Download GLY 1001 Earth Science Name:__Answers

ESC 1000 Vocabulary
Chapter 24: Beyond Our Solar System:
Absolute magnitude – The apparent brightness of a star if it were viewed from a distance
of 10 parsecs (32.6 light years). Used to compare the true brightness of stars.
Apparent magnitude – The brightness of a star when viewed from Earth.
Barred spiral – A galaxy having straight arms extending from its nucleus.
Big bang theory – The theory that proposes that the universe originated as a single mass
which subsequently exploded.
Black hole – a massive star that has collapsed to such a small volume that the gravity
prevents the escape of all radiation.
Bright nebula – A cloud of glowing gas excited by ultraviolet radiation from hot stars.
Dark nebula – A cloud of interstellar dust that obscures the light of more distant stars and
appears as an opaque curtain.
Degenerate matter Elliptical galaxy – A galaxy that is round or elliptical in outline. It contains little gas and
dust, no disk, or spiral arms, and few, hot bright stars.
Emission nebula – A gaseous nebula that derives its visible light from the fluorescence of
ultraviolet light from a star in or near the nebula.
Eruptive variable – A star that varies in brightness.
Galactic cluster – A system of galaxies containing from several to thousands of member
galaxies.
Hertzsprung-Russell (H-R) diagram – A plot of stars according to their absolute
magnitudes and spectral types.
Hubble’s law – Relates the distance to a galaxy and its velocity.
Hydrogen burning – The conversion of hydrogen through fusion to form helium.
Interstellar matter – Dust and gases found between stars.
Irregular galaxy – A galaxy that lacks symmetry
Light-year – The distance light travels in a year, about six trillion miles.
Local Group – The cluster of 20 or so galaxies to which our galaxy belongs.
Magnitude – A number given to a celestial object to express its relative brightness.
Main-sequence stars – A sequence of stars on the Hertzsprung-Russell Diagram,
containing the majority of stars, that runs diagonally from upper left to lower right.
Nebula – A cloud or stellar gas and/or dust.
Neutron star – A star of extremely high density composed entirely of neutrons.
Nova - A star that explosively increases in brightness.
Planetary nebula – A shell of incandescent gas expanding from a star.
Protostar – A collapsing cloud of gas and dust destined to becomes a star.
Pulsar – A variable radio source of small size that emits radio pulses in very regular
periods.
Pulsating variable - A variable star that pulsates in size and luminosity.
Red giant – A large, cool star of high luminosity, a star occupying the upper-right portion
of the Hertzsprung-Russell Diagram.
Reflection nebula – A relatively dense dust cloud in interstellar space that is illuminated
by starlight.
Spiral galaxy – A flattened, rotating galaxy with pinwheel-like arms of interstellar
material and young stars winding out from its nucleus.
Stellar parallax – A measure of stellar distance.
Supergiant – A very large star of high luminosity.
Supernova – An exploding star that increases in brightness many thousands of times.
White dwarf – A star that has exhausted most or all of its nuclear fuel and has collapsed
to a very small size; believed to be near its final stage of evolution.
Chapter 24 Word List
Absolute magnitude
Apparent magnitude
Barrel spiral galaxy
Big bang
Black hole
Bright nebula
Dark nebula
Degenerate matter
Elliptical galaxy
Emission nebula
Eruptive variables
Galactic cluster
Hertzsprung-Russell (H-R)
diagram
Hubble’s law
Hydrogen burning
Interstellar dust
Irregular galaxy
Light-year
Local Group
Magnitude
Main-sequence stars
Nebula
Neutron star
Nova
Planetary nebula
Protostar
Pulsar
Pulsating variables
Red giant
Reflection nebula
Spiral galaxy
Stellar parallax
Supergiant
Supernova
White dwarf