Andromeda
Andromeda, or M31, is the nearest large galactic neighbour of the Milky Way, about 2.5 million light-years away. A Hubble panorama released in 2025 resolves roughly 200 million stars across its inclined disk, only part of its full population. Comparing stellar ages, colours, dust and differences between regions helps reconstruct star formation and past mergers. The external view complements measurements made from inside our own galaxy.
NASA, ESA, Benjamin F. Williams (UWashington), Zhuo Chen (UWashington), L. Clifton Johnson (Northwestern); Image Processing: Joseph DePasquale (STScI)Individual planetary systems are not mapped in this galaxy.
NASA · Andromeda 
