Seabirds like the Northern Gannet plunge directly into the sea in pursuit of fish, sometimes from as high as 100 feet (30 meters). The birds’ spear-like bills and expertly tucked wings minimize splash upon impact, but water still ripples out in tiny waves.

Now, let’s switch to space — and swap the bird for a tiny galaxy and the ocean for a vast galaxy.

A tiny blue dwarf galaxy flew through the far more massive Bullseye galaxy 50 million years ago with similar effects, producing at least nine star-filled rings in its larger companion. In space, those “waves” ripple out differently. The gas, dust, and stars are pushed both inward and outward.

Seeing an effect like this in great detail is highly unusual. Both the Hubble Space Telescope and the W. M. Keck Observatory in Hawaii proved that the Bullseye galaxy has nine rings — six more than any other known galaxy. Plus, Hubble identified which galaxy dropped through the Bullseye’s core: The blue dwarf galaxy that now “sits” directly to its left.