Another dazzling result debuted at the annual meeting of the American Astronomical Society. The Hubble Space Telescope has recorded a double Einstein ring, a cosmic mirage arising from the gravitational lensing predicted by Einstein in the theory of general relativity.
Hubble has found a triplet of galaxies 2 , 6 and 11 billion
light-years away--lying exactly behind each other in the line of sight from the solar system The
light from the more distant is bent by the gravity of the
nearer one, creating two nested rings. If more double rings are found, spectroscopy may tell if the expansion
rate of the universe has changed over time.