The same foreground galaxy can — in theory — simultaneously lens multiple background galaxies. (sciencedaily.com)
Acting as a «natural telescope» in space, the gravity of the extremely massive foreground galaxy cluster MACS J2129 - 0741 magnifies, brightens, and distorts the far - distant background galaxy MACS2129 - 1, shown in the top box. (sciencedaily.com)
As light from background quasars passes through the gas and dust in foreground galaxies and cosmic filaments, it carries information about speed, composition and temperature of the intervening space. (ibtimes.com)