Editing 1929 in science (section)

==Astronomy and space exploration==
* July – [[Henry Norris Russell]] publishes his finding that [[hydrogen]] is the principal constituent of stars,<ref>{{cite journal|last=Russell|first=Henry|date=July 1929|title=On the Composition of the Sun's Atmosphere|bibcode=1929ApJ....70...11R|doi=10.1086/143197|journal=[[Astrophysical Journal]]|volume=70|page=11}}</ref> acknowledging the previous demonstration of this by [[Cecilia Payne]].<ref>{{cite web|last=Padman|first=Rachel|year=2004|title=Cecilia Payne-Gaposchkin (1900-1979)|url=http://www.newn.cam.ac.uk/about-newnham/college-history/biographies/content/cecila-payne-gaposchkin|work=Biographies|publisher=[[Newnham College, Cambridge]]|access-date=2021-04-01}}</ref>
* July 17 – [[Robert H. Goddard]] tests the first [[rocket]] to carry scientific instruments (a [[barometer]] and a [[camera]]).
* [[Edwin Hubble]] publishes his discovery that the speed at which [[galaxy|galaxies]] recede positively correlates with their distance, which becomes known as [[Hubble's law]], the basis for understanding that the [[universe]] is expanding.
* [[George Gamow]] proposes [[hydrogen]] [[nuclear fusion|fusion]] as the energy source for [[star]]s.
* [[Clyde Tombaugh]] discovers several [[asteroid]]s: [[2839 Annette]], [[3583 Burdett]], [[3824 Brendalee]], [[1929 VS]], [[1929 VD1]].
* [[Harold Horton Sheldon]] writes about the serious possibility of man visiting other planets through the use of rockets.<ref>{{cite news|title=Dr. H. H. Sheldon, a physicist, dies|url=https://www.nytimes.com/1964/12/24/dr-h-h-sheldon-a-physicist-dies.html?_r=1|newspaper=[[The New York Times]]|location=New York City|date=1964-12-24|accessdate=2015-11-21}}</ref>
* [[Konstantin Tsiolkovsky]] proposes the construction of [[multistage rocket]]s in his book «Космические поезда» (''Cosmic Trains'').