Hubble-Lemaitre Law

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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 (viewed here). 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).

An electronic vote has been conducted among all members of the International Astronomical Union, and the resolution to recommend renaming the Hubble law as the Hubble–Lemaître law has been accepted. The Hubble–Lemaître law describes the effect by which objects in an expanding Universe move away from each other with a velocity proportionally related to their distance. This resolution was proposed in order to pay tribute to both Lemaître and Hubble for their fundamental contributions to the development of modern cosmology.

The discovery of the apparent recession of galaxies is a founding pillar of modern cosmology and a major milestone of astronomical research. To acknowledge the scientific contributions of Belgian astronomer Georges Lemaître to the scientific theory of the expansion of the Universe, and by vote of its members, the International Astronomical Union (IAU) has decided to recommend the Hubble law to be renamed as the Hubble–Lemaître law.

Following a period of consultation with the astronomical community, the resolution to suggest renaming the Hubble law was presented and discussed at the XXX General Assembly of the IAU, held in Vienna (Austria) in August 2018. All Individual and Junior Members of the IAU (11072 individuals) were invited to participate in an electronic vote, which concluded at midnight UT on 26 October 2018. 4060 cast a vote by the deadline (37%). The proposed resolution has been accepted with 78% of the votes in favour and 20% against (and 2% abstaining). One of the IAU’s roles is to foster exchanges of views and international discussions — and it strives to contribute to scientific discourses with historical facts. To honour the intellectual integrity and the supremely significant discovery by Georges Lemaître, the IAU is pleased to recommend that the expansion of the Universe be referred to as the Hubble–Lemaître law.