The astrophysicist Dr. Jaqueline Hewitt, known for her pioneering work on gravitational lensing, was born #OTD in 1958. In 1987 she led the team of observers at the Very Large Array that discovered the first Einstein ring.
Images: Hewitt et al, Nature 333, 537 (1988)
Images: Hewitt et al, Nature 333, 537 (1988)
We see an Einstein ring when light rays from a distant source are gravitationally lensed by a massive object in the foreground, so that the source of the light appears ring-like in shape. It requires a delicate alignment of the source, the lensing object, and the Earth.
Einstein himself was skeptical about the prospects of seeing a ring. He imagined both the source and the lensing object to be pointlike. In that case, the precise alignment needed to form a complete ring just seemed too unlikely.
But, as Hewitt and her colleagues pointed out, the possibility of a lensing mass appearing in front of an extended object (like a radio galaxy) wasn't too unlikely at all. Many more Einstein Rings, like LRG 3-757, have been discovered since then.
Image: ESA/Hubble & NASA
Image: ESA/Hubble & NASA
Einstein rings (or, in this case, arcs that nearly form a ring) know that things here on Earth seem pretty grim, but wish you a nice day nonetheless.
Image Credit: NASA / ESA / Hubble Space Telescope
Image Credit: NASA / ESA / Hubble Space Telescope
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