Milky Way And Andromeda Will Collide In 4.5 Billion Years, Study Finds

Andromeda galaxy is our nearest major galactic neighbor. This image was taken by Hubble and was assembled from 7,398 exposures that were taken throughout 411 pointings of the telescope.   ( NASA, ESA, J. Dalcanton, B.F. Williams and L.C. Johnson (University of Washington), the PHAT team and R. Gendler )

A new study finds that it may actually take a bit longer before the Milky Way collides with Andromeda. Based on observations by ESA’s Gaia spacecraft, the collision will likely happen 4.5 billion years from now.

Neighbor Galaxies

Previous estimates suggested that the collision between the Milky Way and Andromeda will probably happen in 3.9 billion years. Now, analysis of data gathered by the Gaia spacecraft suggests that it will happen in 4.5 billion years.

In the new study published in The Astrophysical Journal, researchers tracked stars in the Milky Way, in Andromeda, as well as in the Spiral Triangulum. According to them, the two neighbor galaxies are about 2.5 to 3 million light-years away from the Milky Way and are close enough to each other that they may be interacting.

Milky Way And Andromeda Collision

By tracking the individual stars in the galaxies, researchers were able to track the rotation rates of Andromeda and Spiral Triangulum, and map out the how both galaxies have been moving through space in the past and how they are likely to move in the next billion years. This gave them an estimate that the collision will likely occur in 4.5 billion years and that it will probably happen as a sideswipe rather than a head-on collision.

When this happens, it is unlikely that our own solar system will be disrupted because of the distance between the stars.


Messier 31, more commonly known as the Andromeda Galaxy, is our nearest galactic neighbor. It is best observed in November and can even be seen with the naked eye even with moderate light pollution.

Because it is so visible, it’s difficult to say who exactly discovered the galaxy. That said, it was first reported in the year 964 book The Book of Fixed Stars by Persian astronomer Abd al-rahman al-Sufi.

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