One of the most striking features of the distribution of matter in the universe is its filamentary appearance, with long, luminous strands of galaxies woven together into a vast cosmic web.
Nowhere is this more evident than the Perseus-Pisces Supercluster. This colossal chain of galaxies snakes across more than 50° of the northern sky, fed by a network of smaller filaments that resemble tributaries flowing into a river. Embedded within these filaments are densely populated groups and clusters of galaxies. Between them lie immense voids.
Our own Milky Way Galaxy resides in the outskirts of a similar structure known as the Laniakea Supercluster. (Laniakea means “immeasurable heaven” in Hawaiian.) Home to an estimated 100,000 galaxies, it’s a tangled knot of filaments stretching half a billion light-years from end to end. University of Hawaii astronomer Brent Tully, whose team discovered Laniakea in 2014, likened it to “finding out for the first time that your hometown is actually part of a much larger country that borders other nations.”