"EINSTEIN RING SPOTTED BY HUBBLE"
This image, taken with the Hubble Space Telescope, shows a distant galaxy located in the constellation
Fornax. It is the largest and one of the most complete Einstein rings ever discovered.
This object’s unusual shape is the result of gravitational lensing. Albert Einstein,
in his general theory of relativity, first theorised that a large gravitational field
could act as a lens.
A huge amount of matter, like a cluster of galaxies, creates a gravitational field that
distorts and magnifies the light from distant galaxies that are behind it, but in the same
line of sight. The effect is like looking through a giant magnifying glass.
In this case, the light from the background galaxy was distorted into the curve we see
by the gravity of the galaxy cluster sitting in front of it. The near exact alignment of
the background galaxy with the central elliptical galaxy of the cluster, seen in the middle
of this image, has warped and magnified the image of the background galaxy around itself
into an almost perfect ring.
To get this clear an image of the far-distant galaxy on its own, Hubble’s 8-foot primary
mirror would have to have a diameter of 157 feet.
Objects like these allow us to research galaxies that would otherwise be too faint and distant
to see in such detail, helping us learn more about our amazing universe!
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