arXiv:1104.3031v1 [physics.hist-ph] 15 Apr 2011The linear redshift-distance r elationship:Lemaˆıtre beats Hubble by two yearsEdwin Hubble is often credited with discovering the expanding Universebased on spectra taken by him. There are several errors in this statement a ndwe feel that it is the responsibility of those who are aware of the historicalfacts to set the record straight.The detection of the expansion of the Universe is one of the most impor-tant scientific discoveries of the 20th century. It is still widely held that in1929 Edwin Hubble discovered t he expanding Universe (Hubble 1929) andthat this discovery was based on his extended observations of redshifts inspiral nebulae. Both statements are incorrect. There is little excuse for this,since there exists sufficient well-supported evidence about the circumstancesof the discovery. The circumstances have been well documented even recentlywith the publication of two books: Bartusiak (201 0), Nussbaumer & Bieri(2009). Both were positively reviewed in the December 2009 issue of PhysicsToday.The facts are simple: Friedman (1922) was the first to publish non-static solutions to Einstein’s field equations. However, he did not extendthat into a cosmological model built on astronomical observations. In 192 7Lemaˆıtre rediscovered these dynamical solutions. In t he same publicationhe extracted (on theoretical grounds) the linear velocity–distance relation-ship v=Hr. Combining redshifts published by Str¨omberg (1925) (who reliedmostly on redshifts from Slipher (e.g. Slipher 1917)) and Hubble’s distancesvia magnitudes ( Hubble 1926), he calculated for the “Hubble constant” twovalues, 575 and 670 km/sec/Mpc depending on how the data is grouped. ForLemaˆıtre these results showed that the Universe was expanding. Two yearslater Hubble found the same velocity–distance relationship v=Hr on obser-vational g r ounds from practically the same observations that Lemaˆıtre usedin 1927. However, Hubble does not credit anyone for the r edshifts, most ofwhich ag ain came from Slipher.A number of today’s professional astronomers and popular authors (e.g.Singh 2005) believe that the entirety of Lemaˆıtre’s 1927 paper (publishedin French in an otherwise obscure journal) was re-published in English inthe Monthly Notices of the Royal Astronomical Society (MNRAS) in 1931(Lemaˆıtre 1931) with the help of Eddington. This is also incorrect as the twopages from the 1927 paper that contain Lemaˆıtre’s estimates of the HubbleConstant are not in the 1931 MNRAS paper for reasons that have never b een1properly explained.Unfortunately there have been severa l recent examples of prominent peo-ple writing in the popular press who continue to promote Hubble’s discoveryof the expansion of the Universe (for example, see The New York Times,15 January 2011 Op-Ed by Brian Greene). Not only have the two booksmentioned previously discussed the history of the discovery, but others havestated the facts as well (e.g. Peebles 1984).There is a great irony in these falsehoods still being promoted today.Hubble himself never came out in favor of an expanding Universe, on thecontrar y, he doubted it to the end of his days. On the other hand it wasLemaˆıtre who was the first to combine theoretical and observational argu-ments to show that we live in an expanding Universe. This vital fact is far toooften brushed aside, whereas it should be accepted as an essentia l ingredientin the history of science.ReferencesBartusiak, M. 2010, “The Day We Discovered the Universe”, Vintage, ISBN-10: 9780307276605Friedman. A. 1922, “¨Uber die Kr¨ummung des Raumes”, Zeitschrift f¨urPhysik, 1 0, 377.Hubble, E. 1926, “Extra-Galactic Nebulae”, Astrophysical Journal, 64, 321Hubble, E. 1 929, “A Relation between Distance and Ra dia l Velocity amongExtra-Galactic Nebulae”, Proceedings of the National Academy of Sciencesof the United States of America, Vol. 15, Issue 3, p.1 68Lemaˆıtre , G. 1927, “Un univers homog`ene de masse constante et de rayoncroissant, rendant compte de la vitesse radiale des n´ebuleuses extragalac-tiques”, Annales de la Soci´et´e scientifique de Bruxelles, s´erie A, vol. 47, p.49Lemaˆıtre , G. 1931, “A Homogeneous Universe of Constant Mass and Increas-ing R adius accounting for the Radial Velocity of Extra-g alactic Nebulae”,Monthly Notices of the R oyal Astronomical Society, 91, 483Nussbaumer, H. & Bieri, L. 200 9 “Discovering the Expanding Universe, Cam-bridge University Press, ISBN-10: 97805215148422Peebles, P.J.E. 1984, “Impact of Lemaˆıtre’s ideas on modern cosmology”,in The Big Bang and Georges Lemaˆıtre ; Proceedings of the SymposiumLouvain-la-Neuve, Belgium, October 1 0-13, 1 983 (A85-48726 2 4-90). Dor-drecht, D. Reidel Publishing Co., 19 84, p. 23-30Singh, S. 2005, “Big Ba ng: The Origin of the Universe”, Harper Perennial,ISBN-10: 9780007162215Slipher, V. M. 1917, “Nebulae”, Proceedings of the American PhilosophicalSociety, vol. 5 6, p. 403Str¨omberg, G. 1925, “Analysis of Radial Velocities of Globular Clusters andNon-Galactic Nebulae”, Astrophysical Journal, 61, 353Michael Way is a research scientist at The Goddard Institute for Space Stud-ies in New York City and an Adjunct Professor at Hunter College, CityUniversity of New York, USAHarry Nussbaumer is an Astronomy professor emeritus at ETH Zurich, Switzer-land. He recently published as firs t author the book “D i scovering the Expand-ing