Image: Gravitational lensing in galaxy YGKOW G1

Jan 27, 2014
Credit: ESA/NASA

(Phys.org) —In this new Hubble image two objects are clearly visible, shining brightly. When they were first discovered in 1979, they were thought to be separate objects—however, astronomers soon realized that these twins are a little too identical! They are close together, lie at the same distance from us, and have surprisingly similar properties. The reason they are so similar is not some bizarre coincidence; they are in fact the same object.

These cosmic doppelgangers make up a double quasar known as QSO 0957+561, also known as the "Twin Quasar," which lies just under 14 billion light-years from Earth. Quasars are the intensely powerful centers of distant galaxies. So, why are we seeing this quasar twice?

Some 4 billion light-years from Earth—and directly in our line of sight—is the huge galaxy YGKOW G1. This galaxy was the first ever observed , an object with a mass so great that it can bend the light from objects lying behind it. This phenomenon not only allows us to see objects that would otherwise be too remote, in cases like this it also allows us to see them twice over.

Along with the cluster of galaxies in which it resides, YGKOW G1 exerts an enormous gravitational force. This doesn't just affect the galaxy's shape, the stars that it forms, and the objects around it—it affects the very space it sits in, warping and bending the environment and producing bizarre effects, such as this quasar double image.

The first detection of gravitational lensing meant more than just the discovery of an impressive optical illusion allowing telescopes like Hubble to effectively see behind an intervening galaxy. It was evidence for Einstein's theory of general relativity. This theory had identified as one of its only observable effects, but until the observation of these quasar "twins," no such lensing had been observed since the idea was first mooted in 1936.

Explore further: Is the universe finite or infinite?

Related Stories

Image: Hubble shoots Bright Quasar 3C 273

Nov 25, 2013

(Phys.org) —This image from Hubble's Wide Field and Planetary Camera 2 (WFPC2) is likely the best of ancient and brilliant quasar 3C 273, which resides in a giant elliptical galaxy in the constellation ...

A space-time magnifying glass

May 15, 2013

(Phys.org) —Bright arcs are smeared around the heart of galaxy cluster Abell S1077 in this image taken by the NASA/ESA Hubble space telescope. The arcs are stretched images of distant galaxies distorted ...

Most distant gravitational lens helps weigh galaxies

Oct 17, 2013

An international team of astronomers has found the most distant gravitational lens yet—a galaxy that, as predicted by Albert Einstein's general theory of relativity, deflects and intensifies the light of ...

Astronomers discover an unusual cosmic lens

Jul 16, 2010

Astronomers at the California Institute of Technology (Caltech) and Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland have discovered the first known case of a distant galaxy being ...

A serendipitous gravitational lens

Nov 21, 2011

(PhysOrg.com) -- The path traveled by a light beam will bend in the presence of matter. This remarkable prediction, reached by Einstein in his theory of general relativity, was confirmed by observations of ...

Recommended for you

Rocky planets may orbit many double stars

2 hours ago

Luke Skywalker's home in "Star Wars" is the desert planet Tatooine, with twin sunsets because it orbits two stars. So far, only uninhabitable gas-giant planets have been identified circling such binary stars, ...

Is the universe finite or infinite?

Mar 27, 2015

Two possiblities exist: either the Universe is finite and has a size, or it's infinite and goes on forever. Both possibilities have mind-bending implications.

'Teapot' nova begins to wane

Mar 27, 2015

A star, or nova, has appeared in the constellation of Sagittarius and, even though it is now waning, it is still bright enough to be visible in the sky over Perth through binoculars or a telescope.

Dark matter is darker than once thought

Mar 27, 2015

This panel of images represents a study of 72 colliding galaxy clusters conducted by a team of astronomers using NASA's Chandra X-ray Observatory and Hubble Space Telescope. The research sets new limits on ...

Galaxy clusters collide—dark matter still a mystery

Mar 26, 2015

When galaxy clusters collide, their dark matters pass through each other, with very little interaction. Deepening the mystery, a study by scientists at EPFL and the University of Edinburgh challenges the ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

antialias_physorg
5 / 5 (3) Jan 27, 2014
This theory had identified gravitational lensing as one of its only observable effects

This makes it sound as if there were only a few observable effects of relativity - but there are many such effects: From time dilation/space contraction for satellites to mass increase in particle accelerators to the color of gold (wich, if you'd leave relativistic effects out of the equations, would look silver)

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.