doi.org/10.1051/0004-6361/202557993
Credibility: 989
#expansion of the universe
A new and comprehensive study, which brought together decades of independent research, shows that there is something wrong with our understanding of how the Universe expands
The difference between the measurements is not an error or chance-it indicates that an important piece of current physics is missing.
Astronomers measure the rate of expansion of the Universe, called the Hubble constant, in two main ways.
One uses the oldest light in the cosmos, the cosmic microwave background, which came shortly after the Big Bang.
The other observes the nearby Universe, using stars and supernovae whose distances we know well.
These two methods should give the same result, but they don’t.
This discrepancy, known as Hubble tension, is too large to be explained by statistical uncertainties.
To resolve the doubt, a large group of astronomers met, analyzed the best available data, and voted on the most reliable methods.
The result, published in April 2026 in the journal Astronomy & Astrophysics, is the most precise value ever obtained for the local expansion of the Universe: 73.50 km/s per megaparsec, with only 1.09% uncertainty.
Even so, the tension remains.
Richard Anderson, one of the study’s authors, explains: “Comparing the value of the expansion measured in the nearby Universe with that measured in the primordial Universe tests basic physics on cosmic scales.
And the result says that something is missing.”
A network of cosmic distances
Instead of using just a traditional “distance ladder,” the researchers created a true network called the Local Distance Network.
It brings together dozens of different measurement methods, with many intentional overlaps to reduce errors.
If one method is removed (for example, that of Cepheid stars), the result hardly changes.
This gives a lot of confidence to the work.
The network relies on secure “anchors”: objects whose distances have been measured directly, such as by parallax (the same principle we use when we close one eye and then the other to see a finger “jump”).
They used the galaxy NGC 4258, the Magellanic Clouds, variable stars in the Milky Way, old red giants, megamasers (true cosmic lasers), and more than 7,500 galaxies observed by telescopes such as Hubble and DESI, up to distances of more than a billion light-years.
John Blakeslee, another author, suggests that primordial magnetic fields could be one of the new explanations for the observed difference in the cosmic microwave background.
Most importantly, this work is not just a new number: it is an open and modular framework, built by the scientific community.
With the new telescopes to come, it will be possible to test the ideas even better.
For now, however, the message is clear: our current model of the cosmos is incomplete, and we need new physics to understand dark energy and the ultimate fate of the Universe.
Published in 04/17/2026 08h39
Text adapted by AI (Grok) and translated via Google API in the English version. Images from public image libraries or credits in the caption. Information about DOI, author and institution can be found in the body of the article.
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