Webb telescope captures galaxy three times: Why it happened

The James Webb Space Telescope captured an image that shows the same galaxy three times due to gravitational lensing from a galaxy cluster that is 3.2 billion light-years from Earth.

Webb telescope captures galaxy three times: Why it happened

The James Webb Space Telescope has captured an image that may make viewers double take. 

The shot features a special galaxy cluster – known as RX J2129 – and three different images of the same supernova-hosting galaxy.

RX J2129 is located approximately 3.2 billion light-years from Earth in the constellation Aquarius. 

The tripled galaxy is shown this way due to gravitational lensing. 

Gravitational lensing occurs when a massive celestial body causes a sufficient curvature of spacetime to bend the path of light traveling past or through it – like a vast lens.

The mass and gravity of the galaxy cluster is so great that time and space around it is warped, magnifying, multiplying and distorting galaxies behind it.

The supernova in the triple-lensed background galaxy was discovered by astronomers using the Hubble Space Telescope. 

It contains a Type Ia supernova. Supernovae are explosions that take place during the final stages of the death of a supermassive star. A Type Ia supernova occurs roughly once every 500 years in the Milky Way and NASA says evidence shows it originates from some binary star systems that contain at least one white dwarf – the small, hot core remnant of a sun-like star.

The supernovae produce a fairly consistent luminosity, which allows astronomers to calculate astronomical distances. Scientists are able to understand how strongly the galaxy cluster is magnifying background objects and how massive it is. 

"As well as distorting the images of background objects, gravitational lenses can cause distant objects to appear much brighter than they would otherwise," the European Space Agency said in a post. "If the gravitational lens magnifies something with a known brightness, such as a Type Ia supernova, then astronomers can use this to measure the ‘prescription’ of the gravitational lens."

Furthermore, the spectroscopy of the supernova was obtained, allowing for the comparison of the supernova to Type Ia supernovae in the nearby universe. 

The agency said that this is an important way to verify that methods of measuring vast distances works as expected.