plate 4 · laniakea
zoom out a thousandfold and galaxies become dust. what remains are clusters — thousands of galaxies deep — and the slow rivers of matter that feed them. this map projects real cluster positions onto the supergalactic plane, the flat sheet most of the nearby universe happens to lie in.
the local universe, ~1.5 Gly across
S shapley o coma
' ' '
' ' ' '
' '
' hydra o '
centaurus C V virgo'
' + <- here
norma (GA) N o fornax P perseus-pisces
' o pavo-indus '
' '
' ' ' '
' ' ' ' '
' ' ' = laniakea (schematic): the basin whose galaxy flows
converge near the norma cluster / great attractor.
the nearest big city is the virgo cluster, ~54 million light-years up the map. but virgo, and we, and everything inside the dotted boundary are all drifting toward the same place: a mass concentration behind the norma cluster known since the 1980s as the great attractor. tully and colleagues (2014) traced those flows and named the whole basin laniakea — hawaiian for “immense heaven” — 500 million light-years across, about 10^17 suns, 100,000 galaxies.
it may not even be the whole story. the cosmicflows-4 velocity map (2024) suggests laniakea is itself a suburb of the shapley concentration’s basin — a structure ten times larger. our address keeps growing. relative to the cosmic microwave background, the local group moves at 620 km/s toward that upper left corner, and nobody fully knows why.