While hunting for dark matter, astronomers accidentally discovered the first known stellar stream stretching between galaxies. The trail of stars is also the longest ever seen.

Intergalactic 'stream of stars' 10 times longer than the Milky Way is the 1st of its kind ever spotted

Source: space
Source Link: https://www.space.com/intergalactic-stream-of-stars-10-times-longer-than-milky-way