Stars, Galaxies, and the Universe Flashcards
star
a large celestial body that is decomposed of gas and that emits light
Doppler affect
an observed change in the frequency of a wave when the source or observer is moving
light year
the distance the light travels in one year
parallax
an apparent shift in the position of an object when viewed from different locations
apparent magnitude
the brightest that a star would have at a distance of 32.6 light-year from earth
main sequence
the location on the h-r diagram were most stars lie it has a diagonal pattern from the lower right to that to the upper left
nebula
a large cloud of gas and dust in interstellar space a region in space were stars are born
giant
a very large and bright star whose hot core has used most of its hydrogen
white dwarf
a small hot dim star that is the leftover center of an old star
nova
a star that suddenly becomes brighter
neutron
a star that has collapsed under gravity to the point that the electrons and protons have smashed together to form neutrons
pulsar
a rapidly spinning neutron star that emits pulses of radio and optical energy
black hole
an object so massive and dense that Evan light cannot escape its gravity
constellation
one of 88 regions into which the sky been divided in order to describe the locations of celestial objects of stars organized in a pattern
galaxy
a collection of stars dust and gas bound together by gravity
quasar
quasar seller radio source a very luminous object that produce energy at a high rate
cosmology
the study of the origin of the universe
big bang theory
the theory that all matter and energy in the universe was compressed into an extremely small volume that is 13 15 billion years ago exploded in all directions
cosmetic radiation
radiation uniformly detected in the big bang
absolute magnitude
the brightness that a star would at a distance 32.6 years from earth
