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| The Penguin and the Egg, galaxies jointly known as Arp 142, are engaged in a dynamic interaction captured by NASA’s James Webb Space Telescope. This near- and mid-infrared image reveals their active embrace, showcasing scattered stars in blue. Their close encounter, occurring between 25 and 75 million years ago, sparked intense star formation in the Penguin due to gravitational forces, despite both galaxies being of similar mass, preventing one from consuming the other. This image marks Webb’s second year of scientific operations, highlighting its capability to observe celestial phenomena with unprecedented clarity. |
In celebration of its second science anniversary, NASA’s James Webb Space Telescope has proven indispensable with its continuous observations, capturing images and detailed spectra crucial for astronomical research. Its contributions have sparked a flurry of discoveries worldwide, underscoring its pivotal role in unraveling the cosmos.
“Since President Biden and Vice President Harris unveiled the inaugural image from the James Webb Space Telescope two years ago, Webb has relentlessly delved into the universe’s mysteries,” remarked NASA Administrator Bill Nelson. “From breathtaking images spanning the farthest reaches of space and time, Webb’s capabilities are illuminating our cosmic surroundings anew, igniting inspiration among future generations of scientists, astronomers, and explorers.”
“In just two years, Webb has transformed our view of the universe, enabling the kind of world-class science that drove NASA to make this mission a reality,” said Mark Clampin, director of the Astrophysics Division at NASA Headquarters in Washington. “Webb is providing insights into longstanding mysteries about the early universe and ushering in a new era of studying distant worlds, while returning images that inspire people around the world and posing exciting new questions to answer. It has never been more possible to explore every facet of the universe.”
The James Webb Space Telescope’s specialization in capturing infrared light, beyond human vision, offers a unique perspective on galaxies like Arp 142, where the Penguin (NGC 2936) and the Egg (NGC 2937) are engaged in a slow cosmic dance. Webb’s observations, combining near- and mid-infrared data from NIRCam and MIRI, reveal a blue haze of mixed stars and gas surrounding these galaxies, a result of their interaction.
Their ongoing gravitational dance began 25 to 75 million years ago during their initial close pass. They continue to orbit each other, completing several more encounters before eventually merging into a single galaxy hundreds of millions of years from now. Webb’s detailed observations of Arp 142 highlight the telescope’s capability to capture the intricacies of galactic interactions and deepen our understanding of cosmic evolution.
Interacting Galaxies Arp 142.
Surrounding these newly formed stars is a smoky material containing carbon-rich molecules known as polycyclic aromatic hydrocarbons, excellently detected by Webb. Additionally, fainter, deeper orange arcs of dust sweep from the beak to the tail feathers.In contrast, the Egg retains its compact, elliptical shape largely unchanged. Being an elliptical galaxy, it houses older stars and contains much less gas and dust susceptible to being pulled away for star formation. Had both been spiral galaxies, each would have concluded their initial gravitational encounter with newly formed stars and tidal tails.
One key reason for the Egg’s relatively undisturbed appearance lies in the galaxies’ similar mass or weight. This parity ensures that the smaller-looking elliptical galaxy was neither consumed nor significantly distorted by the Penguin during their cosmic interaction.
It’s estimated that the Penguin and the Egg are approximately 100,000 light-years apart, a relatively close distance in astronomical terms. To put this in perspective, our own Milky Way galaxy and our nearest neighbor, the Andromeda Galaxy, are separated by about 2.5 million light-years. Although the Milky Way and Andromeda will also interact in the future, this won’t occur for another 4 billion years.Now, shift your gaze to the top right to observe a galaxy that isn’t part of this celestial dance. This edge-on galaxy, known as PGC 1237172 and located 100 million light-years closer to Earth, stands out. It’s relatively young, bustling with vibrant new blue stars.
Here’s another intriguing aspect: switch to Webb’s mid-infrared-only image, and you’ll notice PGC 1237172 practically disappears. Mid-infrared light predominantly captures cooler, older stars and a substantial amount of dust. Since this galaxy’s stellar population is predominantly young and filled with hot, blue stars, it becomes almost invisible in mid-infrared light due to the absence of these cooler components.
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| NASA’s James Webb Space Telescope’s mid-infrared view of interacting galaxies Arp 142 showcases primary colors: the Egg appears as a small teal oval, composed of old stars with depleted gas and dust. Meanwhile, the Penguin displays vibrant pink and purple hues, highlighting active star-forming regions rich in polycyclic aromatic hydrocarbons. |
Also, take a moment to scan the background of Webb’s image, filled with a multitude of distant galaxies. Some exhibit familiar spiral and oval shapes akin to those seen within the Penguin’s “tail feathers,” while others appear as shapeless dots scattered throughout.This abundance illustrates the remarkable sensitivity and resolution of Webb’s infrared instruments. (Contrast Webb’s view with the 2018 composite image combining infrared light from NASA’s retired Spitzer Space Telescope and near-infrared and visible light from Hubble Space Telescope.) Despite these observations spanning just a few hours, Webb has unveiled significantly more distant, redder, and dustier galaxies than its predecessors—a testament to its potential in advancing our comprehension of the universe.
Curious for more? Take a virtual tour of the image, “fly through” it using visualization tools, and compare Webb’s findings with those from the Hubble Space Telescope. Arp 142 resides 326 million light-years away in the constellation Hydra.
