Space Telescopes Capture the Most Colorful Image of the Universe Yet

A combination of Hubble and James Webb images offers an extraordinarily intense view into space – and of a flickering “Christmas Tree Galaxy Cluster”.

The detail shows the enigmatic star system "Mothra", which appears extremely magnified and bright.

Hardly a week goes by without sensational images from the depths of space causing a stir. Now, the two largest telescopes outside Earth, the James Webb Space Telescope, which has been providing unprecedented sharp views of the universe from a distance of 1.5 million kilometers since 2022, and its predecessor, the Hubble Space Telescope, have joined forces. The result is impressive.

With such combined capabilities, scientists from NASA, ESA, and the Canadian Space Agency (CSA) focused on the galaxy cluster MACS0416. The cluster is approximately 4.3 billion light-years away from Earth and consists of two colliding galaxies that will eventually merge into an even larger structure. According to NASA and ESA, the recently released image combines the advantages of both telescopes to provide one of the most in-depth views of the universe ever captured using visible and infrared light. Additionally, the spectacular image, which includes a wealth of galaxies outside the cluster, is the most color-intensive ever recorded.

Christmas Tree Galaxy Cluster

The whole picture doesn’t become clear until you combine Webb data with Hubble data,” said Rogier Windhorst of Arizona State University, whose team conducted the Webb observations. To create the image of the colorful galaxy activity, the shortest wavelengths of light were colored blue, the longest red, and the middle ones green. Blue galaxies are relatively close and often exhibit intense star formation, while red galaxies tend to be more distant. However, some galaxies appear red because they contain large amounts of cosmic dust that absorbs blue light.

We’re calling MACS0416 the Christmas Tree Galaxy Cluster,” said Haojing Yan of the University of Missouri in Columbia, “because it is so colorful and because of the flickering lights we find in it. We can see transients everywhere.” Transients are objects whose brightness changes over time. During three observation phases, occurring a few weeks apart, the research team identified 14 such transients. Twelve of them are attributed to gravitational lensing effects, making stars or star systems appear extremely enlarged for a short period of time. Two others are likely supernovae.

Monstrous Star System

This panchromatic view of galaxy cluster MACS0416 was created by combining infrared observations from the NASA/ESA/CSA James Webb Space Telescope with visible-light data from the NASA/ESA Hubble Space Telescope.

One transient star system stood out among the others because it appeared to have grown by a factor of 4000. The team nicknamed the system “Mothra,” located in a galaxy that existed approximately three billion years after the Big Bang, after a giant monster from Japanese cinema. “Mothra” is extremely bright and enlarged. Interestingly, it was discovered by Hubble several years ago—a highly unusual occurrence, as only a specific constellation of the galaxy in the foreground and the star in the background allow for this gravitational lensing effect.

According to the scientists, a spherical star cluster acting as an additional magnifying lens is the most likely explanation, but Webb cannot directly observe it because of its faintness. However, the exact nature of this lens remains, for now, in the dark.