definitionss Flashcards
spectograph
A spectograph is a device used to split light energy into patterns of colours. Each element has its own unique spectrum. The stars spectrum is compared with the known spectra of elements
Retrograde motion
Retrograde motion is when one planet laps another so then the planet moves backwards and then forwards again.
Altitude
Altitude is the angular height of a celestial object, measured from the horizon.
Azimuth
Azimuth is the distance measured from north along the horizon to a point directly below the celestial object.
ecliptic
The ecliptic is the path across the sky that the sun, moon, planets and the zodiac constellations appear to follow over the course of the year.
asterism
An asterism is a pattern of stars in the sky.
constellation
A constellation is a regrouping of stars, as observed from earth.
galaxies
Galaxies= collections of millions to hundreds of billions of stars, planets gas and dust, measuring up to 100 000 light years across.
dwarf planets
Dwarf planets = a celestial object that orbits the sun but does not dominate its orbit.
stars
Stars are massive collections of gases held together by their own gravity and emitting huge amounts of energy.
cosmology
Cosmology is the study of the university.
comets
Large chunks of ice, dust and rock that orbit the sun and range in size from less than 100 m to 40 km across.
meteorioid/meteor/meteorite
A meteoroid is a piece of metal or rock that is smaller than an asteroid.
Most are the size of dust particles, but some can be as large as a car/building.
Sometimes they get pulled into earth’s atmosphere, friction causes them to burn up, creating a bright streak across the sky known as a meteor.
Meteorites are larger meteors that do not burn up completely in the atmosphere and their remains, which we call meteorites, crash to the ground.
Meteoroid = in space Meteor = in atmosphere Meteorite = hitting the earth
asteroids
Asteroids are composed of rock and metal. Although they orbit the sun, they are too small to be considered planets.
Most asteroids lie in the asteroid belt, between Mars and Jupiter.
apparent & absolute magnitude
Apparent magnitude is the brightness of stars in the night sky as they appear from earth. Brightest stars - magnitude 1 Faintest stars - magnitude 6
Absolute magnitude is the brightness of stars as if they were all located 33 ly from earth. Gives you a much better idea of the actual luminosity of a celestial object than does the apparent magnitude and allows you to compare stars as if they were the same distance way.
