‘According to Einstein’s general theory of relativity, light bends around objects with large masses, such as galaxies. This sometimes causes a phenomenon known as gravitational lensing, which brightens, magnifies, and distorts light from objects behind.

In rare cases, a gravitational lens can even split light passing through it and make it appear multiple times. Such a phenomenon is called an “Einstein’s cross” due to the shape that these split repetitions of light form.

A new Einstein’s cross has recently been observed and described in a scientific paper. The discovery was made by a research team from the Atacama Large Millimeter/Submillimeter Array (ALMA), a space telescope located in northern Chile, using observation data from ALMA and other telescopes. The light of the cross comes from HerS-3, a galaxy located 11.6 billion light years away, with the gravitational lensing being generated by four giant galaxies located between HerS-3 and the Earth. These giant galaxies are located some 7.8 billion light years away.

The gravitational lensing not only splits the light source, but magnifies it, allowing a detailed view of the light source behind the lens. Thanks to this, the team says that HerS-3 appears to be a bright starburst galaxy—a galaxy undergoing explosive star formation—and was formed at a time when star formation was at its peak throughout the universe. HerS-3 also has a tilted, rotating disk, from the center of which gas is gushing out at a furious rate, the team say.…’ —Shigeyuki Hando via WIRED