到1917年,斯莱弗量测了25个“螺旋星云”的径向速度,发现除了三个星系之外,其它星系都以相当快的速度远离我们。斯莱弗自己推测,这可能是由于我们自己星系的运动,就像在他的样本中一样,那些向我们移动的星系和那些远离我们的星系大致相反的方向[20]。事后看来,这是第一个支援膨胀宇宙模型的数据。后来,埃德温·哈伯将斯莱弗和其它径向速度的光谱测量与哈伯自己对星系距离的测定相结合,导致哈伯发现了星系距离和红移之间的比例关系(当时是粗略的),今天称为哈伯-勒梅特定律(以前称为哈伯定律,国际天文学联合会2018年10月的决定建议使用这个新名称[21]),是由哈伯和休马森于1929年提出,并成为膨胀宇宙(英语:Expansion of the universe)现代模型的基础。
Nesto (sic) Slipher, 93, Astronomer, Dies, The New York Times (Flagstaff, AZ), November 9, 1969: 47 (November 10, 1969), ISSN 1452424请检查|issn=值 (帮助)请检查|publication-date=中的日期值 (帮助); 使用|accessdate=需要含有|url= (帮助)
Way, M.J.; D. Hunter (编). Origins of the Expanding Universe: 1912–1932.. San Francisco: ASP Conference Series 471. Astronomical Society of the Pacific. 2013.
Nussbaumer, Harry. 'Slipher's redshifts as support for de Sitter's model and the discovery of the dynamic universe' In Origins of the Expanding Universe: 1912–1932. Astronomical Society of the Pacific. 2013: 25–38.Physics ArXiv preprint (页面存档备份,存于互联网档案馆)
O'Raifeartaigh, Cormac. The Contribution of V.M. Slipher to the discovery of the expanding universe in 'Origins of the Expanding Universe'. Astronomical Society of the Pacific. 2013: 49–62.Physics ArXiv preprint (页面存档备份,存于互联网档案馆)
Graves Hoyt, William. Crawford Jr., Bryce; McEuen, Caroline K. , 编. Vesto Melvin Slipher. Biographical Memoirs of the National Academy of Sciences of the United States of America (National Academy Press). 1980, 52: 413.
Graves Hoyt, William. Crawford Jr., Bryce; McEuen, Caroline K. , 编. Vesto Melvin Slipher. Biographical Memoirs of the National Academy of Sciences of the United States of America (National Academy Press). 1980, 52: 414.
Graves Hoyt, William. Crawford Jr., Bryce; McEuen, Caroline K. , 编. Vesto Melvin Slipher. Biographical Memoirs of the National Academy of Sciences of the United States of America (National Academy Press). 1980, 52: 415.
Graves Hoyt, William. Crawford Jr., Bryce; McEuen, Carolina K. , 编. Vesto Melvin Slipher. Biographical Memoirs of the National Academy of Sciences of the United States of America (National Academy Press). 1980, 52: 414.
Graves Hoyt, William. Crawford Jr., Bryce; McEuen, Caroline K. , 编. Vesto Melvin Slipher. Biographical Memoirs of the National Academy of Sciences of the United States of America (National Academy Press). 1980, 52: 414–415.
Slipher first reports on the making the first Doppler measurement on September 17, 1912 in The radial velocity of the Andromeda Nebula (页面存档备份,存于互联网档案馆) in the inaugural volume of the Lowell Observatory Bulletin, pp. 2.56–2.57. In his report Slipher writes: "The magnitude of this velocity, which is the greatest hitherto observed, raises the question whether the velocity-like displacement might not be due to some other cause, but I believe we have at present no other interpretation for it." Three years later, Slipher wrote a review in the journal Popular Astronomy, Vol. 23, pp. 21–24 Spectrographic Observations of Nebulae (页面存档备份,存于互联网档案馆), in which he states, "The early discovery that the great Andromeda spiral had the quite exceptional velocity of -300 km(/s) showed the means then available, capable of investigating not only the spectra of the spirals but their velocities as well." Slipher reported the velocities for 15 spiral nebula spread across the entire celestial sphere, all but three having observable "positive" (that is recessional) velocities.