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chapter 21vocab
Question | Answer |
---|---|
how bright a star appears to an observer on earth | apparent magnitude |
the average distance between earth and the sun, about 159 million km | Astronomical unit |
theory that the unuverse was originally a single dense sphere od hydrogen that exploded into gigantic expanding cloud that eventually condensed into seperate galixies | Big Band hypothesis |
massive objects in space whos gravitational forces are so strong that light rays cannot escape | black holes |
a group of stars that appears to form a pattern in the sky | constellation |
a group of million, oor even billions of stars held together by gravity | galaxy |
the distance a ray of light travels in one year, about 9.5 trillion km. | light-year |
the actual, or true brightness of a star | luminosity |
a large cloud of gas and dust in space | nebula |
the dense core that remains after a large star explodes | neuton star |
a star that has flared into intense brightness | nova |
an intensely bright object caused by the explosion of a massive red giant star | supernova |