A Milky Way Star Cluster Now Dated to 13.4 Billion Years

Astronomers have dated a star cluster hidden behind the dust of the Galactic bulge at 13.4 billion years, give or take 0.4 billion, which would put its formation close to the beginning of the universe. The measurement of VVV CL001, in a paper posted on 20 October 2026 and accepted by Astronomy & Astrophysics, comes from J. Olivares Carvajal and eleven co-authors working with near-infrared photometry from the VISTA Variables in the Via Lactea survey.

The figure matters because the oldest globular cluster in a galaxy sets a floor under the age of that galaxy, and in this case under the age of the universe, currently put at about 13.8 billion years. An age of 13.4 billion years would place the cluster's stars roughly 400 million years after the Big Bang.

What the dust hides

VVV CL001 sits at galactic coordinates of 5.26 degrees longitude and 0.77 degrees latitude, close to the centre of the Milky Way and behind interstellar clouds thick enough to absorb visible light. ESO announced its discovery in 2011 from VISTA survey data, describing a low-mass cluster beside the brighter UKS 1 and noting that its distance remained uncertain. The new paper reports a distance of 7.34 plus or minus 0.46 kiloparsecs, which the authors call the most precise reported so far, and a metallicity of about minus 2.2 dex.

Low metallicity is what makes the result interesting rather than merely old. Clusters that formed before successive generations of stars enriched the surrounding gas should carry the fewest heavy elements, so the most metal-poor cluster in a region is the natural candidate for its oldest. The authors say the orbit confirms the cluster belongs to the bulge, which together with its age and composition could tie it to the early assembly of the proto-Milky Way and extend the metal-poor end of the clusters believed to have formed in place rather than arrived in a merger.

Dating material directly rather than inferring it from models is the harder route in both astronomy and planetary science; Parallax Nexus covered Japan's MMX launch to Phobos in October, a mission built around returning at least 10 grams of regolith for exactly that reason.

A second team, a different number

The 13.4 billion year figure is contested, and the clearest challenge comes from work on the same object. A separate study of VVV-CL001, combining medium-resolution FORS2 spectra from the Very Large Telescope with astrometry and near-infrared photometry, derived an age of 12.1 billion years, with an uncertainty of plus 1.0 and minus 1.2 billion. It agreed closely on composition, at minus 2.25 plus or minus 0.05 dex, and on distance, at 7.1 kiloparsecs. The gap between the two ages is 1.3 billion years, wider than either error bar.

The cluster is not clearly ahead of its neighbours either. The new paper cites a 2024 measurement of 13.2 billion years for NGC 6558 and a 2026 estimate of 13.6 billion years for the relatively metal-rich bulge cluster Ton 2. On age alone, VVV CL001 belongs to a tight group of very old bulge clusters rather than standing apart from them, which is why the paper's title claims a strong candidate and not a record.

The honest reading is that this is an age read off a colour-magnitude diagram seen through heavy reddening in a crowded field, and the quoted 0.4 billion years is the statistical uncertainty rather than the full systematic budget that isochrone fitting carries in such conditions. What would settle the question is not another age from the same kind of data but a different method applied to the same stars. Until that exists, the Milky Way has several clusters that could be its oldest and no agreed way to rank them.