Free Astronomy Magazine March-April 2026

20 MARCH-APRIL 2026 ASTRO PUBLISHING 4485 form the system Arp 269, which is featured in the Atlas of Pe- culiar Galaxies. At such a close dis- tance (and with Webb’s impressive ability to peer through dusty cosmic clouds) these galaxies allow as- tronomers to witness up close the kinds of galaxy interactions that were common billions of years ago. Dwarf galaxies likely share many similarities with young galaxies in the early Universe: they are much less massive than galaxies like the Milky Way, they typically have small amounts of metals (what astron- omers call elements heavier than helium), and they contain a lot of gas and relatively few stars. When nearby dwarf galaxies collide, merge, or steal gas from one an- other, it can tell us how galaxies bil- lions of years ago might have grown and evolved. The nearby dwarf galaxies NGC 4490 and NGC 4485 form an intriguing pair. Nearly three decades ago, astronomers discov- ered a wispy bridge of gas connect- ing the two galaxies, showing that they have interacted in the past. Despite many studies with powerful telescopes like the NASA/ESA Hub- ble Space Telescope, the history be- tween NGC4490 and NGC 4485 has remained mysterious. Recently, Webb observed this curi- ous galactic pair as part of the Feed- back in Emerging extrAgalactic Star clusTers (FEAST) programme. The FEAST programme used Webb’s sen- sitive infrared eyes to reveal the for- mation of new stars in different types of nearby galaxies. T he NASA/ESA/CSA James Webb Space Telescope has spied a pair of dwarf galaxies en- gaged in a gravitational dance. These two galaxies are named NGC 4490 and NGC 4485, and they’re lo- cated about 24 million light-years away in the constellation Canes Ve- natici (The Hunting Dogs). Aside from the Milky Way’s own dwarf companions (the Large and Small Magellanic Clouds), this is the closest known interacting dwarf- dwarf system where astronomers have directly observed both a gas bridge and resolved stellar popula- tions. Together NGC 4490 and NGC A pair of dwarf galaxies engaged in a gravitational dance by NASA/ESA/CSA NASA Webb Mission Team