Carta:    UN B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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Magnitud Absoluta
Una escala para medir el brillo real de un objeto celestial sin las estadísticas para la distancia del objeto. Medidas absolutas de la magnitud cómo es brillante un objeto aparecería si estaba exactamente a 10 parsec (cerca de 33 años ligeros) lejos de la tierra. En esta escala, el sol tiene una magnitud absoluta de +4,8 mientras que tiene una magnitud evidente de -26,7 porque es así que cercano.

Absoluto Cero
La temperatura en la cual no se emite el movimiento de todas las paradas de los átomos y de las moléculas y ningún calor. El absoluto cero se alcanza en 0 grados Kelvin o -273,16 grados de centígrado.

Aumento
El proceso cerca donde el polvo y el gas acumularon en cuerpos más grandes tales como estrellas y planetas.

Albedo
La característica reflexiva de un objeto no-luminoso.   Un espejo perfecto tendría un albedo de el 100% mientras que un calabozo tendría un albedo de 0%.

Altitud
La distancia angular de un objeto sobre el horizonte.

Antimatter
Partículas que consisten en de la materia con las cargas enfrente de el de la materia ordinaria.   En antimatter, los protones tienen una carga negativa mientras que los electrones tienen una carga positiva.

Apastron
La punta de la separación más grande de dos estrellas, tales como adentro un sistema binario de la estrella.

Abertura
La talla de la apertura con la cual la luz pasa en un instrumento óptico tal como una cámara fotográfica o un telescopio. Un número más alto representa una apertura más pequeña mientras que un número más bajo representa una apertura más grande.

Asteroid
Un cuerpo planetario pequeño en órbita alrededor del sol, más grande que un meteoro pero más pequeño que un planeta.   La mayoría de los asteroides se pueden encontrar en una correa entre las órbitas de Marte y Júpiter.   Las órbitas de algunos asteroides los toman cerca del sol, que también los toma a través de los caminos de los planetas.

Unidad Astronómica (Au)
Una unidad de la medida igual a la distancia media entre la tierra y el sol, aproximadamente 93 millones de millas.

Atmósfera
Una capa de gases que rodean un planeta, una luna, o una estrella.   La atmósfera de la tierra es 120 millas de grueso y se compone principalmente del nitrógeno, del oxígeno, del bióxido de carbono, y de algún otro los gases del rastro.

Aurora
Un resplandor en el ionosphere de un planeta causado por la interacción entre el campo magnético del planeta y las partículas cargadas del sol. Este fenómeno se conoce como el Aurora Borealis en el hemisferio norteño de la tierra y el Aurora australis en el hemisferio meridional de la tierra.

Eje
También conocido como los postes, esto es una línea imaginaria a través del centro de la rotación de un objeto.

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Barra
Una unidad de la medida de presión atmosférica. Una barra es igual a 0,987 atmósferas, 1,02 kg/cm2, 100 kilopascal, y pulgada de 14,5 lbs/square.

Binario
Un sistema de dos estrellas que giran alrededor de un centro de gravedad común.

Calabozo
La base derrumbada de una estrella masiva.   Estrellas que son derrumbamiento muy masivo de la voluntad bajo su propia gravedad cuando se agota su combustible.   El derrumbamiento continúa hasta que toda la materia se machaca fuera de existencia en qué se conoce como singularidad.   La gravitación es tan fuerte que la luz no uniforme puede escaparse.

Blueshift
Una rotación en las líneas del espectro de un objeto hacia el extremo azul   Blueshift indica que un objeto se está moviendo hacia el observador. Cuanto más grande es el blueshift, más rápidamente el objeto se está moviendo.

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Caldera
Un tipo de cráter volcánico que es extremadamente grande, formado generalmente por el derrumbamiento de un cono volcánico o por una explosión volcánica violenta.   El lago crater es un ejemplo de una caldera en la tierra.

Postes Celestiales
Los postes del norte y del sur de la esfera celestial.

Esfera Celestial
Una esfera imaginaria alrededor de la tierra en la cual las estrellas y los planetas aparecen ser colocados.

Caos
Un área distintiva del terreno quebrado.

Chasma
Otro nombre describía una barranca.

Chondrule
Las esferas pequeñas, vidriosas encontraron comúnmente en meteoritos.

Chromosphere
La parte de la atmósfera del sun apenas sobre la superficie.

Coma
Un área del polvo o del gas que rodea el núcleo de un cometa.

Cometa
Una bola gigantesca del hielo y de la roca que mueven en órbita alrededor del sol en una órbita altamente excéntrica. Algunos cometas tienen una órbita que los traiga cerca del sol donde forman una cola larga del gas y el polvo mientras que son calentados por los rayos del sun.

Conjunción
Un acontecimiento que ocurre cuando objetos dos o más celestiales aparece cierre cercano junto en el cielo.

Constelación
El agrupar de las estrellas que hacen un cuadro imaginario en el cielo.

Rayo Cósmico
Núcleos atómicos (sobre todo protones) que se observan para pulso la atmósfera de la tierra con cantidades extremadamente altas de energía.

Cadena Cósmica
Una configuración del tubelike de la energía que se cree para haber existido en el universo temprano. Una cadena cósmica tendría un espesor más pequeño que un trillionth de una pulgada pero su longitud extendería a partir de un extremo del universo visible al otro.

Cosmology
Una ramificación de la ciencia que se ocupa de estudiar el origen, la estructura, y la naturaleza del universo.

Cráter
Una depresión en forma de cuenco formó por el impacto de un asteroide o de un meteoro. También la depresión alrededor de la apertura de un volcán.

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Materia Oscura
Un término describía la materia en el universo que no puede ser visto, pero se puede detectar por sus efectos gravitacionales sobre otros cuerpos.

Declinación
La distancia angular de un objeto en el cielo del ecuador celestial.

Densidad
La cantidad de materia contenida dentro de un volumen dado. La densidad se mide en gramos por centímetro cúbico (o kilogramos por litro). La densidad del agua es 1,0, el hierro es 7,9, y el terminal de componente es 11,3.

Disco
La superficie del sol o del otro cuerpo celeste proyectó contra el cielo.

Asteroide Doble
Dos asteroides que giran alrededor de uno a y son ligados por la gravedad entre ellos. También llamó un asteroide binario.

Efecto De Doppler
El cambio evidente en la longitud de onda del sonido o de la luz emitida por un objeto en lo referente a la posición de un observador. Un objeto que acerca al observador tendrá una longitud de onda más corta (azul) mientras que una voluntad ausente de mudanza del objeto tiene una longitud de onda (roja) más larga. El efecto de Doppler se puede utilizar para estimar la velocidad y la dirección de un objeto.

Estrella Doble
El agrupar de dos estrellas.   Ésta que agrupa puede ser evidente, donde las estrellas se parecen cercanas juntas, o comprobación, tal como un sistema binario.

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Excentricidad
La medida de cómo la órbita de un objeto diferencia de un círculo perfecto. La excentricidad define la dimensión de una variable de la órbita de un objeto.

Eclipse
El bloqueo total o parcial de un cuerpo celeste por otro.

Radiación Electromágnetica
Otro término para la luz. Ondas de la luz creadas por fluctuaciones de campos eléctricos y magnéticos en espacio.

Espectro Electromágnetico
La gama completa de frecuencias, de las ondas de radio a las ondas gammas, que caracteriza la luz.

Elipse
Una elipse es una dimensión de una variable oval. Johannes Kepler descubrió que las órbitas de los planetas eran elípticas en dimensión de una variable más bien que circular.

Galaxia Elíptica
Una estructura de la galaxia que formada como una elipse y es lisa y falta las estructuras complejas tales como brazos espirales.

Equinoccio
Las dos puntas en las cuales el sol cruza el ecuador celestial en su camino anual en el cielo. Los equinoccios ocurren encendido o de marcha cercana la 21 y de septiembre el 22.   Los equinoccios señalan el comienzo de las estaciones del resorte y del otoño.

Velocidad Del Escape
La velocidad requerida para un objeto para escapar la gravitación del planeta o del otro cuerpo.

Horizonte Del Acontecimiento
El límite invisible alrededor de un calabozo más allá de el cual nada puede escapar la gravitación - luz no uniforme.

Extinción
El amortiguar evidente de la estrella o del planeta cuando punto bajo en el horizonte debido a la absorción por la atmósfera de la tierra.

Extragalactic
Un término de el cual significa el exterior o más allá de nuestra propia galaxia.

Extraterrestre
Un término describía cualquier cosa que no origina en la tierra.

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Filamento
Un hilo del gas fresco suspendió concluído la fotosfera por los campos magnéticos, que aparece oscura según lo visto contra el disco del sol.

Buscador
Un pequeño, telescopio del ancho-campo asociado a un telescopio más grande.   El buscador se utiliza para ayudar a señalar el telescopio más grande a la localización que ve deseada.

Bola de fuego
Un meteorito extremadamente brillante. También conocido como bolides, las bolas de fuego pueden ser varias veces más brillantes que la Luna Llena. Algunos se pueden incluso acompañar por un auge acústico.

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Halo Galáctico
El nombre dado a la región esférica que rodea el centro, o el núcleo de una galaxia.

Núcleo Galáctico
Una concentración apretada de estrellas y del gas encontró en las regiones íntimas de una galaxia. Los astrónomos ahora creen que los calabozos masivos pueden existir en el centro de muchas galaxias.

Galaxia
El agrupar grande de estrellas.   Las galaxias se encuentran en una variedad de tallas y de dimensión de una variable.   Nuestra propia galaxia lechosa de la manera es espiral en dimensión de una variable y contiene vario mil millones estrellas.   Algunas galaxias son así que distante sus millones ligeros de las tomas de años para alcanzar la tierra.

Lunas Galileas
El nombre dado a cuatro lunas más grandes de Júpiter, Io, Europa, Callisto & Ganymede. Fueron descubiertas independientemente por galileo galilei y Simon Marius.

Rayo gama
La energía más alta, la forma más corta de la longitud de onda de radiación electromágnetica.

Lente Gravitacional
Una concentración de la materia tal como una galaxia o el racimo de galaxias que se dobla los rayos ligeros de un fondo se opone. El lensing gravitacional da lugar a imágenes duplicadas de objetos distantes.

Gravedad
Una fuerza física mutua de la naturaleza que hace a dos cuerpos atraerse.

Efecto Del Invernadero
Un aumento en temperatura causó cuando se pasa la radiación solar entrante pero la radiación termal saliente es bloqueada por la atmósfera. El bióxido de carbono y el vapor de agua son dos de los gases principales responsables de este efecto.

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Heliopause
La punta en W *** TRANSLATION ENDS HERE ***hich the solar wind meets the interstellar medium or solar wind from other stars.

Heliosphere
The space within the boundary of the heliopause containing the Sun and the solar system.

Hydrogen
An element consisting of one electron and one proton.  Hydrogen is the lightest of the elements and is the building block of the universe.  Stars form from massive clouds of hydrogen gas.

Hubble's Law
The law of physics that states that the farther a galaxy is from us, the faster it is moving away from us.

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Ice
A term used to describe water or a number of gases such as methane or ammonia when in a solid state.

Inferior Conjunction
A conjunction of an inferior planet that occurs when the planet is lined up directly between the Earth and the Sun.

Inferior Planet
A planet that orbits between the Earth and the Sun.  Mercury and Venus are the only two inferior planets in our solar system.

Interplanetary Magnetic Field
The magnetic field carried along with the solar wind.

Interstellar Medium
The gas and dust that exists in open space between the stars.

Ionosphere
A region of charged particles in a planet's upper atmosphere. In Earth's atmosphere, the ionosphere begins at an altitude of about 25 miles and extends outward about 250.

Iron Meteorite
A meteorite which is composed mainly of iron mixed with smaller amounts of nickel.

Irregular Galaxy
A galaxy with no spiral structure and no symmetric shape. Irregular galaxies are usually filamentary or very clumpy in shape.

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Kelvin
A temperature scale used in sciences such as astronomy to measure extremely cold temperatures. The Kelvin temperature scale is just like the Celsius scale except that the freezing point of water, zero degrees Celsius, is equal to 273 degrees Kelvin. Absolute zero, the coldest known temperature, is reached at 0 degrees Kelvin or -273.16 degrees Celsius.

Kiloparsec
A distance equal to 1000 parsecs.

Kirkwood Gaps
Regions in the main belt of asteroids where few or no asteroids are found. They were named after the scientist who first noticed them.

Kuiper Belt
A large ring of icy, primitive objects beyond the orbit of Neptune. Kupier Belt objects are believed to be remnants of the original material that formed the solar system. Some astronomers believe Pluto and Charon are Kuiper Belt objects.

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Lenticular Galaxy
A disk-shaped galaxy that contains no conspicuous structure within the disk. Lenticular galaxies tend to look more like elliptical galaxies than spiral galaxies.

Libration
An effect caused by the apparent wobble of the Moon as it orbits the Earth. The Moon always keeps the same side toward the Earth, but due to libration, 59% of the Moon's surface can be seen over a period of time.

Light Year
An astronomical unit of measure equal to the distance light travels in a year, approximately 5.8 trillion miles.

Limb
The outer edge or border of a planet or other celestial body.

Luminosity
The amount of light emitted by a star.

Lunar Eclipse
A phenomenon that occurs when the Moon passes into the shadow of the Earth.   A partial lunar eclipse occurs when the Moon passes into the penumbra, or partial shadow.   In a total lunar eclipse, the Moon passes into the Earth's umbra, or total shadow.

Lunar Month
The average time between successive new or full moons. A lunar month is equal to 29 days 12 hours 44 minutes. Also called a synodic month.

Lunation
The interval of a complete lunar cycle, between one new Moon and the next.  A lunation is equal to 29 days, 12 hours, and 44 minutes.

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Magellanic Clouds
Two small, irregular galaxies found just outside our own Milky Way galaxy.  The Magellanic clouds are visible in the skies of the southern hemisphere.

Magnetic Field
A condition found in the region around a magnet or an electric current, characterized by the existence of a detectable magnetic force at every point in the region and by the existence of magnetic poles.

Magnetic Pole
Either of two limited regions in a magnet at which the magnet's field is most intense.

Magnitude
The degree of brightness of a star or other object in the sky according to a scale on which the brightest star has a magnitude -1.4 and the faintest visible star has magnitude 6. Sometimes referred to as apparent magnitude. In this scale, each number is 2.5 times the brightness of the previous number. Thus a star with a magnitude of 1 is 100 times brighter than on with a visual magnitude of 6.

Main Belt
The area between Mars and Jupiter where most of the asteroids in our solar system are found.

Major Planet
A name used to describe any planet that is considerably larger and more massive than the Earth, and contains large quantities of hydrogen and helium. Jupiter and Neptune are examples of major planets.

Mass
A measure of the total amount of material in a body, defined either by the inertial properties of the body or by its gravitational influence on other bodies.

Matter
A word used to describe anything that contains mass.

Meridian
An imaginary circle drawn through the North and South poles of the celestial equator.

Metal
A term used by astronomers to describe all elements except hydrogen and helium.

Meteor
A small particle of rock or dust that burns away in the Earth's atmosphere.   Meteors are also referred to as shooting stars.

Meteor Shower
An event where a large number of meteors enter the Earth's atmosphere from the same direction in space at nearly the same time.   Most meteor showers take place when the Earth passes through the debris left behind by a comet.

Meteorite
An object, usually a chunk or metal or rock, that survives entry through the atmosphere to reach the Earth's surface.  Meteors become meteorites if they reach the ground.

Meteoroid
A small, rocky object in orbit around the Sun, smaller than an asteroid.

Minor Planet
Another name used to describe a large asteroid.

Molecular Cloud
An interstellar cloud of molecular hydrogen containing trace amounts of other molecules such as carbon monoxide and ammonia.

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Nadir
A term used to describe a point directly underneath an object or body.

Nebula
A cloud of dust and gas in space, usually illuminated by one or more stars. Nebulae represent the raw material the stars are made of.

Neutron Star
A compressed core of an exploded star made up almost entirely of neutrons. Neutron stars have a strong gravitational field and some emit pulses of energy along their axis. These are known as pulsars.

Newton's First Law of Motion
A body continues in its state of constant velocity (which may be zero) unless it is acted upon by an external force.

Newton's Second Law of Motion
For an unbalanced force acting on a body, the acceleration produced is proportional to the force impressed; the constant of proportionality is the inertial mass of the body.

Newton's Third Law of Motion
In a system where no external forces are present, every action force is always opposed by an equal and opposite reaction.

Nova
A star that flares up to several times its original brightness for some time before returning to its original state.

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Oblateness
A measure of flattening at the poles of a planet or other celestial body.

Occultation
An event that occurs when one celestial body conceals or obscures another. For example, a solar eclipse is an occultation of the Sun by the Moon.

Open Cluster
A collection of young stars that formed together. They may or may not be still bound by gravity. Some of the youngest open clusters are still embedded in the gas and dust from which they formed.

Opposition
The position of a planet when it is exactly opposite the Sun as seen from Earth. A planet at opposition is at its closest approach to the Earth and is best suitable for observing.

Orbit
The path of a celestial body as it moves through space.

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Parallax
The apparent change in position of two objects viewed from different locations.

Parsec
A large distance often used in astronomy.   A parsec is equal to 3.26 light years.

Perigee
The point in the orbit of the Moon or other satellite at which it is closest to the Earth.

Perihelion
The point in the orbit of a planet or other body where it is closest to the Sun.

Perturb
To cause a planet or satellite to deviate from a theoretically regular orbital motion.

Phase
The apparent change in shape of the Moon and inferior planets as seen from Earth as they move in their orbits.

Photon
A particle of light composed of a minute quantity of electromagnetic energy.

Photosphere
The bright visible surface of the Sun.

Planet
A very large body in orbit around a star. Planets can be composed mainly of rock or of dense gases.

Planetary Nebula
A shell of gas surrounding a small, white star.  The gas is usually illuminated by the star, producing a variety of colors and shapes.

Planitia
A low plain.

Planum
A high plain or plateau.

Plasma
A form of ionized gas in which the temperature is too high for atoms to exist in their natural state.  Plasma is composed of free electrons and free atomic nuclei.

Protostar
Dense regions of molecular clouds where stars are forming.

Pulsar
A spinning neutron star that emits energy along its gravitational axis. This energy is received as pulses as the star rotates.

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Quasar
An unusually bright object found in the remote areas of the universe. Quasars release incredible amounts of energy and are among the oldest and farthest objects in the known universe.  They may be the nuclei of ancient, active galaxies.

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Radiant
A point in the sky from which meteors in a meteor shower seem to originate.

Radiation
Energy radiated from an object in the form of waves or particles.

Radiation Belt
Regions of charged particles in a magnetosphere.

Red Giant
A stage in the evolution of a star when the fuel begins to exhaust and the star expands to about fifty times its normal size.  The temperature cools, which gives the star a reddish appearance.

Redshift
A shift in the lines of an object's spectrum toward the red end.  Redshift indicates that an object is moving away from the observer. The larger the redshift, the faster the object is moving.

Resonance
A state in which an orbiting object is subject to periodic gravitational perturbations by another.

Retrograde Motion
The phenomenon where a celestial body appears to slow down, stop, them move in the opposite direction. This motion is caused when the Earth overtakes the body in its orbit.

Right Ascension
The amount of time that passes between the rising of Aries and another celestial object.  Right ascension is one unit of measure for locating an object in the sky.

Ring Galaxy
A galaxy that has a ring-like appearance. The ring usually contains luminous blue stars. Ring galaxies are believed to have been formed by collisions with other galaxies.

Roche Limit
The smallest distance from a planet or other body at which purely gravitational forces can hold together a satellite or secondary body of the same mean density as the primary. At a lesser distance the tidal forces of the primary would break up the secondary.

Rotation
The spin of a body about its axis.

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Satellite
A natural or artificial body in orbit around a planet.

Scopulus
A lobate or irregular scarp.

Scarp
A line of cliffs produced erosion or by the action of faults.

Seyfert Galaxy
A main-sequence star which rotates rapidly, causing a loss of matter to an ever-expanding shell.

Shell Star
A satellite which constrains the extent of a planetary ring through gravitational forces. Also known as a shepherd moon.

Sidereal Month
The average period of revolution of the Moon around the Earth in reference to a fixed star, equal to 27 days, 7 hours, 43 minutes in units of mean solar time.

Solar Cycle
The approximately 11-year quasi-periodic variation in frequency or number of solar active events.

Solar Eclipse
A phenomenon that occurs when the Earth passes into the shadow of the Moon. A total solar eclipse  occurs when the Moon is close enough to completely block the Sun's light.  An annular solar eclipse occurs when the Moon is farther away and is not able to completely block the light.  This results in a ring of light around the Moon.

Solar Flare
A bright eruption of hot gas in the Sun's photosphere.   Solar prominences are usually only detectable by specialized instruments but can be visible during a total solar eclipse.

Solar Nebula
The cloud of dust and gas out of which the solar system was believed to have formed about 5 billion years ago.

Solar Wind
A flow of charged particles that travels from the Sun out into the solar system.

Spectrum
Grass-like patterns of gas seen in the atmosphere of the Sun.

Spiral Galaxy
A galaxy that contains a prominent central bulge and luminous arms of gas , dust, and young stars that wind out from the central nucleus in a spiral formation. Our galaxy, the Milky Way, is a spiral galaxy.

Star
A giant ball of hot gas that creates and emits its own radiation through nuclear fusion.

Star Cluster
A large grouping of stars, from a few dozen to a few hundred thousand, that are bound together by their mutual gravitational attraction.

Steady State Theory
The theory that suggests the universe is expanding but exists in a constant, unchanging state in the large scale.  The theory states that new matter is being continually being created to fill the gaps left by expansion.  This theory has been abandoned by most astronomers in favor of the big bang theory.

Sunspot
Areas of the Sun's surface that are cooler than surrounding areas.  The usually appear black on visible light photographs of the Sun.  Sunspots are usually associated disturbances in the Sun's electromagnetic field.

Supergiant
The stage in a star's evolution where the core contracts and the star swells to about five hundreds times its original size.  The star's temperature drops, giving it a red color.

Superior Conjunction
A conjunction that occurs when a superior planet passes behind the Sun and is on the opposite side of the Sun from the Earth.

Superior Planet
A planet that exists outside the orbit of the Earth.  All of the planets in our solar system are superior except for Mercury and Venus.  These two planets are inferior planets.

Supernova
A supernova is a cataclysmic explosion caused when a star exhausts its fuel and ends its life.   Supernovae are the most powerful forces in the universe.  All of the heavy elements were created in supernova explosions.

Supernova Remnant
An expanding shell of gas ejected at high speeds by a supernova explosion. Supernova remnants are often visible as diffuse gaseous nebulae usually with a shell-like structure. Many resemble "bubbles " in space.

Synodic Period
The interval between points of opposition of a superior planet.

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Telescope
An instrument used to collect large amounts of light from far away objects and increase their visibility to the naked eye.  Telescopes can also enlarge objects that are relatively close to the Earth.

Terminator
The boundary between the light side and the dark side of a planet or other body.

Terrestrial
A term used to describe anything originating on the planet Earth.

Tidal Force
The differential gravitational pull exerted on any extended body within the gravitational field of another body.

Tidal Heating
Frictional heating of a satellite's interior due to flexure caused by the gravitational pull of its parent planet and/or other neighboring satellites.

Transit
The passage of a celestial body across an observer's meridian; also the passage of a celestial body across the disk of a larger one.

Trojan
An object orbiting in the Lagrange points of another (larger) object. This name derives from a generalization of the names of some of the largest asteroids in Jupiter's Lagrange points. Saturn's moons Helene, Calypso and Telesto are also sometimes called Trojans.

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Ultraviolet
Electromagnetic radiation at wavelengths shorter than the violet end of visible light. The atmosphere of the Earth effectively blocks the transmission of most ultraviolet light, which can be deadly to many forms of life.

Universal Time (UT)
Also known as Greenwich Mean Time, this is local time on the Greenwich meridian. Universal time is used by astronomers as a standard measure of time.

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Van Allen Belts
Radiation zones of charged particles that surround the Earth.  The shape of the Van Allen belts is determined by the Earth's magnetic field.

Variable Star
A star that fluctuates in brightness.  These include eclipsing binaries.

Visible Light
Wavelengths of electromagnetic radiation that are visible to the human eye.

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Wavelength
The distance between consecutive crests of a wave.  This serves as a unit of measure of electromagnetic radiation.

White Dwarf
A very small, white star formed when an average sized star uses up its fuel supply and collapses. This process often produces a planetary nebula, with the white dwarf star at its center.

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X-ray
Electromagnetic radiation of a very short wavelength and very high-energy. X-rays have shorter wavelengths than ultraviolet light but longer wavelengths than cosmic rays.

X-ray Astronomy
The field of astronomy that studies celestial objects by the x-rays the emit.

X-ray Star
A bright celestial object that gives off x-rays as a major portion of its radiation.

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Yellow Dwarf
An ordinary star such as the Sun at a stable point in its evolution.

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Zenith
A point directly overhead from an observer.

Zodiac
An imaginary belt across the sky in which the Sun, Moon, and all of the planets can always be found.

Zodiacal Light
A faint cone of light that can sometimes be seen above the horizon after sunset or before sunrise.   Zodiacal light is caused by sunlight reflecting off small particles of material in the plane of the solar system.

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