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Grade 8 8.8(A)
describe components of the universe, including stars, nebulae, and galaxies...
Term | Definition |
---|---|
Universe | space and all the matter and energy in it |
Star | a large celestial body that is composed of gas and that emits light |
Nebula | a large cloud of gas and dust in interstellar space; a region in space where stars are born |
Galaxy | a collection of stars, dust, and gas bound together by gravity |
Hertzsprung-Russell diagram | a graph that shows the relationship between a star's surface temperature and absolute magnitude |
Nuclear reaction | A reaction, as in fission, fusion, or radioactive decay, that alters the energy, composition, or structure of an atomic nucleus. |
Milky Way Galaxy | the galaxy containing the solar system; consists of millions of stars that can be seen as a diffuse band of light stretching across the night sky |
Luminosity | the actual brightness of an object such as a star |
Spectral Class | any of various groups into which stars are classified according to characteristic spectral lines and bands. |
Kelvin | A unit of absolute temperature equal to 1/273.16 of the absolute temperature of the triple point of water. |