Editing Einstein ring (section)

== Extra rings ==
[[File:SDSSJ0946+1006.jpg|thumb|SDSSJ0946+1006 is a Double Einstein Ring. Credit: [[Hubble Space Telescope|HST]]/[[NASA]]/[[ESA]]]]

Using the Hubble Space Telescope, a double ring has been found by Raphael Gavazzi of the [[STScI]] and Tommaso Treu of the [[University of California, Santa Barbara]]. This arises from the light from three galaxies at distances of 3, 6, and 11 billion light years. Such rings help in understanding the distribution of [[dark matter]], [[dark energy]], the nature of distant galaxies, and the [[curvature of the universe]]. The odds of finding such a double ring around a massive galaxy are 1 in 10,000. Sampling 50 suitable double rings would provide astronomers with a more accurate measurement of the dark matter content of the universe and the equation of state of the dark energy to within 10 percent precision.<ref>{{cite web |url=http://hubblesite.org/newscenter/archive/releases/2008/04/full/ |title=Hubble Finds Double Einstein Ring |access-date=2008-01-26 |work=Hubblesite.org |publisher=[[Space Telescope Science Institute]] }}</ref>

=== Simulation ===
Below in the Gallery section is a simulation depicting a zoom on a [[Schwarzschild metric|Schwarzschild black hole]] in the plane of the [[Milky Way]] between us and the centre of the galaxy. The first Einstein ring is the most distorted region of the picture and shows the [[Disc (galaxy)|galactic disc]]. The zoom then reveals a series of 4 extra rings, increasingly thinner and closer to the black hole shadow. They are multiple images of the galactic disk. The first and third correspond to points which are behind the black hole (from the observer's position) and correspond here to the bright yellow region of the galactic disc (close to the galactic center), whereas the second and fourth correspond to images of objects which are behind the observer, which appear bluer, since the corresponding part of the galactic disc is thinner and hence dimmer here.