Editing Andromeda Galaxy (section)

=== 21st century ===
[[File:Largest Mosaic of Andromeda by Hubble jan 16 2025-extra details.jpg | thumb | Largest Mosaic of Andromeda by Hubble with details: (a) Clusters of bright blue stars embedded within the galaxy, background galaxies seen much farther away, and photo-bombing by a couple bright foreground stars that are actually inside our Milky Way; (b) NGC 206 the most conspicuous star cloud in Andromeda; (c) A young cluster of blue newborn stars; (d) The satellite galaxy M32, that may be the residual core of a galaxy that once collided with Andromeda; (e) Dark dust lanes across myriad stars.<ref>{{cite web |title=Hubble's panoramic view of the Andromeda Galaxy (annotated) |url=https://esahubble.org/images/heic2501b/ |website=www.esahubble.org |access-date=17 February 2025 |language=en}}{{source-attribution}}</ref>]]
In 2009, an occurrence of [[microlensing]]—a phenomenon caused by the deflection of light by a massive object—may have led to the first discovery of a planet in the Andromeda Galaxy.<ref name="Ingrosso 2009"/>

In 2020, observations of linearly polarized radio emission with the [[Westerbork Synthesis Radio Telescope]], the [[Effelsberg 100-m Radio Telescope]], and the [[Very Large Array]] revealed ordered magnetic fields aligned along the "10-kpc ring" of gas and star formation.<ref name="Beck 2020"/>

In 2025, NASA published a huge mosaic made by the Hubble Space Telescope, assembled from approximately 600 separate overlapping fields of view taken over 10 years of Hubble observation. Hubble resolves an estimated 200 million stars that are hotter than our Sun, but still a fraction of the galaxy’s total estimated stellar population.