Free Astronomy Magazine September-October 2024

44 SEPTEMBER-OCTOBER 2024 ASTRO PUBLISHING mysteries about the early universe and ushering in a new era of study- ing 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 telescope’s specialization in cap- turing infrared light — which is be- yond what our own eyes can detect — shows these galaxies, collectively known as Arp 142, locked in a slow cosmic dance. Webb’s observations, which combine near- and mid-in- frared light from Webb’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument), respec- tively, clearly show that they are joined by a haze represented in blue that is a mix of stars and gas, a re- sult of their mingling. Their ongoing interaction was set in motion between 25 and 75 million years ago, when the Penguin (indi- vidually cataloged as NGC 2936) and the Egg (NGC 2937) completed their first pass. They will go on to shimmy and sway, completing several addi- tional loops before merging into a single galaxy hundreds of millions of years from now. Before their first approach, the Pen- guin held the shape of a spiral. Today, its galactic center gleams like an eye, its unwound arms now shap- ing a beak, head, backbone, and fanned-out tail. Like all spiral galaxies, the Penguin is still very rich in gas and dust. The galaxies’ “dance” gravitationally pulled on the Penguin’s thinner areas of gas and dust, causing them to crash in waves and form stars. Look for those 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 is exceptional at de- tecting. Dust, seen as fainter, deeper orange arcs also swoops from its beak to tail feathers. In contrast, the Egg’s compact shape remains largely unchanged. As an elliptical galaxy, it is filled with aging stars, and has a lot less gas and dust that can be pulled away to form new stars. If both were spiral galaxies, each would end the first “twist” with new star formation and twirling curls, known as tidal tails. Another reason for the Egg’s undis- turbed appearance: These galaxies have approximately the same mass or heft, which is why the smaller- looking elliptical wasn’t consumed or distorted by the Penguin. It is estimated that the Penguin and the Egg are about 100,000 light- years apart — quite close in astro- nomical terms. For context, the Milky Way galaxy and our nearest neighbor, the Andromeda Galaxy, are about 2.5 million light-years apart. They too will interact, but not for about 4 billion years. The Penguin and the Egg as seen by Webb by NASA/ESA/CSA Claire Blome Christine Pulliam T wo for two! A duo of interact- ing galaxies commemorates the second science anniver- sary of NASA’s James Webb Space Telescope, which takes constant ob- servations, including images and highly detailed data known as spec- tra. Its operations have led to a “pa- rade” of discoveries by astronomers 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 Admin- istrator Bill Nelson. “With remark- able images from the corners of the cosmos, going back nearly to the beginning of time, Webb’s capabili- ties are shedding new light on our celestial surroundings and inspiring future generations of scientists, as- tronomers, and explorers.” “In just two years, Webb has trans- formed 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 Astro- physics Division at NASA Headquar- ters in Washington. “Webb is providing insights into longstanding !