The James Webb Space Telescope has captured a breathtaking image of a “green monster” inside a young supernova, offering a glimpse into the heart of stellar explosions. This newly revealed phenomenon, glowing in a vibrant green hue, is a complex structure formed by the supernova’s shockwaves interacting with surrounding gas and dust. The image provides astronomers with unprecedented insight into the early stages of a supernova’s life cycle, shedding light on the cosmic processes that drive these powerful stellar events. As Webb continues to peer into distant corners of the universe, its discoveries, like this one, promise to unlock deeper mysteries of how stars live and die, and how these cataclysmic explosions shape the evolution of galaxies.

This side-by-side comparison shows observations of the Southern Ring Nebula in near-infrared light, left, and mid-infrared light, right, from NASA's Webb telescope. The Southern Ring Nebula is 2,000 light-years away from Earth. This large planetary nebula includes an expanding cloud of gas around a dying star, as well as a secondary star earlier on in its evolution.
President Joe Biden <a href="https://www.cnn.com/2022/07/11/world/james-webb-space-telescope-first-image-scn/index.html" target="_blank">released one of Webb's first images</a> on July 11, and it's "the deepest and sharpest infrared image of the distant universe to date," according to NASA. The image shows SMACS 0723, where a massive group of galaxy clusters act as a magnifying glass for the objects behind them. Called gravitational lensing, this created Webb's first deep field view of incredibly old and distant, faint galaxies.
This composite image of nebula NGC 1333 captures minute detail of young stars and brown dwarfs. These details were previously obscured in Hubble Telescope's images of the same nebula.
This composite image of nebula NGC 1333 captures minute detail of young stars and brown dwarfs. These details were previously obscured in Hubble Telescope’s images of the same nebula.

ESA/Webb/NASA/CSA

NASA released this image of galaxy Arp 142 on July 12, to mark the two-year anniversary of the James Webb Space Telescope.
This Webb image shows a densely populated spiral galaxy anchored by a central region that has a light blue haze, known NGC 628. It's 32 million light-years away in the constellation Pisces.
In this new image of Uranus, the planet shines shine brightly, along with its many rings and moons.
The James Webb Space Telescope's shot of supernova remnant Cassiopeia A shows elaborate details visible for the first time.
There are approximately 500,000 stars in this image of the Sagittarius C region of the Milky Way. The bright cyan area contains emissions from ionized hydrogen.
Galaxy cluster MACS0416 is seen here in exquisite detail thanks to a composite image created with data from both NASA's James Webb and Hubble space telescopes.
Scientists are hoping to gain more information about the origins of the Crab Nebula, thanks to new details spotted by the James Webb Space Telescope.
This image shows the Ring Nebula in exceptional detail, like the filament elements in the ring's inner section.
Earendel, the most distant star ever discovered, can be seen in this image of the Sunrise Arc galaxy.
The Ring Nebula is seen in breathtaking detail, in a composite image released on August 4.
The James Webb Space Telescope captured a high-resolution image of a pair of actively forming stars called Herbig-Haro 46/47. The stellar duo, only a few thousand years old, is located at the center of the red diffraction spikes.
The James Webb Space Telescope captured a detailed closeup of the birth of sunlike stars in the Rho Ophiuchi cloud, the closest star-forming region located 390 light-years from Earth. The young stars release jets that cause the surrounding gas to glow. The image's release marks the first anniversary of Webb's observations of the cosmos.
Saturn and its moons were captured by NASA's James Webb Space Telescope June 25. The image shows details of the planet's atmosphere and ring system.
The James Webb Space Telescope captured the Orion Bar, a part of the Orion Nebula that is being eroded by stellar radiation emanating from the Trapezium Cluster.
This composite image, shot from the James Webb Space Telescope's MIRI and NIRCam instruments, shows the bright clusters of stars and dust from barred spiral galaxy NGC 5068.
Webb captured a burst of star formation triggered by two colliding spiral galaxies called Arp 220. The phenomenon is the closest ultra-luminous galactic merger to Earth.
Dusty rings surround Fomalhaut, a young star outside of our solar system that's 25 light-years from Earth.
The Wolf-Rayet star WR 124 was one of the James Webb Space Telescope's first discoveries, spotted in June 2022.
Stunning details can be seen in this Webb telescope photo of supernova remnant Cassiopeia A, which is 11,000 light-years from Earth.
Webb's image of ice giant Uranus shows off the planet's incredible rings and a bright haze covering its north polar cap (right). A bright cloud lies at the cap's edge and a second one is seen at left.
The James Webb Space Telescope captured 50,000 sources of near-infrared light in a new image of Pandora's Cluster, a megacluster of galaxies. The cluster acts like a magnifying glass, allowing astronomers to see more distant galaxies behind it.
Stars shine through the hazy material of the Chamaeleon I dark molecular cloud, which is 630 light-years away from Earth.
The James Webb Space Telescope spotted NGC 346, one of the most dynamic star-forming regions near the Milky Way, located in a dwarf galaxy called the Small Magellanic Cloud.
Two galaxies, known as II ZW96, form a swirl shape while merging in the constellation Delphinus.
The James Webb Space Telescope revealed features of a new protostar forming.
The James Webb Space Telescope captured a new perspective of the Pillars of Creation in mid-infrared light. The dust of this star-forming region, rather than the stars themselves, is the highlight, and resembles ghostly figures.
Webb captured a highly detailed snapshot of the so-called <a href="https://www.cnn.com/2022/10/19/world/webb-telescope-pillars-of-creation-scn/index.html" target="_blank">Pillars of Creation,</a> a vista of three looming towers made of interstellar dust and gas that's speckled with newly formed stars. The area, which lies within the Eagle Nebula about 6,500 light-years from Earth, had previously been captured by the Hubble Telescope in 1995, creating an image deemed "iconic" by space observers.
The two stars in WR140 produce shells of dust every eight years that look like rings, as captured by the Webb telescope.
The James Webb Space Telescope and Hubble Space Telescope contributed to this image of galactic pair VV 191. Webb observed the brighter elliptical galaxy (left) and spiral galaxy (right) in near-infrared light, and Hubble collected data in visible and ultraviolet light.
The James Webb Space Telescope captured spiral galaxy IC 5332, which is over 29 million light-years away. The observatory's MIRI instrument<a href="http://www.cnn.com/2022/09/27/world/spiral-galaxy-james-webb-new-images-scn/index.html" target="_blank"> peered through interstellar dust to see the galaxy's "bones."</a>
Webb captured the clearest view of the Neptune's rings in over 30 years.
The inner region of the <a href="https://www.cnn.com/2022/09/12/world/james-webb-space-telescope-image-orion-nebula-scn/index.html" target="_blank">Orion Nebula</a> as seen by the telescope's NIRCam instrument. The image reveals intricate details about how stars and planetary systems are formed.
NASA released a mosaic image of the <a href="https://www.cnn.com/2022/09/06/world/webb-telescope-tarantula-nebula-stars-image-scn/index.html" target="_blank">Tarantula Nebula</a> on Tuesday, September 6. The image, which spans 340 light-years, shows tens of thousands of young stars that were previously obscured by cosmic dust.
A new image of the Phantom Galaxy, which is 32 million light-years away from Earth, combines data from the James Webb Space Telescope and the Hubble Space Telescope.
NASA <a href="https://www.cnn.com/2022/08/22/world/jupiter-images-webb-telescope-nasa-scn/index.html" target="_blank">released an image</a> of Jupiter on Monday, August 22, that shows the planet's famous Great Red Spot appearing white.
The James Webb Space Telescope <a href="https://www.cnn.com/2022/08/02/world/webb-telescope-cartwheel-galaxy-image-scn/index.html" target="_blank">captured the Cartwheel galaxy,</a> which is around 500 million light-years away, in a photo released by NASA on August 2.
Webb's landscape-like view, called "Cosmic Cliffs," is actually the edge of a nearby, young, star-forming region called NGC 3324 in the Carina Nebula. The telescope's infrared view reveals previously invisible areas of star birth.
The five galaxies of Stephan's Quintet can be seen here in a new light. The galaxies appear to dance with one another, showcasing how these interactions can drive galactic evolution.
This side-by-side comparison shows observations of the Southern Ring Nebula in near-infrared light, left, and mid-infrared light, right, from NASA's Webb telescope. The Southern Ring Nebula is 2,000 light-years away from Earth. This large planetary nebula includes an expanding cloud of gas around a dying star, as well as a secondary star earlier on in its evolution.
President Joe Biden <a href="https://www.cnn.com/2022/07/11/world/james-webb-space-telescope-first-image-scn/index.html" target="_blank">released one of Webb's first images</a> on July 11, and it's "the deepest and sharpest infrared image of the distant universe to date," according to NASA. The image shows SMACS 0723, where a massive group of galaxy clusters act as a magnifying glass for the objects behind them. Called gravitational lensing, this created Webb's first deep field view of incredibly old and distant, faint galaxies.
This composite image of nebula NGC 1333 captures minute detail of young stars and brown dwarfs. These details were previously obscured in Hubble Telescope's images of the same nebula.
NASA released this image of galaxy Arp 142 on July 12, to mark the two-year anniversary of the James Webb Space Telescope.

Observing the universe with the James Webb Space Telescope
1 of 41

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.

CNN — 

The James Webb Space Telescope has spied colorful, never-before-seen details in one of the most well-observed remnants of an exploded star.

The glowing gas and dust of Cassiopeia A is all that remains of a star that exploded in a supernova, and its light reached Earth for the first time 340 years ago. It’s the youngest known supernova remnant in our galaxy, which is why the celestial object has been studied by a multitude of ground and space-based telescopes.

Cassiopeia A is located 11,000 light-years away in the Cassiopeia constellation, and the remnant stretches for 10 light-years.

Insights from Cas A, as the remnant is also known, allow scientists to learn more about how stellar explosions occur.

Astronomers turned the Webb telescope and its instruments in the direction of Cas A to see if the observatory’s infrared capabilities could pick up anything other telescopes have missed. Infrared light is invisible to the human eye, allowing Webb to spy otherwise invisible aspects of the universe.

“Cas A represents our best opportunity to look at the debris field of an exploded star and run a kind of stellar autopsy to understand what type of star was there beforehand and how that star exploded,” said Danny Milisavljevic, assistant professor at Purdue University and principal investigator of the Webb program that captured the new observations, in a statement.

“Compared to previous infrared images, we see incredible detail that we haven’t been able to access before,” said co-investigator Tea Temim, research astronomer at Princeton University, in a statement.

wonders of the universe Cassiopeia A

Titanium bubbles discovered in supernova could help solve mystery of exploding stars

Webb’s new infrared image of Cas A has been translated into visible light so the human eye can see the remnant’s colors. Red and orange light on the remnant’s exterior indicates warm dust, where material ejected from the star before it exploded is colliding with surrounding gas and dust.

Inside the bubble-like structure of the remnant, bright pink light can be seen, along with features that resemble clumps and knots. This material came from the exploded star and includes glowing heavy elements like argon, neon and oxygen.

The colorful supernova remnant Cassiopeia A was captured in infrared light by the Webb telescope.
The colorful supernova remnant Cassiopeia A was captured in infrared light by the Webb telescope.

NASA/ESA/CSA/D. D. Milisavljevic/T. Temim/I. De Looze

A bright green loop along the right side of the bubble has also captured the interest of researchers.

“We’ve nicknamed it the Green Monster in honor of Fenway Park in Boston. If you look closely, you’ll notice that it’s pockmarked with what look like mini-bubbles,” said Milisavljevic. “The shape and complexity are unexpected and challenging to understand.”

The team is still trying to understand the sources behind all of the different colors in the image.

Studying remnants like Cas A can help scientists understand cosmic dust, a building block for stars and planets, and how exploded stars release elements crucial for life.

“By understanding the process of exploding stars, we’re reading our own origin story,” Milisavljevic said. “I’m going to spend the rest of my career trying to understand what’s in this data set.”