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patterns of stars in the sky
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Constellation
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the light you see with your eyes
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visible light
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energy that can travel through space in the
form of waves
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electromagnetic radiation
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the distance between the crest of one wave and the crest of the next wave
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wavelength
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a range of different colors with different
wavelengths
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spectrum
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uses convex lenses to gather a large amount of light and focus it on a small area
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refracting telescope
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a piece of transparent glass curved so
that the middle is thicker than the edges
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convex lens
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uses a mirror to gather a large amount of light and focus it on a small area
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reflecting telescope
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detects radio waves from objects in
space
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radio telescope
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a building that contains one or more telescopes; usually built on mountaintops
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observatory
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breaks light from an object into colors and
photographs the resulting spectrum; provides astronomers information about stars chemical composition and temperature
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spectrograph
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a structure that contains billions of stars
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galaxy
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all of space and everything in it
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universe
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the distance light travels in one year; about
9.5 million, million kilometers; a unit of distance not time
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light-year
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the apparent change in position of an object
when you look at it from different places
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parallax
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very large stars
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giant star
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a star’s brightness as seen from Earth
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apparent magnitude
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the brightness a star would have if it were
a standard distance from Earth
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absolute magnitude
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a graph that shows the relationship between
a star’s brightness and temperature
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Hertzsprung-Russell diagram
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90% of all stars; a diagonal line of stars on
the H-R diagram; surface temperature increases as brightness increases
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main sequence
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a tiny star left over when a giant star explodes;
a neutron star that gives off radio waves
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pulsar
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where stars begin their lives; a large amount of gas and dust spread out in an immense volume
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nebula
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the earliest stage of a star’s life
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protostar
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formed when red giants grow bigger and the
outer parts drift out into space leaving the blue-white core of the star
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white dwarf
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when a giant or supergiant star suddenly explodes and becomes very bright
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supernova
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the material left after a supernova, smaller and denser than white dwarfs
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neutron star
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remains of a massive star that has died; due to extreme mass, gravity is strong
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black hole
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bright objects that are very far away; the most
distant objects in the universe
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quasar
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star systems with two stars
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binary star
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a star system in which one star blocks the light from another star
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eclipsing binary
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a large group of stars that have arms that spiral outward, like a pinwheel; the Milky Way is this type of galaxy
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spiral galaxy
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a large group of stars that look like flattened disks; have very little gas and dust between the stars
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elliptical galaxy
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large groups of stars without a definite shape
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irregular galaxy
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the theory that states the universe formed in an enormous explosion 10 to 15 billion years ago
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big bang
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