obama studies 1 Flashcards
absolute magnitude
a measuring system to measure how bright a star would be if seen from a certain point.
apparent magnitude
the brightness of a star as seen from earth
galaxy
a large collection of stars, dust, and gas bound together by gravity
H-R Diagram
Hertßprung-Russell diagram, a graph that shows the relationship between a star’s surface temperature and absolute magnitude
light-year
the distance that light travels in a year
luminosity
the actual brightness of an object such as a star
main sequence
the region on the H-R diagram where stars spend most of their lives; it has a diagonal pattern
nebula
a large cloud of dust and gas in interstellar space; a region in space where stars are born.
neutron star
the core of a supernova that has collapsed due to gravity to the point that the electrons and protons have smashed together to form neutrons.
planet
a relatively large spherical body that orbits a star
pulsar
a highly magnetized rotating neutron star that emits a beam of electromagnetic radiation
revolution
the motion of a body that travels around another body in space; one trip along an orbit.
rotation
the spin of a body on its axis
solar system
the collection of large and small bodies that orbit our central star, the sun
star
a large celestial bodythat is composed of gas and that emits light; the sun is a typical star
