Stars and Galaxies Flashcards
galaxy
a group of solar systems, dust, and gas held together by gravity, usually revolving around a black hole
Milky Way
The galaxy in which our solar system is a part
planetary nebula
a large cloud of gas and dust in outer space ejected by an aging star near the end of its life cycle
supernova
the extremely bright, super-powerful explosion of a star.
black hole
a region of spacetime where gravity is so strong that nothing – not even light – can escape from it.
white dwarf
stars that have burned up all of the hydrogen they once used as nuclear fuel
red giant
a dying star in the final stages of stellar evolution
stellar nebula
a cloud of gas and dust that forms a new star
gravity
the force by which a planet or other body draws objects toward its center.
star
huge celestial bodies made mostly of hydrogen and helium that produce light and heat through nuclear fusion
nucleosynthesis
the formation of elements by nuclear fusion inside stars
neutron star
are small dense stars which form as the result of the collapse of the core of a massive star during a supernova
red-shift
when lightwaves lengthen as they are moving away from the observer and shift to the red end of the spectrum
blue-shift
when lightwaves shorten as they are moving toward the observer and shift to the blue end of the spectrum
apparent magnitude
the brightness of a star as it appears from Earth
elliptical galaxy
a group of solar systems, dust, and gas held together by gravity which has a shape that is round and smooth
spiral galaxy
a group of solar systems, dust, and gas held together by gravity that forms a rotating disc with spiral ‘arms’ that curve out from a dense central region
irregular galaxy
a group of solar systems, dust, and gas held together by gravity that have no organized shape
H-R Diagram
a diagram that shows the relationship between a star’s temperature and its luminosity
luminosity
the intrinsic brightness of a celestial object
