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
wavelength
the distance between two adjacent troughs or crests of a wave
supernova
a gigantic explosion in which a massive star throws its outer layers into space, but its core remains
universe
space and all matter and energy in it
white dwarf
the hot, dense, dim core of matter
spiral galaxy
a galaxy shaped like a spiral
elliptical galaxy
a spherical or elongated galaxy with a bright center
irregular galaxy
irregular-shaped galaxy
el. spectrum
all waves of the el. spectrum
