Unit 6 Universe Vocabulary Flashcards
A brightness scale used to measure of how bright a star would be if it were seen from a standard distance
Absolute magnitude
the brightness of a star as seen from earth
apparent magnitude
a large collection of stars, dust, and gas bound together by gravity
galaxy
Hertzsprung-Russell diagram, a graph that shows the relationship between a star’s surface temperature and absolute magnitude.
H-R Diagram
the distance that light travels through space in or year; about 9.46 trillion kilometers
light-year
the actual brightness of an object such as a star
luminosity
the region on the H-R diagram where stars spend most of their lives; it has a diagonal pattern
main sequence
a large could of dust and gas in interstellar space; a region in space where stars are born
nebula
the core of a supernova that has collapsed under gravity to the point that the electrons and protons have smashed together and formed neutrons
neutron star
a relatively large spherical body that orbits a star
planet
a highly magnetized rotating neutron star that emits a beam of electromagnetic radiation
pulsar
the motion of a body that travels around another body in space; one trip along an orbit
revolution
the spin of a body on its axis
rotation
the collection of large and small bodies that orbit our central star, the sun
solar system
a large celestial body that is composed of gas and that emits light; the sun is a typical star
star
the distance between two adjacent troughs or crests of a wave
wavelength
a gigantic explosion in which a massive star throws its out layers into space, but its core remains
supernova
space and all matter and energy in it
universe
the hot, dense, dim core of matter that remains from the collapse of a low-mass star
white dwarf
a galaxy shaped like a pinwheel, with a bulge in the center and spiral arms extending outwards
spiral galaxy
a spherical or elongated galaxy with a bright center and very little dust and gas
elliptical galaxy
a galaxy with an irregular shape that does not fit into any other category
irregular galaxy
all of the different wavelengths of electromagnetic radiation from radio waves to gamma rays
electromagnetic spectrum
the theory that all matter and energy in the universe was compressed into an extremely small volume that 13 billion to 15 billion years ago exploded and began expanding in all directions
big bang theory
CMB; the electromagnetic radiation left over from the formation of the universe
cosmic microwave background
a phenomenon which occurs when a star oa galaxy is moving away from te eairth and its
redshift
an observed change in the frequency or wavelength when the source is moving with respect to the observer
doppler effect
a tool used to collect light from stars and separate the colors in the light
spectroscope
