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72 Cards in this Set
- Front
- Back
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What is Astronomy?
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The study of the Universe
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What is a light year?
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distance light travels in a year
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How many miles does light travel in a year?
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10 trillion miles
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How long does a light year last for?
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One year
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About how many stars does our galaxy contain?
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200 billion
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Galaxies form cluster which form together to form what?
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Filaments
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the largest identifiable structure in the universe are?
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Filaments
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A theory can:
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Be proven wrong but never right
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Observation leads to:
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Theory
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Theory leads to:
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Prediction
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Prediction leads to:
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New phenomena or observation
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About how many stars are visible at one time?
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3000
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Polaris is?
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A star almost due north known as north star
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The predictions of individuals based on star patterns at birth is?
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Astrology
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Stars seem to be on the inner surface of a sphere surrounding earth. this sphere is called?
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Celestial sphere
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Declination
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degrees north or south on celestial equator. Its like Latitude
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Right ascension
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runs eastward on the celestial equator. Like Longitude
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Stars seem to move across celestial sphere but in reality our earth:
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Rotates and spins on its axis
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Angular size of an object depends on:
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Actual size
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The daily cycle is called?
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Di-vernal motion or Solar day
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Earth rotates _____ than 360 degrees in solar day
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More than
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When earth rotates exactly 360 degrees this is called a:
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Sidereal day
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a sidereal day is four minutes ___ than a solar day
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shorter
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a solar day is four minutes ___ than a sidereal day
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Longer
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Solar noon is when:
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Sun is at its highest point
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Solar day is based on:
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consecutive noon transits of the sun
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normal time keeping is based on:
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solar day
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the apparent yearly path of the sun
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Ecliptic
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lunar eclipse
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earth is between moon and sun.
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solar eclipse:
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moon between earth and sun
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eclipse occur every:
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Six months
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Parallax:
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Apparent motion of a star from two vantage points
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Constellations
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A pattern formed by prominent stars within apparent proximity
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total constellations:
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88 and 44 at one time
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Asterism
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Pattern seen in earths sky which is not official constellation. Ex: Big Dipper
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Distance and actual brightness account for:
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Apparent star brightness
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1=brightest 6=dimmest
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Hipparchus apparent magnitude scale
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Zenith
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Highest point
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cardinal directions
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North, south, east, west
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circum polar
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when a star does not rise or set
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Epicycle
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small circle that planet moves around
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center of epicycle that planet revolves around earth
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Deferent
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Eratosthenes
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first determined earths circumference
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Transition of energy through space without physical connection through varying electric and magnetic fields
AKA: Light |
Electromagnetic Radiation
(EM Radiation) |
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this is used to differentiate different kinds of light
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Wave length
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distance between crests
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Wave length
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number of wave crests that pass a given point per second
(Units of HZ) |
Frequency
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Period
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time between passage of successive crests
(units of seconds) |
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Period and Frequency are:
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Inversely proportional to each other
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Speed of which Crests move:
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Velocity
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Wavelength/period=
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velocity
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Electromagnetic Waves do not need a _____ like water and sound waves do
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medium
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light particles, contain energy but not mass
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Photon
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the slight bending of light as it goes around an object
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Diffraction
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radiation emitted by an object depending only on its temperature
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Black Body spectrum
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zero degrees kelvin
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coldest possible temperature
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water freezes
water boils |
273 k
373 k |
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Doppler Effect
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if one is moving toward a radiation source the wavelength seems shorter (bluer) if moving away the wave length seems longer (redder)
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reason for seasons
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Earths tilt
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Hans Lippershey invented
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Opticle Telescope
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first telescope with mirrors made by:
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Newton
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Newtonian has a
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secondary mirror
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the most basic telescope
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prime focus telescope
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bigger telescopes have:
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More light gathering power
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star twinkling due to
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atmospheric bluring
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seeing
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quality of atmosphere in general
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active optics
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control mirrors of telescope based on temperature and orientation
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ability to distinguish adjacent objects in sky:
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resolution
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Absorption spectra must have:
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Hot dense core with cooler gas around
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continuous spectrum
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Hot dense energy source
looks continuous no lines |
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Emission Spectrum
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Hot low density cloud
dark background white lines |
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Absorption
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hot dense energy source that passes through low density cloud
light background with dark lines |
