Free Astronomy Magazine March-April 2026

21 MARCH-APRIL 2026 ASTRO PUBLISHING now trails between the galaxies like dancers connected by outstretched arms. Along the newly formed bridge of gas and within the two galaxies, this interaction spurred a burst of new stars. The concentrated areas of bright blue that appear throughout the field indicate highly ionised regions of gas by the recently formed star clusters. Just 30 million years ago, these galaxies burst alight with stars once more, with new clusters coa- lescing where the gas of the two galaxies mixed together. By captur- ing the history of the galactic dancers NGC 4490 and NGC 4485, Webb has revealed new details in how dwarf galaxies interact, giving us a glimpse of how small galaxies near and far grow and evolve. T his Webb image shows two interacting galaxies. NGC 4490 occupies the left side, while NGC 4485 appears as a white glowing hue in the top right of the field. Both galaxies are connected by a bright stream of red stretching from the top left of the image, through the bottom centre, and ending at the right under galaxy NGC 4485. There are regions of bright blue ionised gas visible in concen- trated areas of the red stream. The background is black with multiple galaxies in various shapes throughout. [ESA/Webb, NASA & CSA, A. Adamo (Stockholm Uni- versity), G. Bortolini, and the FEAST JWST team] The image presented above was de- veloped using data from Webb’s Near-InfraRed Camera (NIRCam) and Mid-InfraRed Instrument (MIRI), as well as a single narrow-band fil- ter from Hubble (657N). It reveals NGC 4490 and NGC 4485 in never- before-seen detail and illuminates the bridge of gas and stars that con- nects them. NGC 4490 is the domi- nant object occupying the left side of the image, while NGC 4485 is the smaller galaxy that hosts the top- right portion of the image. By dis- secting these galaxies star by star, researchers were able to map out where young, middle-aged, and old stars reside, and trace the timeline of the galaxies’ interaction. Roughly 200 million years ago, these galaxies whirled close to one another before waltzing away. The larger galaxy, NGC 4490, ensnared a stream of gas from its companion, and this gas !