Blazars sometimes exhibit it when expelling high-velocity jets of plasma. Barnard‘s Star notably also shows it. While its opposite is nearly ubiquitous, this effect is measured only in about 100 galaxies, most of which are gravitationally-bound dwarf
Blazars sometimes exhibit it when expelling high-velocity jets of plasma. Barnard‘s Star notably also shows it. While its opposite is nearly ubiquitous, this effect is measured only in about 100 galaxies, most of which are gravitationally-bound dwarfs in the local group, and which include the Andromeda galaxy. It is so rare because very few objects have enough  motion to counteract the Hubble expansion of the universe. FTP, name this shortening of the wavelength of light emitted  by approaching objects, the opposite of the red shift.
Blazars sometimes exhibit it when expelling high-velocity jets of plasma.