Credit: NASA & ESA
In the centre of this image, taken with the NASA/ESA Hubble Space Telescope, are two faint galaxies that seem to be smiling.
You can make out two orange eyes and a white button nose. In the case
of this “happy face”, the two eyes are the galaxies SDSSCGB 8842.3 and
SDSSCGB 8842.4 and the misleading smile lines are actually arcs caused
by an effect known as strong gravitational lensing.
Massive structures in the Universe exert such a powerful
gravitational pull that they can warp the spacetime around them and act
as cosmic lenses which can magnify, distort and bend the light behind
them. This phenomenon, crucial to many of Hubble’s discoveries, can be
explained by Einstein’s theory of general relativity.
In this special case of gravitational lensing, a ring — known as an Einstein Ring
— is produced from this bending of light, a consequence of the exact
and symmetrical alignment of the source, lens and observer and resulting
in the ring-like structure we see here.
Hubble has provided astronomers with the tools to probe these massive
galaxies and model their lensing effects, allowing us to peer further
into the early Universe than ever before. This object was studied by
Hubble’s Wide Field and Planetary Camera 2 (WFPC2) and Wide Field Camera 3 (WFC3) as part of a survey of strong lenses.
A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Judy Schmidt.
