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NASA’s James Webb Space Telescope shows a pair of intertwined galaxies in infrared light, its latest release in an ongoing series of observations.

The James Webb Space Telescope operates around the clock, often surprising researchers with its highly detailed—and incredibly precise—infrared images and data. These wavelengths of light, which lie beyond what our eyes can see, were largely unattainable at this level of detail until Webb began making scientific observations on July 12, 2022, on behalf of astronomers from whole world.

To honor its second science anniversary, the telescope observed Arp 142, an interacting pair of galaxies called the Penguin and the Egg. The main image combines near- and mid-infrared light that visually highlights how the galaxies are interacting — look for the faint inverted blue U shape that wraps around both galaxies — along with a “star party,” an abundance of recent star formation, in Penguin.

Webb’s mid-infrared view of interacting galaxies Arp 142 appears to sing in primary colors. The background of space is like a gaping darkness, speckled with bright, multicolored beads. This image was taken by MIRI, the telescope’s Mid-Infrared Instrument, which astronomers use to study colder and older objects, dust and extremely distant galaxies. Courtesy: NASA, ESA, CSA, STScI

A vivid portrait of interacting galaxies marks the second anniversary of the Webb Space Telescope

Two for two! A duo of interacting galaxies is marking the second science anniversary of NASA’s James Webb Space Telescope, which makes constant observations, including images and highly detailed data known as spectra. His operations led to a “parade” of discoveries by astronomers from around the world.

“Since President Biden and Vice President Harris unveiled the first image from the James Webb Space Telescope two years ago, Webb has continued to unlock the mysteries of the universe,” said NASA Administrator Bill Nelson. “With remarkable images from the corners of space going back almost to the beginning of time, Webb’s capabilities are shedding new light on our celestial environment and inspiring future generations of scientists, astronomers and explorers.”

“In just two years, Webb has transformed our view of the universe, enabling the world-class science that has driven NASA to make this mission a reality,” said Mark Clampin, director of the Astrophysics Division at NASA Headquarters in Washington. “Webb provides insights into long-standing mysteries about the early universe and ushers in a new era of studying distant worlds, while returning images that inspire people around the world and pose exciting new questions to answer.” It has never been more possible to explore every aspect of the universe.”

This “penguin party” is loud! The distorted spiral galaxy in the center, the Penguin, and the compact elliptical galaxy on the left, the Egg, are locked in an active embrace. A new near- and mid-infrared image from the James Webb Space Telescope, taken to mark its second year in science, shows that their interaction is marked by a faint inverted U-shaped blue glow.
The pair, known jointly as Arp 142, made their first pass between 25 and 75 million years ago, causing “fireworks” or new star formation in Penguin. In the most extreme cases, mergers can cause galaxies to form thousands of new stars per year for several million years. For the penguin, research suggests that about 100 to 200 stars formed per year. By comparison, our Milky Way galaxy (which is not interacting with a galaxy of the same size) forms approximately six to seven new stars per year.
Courtesy: NASA, ESA, CSA, STScI

Insightful observations of galactic interactions

The telescope’s specialization in capturing infrared light – which goes beyond what our own eyes can detect – shows these galaxies, known as Arp 142, locked in a slow cosmic dance. Webb’s observations, which combine near- and mid-infrared light from Webb’s NIRCam (Near Infrared Camera) and MIRI (Mid-Infrared Instrument), respectively, clearly show that they are joined by a nebula, represented in blue, which is a mixture of stars and gas resulting from their mixing.

Their ongoing interaction was set in motion between 25 and 75 million years ago when the Penguin (individually cataloged as NGC 2936) and the Egg (NGC 2937) completed their first transit. They will continue to twinkle and oscillate, completing several additional rounds before merging into a single galaxy in hundreds of millions of years.

Two penguins, two eggs — two very different color schemes! The Hubble Space Telescope captured visible light observing Arp 142, nicknamed The Penguin and the Egg, in 2013. At right is the James Webb Space Telescope’s near-infrared image of the same region. Courtesy: NASA, ESA, CSA, STScI

The evolution of the penguin and the egg

Before their first approach, the penguin had the shape of a spiral. Today, its galactic center shines like an eye, and its evolved arms now form a beak, head, spine, and spreading tail.

Like all spiral galaxies, Penguin is still very rich in gas and dust. The galaxies’ “dance” gravitationally attracted Penguin’s thinner regions of gas and dust, causing them to break up in waves and form stars. Look for these areas in two places: what looks like a fish in its “beak” and the “feathers” in its “tail.”

Surrounding these newer stars is smoke-like material that includes carbon-containing molecules known as polycyclic aromatic hydrocarbons, which Webb was exceptional at detecting. Dust, seen as fainter, deeper orange arcs, also rises from its beak to its tail feathers.

In contrast, the compact shape of the egg remains largely unchanged. As an elliptical galaxy, it is full of aging stars and has much less gas and dust that can be pulled in to form new stars. If both were spiral galaxies, each would complete the first “spin” with the formation of a new star and swirling curls known as tidal tails.

Another reason for the Egg’s undisturbed appearance: These galaxies have roughly the same mass, or gravity, so the smaller-looking elliptical shape hasn’t been swallowed up or distorted by the Penguin.

This video looks at Arp 142, an interacting pair of galaxies known as the Penguin and the Egg, located 326 million light-years from Earth. The journey begins and ends on a new mid- and near-infrared image from the James Webb Space Telescope and includes a brief fade-in to a visible-light image from Hubble Space Telescope. The pair are separated by only 100,000 light-years—relatively close in astronomical terms. Ours Milky Way galaxy and its nearest neighbor, the Andromeda galaxy, are separated by about 2.5 million light years. This tour highlights what has happened since they interacted, including a blue mist that joins them. Also look for contrasting views of the spiral galaxy in the upper right, which “disappears” in Webb’s mid-infrared view. Courtesy: NASA, ESA, CSA, STScI, Daniel Kirschenblatt (STScI)

The larger context of galactic interactions

The Penguin and the Egg are estimated to be about 100,000 light-years apart – quite close in astronomical terms. For context, the Milky Way galaxy and our nearest neighbor, the Andromeda galaxy, are about 2.5 million light-years apart. They will also interact, but not for about 4 billion years. (See the video below.)

This scientific visualization of a computer simulation depicts the imminent collision between our Milky Way Galaxy and the Andromeda Galaxy (also known as Messier 31). Observations by NASA’s Hubble Space Telescope show that the two galaxies, drawn toward each other by their mutual gravity, will crash together in a near-head-on collision in about 4 billion years.

Now look to the top right to see a galaxy that isn’t in this party. This terminal galaxy, cataloged as PGC 1237172, is 100 million light-years closer to Earth. It’s also quite young, teeming with new, blue stars.

Want another party trick? Switch to the Webb mid-infrared image (the second image on this page) to see PGC 1237172 practically disappearing. Mid-infrared light largely captures cooler, older stars and an incredible amount of dust. Because the galaxy’s stellar population is so young, it “disappears” in mid-infrared light.

Also, take a moment to scan the background. The web image overflows with galaxies far away. Some take on spiral and oval shapes, such as those embedded in the penguin’s “tail feathers,” while others scattered throughout are shapeless dots. This is a testament to the sensitivity and resolution of the telescope’s infrared instruments. (Compare Webb’s view with the 2018 observation, which combined infrared light from NASA’s retired Spitzer Space Telescope and near-infrared and visible light from NASA’s Hubble Space Telescope.) Although these observations only took a few hours, Webb revealed a lot more distant, redder, and dustier galaxies than previous telescopes—one more reason to expect Webb to continue to expand our understanding of everything in the universe.

This visualization explores the three-dimensional structure of Arp 142, a pair of interacting galaxies called the Penguin and the Egg, as seen in near-infrared light from the James Webb Space Telescope.

Arp 142 is located 326 million light years from Earth in the constellation Hydra.

The James Webb Space Telescope is the world’s leading space science observatory. Webb solves mysteries in our solar system, looks beyond distant worlds around other stars, and explores the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA and its partners ESA (European Space Agency) and CSA (Canadian Space Agency).