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Ch. 21 Earth Science
7th Grade finals test
Term | Definition |
---|---|
telescope | A device that makes distant objects appear to be closer |
electromagnetic radiation | energy that can travel through space in the form of waves |
wavelength | distance between the crest of one wave and the crest of the next wave |
spectrum | a range of different colors of different wavelengths |
optical telescope | uses lenses or mirrors |
refracting telescope | uses convex lens |
convex lens | a piece of transparent, curved glass |
reflecting telescope | a curved mirror that collects light |
radio telescopes | curved lenses that reflect other waves and focus on radio |
observatory | a building that contains one or more telescopes |
constellation | an imaginary pattern "drawn" by the stars |
spectrograph | breaks light in to colors and and produces images of it |
apparent brightness | brightness seen on earth |
absolute brightness | the brightness the star would have if it were at a standard disatnce from Earth |
light year | distance that light travels in one year |
parallax | apparent change in position of an object when looking at it from a different place |
main sequence | surface temperature increases, and is the main life of a star |
binary star | a two star system |
eclipsing binary | a binary system in which the dim star eclipses the bright star |
open cluster | a much less dense cluster of stars |
globular cluster | a much more dense cluster of stars with millions of them |
galaxy | a group of stars, dust, and ice held together by gravity |
quasar | active young galaxies with giant black holes |
universe | all of space and everything in it |