Researchers using the Hubble telescope say that there may be as many as 500,000 naturally occurring "lenses" visible from Earth, which give them a glimpse far deeper into the distant universe than they would otherwise be able to see.
The phenomenon, called gravitational lensing, happens when a large galaxy or cluster of galaxies lies directly between a more distant galaxy and the Earth. The light from the more distant galaxy is bent by the gravity of the intervening object, often being magnified considerably.
When the distant galaxy, the "lens" and the observer – in this case the Hubble telescope – are lined up perfectly, a phenomenon called an Einstein ring can emerge (so called because Einstein's General theory of relativity predicted the curvature of space producing the effect) , in which a perfect image of the distant galaxy can be seen, but in the form of a bright ring around the intervening object.
As part of a project called COSMOS, researchers started with a catalog of about 2 million galaxies, and worked to identify which ones might serve as gravitational lenses. In an area of sky roughly nine times the area of the moon, they have now found 67, including several of the perfect rings.
Extrapolating that result to the entire sky (as seen from near-Earth environs), researchers say that a good half-million of these gravitational lenses may be visible, providing astronomers with a wealth of new views, and an increasing ability to understand the composition of the distant, early universe.
Hubble discovers 67 gravitationally-lensed galaxies in the distant universe [ESA]
(Image: An Einstein ring seen in an image from the COSMOS project.
Credit: NASA/ ESA/ Zentrum für Astronomie, University of Heidelberg (C.
Faure)/ Laboratoire d’Astrophysique de Marseille (J.P. Kneib) )
