[Paper Review] Hubble Law or Hubble-Lemaître Law? The IAU Resolution

Helge Kragh|arXiv (Cornell University)|Sep 7, 2018

History and Developments in Astronomy6 citations

TL;DR

This paper critically examines the International Astronomical Union's (IAU) 2018 resolution to rename the Hubble Law to the Hubble-Lemaître Law, arguing that the historical justification for the change is flawed. Kragh contends that the resolution oversimplifies the complex historical development of cosmological discoveries in the late 1920s and misrepresents the contributions of both Edwin Hubble and Georges Lemaître, calling for a more nuanced understanding of their respective roles in establishing the expansion of the universe.

ABSTRACT

The Hubble law, widely considered the first observational basis for the expansion of the universe, may in the future be known as the Hubble-Lemaître law. This is what the General Assembly of the International Astronomical Union recommended at its recent meeting in Vienna. However, the resolution in favour of a renamed law is problematic in so far as concerns its arguments based on the history of cosmology in the relevant period from about 1927 to the early 1930s. A critical examination of the resolution reveals flaws of a non-trivial nature. The purpose of this note is to highlight these problems and to provide a better historically informed background for the voting among the union's members, which in a few months' time will result in either a confirmation or a rejection of the decision made by the General Assembly.

Motivation & Objective

• To evaluate the historical accuracy of the IAU's rationale for renaming the Hubble Law to the Hubble-Lemaître Law.
• To challenge the resolution's portrayal of the relative contributions of Edwin Hubble and Georges Lemaître in the discovery of the expanding universe.
• To provide a more historically informed background for the IAU members' decision on the name change.
• To highlight non-trivial flaws in the resolution's historical arguments concerning cosmological research from 1927 to the early 1930s.
• To advocate for a re-evaluation of the naming decision based on sound historical scholarship.

Proposed method

• Analyzes primary historical sources, including Hubble's and Lemaître's original publications from the late 1920s.
• Compares the scientific content and impact of Hubble's 1929 paper with Lemaître's 1927 work, which predated Hubble's by two years.
• Assesses the IAU resolution's historical claims using documented evidence from the history of science.
• Evaluates the role of translation, recognition, and citation practices in shaping the historical narrative of the law's discovery.
• Highlights discrepancies between the resolution’s narrative and the actual sequence of scientific contributions.
• Draws on established scholarship in the history and philosophy of physics to contextualize the naming debate.

Experimental results

Research questions

• RQ1 What were the actual scientific contributions of Edwin Hubble and Georges Lemaître to the discovery of the expanding universe?
• RQ2 How accurate is the IAU resolution’s historical account of the development of the law from 1927 to the early 1930s?
• RQ3 Why did Lemaître’s 1927 paper receive less recognition at the time compared to Hubble’s 1929 paper?
• RQ4 To what extent does the IAU resolution reflect a correct understanding of the historical priority and scientific merit of both scientists?
• RQ5 What are the implications of renaming the law for the historical record and the recognition of scientific contributions?

Key findings

• The IAU resolution's claim that Lemaître should be credited with the discovery of the expansion law is historically oversimplified and lacks sufficient scholarly grounding.
• Lemaître's 1927 paper, which contained the first derivation of the linear relationship between redshift and distance, was largely overlooked at the time due to being published in a lesser-known journal and in French.
• Hubble’s 1929 paper, though published later, gained widespread recognition because of its clear presentation, use of observational data, and publication in a major English-language journal.
• The resolution fails to acknowledge the complex interplay of language, visibility, and citation practices that influenced the scientific reception of both works.
• The historical record does not support the conclusion that Lemaître’s contribution should supersede or equal Hubble’s in terms of scientific impact and recognition.
• The renaming of the law risks distorting the historical narrative by implying a priority that is not fully supported by the evidence.