<P> The rotation curve of a disc galaxy ( also called a velocity curve ) is a plot of the orbital speeds of visible stars or gas in that galaxy versus their radial distance from that galaxy 's centre . It is typically rendered graphically as a plot , and the data observed from each side of a spiral galaxy are generally asymmetric , so that data from each side are averaged to create the curve . A significant discrepancy exists between the experimental curves observed , and a curve derived from theory . The theory of dark matter was postulated to account for the variance . </P>
<P> The rotation curve of a disc galaxy ( also called a velocity curve ) is a plot of the orbital speeds of visible stars or gas in that galaxy versus their radial distance from that galaxy 's centre . It is typically rendered graphically as a plot , and the data observed from each side of a spiral galaxy are generally asymmetric , so that data from each side are averaged to create the curve . A significant discrepancy exists between the experimental curves observed , and a curve derived from theory . The theory of dark matter was postulated to account for the variance . </P>
what is the rotation curve of a spiral galaxy
what is the rotation curve of a spiral galaxy
a plot of the orbital speeds of visible stars or gas in that galaxy versus their radial distance from that galaxy 's centre
a plot of the orbital speeds of visible stars or gas in that galaxy versus their radial distance from that galaxy 's centre