. . . . . . . . . . . . . . . . . . . "A gravitational mirage or cosmic mirage is an optical phenomenon affecting the appearance of a distant star or galaxy, seen only through a telescope. It can take the form of a ring or rings partially or completely surrounding the object, a duplicate image adjacent to the object, or multiple duplicate images surrounding the object. Sometimes the direct view of the original object itself is dimmed or absent. The illusion is caused by a gravitational lens, in space between the object and the observer's telescope, which bends light as it travels. The effect is analogous to the atmospheric mirage, which has been observed since antiquity, in circumstances where the air temperature varies strongly with height over the ground or sea; the rapidly changing refractive index bends light, producing inverted and/or multiple images \"floating\" in the air. Ring-shaped gravitational mirages are referred to as Einstein rings, and one multiple-image gravitational mirage is named the Einstein Cross, as tribute for Einstein's predictions regarding gravitational lensing."@en . "A gravitational mirage or cosmic mirage is an optical phenomenon affecting the appearance of a distant star or galaxy, seen only through a telescope. It can take the form of a ring or rings partially or completely surrounding the object, a duplicate image adjacent to the object, or multiple duplicate images surrounding the object. Sometimes the direct view of the original object itself is dimmed or absent."@en . . . "3027"^^ . . "Gravitational mirage"@en . "6753860"^^ . . . . . . . . . . . "858964622"^^ . . . . . . . . .