Hubble captures an “Einstein ring”

A new photograph from the Hubble Space Telescope shows a magnificent “Einstein ring” billions of light years from Earth – a phenomenon named after Albert Einstein, who predicted that gravity could bend light.

The round object at the center of the photograph released by the European Space Agency is actually three galaxies that appear as seven, with four distinct images of the most distant galaxies forming a visible ring around the others.

The most distant galaxy – a special type of very bright galaxy with a gigantic black hole at its center known as a quasar – is located about 15 billion light years from Earth.

At such a great distance, it should be invisible to even the best space telescopes, but its light is bent by the two galaxies opposite, about 3 billion light-years away, so its image appears to us in five distinct places: four times in the ring and once in the center of the ring, although this can only be detected in the digital telescope data.

This rare phenomenon is named after Einstein, the physicist who predicted in 1911 that gravity would affect light just as it affects physical matter. Einstein proposed the idea as a test of his general theory of relativity in 1915, and in 1919 British astronomer Arthur Eddington confirmed the effect during a solar eclipse on Principe Island off the west coast. from Africa, noting that the stars near the eclipsed disk seemed slightly out of place because their light was bent by the sun’s gravity.

Telescopes in Einstein’s time were unable to detect other signs of the phenomenon. It was first seen by astronomers at Kitt Peak Observatory in Arizona in 1979 as Twin Quasar QSO 0957 + 561, a single quasar that looks like two here on Earth because its image is “lens gravitational ”by a closer but invisible galaxy.

Since then, astronomers have discovered hundreds of Einstein rings, although the alignment of distant galaxies must be perfect and none can be seen without a large telescope. A common formation is Einstein’s Cross, where a distant galaxy appears as four separate images around a galaxy closer to Earth, but the nearest galaxy is too dark to see.

Einstein’s rings and Einstein’s crosses are more than just a phenomenon – the gravitational lens allows astronomers to look much deeper into the depths of the universe, and also reveals otherwise hidden details of the galaxies that cause the lens.

“Einstein’s rings and Einstein’s crosses are probably evidence of more matter in the nearest galaxies than it appears, and that most likely means dark matter,” Ed Krupp said, astronomer and director of the Griffith Observatory in Los Angeles. Their distribution can “help shed light on the identity and distribution of dark matter and the relativistic geometry of the entire universe.”

Such gravitational lenses have also been used to spy on some of the most distant dwarf galaxies in the universe, which, being among the oldest, can tell astronomers more about the formation of galaxies; while the gravitational “microlens” – variations in the light of individual stars – has been used to reveal the invisible presence of distant exoplanets, Krupp said in an email.