Wikimedia/EmDee, CC BY-SA
Astronomers are engaged in a lively debate over plans to rename one of the laws of physics.
It came out at night at the 30e Meeting of the International Astronomical Union (IAU), in Vienna, where members of the General Assembly discussed a resolution on changing the name of the Hubble Act to the Hubble-Lemaître Act.
The resolution is intended to commend the work of the Belgian astronomer Georges Lemaître and his contribution – together with the American astronomer Edwin Hubble – to our understanding of the expansion of the universe.
While most (but not all) of the members were at the meeting for the resolution, a decision gave all members of the International Astronomical Union the chance to vote. The vote was then reduced to a straw and at a later date the resolution will be formally voted on by electronic ballot.
Well, that’s a pretty clear majority in favor of renaming the Hubble Act the Hubble-Lemaître Act. But the vote is not yet binding – online voting will take place in Sept & Oct #IAU2018
— Keith Smith (@DrKeithSmith) August 30, 2018
Giving all members a say through electronic voting was introduced after criticism of the IAU’s 2006 general assembly, when a resolution was passed to define a planet — demoting Pluto to a dwarf planet.
But changing the name of the Hubble Law raises the question of who should be honored in naming the laws of nature, and whether the IAU should be involved in any decision.
An expanding universe
The Expansion of the Universe Was One of the Most Amazing Discoveries of the 20e century.
Expansion here means that the distance between galaxies generally increases with time, and it increases uniformly. No matter where you are and which direction you look, you still see a universe expanding.
If you really try to imagine all this, you could end up with a headspin or worse. The rate at which the universe is currently expanding is described by the Hubble law, named after Edwin Hubble, whose 1929 paper reported that astronomical data indicate the universe’s expansion.
But Hubble was not the first. In 1927 Georges Lemaître had already published an article on the expansion of the universe. His article was written in French and published in a Belgian magazine.
Lemaître presented a theoretical basis for the expansion of the universe and used the astronomical data (the same data Hubble used in his 1929 paper) to deduce the rate at which the universe is expanding.
In 1928, the American mathematician and physicist Howard Robertson also published an article in Philosophical Magazine and Journal of Sciencewhere he derived the formula for the expansion of the universe and derived the expansion rate from the same data used by Lemaître (a year earlier) and Hubble (a year later).
Robertson was not aware of Lemaître’s work. Given the limited popularity of the Belgian magazine in which Lemaître’s article appeared and the French language used, it is claimed that his remarkable discovery went largely unnoticed by the astronomical community at the time.
But the findings published by Hubble in 1929 were most likely influenced by Lemaître. In July 1928 Lemaître and Hubble met at the 3rd meeting of the International Astronomical Union in Leiden. At the meeting, they discussed the astronomical evidence that suggests the expansion of the universe.