Hubble’s Law no more


An important law of cosmology gets a name change. Andrew Masterson reports.


Edwin Hubble, photographed in 1951. He now shares the name of his famous law with Belgian astronomer Georges Lemaitre.

Edwin Hubble, photographed in 1951. He now shares the name of his famous law with Belgian astronomer Georges Lemaitre.

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One of the most fundamental concepts in cosmology has been renamed, following a poll conducted among members of the International Astronomical Union (IAU).

Henceforth the Hubble Law – which describes the way in which galaxies move away from each other and is fundamental, when viewed in reverse, to the theory of the Big Bang – will be known as the Hubble-Lemaitre Law.

The Hubble Law was so named in honour of US astronomer Edwin Hubble, who provided evidence that the speed at which galaxies travel increases in proportion to its distance from Earth (or, indeed, any given point in the universe). He presented his evidence for this in 1929.

However, it is widely acknowledged that his work expanded upon calculations made by another astronomer, Belgian physicist (and priest) George Lemaitre, published two years earlier.

In that sense, the decision of the IAU merely corrects a historical injustice.

The proposal to change the name was first put to the General Assembly of the IAU in Vienna, Austria, in August 2018.

Among other matters raised in the formal paperwork, the IAU executive committee recommended the change in order to “pay tribute to both George Lemaitre and Edwin Hubble for their fundamental contributions to the development of modern cosmology” and “to honour the intellectual integrity of George Lemaitre that made him value more the progress of science than his own visibility”.

As a result, all members of the organisation were invited to submit an electronic vote on the issue by October 26. Some 4060 people – or 37% of the membership – did so. The results were 78% in favour of the renaming, and 20% opposed. The remaining 2% of the voters abstained (raising in the process the possibility of quantum state participation in which a person can simultaneously vote and not vote).

  1. https://www.iau.org/static/archives/announcements/pdf/ann18029e.pdf
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