The most distant gravitational lens ever discovered proved the existence of a galaxy that Albert Einstein predicted decades ago.
The lens allowed the researchers to measure the mass of the far-off galaxy, which is believed to deflect and intensify light as Einstein predicted in his notorious general theory of relativity, a Max Planck Institute news release reported.
A gravitational lens consists of two objects. One object is farther away and emits light, the other is closer to Earth and uses gravity to deflect the light. When the viewer is correctly aligned with the two objects they witness an "Einstein ring," which is a perfect circle of light.
"The discovery was completely by chance. I had been reviewing observations from an earlier project with the goal of measuring masses of old, distant galaxies by looking at the motion of their stars. Among the galaxy spectra" - the rainbow-like split of a galaxy's light into myriads of different shades of color - I noticed a galaxy that was decidedly odd. It looked like an extremely young galaxy, and at an even larger distance than I was aiming for. It shouldn't even have been part of our observing program!" MPIA's Arjen van der Wel, said.
At first the researchers thought the object was an older galaxy, but there were some "irregular features" that made the researchers believe they were looking at something more unusual. Upon further investigation they saw an almost perfect Einstein ring.
The discovery did bring up some questions; these lenses should be extremely rare, but scientists have found a number over the years. Either the scientists have been exceptionally lucky over the years, or there are more young galaxies that we previously thought.
The first lens was found in 1979, and since then there have been numerous discoveries. Since light is affected by gravity, it will be deflected as it passes these galaxies.
Using these lenses, researchers can determine the mass of the objects that are bending the light. They can even help determine the mass of dark matter, which does not give off or absorb light and is virtually invisible except for its gravitational force.
The lens also amps up background light, making it easier for researchers to see the universe.
