Hubble study reveals Andromeda's star formation slowing, collision with Milky Way in doubt
A study using Hubble Space Telescope data published on July 27, 2026, reveals that star formation in the Andromeda Galaxy has been slowing over the last 500 million years, while a separate finding suggests the Milky Way may not.
A study using Hubble Space Telescope data published July 27, 2026, found that star formation in the Andromeda Galaxy has slowed over the past 500 million years. Researchers attribute most of the decline to reduced activity in a large ring where star formation is concentrated.
Star formation in the Andromeda Galaxy has been slowing for the past 500 million years, according to a study published July 27, 2026, that used data from the Hubble Space Telescope. Andromeda, cataloged as Messier 31, is a barred spiral galaxy about 2.5 million light-years from Earth. It is the nearest major galaxy to the Milky Way, with a diameter of 152,000 light-years. The study, based on the Panchromatic Hubble Andromeda Southern Treasury survey, attributed most of the slowdown to declining activity in a large ring where much of the star formation occurs, according to NASA. The findings come alongside a separate NASA study suggesting the Milky Way may not collide with Andromeda in 5 billion years as long believed. Together, the research reshapes understanding of our galactic neighbor’s past and future.
Hubble data shows star formation in Andromeda slowing over 500 million years
A study using Hubble Space Telescope data, published on July 27, 2026, has found that star formation in the Andromeda Galaxy (M31) has been slowing down over the last 500 million years. The Hubble telescope provided an unusually detailed view of the barred spiral galaxy, the nearest major galaxy to the Milky Way at 2.5 million light-years from Earth.
According to NASA, most of the slowdown is attributed to declining activity in a large ring where much of the star formation occurs. Researchers also noted that star formation activity near the dwarf galaxy M32 is lower than in other regions of Andromeda, according to researchers. The study drew on data from the Panchromatic Hubble Andromeda Southern Treasury survey.
New collision timeline upends 5-billion-year prediction for Milky Way and Andromeda
A recent study, drawing on Hubble Space Telescope data, has cast doubt on a long-held prediction: that the Milky Way and the Andromeda Galaxy would collide in roughly 5 billion years. According to NASA, the new analysis suggests such a merger may not occur. Andromeda, catalogued as Messier 31, is a barred spiral galaxy and the nearest major galaxy to our own. It lies about 765 kiloparsecs (2.5 million light-years) from Earth and has a D25 isophotal diameter of approximately 46.56 kiloparsecs (152,000 light-years). The revision to the collision timeline stems from fresh observations of the galaxy’s dynamics, though the exact implications remain under study.
Ultra-faint dwarf galaxy possibly 12.5 billion years old found near Andromeda
Researchers have reported the discovery of a new ultra-faint dwarf galaxy in the vicinity of Andromeda. According to the researchers, the galaxy may be 12.5 billion years old. The finding was published in the journal Astronomy & Astrophysics.
The study of star formation in Andromeda used data from the Panchromatic Hubble Andromeda Southern Treasury survey, researchers said. Separately, NASA and international space partners have created a new composite image of the Andromeda Galaxy, according to the agencies.
Andromeda constellation: from Ptolemy's catalog to modern astronomy
The Andromeda constellation first appeared in the 2nd-century star catalog of the Greco-Roman astronomer Ptolemy, one of the 48 constellations he listed. It remains one of the 88 modern constellations, located in the northern celestial hemisphere. Named after the daughter of Cassiopeia in Greek myth, the constellation is most prominent during autumn evenings in the Northern Hemisphere. Within its boundaries lies the Andromeda Galaxy (Messier 31), a barred spiral galaxy cataloged as M31 and NGC 224, roughly 2.5 million light-years from Earth.
Andromeda constellation catalogued by Ptolemy
Study on Andromeda star formation published
Frequently asked questions
Is the Andromeda Galaxy still forming stars?
A study using Hubble Space Telescope data, published on July 27, 2026, found that star formation in the Andromeda Galaxy (M31) has been slowing down over the last 500 million years. Most of the slowdown is attributed to declining activity in a large ring where much of the star formation occurs, according to NASA.
Will the Milky Way and Andromeda collide?
A recent study suggests that the Milky Way may not collide with Andromeda as previously thought. The earlier belief was that the two galaxies would collide in about 5 billion years, according to NASA.
How far away is Andromeda from Earth?
The Andromeda Galaxy is approximately 765 kiloparsecs (2.5 million light-years) from Earth. It has a D25 isophotal diameter of about 46.56 kiloparsecs (152,000 light-years), according to NASA.
Was a new galaxy discovered near Andromeda?
Researchers have reported the discovery of a new ultra-faint dwarf galaxy near Andromeda. According to the researchers, the galaxy may be 12.5 billion years old. The discovery was published in the journal Astronomy & Astrophysics.
How did Hubble study Andromeda's star formation?
The study used data from the Panchromatic Hubble Andromeda Southern Treasury survey, according to researchers. NASA also noted that the Hubble Space Telescope provided a detailed view of the galaxy, allowing it to be explored in unprecedented detail.
Compiled from reporting by 9 independent outlets. How we source our reporting.
