EU - Chapter 9 Vocabulary Flashcards
Altitude
The measurement that describes the vertical position of an object in relation to the horizon; measured in degrees from the horizon to a point directly overhead, known as the zenith (Pg. 309)
Asterisms
A smaller, recognizable star pattern without a larger constellation (Pg .306)
Asteroid Belt
A region of rocky debris that forms a ring all the way around the Sun at a distance of about 3 AU (Pg. 336)
Asteroids
A metallic, rocky body without atmosphere that orbits the Sun but is too small to be classified as a planet or dwarf planet (Pg. 336)
Astronomers
A person who knows and studies astronomy (Pg. 305)
Astronomical Bodies
An object in space, including Earth (Pg. 305)
Astronomical Unit (AU)
A unit of measure used to measure distances in space; one AU equals the average distance between the Sun and Earth, about 150 million kilometres (Pg. 332)
Astronomy
The study of objects and phenomena in space (Pg. 305)
Aurora Australis
The light displays in the Southern Hemisphere cause by the solar wind interacting with particles in Earth’s atmosphere (Pg. 323)
Aurora Borealis
the light displays in the Northern Hemisphere cause by the solar wind interacting with particles in Earth’s atmosphere (Pg. 323)
Azimuth
The measurement that describes the horizontal position of a celestial body in relation to due north; measured in degrees along the horizon starting from due north, moving in a clockwise direction
Celestial Bodies
An object that can be observed in the sky; does not include Earth (Pg. 305)
Comets
A celestial object made of ice and dust that travels in an elliptical orbit around the Sun (Pg. 338)
Constellation
A group of stars that, observed from Earth, resembles a form (305)
Declination
The vertical coordinate measurement that describes the position of a celestial body on the celestial sphere, similar to latitude; measured in units of degrees (Pg. 310)
Dwarf Planet
An astronomical body that orbits the Sun, has enough mass to from a roughly spherical shape under its own gravitational force, and has an eccentric orbit or orbits in a zone that contains many other objects; protoplanets are a subgroup of dwarf planets; Pluto is a well known example of a dwarf planet (Pg. 337)
Ecliptic
The apparent path of the Sun and planets as observed from Earth as the move through the sky during the year (Pg. 316)
Equinoxes
The day of the year when the hours of daylight and hours of night are equal in length; the vernal equinox occurs around March 21 and the autumnal equinox occurs around September 22 (Pg. 308)
Light-year (ly)
A unit of measure used to measure distances in space; one light-year equals the distance that a beam of light travels through space in one year, equivalent to 63 000 AU or 9000 billion km (Pg. 332)
Lunar Eclipse
A celestial event that occurs when Earth blocks all or part of the Sun’s light shinning on the Moon, making the Moon briefly disappear (Pg. 320)
Meteor
A meteoroid that enters Earth’s atmosphere and burns up as it collides with gas molecules (Pg. 339)
Meteorite
A meteor that does not burn up completely and strikes Earth’s surface (Pg. 339)
Nebula
A cloud of dust and gases in space, which scientists believe is an area of star formation (Pg. 330)
Nebular Theory
The theory that explains the formation of the solar system and other start-and-planet systems from nebulae (Pg. 330)
Orbit
The path along which an object, such as a planet, travels around another object, such as a star; Earth travels around the Sun in a slight elliptical orbit (Pg. 317)
Planet
An astronomical body that orbits one or more stars and is capable of forming into a spherical shape under its own gravitational force, or gravity (Pg. 331)
Revolution
One complete orbit of one object around another; one revolution of Earth around the Sun takes one year (Pg. 317)
Right Ascension (RA)
The horizontal coordinate measurement that describes the position of a celestial body on the celestial sphere, similar to longitude; measured in units of hours, minutes, and seconds (Pg. 310)
Rotation
One complete spin of an object, such as a planet, on its axis; one rotation or Earth takes 24 hours (Pg. 316)
Satellite
An object that obits a planet, such as a moon; satellites may be natural or artificial (Pg. 318)
Solar Eclipse
A celestial event that occurs when the Moon lies directly between Earth and the Sun, blocking all or part of the Sun’s light to viewers on Earth (Pg. 319)
Solar Flare
A high energy, massive explosion at the surface of the Sun (Pg. 322)
Solar Prominence
A large, low energy, curved, bright stream of particles (Pg. 322)
Solar System
The Sun and all the planets and other celestial objects, such as moons, comets, and asteroids, that are held by the Sun’s gravity and orbit around it (Pg. 329)
Solar Wind
The constant flow of particles streaming out of the Sun’s surface in all directions (Pg. 323)
Solstices
The longest period of daylight or night in a year; the summer solstice is the longest day of the year and occurs around June 21 in the northern hemisphere; the winter solstice is the longest night of the year and occurs around December 21 in the northern hemisphere (Pg. 307)
Star
A body of electrically charged gas, or plasma, that emits energy from nuclear reactions taking place in its core (Pg. 321)
Sunspot
A region on the Sun’s surface that is cooler than the surrounding areas (Pg. 321)
