What is the current consensus about the age variation of the existing galaxies in our observable universe?

Not to be confused with the age of very distant galaxies as observed today by our telescopes which is actually observing these distant galaxies as they were many billions of years ago in the early formation but instead I am asking about their absolute age today assuming they still exist?

I mean, a hypothetical observer located in these very distant galaxies and looking at our home galaxy would also see our galaxy not at its current state but how it looked like billions of years ago. I am not asking this but if all the galaxies were formed more or less at the same time according to the Big Bang theory?

In general how you estimate the age of a galaxy?

  • $\begingroup$ Most observable galaxies are 10 to 13.6 Gyr old, but some are as young as 0.5 Gyr (ibid.) $\endgroup$
    – J.G.
    May 9 at 8:40
  • $\begingroup$ @J.G.Yes. I checked the internet before asking and came accroos this age you mention but hopping if there is a more updated information about this matter because the latest strange findings of JWST about very early galaxies after the Big Bang appearing much more mature than predicted. Maybe it is not because faster evolution than expected but rather that they are older in age than we think of or even the age of the observable universe is larger than approximmatetly 13.8 bly or the majority of galaxies were created in a much more narrow time period? $\endgroup$
    – Markoul11
    May 9 at 8:58
  • 2
    $\begingroup$ If Andromeda and the Milky Way collide now how old will be the resulting galaxy Milkomeda ? $\endgroup$
    – M06-2x
    May 9 at 10:38
  • $\begingroup$ @M06-2x "If Andromeda and the Milky Way collide now how old will be the resulting galaxy Milkomeda ?" The oldest of the two? $\endgroup$
    – Markoul11
    May 9 at 11:06
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    $\begingroup$ Some would say significantly older than the two primordial galaxies. This is an example to show how complex is the question of age. $\endgroup$
    – M06-2x
    May 9 at 11:29

1 Answer 1


Galaxies began forming around 200 million to 300 million years after the Big Bang, over the billions of years and not synchronously. The formation is still an ongoing process. There are older galaxies such as the Milky-Way, 13.2 billion years old, and there are younger galaxies.

One can regard the formation of the galaxies as a self-organisation process, a kind of pattern formation, which depends on a number of parameters, such as (1) the density of matter in the different regions of the universe, (2) the presence of dark matter in those regions, as well as (3) the influence of cosmic radiation.


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