Why does Einstein's Cross show four images instead of a distorted ring?

[Hydr0matic]

Tell me if I've got this right ... The light from a distant quasar is bent around a more nearby galaxy, which is acting like a lens producing multible images of the quasar.. correct ?

What's up with this ? Is the lensing galaxy rectangular ? Why is the "lensing effect" producing four distinct images and not some distorted circular patterns ?

 

[MrCaN]

It's not rectangular, the lining is just that good, it is an oddity, but one that sheds a lot of light, no pun intended, on gravitational lensing.

 

[Hydr0matic]

The lining could be perfect and the lensing effect still shouldn't look like that... If the lensing object is spherical it should bend the light from an object behind it equaly in every direction, which will create a "circle of light" around the lensing object, not four distinct copies in a crossformation. Am I mistaken ?

 

[MrCaN]

You took my meaning of lining wrong, its not a straight line, the quasar in the back is off alittle bit, which creates the four points. Actually the light is bent spherecly, but due to the alignment, it peaks at four points, and the other stuff gets lost in space. That is it is so small it doesn't show up, and if you increase the exposure time, the galaxy in front will saturate the image.

 

[Hydr0matic]

Ok, I see... thnx !