Einstein's Cross
image of a quasar
Einstein's Cross [1] is an image of a quasar which is 8,000,000,000 light years (ly) or 2,500,000,000 parsecs (pc) away.
![](http://up.wiki.x.io/wikipedia/commons/thumb/c/c8/Einstein_cross.jpg/250px-Einstein_cross.jpg)
The quasar sits directly behind ZW 2237+030, Huchra's lens, the lensing galaxy. Four images of the same distant quasar appear around this foreground galaxy due to strong gravitational lensing.
According to its redshift, the quasar is about 8 billion light years from Earth, while the lensing galaxy is only 400 million light years away.[2]
Amateur astronomers are able to see some of the cross using telescopes but it requires extremely dark skies and telescope mirrors with diameters of 18 inches or greater.[3][4]
References
change- ↑ Q2237+030 or QSO 2237+0305
- ↑ NASA and ESA (1990). "The gravitational lens G2237 + 0305". HubbleSite. Retrieved July 25, 2006.
- ↑ The Einstein Cross can be seen in Pegasus at 22h40m30.3s +3d21m31s.
- ↑ Crinklaw, Greg. "Focus on Einstein's Cross". Retrieved 2013-06-29.