The giant elliptical galaxy at the center of galaxy cluster Abell S1063 is much larger and more luminous than the Milky Way is, but many other galaxies, even smaller ones, will outshine it. (NASA, ESA, and J. Lotz (STScI))

The Brightest Galaxy In The Universe Is Suprisingly Young And Tiny

The brightest galaxies of all neither have the most stars nor the biggest black holes. Here’s how to solve the mystery.

With some 400 billion stars burning steadily, the Milky Way is just a typical galaxy in the Universe.

The SDSS view in the infrared — with APOGEE — of the Milky Way galaxy as viewed towards the center. Containing some 400 billion stars, infrared wavelengths are the best for viewing as many as possible due to its transparency to light-blocking dust. (Sloan Digital Sky Survey)

Many galaxies are larger, containing tens or hundreds of times as many stars.

The giant elliptical near the center of the Coma Cluster, NGC 4874 (at right), is typical of the largest, brightest galaxies found at the centers of the most massive galaxy clusters. Its stars are primarily older and redder, with only a few populations of bluer stars found sparsely inside. (ESA/Hubble & NASA)

But there are galaxies that are intrinsically brighter because they’re active, irrespective of their size.

Galaxies undergoing massive bursts of star formation can outshine even much larger, typical galaxies. M82, the Cigar Galaxy, is gravitationally interacting with its neighbor (not pictured), causing this burst of active, new star formation, making it much brighter than a typical galaxy of its size and mass. (NASA, ESA, and The Hubble Heritage Team (STScI/AURA))

When new stars form en masse, the most massive ones can shine up to millions of times brighter than a Sun-like star.