Skip to main content
-
elliptical galaxy
-
a galaxy whose shape is an ellipse and that contains no conspicuous interstellar material
-
Hubble constant
-
a constant of proportionality in the law relating the velocities of remote galaxies to their distances
-
Hubble’s law
-
a rule that the radial velocities of remote galaxies are proportional to their distances from us
-
irregular galaxy
-
a galaxy without any clear symmetry or pattern; neither a spiral nor an elliptical galaxy
-
mass-to-light ratio
-
the ratio of the total mass of a galaxy to its total luminosity, usually expressed in units of solar mass and solar luminosity; the mass-to-light ratio gives a rough indication of the types of stars contained within a galaxy and whether or not substantial quantities of dark matter are present
-
redshift
-
when lines in the spectra are displaced toward longer wavelengths (toward the red end of the visible spectrum)
-
spiral galaxy
-
a flattened, rotating galaxy with pinwheel-like arms of interstellar material and young stars, winding out from its central bulge
-
type Ia supernova
-
a supernova formed by the explosion of a white dwarf in a binary system and reach a luminosity of about 4.5 × 10
9
L
Sun
; can be used to determine distances to galaxies on a large scale