes in front of another and blocks the view of the second object; most often used to refer to the phenomenon that occurs when the Moon passes in front of the Sun or when the Moon passes through Earth's shadow

ecliptic:

the plane of the Earth's orbit around the Sun

eigenvalue:

if there exists a vector space such that a linear transformation onto itself produces a new vector equal to a scalar times the original vector, then that scalar is called an eigenfunction

eigenvector:

if there exists a vector space such that a linear transformation onto itself produces a new vector equal to a scalar times the original vector, then that vector is called an eigenvector

Einstein's General Theory of Relativity:

Albert Einstein's generalization of relativity to include systems accelerated with respect to one another; a theory of gravity

electromagnetic radiation:

the form of energy, including light, that transfers information through space

elements:

the members of a set

ellipse:

one of the conic sections, it is defined as the locus of all points such that the sum of the distances from two points called the foci is constant

elliptical:

a closed geometric curve where the sum of the distances of a point on the curve to two fixed points (foci) is constant

elliptical orbit:

a planet, comet, or satellite follows a curved path known as an ellipse when it is in the gravitational field of the Sun or another object; the Sun or other object is at one focus of the ellipse

empirical law:

a mathematical summary of experimental results

empiricism:

the view that the experience of the senses is the single source of knowledge

encoding tree:

a collection of dots with edges connecting them that have no looping paths

endangered species:

a species with a population too small to be viable

epicenter:

the point on Earth's surface directly above the site of an earthquake

epicycle:

the curved path followed by planets in Ptolemey's model of the solar system; planets moved along a circle called the epicycle, whose center moved along a circular orbit around the sun

epicylic:

having the property of moving along an epicycle

equatorial bulge:

the increase in diameter or circumference of an object when measured around its equator usually due to rotation, all planets and the sun have equatorial bulges

equidistant:

at the same distance

equilateral:

having the property that all sides are equal; a square is an equilateral rectangle

equilateral triangle:

a triangle whose sides and angles are equal

equilibrium:

a state of balance between opposing forces

equinox points:

two points on the celestial sphere at which the ecliptic intersects the celestial equator

escape speed:

the minimum speed an object must attain so that it will not fall back to the surface of a planet

Euclidean geometry:

the geometry of points, lines, angles, polygons, and curves confined to a plane

exergy:

the measure of the ability of a system to produce work; maximum potential work output of a system

exosphere:

the outermost layer of the atmosphere extending from the ionosphere upward

exponent:

the symbol written above and to the right of an expression indicating the power to which the expression is to be raised

exponential:

an expression in which the variable appears as an exponent

exponential power series:

the series by which e to the x power may be approximated; e^x = 1 + x + x^2/2! + x^3/3! + …

exponents:

symbols written above and to the right of expressions indicating the power to which an expression is to be raised or the number of times the expression is to be multiplied by itself

externality:

a factor that is not part of a system but still affects it

extrapolate:

to extend beyond the observations; to infer values of a variable outside the range of the observations

farsightedness:

describes the inability to see close objects clearly

fiber-optic:

a long, thin strand of glass fiber; internal reflections in the fiber assure that light entering one end is transmitted to the other end with only small losses in intensity; used widely in transmitting digital information

fibrillation:

a potentially fatal malfunction of heart muscle where the muscle rapidly and ineffectually twitches instead of pulsing regularly

fidelity:

in information theory a measure of how close the information received is to the information sent

finite:

having definite and definable limits; countable

fire:

the reaction of a neuron when excited by the reception of a neuro-transmitter

fission:

the splitting of the nucleus of a heavy atom, which releases kinetic energy that is carried away by the fission fragments and two or three neutrons

fixed term:

for a definite length of time determined in advance

fixed-wing aircraft:

an aircraft that obtains lift from the flow of air over a nonmovable wing

floating-point operations:

arithmetic operations on a number with a decimal point

fluctuate:

to vary irregularly

flue:

a pipe designed to remove exhaust gases from a fireplace, stove, or burner

fluid dynamics:

the science of fluids in motion

focal length:

the distance from the focal point (the principle point of focus) to the surface of a lens or concave mirror

focus:

one of the two points that define an ellipse; in a planetary orbit, the Sun is at one focus and nothing is at the other focus

formula analysis:

a method of analysis of the Boolean formulas used in computer programming

Fourier series:

an infinite series consisting of cosine and sine functions of integral multiples of the variable each multiplied by a constant; if the series is finite, the expression is known as a Fourier polynomial

fractal:

a type of geometric figure possessing the properties of self-similarity (any part resembles a larger or smaller part at any scale) and a measure that increases without bound as the unit of measure approaches zero

fractal forgery:

creating a natural landscape by using fractals to simulate trees, mountains, clouds, or other features

fractal geometry:

the study of the geometric figures produced by infinite iterations

futures exchange:

a type of exchange where contracts are negotiated to deliver commodites at some fixed price at some time in the future

g:

a common measure of acceleration; for example 1 g is the acceleration due to gravity at the Earth's surface, roughly 32 feet per second per second

game theory:

a discipline that combines elements of mathematics, logic, social and behavioral sciences, and philosophy

gametes:

mature male or female sexual reproductive cells

gaming:

playing games or relating to the theory of game playing

gamma ray:

a high-energy photon

general relativity:

generalization of Albert Einstein's theory of relativity to include accelerated frames of reference; presents gravity as a curvature of four-dimensional space-time

generalized inverse:

an extension of the concept of the inverse of a matrix to include matrices that are not square

generalizing:

making a broad statement that includes many different special cases

genus:

the taxonomic classification one step more general than species; the first name in the binomial nomenclature of all species

geoboard:

a square board with pegs and holes for pegs used to create geometric figures

geocentric:

Earth-centered

geodetic:

of or relating to geodesy, which is the branch of applied mathematics dealing with the size and shape of the earth, including the precise location of points on its surface

geometer:

a person who uses the principles of geometry to aid in making measurements

geometric:

relating to the principles of geometry, a branch of mathematics related to the properties and relationships of points, lines, angles, surfaces, planes, and solids

geometric sequence:

a sequence of numbers in which each number in the sequence is larger than the previous by some constant ratio

geometric series:

a series in which each number is larger than the previous by some constant ratio; the sum of a geometric sequence

geometric solid:

one of the solids whose faces are regular polygons

geometry:

the branch of mathematics that deals with the properties and relationships of points, lines, angles, surfaces, planes, and solids

geostationary orbit:

an Earth orbit made by an artificial satellite that has a period equal to the Earth's period of rotation on its axis (about 24 hours)

geysers:

springs that occasionally spew streams of steam and hot water

glide reflection:

a rigid motion of the plane that consists of a reflection followed by a translation parallel to the mirror axis

grade:

the amount of increase in elevation per horizontal distance, usually expressed as a percent; the slope of a road

gradient:

a unit used for measuring angles, in which the circle is divided into 400 equal units, called gradients

graphical user interface:

a device designed to display information graphically on a screen; a modern computer interface system

Greenwich Mean Time:

the time at Greenwich, England; used as the basis for universal time throughout the world

Gross Domestic Product:

a measure in the change in the market value of goods, services, and structures produced in the economy

group theory:

study of the properties of groups, the mathematical systems consisting of elements of a set and operations that can be performed on that set such that the results of the operations are always members of the same set

gyroscope:

a device typically consisting of a spinning wheel or disk, whose spin-axis turns between two low-friction supports; it maintains its angular orientation with respect to inertial conditions when not subjected to external forces

Hagia Sophia:

Instanbul's most famous landmark, built by the emperor Justinian I in 537 C.E. and converted to a mosque in 1453 C.E.

Hamming codes:

a method of error correction in digital information

headwind:

a wind blowing in the opposite direction as that of the course of a vehicle

Heisenberg Uncertainty Principle:

the principle in physics that asserts it is impossible to know simultaneously and with complete accuracy the values of certain pairs of physical quantities such as position and momentum

heliocentric:

Sun-centered

hemoglobin:

the oxygen-bearing, iron-containing conjugated protein in vertebrate red blood cells

heuristics:

a procedure that serves to guide investigation but that has not been proven

hominid:

a member of family Hominidae; Homo sapiens are the only surviving species

Huffman encoding:

a method of efficiently encoding digital information

hydrocarbon:

a compound of carbon and hydrogen

hydrodynamics:

the study of the behavior of moving fluids

hydrograph:

a tabular or graphical display of stream flow or water runoff

hydroscope:

a device designed to allow a person to see below the surface of water

hydrostatics:

the study of the properties of fluids not in motion

hyperbola:

a conic section; the locus of all points such that the absolute value of the difference in distance from two points called foci is a constant

hyperbolic:

an open geometric curve where the difference of the distances of a point on the curve to two fixed points (foci) is constant

Hypertext Markup Language:

the computer markup language used to create documents on the World Wide Web

hypertext:

the text that contains hyperlinks, that is, links to other places in the same document or other documents or multimedia files

hypotenuse:

the long side of a right triangle; the side opposite the right angle

hypothesis:

a proposition that is assumed to be true for the purpose of proving other propositions

ice age:

one of the broad spans of time when great sheets of ice covered the Northern parts of North America and Europe; the most recent ice age was about 16,000 years ago

identity:

a mathematical statement much stronger than equality, which asserts that two expressions are the same for all values of the variables

implode:

violently collapse; fall in

inclination:

a slant or angle formed by a line or plane with the horizontal axis or plane

inclined:

sloping, slanting, or leaning

incomplete interpretation:

a statistical flaw

independent variable:

in the equation y = f(x), the input variable is x (or the independent variable)

indeterminate algebra:

study and analysis of solution strategies for equations that do not have fixed or unique solutions

indeterminate equation:

an equation in which more than one variable is unknown

index (number):

a number that allows tracking of a quantity in economics by comparing it to a standard, the consumer price index is the best known example

inductive reasoning:

drawing general conclusions based on specific instances or observations; for example, a theory might be based on the outcomes of several experiments

Industrial Revolution:

beginning in Great Britain around 1730, a period in the eighteenth and nineteenth centuries when nations in Europe, Asia, and the Americas moved from agrarian-based to industry-based economies

inertia:

tendency of a body that is at rest to remain at rest, or the tendency of a body that is in motion to remain in motion

inferences:

the act or process of deriving a conclusion from given facts or premises

inferential statistics:

analysis and interpretation of data in order to make predictions

infinite:

having no limit; boundless, unlimited, endless; uncountable

infinitesimals:

functions with values arbitrarily close to zero

infinity:

the quality of unboundedness; a quantity beyond measure; an unbounded quantity

information database:

an array of information related to a specific subject or group of subjects and arranged so that any individual bit of information can be easily found and recovered

information theory:

the science that deals with how to separate information from noise in a signal or how to trace the flow of information through a complex system

infrastructure:

the foundation or permanent installations necessary for a structure or system to operate

initial conditions:

the values of variables at the beginning of an experiment or of a set at the beginning of a simulation; chaos theory reveals that small changes in initial conditions can produce widely divergent results

input:

information provided to a computer or other computation system

inspheres:

spheres that touch all the "inside" faces of a regular polyhedron; also called "enspheres"

integer:

a positive whole number, its negative counterpart, or zero

integral:

a mathematical operation similar to summation; the area between the curve of a function, the x-axis, and two bounds such as x = a and x = b; an inverse operation to finding the derivative

integral calculus:

the branch of mathematics dealing with the rate of change of functions with respect to their variables

integral number:

integer; that is, a positive whole number, its negative counterpart, or zero

integral solutions:

solutions to an equation or set of equations that are all integers

integrated circuit:

a circuit with the transistors, resistors, and other circuit elements etched into the surface of a single chip of silicon

integration:

solving a differential equation; determining the area under a curve between two boundaries

intensity:

the brightness of radiation or energy contained in a wave

intergalactic:

between galaxies; the space between the galaxies

interplanetary:

between planets; the space between the planets

interpolation:

filling in; estimating unknown values of a function between known values

intersection:

a set containing all of the elements that are members of two other sets

interstellar:

between stars; the space between stars

intraframe:

the compression applied to still images, interframe compression compares one image to the next and only stores the elements that have changed

intrinsic:

of itself; the essential nature of a thing; originating within the thing

inverse:

opposite; the mathematical function that expresses the independent variable of another function in terms of the dependent variable

inverse operations:

operations that undo each other, such as addition and subtraction

inverse square law:

a given physical quality varies with the distance from the source inversely as the square of the distance

inverse tangent:

the value of the argument of the tangent function that produces a given value of the function; the angle that produces a particular value of the tangent

invert:

to turn upside down or to turn inside out; in mathematics, to rewrite as the inverse function

inverted:

upside down; turned over

ionized:

an atom that has lost one or more of its electrons and has become a charged particle

ionosphere:

a layer in Earth's atmosphere above 80 kilometers characterized by the existence of ions and free electrons

irrational number:

a real number that cannot be written as a fraction of the form a/b, where a and b are both integers and b is not zero; when expressed in decimal form, an irrational number is infinite and nonrepeating

isometry:

equality of measure

isosceles triangle:

a triangle with two sides and two angles equal

isotope:

one of several species of an atom that has the same number of protons and the same chemical properties, but different numbers of neutrons

iteration:

repetition; a repeated mathematical operation in which the output of one cycle becomes the input for the next cycle

iterative:

relating to a computational procedure to produce a desired result by replication of a series of operations

iterator:

the mathematical operation producing the result used in iteration

kinetic energy:

the energy an object has as a consequence of its motion

kinetic theory of gases:

the idea that all gases are composed of widely separated particles (atoms and molecules) that exert only small forces on each other and that are in constant motion

knot:

nautical mile per hour

Lagrange points:

two positions in which the motion of a body of negligible mass is stable under the gravitational influence of two much larger bodies (where one larger body is moving)

latitude:

the number of degrees on Earth's surface north or south of the equator; the equator is latitude zero

law:

a principle of science that is highly reliable, has great predictive power, and represents the mathematical summary of experimental results

law of cosines:

for a triangle with angles A, B, C and sides a, b, c, a² = b² + c² − 2bc cos A

law of sines:

if a triangle has sides a, b, and c and opposite angles A, B, and C, then sin A/a = sin B/b = sin C/c

laws of probability:

set of principles that govern the use of probability in determining the truth or falsehood of a hypothesis

light-year:

the distance light travels within a vaccuum in one year

limit:

a mathematical concept in which numerical values get closer and closer to a given value

linear algebra:

the study of vector spaces and linear transformations

linear equation:

an equation in which all variables are raised to the first power

linear function:

a function whose graph on the x-y plane is a straight line or line segment

litmus test:

a test that uses a single indicator to prompt a decision

locus (pl: loci):

in geometry, the set of all points, lines, or surfaces that satisfies a particular requirement

logarithm:

the power to which a certain number called the base is to be raised to produce a particular number

logarithmic coordinates:

the x and y coordinates of a point on a cartesian plane using logarithmic scales on the x-and y-axes.

logarithmic scale:

a scale in which the distances that numbers are positioned, from a reference point, are proportional to their logarithms

logic circuits:

circuits used to perform logical operations and containing one or more logic elements: devices that maintain a state based on previous input to determine current and future output

logistic difference equation:

the equation x_{(n + 1)} = r × x_{n(1 - xn)} is used to study variability in animal populations

longitude:

one of the imaginary great circles beginning at the poles and extending around Earth; the geographic position east or west of the prime meridian

machine code:

the set of instructions used to direct the internal operation of a computer or other information-processing system

machine language:

electronic code the computer can utilize

magnetic trap:

a magnetic field configured in such a way that an ion or other charged particle can be held in place for an extended period of time

magnetosphere:

an asymmetric region surrounding the Earth in which charged particles are trapped, their behavior being dominated by Earth's magnetic field

magnitude:

size; the measure or extent of a mathematical or physical quantity

mainframes:

large computers used by businesses and government agencies to process massive amounts of data; generally faster and more powerful than desktops but usually requiring specialized software

malfunctioning:

not functioning correctly; performing badly

malleability:

the ability or capability of being shaped or formed

margin of error:

the difference between the estimated maximum and minimum values a given measurement could have

mathematical probability:

the mathematical computation of probabilities of outcomes based on rules of logic

matrix:

a rectangular array of data in rows and columns

mean:

the arithmetic average of a set of data

median:

the middle of a set of data when values are sorted from smallest to largest (or largest to smallest)

megabyte:

term used to refer to one million bytes of memory storage, where each byte consists of eight bits; the actual value is 1,048,576 (2²⁰)

memory:

a device in a computer designed to temporarily or permanently store information in the form of binomial states of certain circuit elements

meridian:

a great circle passing through Earth's poles and a particular location

metallurgy:

the study of the properties of metals; the chemistry of metals and alloys

meteorologist:

a person who studies the atmosphere in order to understand weather and climate

methanol:

an alcohol consisting of a single carbon bonded to three hydrogen atoms and an O–H group

microcomputers:

an older term used to designate small computers designed to sit on a desktop and to be used by one person; replaced by the term personal computer

microgravity:

the apparent weightless condition of objects in free fall

microkelvin:

one-millionth of a kelvin

minicomputers:

a computer midway in size between a desktop computer and a main frame computer; most modern desktops are much more powerful than the older minicomputers and they have been phased out

minimum viable population:

the smallest number of individuals of a species in a particular area that can survive and maintain genetic diversity

mission specialist:

an individual trained by NASA to perform a specific task or set of tasks onboard a spacecraft, whose duties do not include piloting the spacecraft

mnemonic:

a device or process that aids one's memory

mode:

a kind of average or measure of central tendency equal to the number that occurs most often in a set of data

monomial:

an expression with one term

Morse code:

a binary code designed to allow text information to be transmitted by telegraph consisting of "dots" and "dashes"

mouse:

a handheld pointing device used to manipulate an indicator on a screen

moving average:

a method of averaging recent trends in relation to long term averages, it uses recent data (for example, the last 10 days) to calculate an average that changes but still smooths out daily variations

multimodal input/output (I/O):

multimedia control and display that uses various senses and interaction styles

multiprocessing:

a computer that has two or more central processers which have common access to main storage

nanometers:

billionths of a meter

nearsightedness:

describes the inability to see distant objects clearly

negative exponential:

an exponential function of the form y = e^−x

net force:

the final, or resultant, influence on a body that causes it to accelerate

neuron:

a nerve cell

neurotransmitters:

the substance released by a neuron that diffuses across the synapse

neutron:

an elementary particle with approximately the same mass as a proton and neutral charge

Newtonian:

a person who, like Isaac Newton, thinks the universe can be understood in terms of numbers and mathematical operations

nominal scales:

a method for sorting objects into categories according to some distinguishing characteristic, then attaching a label to each category

non-Euclidean geometry:

a branch of geometry defined by posing an alternate to Euclid's fifth postulate

nonlinear transformation:

a transformation of a function that changes the shape of a curve or geometric figure

nonlinear transformations:

transformations of functions that change the shape of a curve or geometric figure

nuclear fission:

a reaction in which an atomic nucleus splits into fragments

nuclear fusion:

mechanism of energy formation in a star; lighter nuclei are combined into heavier nuclei, releasing energy in the process

nucleotides:

the basic chemical unit in a molecule of nucleic acid

nucleus:

the dense, positive core of an atom that contains protons and neutrons

null hypothesis:

the theory that there is no validity to the specific claim that two variations of the same thing can be distinguished by a specific procedure

number theory:

the study of the properties of the natural numbers, including prime numbers, the number theorem, and Fermat's Last Theorem

numerical differentiation:

approximating the mathematical process of differentiation using a digital computer

nutrient:

a food substance or mineral required for the completion of the life cycle of an organism

oblate spheroid:

a spheroid that bulges at the equator; the surface created by rotating an ellipse 360 degrees around its minor axis

omnidirectional:

a device that transmits or receives energy in all directions

Öort cloud:

a cloud of millions of comets and other material forming a spherical shell around the solar system far beyond the orbit of Neptune

orbital period:

the period required for a planet or any other orbiting object to complete one complete orbit

orbital velocity:

the speed and direction necessary for a body to circle a celestial body, such as Earth, in a stable manner

ordinate:

the y-coordinate of a point on a Cartesian plane

organic:

having to do with life, growing naturally, or dealing with the chemical compounds found in or produced by living organisms

oscillating:

moving back and forth

outliers:

extreme values in a data set

output:

information received from a computer or other computation system based on the information it has received

overdubs:

adding voice tracks to an existing film or tape

oxidant:

a chemical reagent that combines with oxygen

oxidizer:

the chemical that combines with oxygen or is made into an oxide

pace:

an ancient measure of length equal to normal stride length

parabola:

a conic section; the locus of all points such that the distance from a fixed point called the focus is equal to the perpendicular distance from a line

parabolic:

an open geometric curve where the distance of a point on the curve to a fixed point (focus) and a fixed line (directrix) is the same

paradigm:

an example, pattern, or way of thinking

parallax:

the apparent motion of a nearby object when viewed against the background of more distant objects due to a change in the observer's position

parallel operations:

separating the parts of a problem and working on different parts at the same time

parallel processing:

using at least two different computers or working at least two different central processing units in the same computer at the same time or "in parallel" to solve problems or to perform calculation

parallelogram:

a quadrilateral with opposite sides equal and opposite angles equal

parameter:

an independent variable, such as time, that can be used to rewrite an expression as two separate functions

parity bits:

extra bits inserted into digital signals that can be used to determine if the signal was accurately received

partial sum:

with respect to infinite series, the sum of its first n terms for some n

pattern recognition:

a process used by some artificial-intelligence systems to identify a variety of patterns, including visual patterns, information patterns buried in a noisy signal, and word patterns imbedded in text

payload specialist:

an individual selected by NASA, another government agency, another government, or a private business, and trained by NASA to operate a specific piece of equipment onboard a spacecraft

payloads:

the passengers, crew, instruments, or equipment carried by an aircraft, spacecraft, or rocket

perceptual noise shaping:

a process of improving signal-to-noise ratio by looking for the patterns made by the signal, such as speech

perimeter:

the distance around an area; in fractal geometry, some figures have a finite area but infinite perimeter

peripheral vision:

outer area of the visual field

permutation:

any arrangement, or ordering, of items in a set

perpendicular:

forming a right angle with a line or plane

perspective:

the point of view; a drawing constructed in such a way that an appearance of three dimensionality is achieved

perturbations:

small displacements in an orbit

phonograph:

a device used to recover the information recorded in analog form as waves or wiggles in a spiral grove on a flat disc of vinyl, rubber, or some other substance

photosphere:

the very bright portion of the Sun visible to the unaided eye; the portion around the Sun that marks the boundary between the dense interior gases and the more diffuse

photosynthesis:

the chemical process used by plants and some other organisms to harvest light energy by converting carbon dioxide and water to carbohydrates and oxygen

pixel:

a single picture element on a video screen; one of the individual dots making up a picture on a video screen or digital image

place value:

in a number system, the power of the base assigned to each place; in base-10, the ones place, the tens place, the hundreds place, and so on

plane:

generally considered an undefinable term, a plane is a flat surface extending in all directions without end, and that has no thickness

plane geometry:

the study of geometric figures, points, lines, and angles and their relationships when confined to a single plane

planetary:

having to do with one of the planets

planisphere:

a projection of the celestial sphere onto a plane with adjustable circles to demonstrate celestial phenomena

plates:

the crustal segments on Earth's surface, which are constantly moving and rotating with respect to each other

plumb-bob:

a heavy, conical-shaped weight, supported point-down on its axis by a strong cord, used to determine verticality in construction or surveying

pneumatic drill:

a drill operated by compressed air

pneumatic tire:

air-filled tire, usually rubber or synthetic

polar axis:

the axis from which angles are measured in a polar coordinate system

pole:

the origin of a polar coordinate system

poll:

a survey designed to gather information about a subject

pollen analysis:

microscopic examination of pollen grains to determine the genus and species of the plant producing the pollen; also known as palynology

polyconic projections:

a type of map projection of a globe onto a plane that produces a distorted image but preserves correct distances along each meridian

polygon:

a geometric figure bounded by line segments

polyhedron:

a solid formed with all plane faces

polynomial:

an expression with more than one term

polynomial function:

a functional expression written in terms of a polynomial

position tracking:

sensing the location and/or orientation of an object

power:

the number of times a number is to be multiplied by itself in an expression

precalculus:

the set of subjects and mathematical skills generally necessary to understand calculus

predicted frame:

in compressed video, the next frame in a sequence of images; the information is based on what changed from the previous frame

prime:

relating to, or being, a prime number (that is, a number that has no factors other than itself and 1)

Prime Meridian:

the meridian that passes through Greenwich, England

prime number:

a number that has no factors other than itself and 1

privatization:

the process of converting a service traditionally offered by a government or public agency into a service provided by a private corporation or other private entity

proactive:

taking action based on prediction of future situations

probability:

the likelihood an event will occur when compared to other possible outcomes

probability density function:

a function used to estimate the likelihood of spotting an organism while walking a transect

probability theory:

the branch of mathematics that deals with quantities having random distributions

processor:

an electronic device used to process a signal or to process a flow of information

profit margin:

the difference between the total cost of a good or service and the actual selling cost of that good or service, usually expressed as a percentage

program:

a set of instructions given to a computer that allows it to perform tasks; software

programming language processor:

a program designed to recognize and process other programs

proliferation:

growing rapidly

proportion:

the mathematical relation between one part and another part, or between a part and the whole; the equality of two ratios

proportionately:

divided or distributed according to a proportion; proportional

protractor:

a device used for measuring angles, usually consisting of a half circle marked in degrees

pseudorandom numbers:

numbers generated by a process that does not guarantee randomness; numbers produced by a computer using some highly complex function that simulates true randomness

Ptolemaic theory:

the theory that asserted Earth was a spherical object at the center of the universe surrounded by other spheres carrying the various celestial objects

Pythagorean Theorem:

a mathematical statement relating the sides of right triangles; the square of the hypotenuse is equal to the sums of the squares of the other two sides

Pythagorean triples:

any set of three numbers obeying the Pythogorean relation such that the square of one is equal to the sum of the squares of the other two

quadrant:

one-fourth of a circle; also a device used to measure angles above the horizon

quadratic:

involving at least one term raised to the second power

quadratic equation:

an equation in which the variable is raised to the second power in at least one term when the equation is written in its simplest form

quadratic form:

the form of a function written so that the independent variable is raised to the second power

quantitative:

of, relating to, or expressible in terms of quantity

quantum:

a small packet of energy (matter and energy are equivalent)

quantum mechanics:

the study of the interactions of matter with radiation on an atomic or smaller scale, whereby the granularity of energy and radiation becomes apparent

quantum theory:

the study of the interactions of matter with radiation on an atomic or smaller scale, whereby the granularity of energy and radiation becomes apparent

quaternion:

a form of complex number consisting of a real scalar and an imaginary vector component with three dimensions

quipus:

knotted cords used by the Incas and other Andean cultures to encode numeric and other information

radian:

an angle measure approximately equal to 57.3 degrees, it is the angle that subtends an arc of a circle equal to one radius

radicand:

the quantity under the radical sign; the argument of the square root function

radius:

the line segment originating at the center of a circle or sphere and terminating on the circle or sphere; also the measure of that line segment

radius vector:

a line segment with both magnitude and direction that begins at the center of a circle or sphere and runs to a point on the circle or sphere

random:

without order

random walks:

a mathematical process in a plane of moving a random distance in a random direction then turning through a random angle and repeating the process indefinitely

range:

the set of all values of a variable in a function mapped to the values in the domain of the independent variable; also called range set

rate (interest):

the portion of the principal, usually expressed as a percentage, paid on a loan or investment during each time interval

ratio of similitude:

the ratio of the corresponding sides of similar figures

rational number:

a number that can be written in the form a/b, where a and b are intergers and b is not equal to zero

rations:

the portion of feed that is given to a particular animal

ray:

half line; line segment that originates at a point and extends without bound

real number:

a number that has no imaginary part; a set composed of all the rational and irrational numbers

real number set:

the combined set of all rational and irrational numbers, the set of numbers representing all points on the number line

realtime:

occuring immediately, allowing interaction without significant delay

reapportionment:

the process of redistributing the seats of the U. S. House of Representatives, based on each state's proportion of the national population

recalibration:

process of resetting a measuring instrument so as to provide more accurate measurements

reciprocal:

one of a pair of numbers that multiply to equal 1; a number's reciprocal is 1 divided by the number

redshift:

motion-induced change in the frequency of light emitted by a source moving away from the observer

reflected:

light or soundwaves returned from a surface

reflection:

a rigid motion of the plane that fixes one line (the mirror axis) and moves every other point to its mirror image on the opposite side of the line

reflexive:

directed back or turning back on itself

refraction:

the change in direction of a wave as it passes from one medium to another

refrigerants:

fluid circulating in a refrigerator that is successively compressed, cooled, allowed to expand, and warmed in the refrigeration cycle

regular hexagon:

a hexagon whose sides are all equal and whose angles are all equal

relative:

defined in terms of or in relation to other quantities

relative dating:

determining the date of an archaeological artifact based on its position in the archaeological context relative to other artifacts

relativity:

the assertion that measurements of certain physical quantities such as mass, length, and time depend on the relative motion of the object and observer

remediate:

to provide a remedy; to heal or to correct a wrong or a deficiency

retrograde:

apparent motion of a planet from east to west, the reverse of normal motion; for the outer planets, due to the more rapid motion of Earth as it overtakes an outer planet

revenue:

the income produced by a source such as an investment or some other activity; the income produced by taxes and other sources and collected by a governmental unit

rhomboid:

a parallelogram whose sides are equal

right angle:

the angle formed by perpendicular lines; it measures 90 degrees

RNA:

ribonucleic acid

robot arm:

a sophisticated device that is standard equipment on space shuttles and on the International Space Station; used to deploy and retrieve satellites or perform other functions

Roche limit:

an imaginary surface around a star in a binary system; outside the Roche limit, the gravitational attraction of the companion will pull matter away from a star

root:

a number that when multiplied by itself a certain number of times forms a product equal to a specified number

rotary-wing design:

an aircraft design that uses a rotating wing to produce lift; helicopter or autogiro (also spelled autogyro)

rotation:

a rigid motion of the plane that fixes one point (the center of rotation) and moves every other point around a circle centered at that point

rotational:

having to do with rotation

round:

also to round off, the systematic process of reducing the number of decimal places for a given number

rounding:

process of giving an approximate number

sample:

a randomly selected subset of a larger population used to represent the larger population in statistical analysis

sampling:

selecting a subset of a group or population in such a way that valid conclusions can be made about the whole set or population

scale (map):

the numerical ratio between the dimensions of an object and the dimensions of the two or three dimensional representation of that object

scale drawing:

a drawing in which all of the dimensions are reduced by some constant factor so that the proportions are preserved

scaling:

the process of reducing or increasing a drawing or some physical process so that proper proportions are retained between the parts

schematic diagram:

a diagram that uses symbols for elements and arranges these elements in a logical pattern rather than a practical physical arrangement

schematic diagrams:

wiring diagrams that use symbols for circuit elements and arranges these elements in a logical pattern rather than a practical physical arrangement

search engine:

software designed to search the Internet for occurences of a word, phrase, or picture, usually provided at no cost to the user as an advertising vehicle

secant:

the ratio of the side adjacent to an acute angle in a right triangle to the side opposite; given a unit circle, the ratio of the x coordinate to the y coordinate of any point on the circle

seismic:

subjected to, or caused by an earthquake or earth tremor

self-similarity:

the term used to describe fractals where a part of the geometric figure resembles a larger or smaller part at any scale chosen

semantic:

the study of how words acquire meaning and how those meanings change over time

semi-major axis:

one-half of the long axis of an ellipse; also equal to the average distance of a planet or any satellite from the object it is orbiting

semiconductor:

one of the elements with characteristics intermediate between the metals and nonmetals

set:

a collection of objects defined by a rule such that it is possible to determine exactly which objects are members of the set

set dancing:

a form of dance in which dancers are guided through a series of moves by a caller

set theory:

the branch of mathematics that deals with the well-defined collections of objects known as sets

sextant:

a device for measuring altitudes of celestial objects

signal processor:

a device designed to convert information from one form to another so that it can be sent or received

significant difference:

to distinguish greatly between two parameters

significant digits:

the digits reported in a measure that accurately reflect the precision of the measurement

silicon:

element number 14, it belongs in the category of elements known as metalloids or semiconductors

similar:

in mathematics, having sides or parts in constant proportion; two items that resemble each other but are not identical

sine:

if a unit circle is drawn with its center at the origin and a line segment is drawn from the origin at angle theta so that the line segment intersects the circle at (x, y), then y is the sine of theta

skepticism:

a tendency towards doubt

skew:

to cause lack of symmetry in the shape of a frequency distribution

slope:

the ratio of the vertical change to the corresponding horizontal change

software:

the set of instructions given to a computer that allows it to perform tasks

solar masses:

dimensionless units in which mass, radius, luminosity, and other physical properties of stars can be expressed in terms of the Sun's characteristics

solar wind:

a stream of particles and radiation constantly pouring out of the Sun at high velocities; partially responsible for the formation of the tails of comets

solid geometry:

the geometry of solid figures, spheres, and polyhedrons; the geometry of points, lines, surfaces, and solids in three-dimensional space

spatial sound:

audio channels endowed with directional and positional attributes (like azimuth, elevation, and range) and room effects (like echoes and reverberation)

spectra:

the ranges of frequencies of light emitted or absorbed by objects

spectrum:

the range of frequencies of light emitted or absorbed by an object

sphere:

the locus of points in three-dimensional space that are all equidistant from a single point called the center

spin:

to rotate on an axis or turn around

square:

a quadrilateral with four equal sides and four right angles

square root:

with respect to real or complex numbers s, the number t for which t² = s

stade:

an ancient Greek measurement of length, one stade is approximately 559 feet (about 170 meters)

standard deviation:

a measure of the average amount by which individual items of data might be expected to vary from the arithmetic mean of all data

static:

without movement; stationary

statistical analysis:

a set of methods for analyzing numerical data

statistics:

the branch of mathematics that analyzes and interprets sets of numerical data

stellar:

having to do with stars

stereographics:

presenting slightly different views to left and right eyes, so that graphic scenes acquire depth

stochastic:

random, or relating to a variable at each moment

Stonehenge:

a large circle of standing stones on the Salisbury plain in England, thought by some to be an astronomical or calendrical marker

storm surge:

the front of a hurricane, which bulges because of strong winds; can be the most damaging part of a hurricane

stratopause:

the boundary in the atmosphere between the stratosphere and the mesosphere usually around 55 kilometers in altitude

stratosphere:

the layer of Earth's atmosphere from 15 kilometers to about 50 kilometers, usually unaffected by weather and lacking clouds or moisture

sublimate:

change of phase from a solid to a gas

sublunary:

"below the moon"; term used by Aristotle and others to describe things that were nearer to Earth than the Moon and so not necessarily heavenly in origin or composition

subtend:

to extend past and mark off a chord or arc

sunspot activity:

one of the powerful magnetic storms on the surface of the Sun, which causes it to appear to have dark spots; sunspot activity varies on an 11-year cycle

superconduction:

the flow of electric current without resistance in certain metals and alloys while at temperatures near absolute zero

superposition:

the placing of one thing on top of another

suspension bridge:

a bridge held up by a system of cables or cables and rods in tension; usually having two or more tall towers with heavy cables anchored at the ends and strung between the towers and lighter vertical cables extending downward to support the roadway

symmetric:

to have balanced proportions; in bilateral symmetry, opposite sides are mirror images of each other

symmetry:

a correspondence or equivalence between or among constituents of a system

synapse:

the narrow gap between the terminal of one neuron and the dendrites of the next

tactile:

relating to the sense of touch

tailwind:

a wind blowing in the same direction of that of the course of a vehicle

tangent:

a line that intersects a curve at one and only one point in a local region

tectonic plates:

large segments of Earth's crust that move in relation to one another

telecommuting:

working from home or another offsite location

tenable:

defensible, reasonable

terrestrial refraction:

the apparent raising or lowering of a distant object on Earth's surface due to variations in atmospheric temperature

tessellation:

a mosaic of tiles or other objects composed of identical repeated elements with no gaps

tesseract:

a four-dimensional cube, formed by connecting all of the vertices of two three-dimensional cubes separated by the length of one side in four-dimensional space

theodolite:

a surveying instrument designed to measure both horizontal and vertical angles

theorem:

a statement in mathematics that can be demonstrated to be true given that certain assumptions and definitions (called axioms) are accepted as true

threatened species:

a species whose population is viable but diminishing or has limited habitat

time dilation:

the principle of general relativity which predicts that to an outside observer, clocks would appear to run more slowly in a powerful gravitational field

topology:

the study of those properties of geometric figures that do not change under such nonlinear transformations as stretching or bending

topspin:

spin placed on a baseball, tennis ball, bowling ball, or other object so that the axis of rotation is horizontal and perpendicular to the line of flight and the top of the object is rotating in the same direction as the motion of the object

trajectory:

the path followed by a projectile; in chaotic systems, the trajectory is ordered and unpredictable

transcendental:

a real number that cannot be the root of a polynomial with rational coefficients

transect:

to divide by cutting transversly

transfinite:

surpassing the finite

transformation:

changing one mathematical expression into another by translation, mapping, or rotation according to some mathematical rule

transistor:

an electronic device consisting of two different kinds of semiconductor material, which can be used as a switch or amplifier

transit:

a surveyor's instrument with a rotating telescope that is used to measure angles and elevations

transitive:

having the mathematical property that if the first expression in a series is equal to the second and the second is equal to the third, then the first is equal to the third

translate:

to move from one place to another without rotation

translation:

a rigid motion of the plane that moves each point in the same direction and by the same distance

tree:

a collection of dots with edges connecting them that have no looping paths

triangulation:

the process of determining the distance to an object by measuring the length of the base and two angles of a triangle

trigonometric ratio:

a ratio formed from the lengths of the sides of right triangles

trigonometry:

the branch of mathematics that studies triangles and trigonometric functions

tropopause:

the boundry in Earth's atmosphere between the troposphere and the stratosphere at an altitude of 14 to 15 kilometers

troposphere:

the lowest layer of Earth's atmosphere extending from the surface up to about 15 kilometers; the layer where most weather phenomena occur

ultra-violet radiation:

electromagnetic radiation with wavelength shorter than visible light, in the range of 1 nanometer to about 400 nanometer

unbiased sample:

a random sample selected from a larger population in such a way that each member of the larger population has an equal chance of being in the sample

underspin:

spin placed on a baseball, tennis ball, bowling ball, or other object so that the axis of rotation is horizontal and perpendicular to the line of flight and the top of the object is rotating in the opposite direction from the motion of the object

Unicode:

a newer system than ASCII for assigning binary numbers to keyboard symbols that includes most other alphabets; uses 16-bit symbol sets

union:

a set containing all of the members of two other sets

upper bound:

the maximum value of a function

vaccuum:

theoretically, a space in which there is no matter

variable:

a symbol, such as letters, that may assume any one of a set of values known as the domain

variable star:

a star whose brightness noticeably varies over time

vector:

a quantity which has both magnitude and direction

velocity:

distance traveled per unit of time in a specific direction

verify:

confirm; establish the truth of a statement or proposition

vernal equinox:

the moment when the Sun crosses the celestial equator marking the first day of spring; occurs around March 22 for the northern hemisphere and September 21 for the southern hemisphere

vertex:

a point of a graph; a node; the point on a triangle or polygon where two sides come together; the point at which a conic section intersects its axis of symmetry

viable:

capable of living, growing, and developing

wavelengths:

the distance in a periodic wave between two points of corresponding phase in consecutive cycles

whole numbers:

the positive integers and zero

World Wide Web:

the part of the Internet allowing users to examine graphic "web" pages

yield (interest):

the actual amount of interest earned, which may be different than the rate

zenith:

the point on the celestial sphere vertically above a given position

zenith angle:

from an observer's viewpoint, the angle between the line of sight to a celestial body (such as the Sun) and the line from the observer to the zenith point

zero pair:

one positive integer and one negative integer

ziggurat:

a tower built in ancient Babylonia with a pyramidal shape and stepped sides