Sometimes, Another Galaxy Passes Through Briefly But Changes You Forever. That’s The Tale Being Told

Sometimes, another galaxy passes through briefly but changes you forever. That’s the tale being told in this Hubble Space Telescope image of galaxy AM 0644-741. Once it was a classic spiral shape, until another galaxy passed directly through it and moved on to parts unknown. The stars, gas, and dust of the spiral arms were disrupted and pushed outward, similar to ripples after a rock has been thrown in a pond. As the ripple of galactic material plows outward into its surroundings, gas clouds collide and are compressed. The clouds can then contract under their own gravity, collapse, and form an abundance of new stars—shown here in bright blue. The core of the galaxy, glowing yellow, remains intact, though not centered. Credit: NASA, ESA, STScI. ALT TEXT: An oval-shaped galaxy with a hazy yellow core is surrounded by a ring of bright blue stars. The core is off-center, much closer to the left-hand edge of the outer ring, like the yolk of an egg. One partial arm of stars wraps beneath and to the right of the core. The remainder of space inside the galaxy’s outer ring of stars is filled with dark gas and dust, and occasional stars or star clusters seen as red or yellow dots. The outer ring of blue stars is interspersed with pink and red areas, with some glowing almost white. A scattering of stars appears in the background in blue and red, with some distant galaxies appearing hazy yellow.