"A Spiral Nebula as a Stellar System, Messier 31", in the Astrophysical Journal

HUBBLE, Edwin.

Published by University of Chicago Press, 1929

HUBBLE, Edwin. "A Spiral Nebula as a Stellar System, Messier 31", in the Astrophysical Journal, volume 59 no. 2, March 1929, being the full monthly issue, cleanly extracted from a larger bound volume. The Hubble appears on pp 103-159 (with 6 plates) in the issue of pp 77-172. [++] This is the statement that M31 (the Andromedia Galaxy), our nearest (large(r)) galactic neighbor that has been known to us at least since the time of al-Sufi in 964 ACE, is not part of our own galaxy but a galaxy unto itself, the discovery of the plurality of galaxies. (And btw we will bump into M31 in about 4 billion years.) [++] "Hubble published his epochal study of the Andromeda "nebula" as an extragalactic stellar system (galaxy) in 1929 [this paper]."--Messier dot SEDS online [++] "In 1922 Ernst Opik presented a method to estimate the distance of Andromeda using the measured velocities of its stars. His result placed the Andromeda Nebula far outside our galaxy at a distance of about 450 kpc (1,500 kly). Edwin Hubble settled the debate in 1925 when he identified extragalactic Cepheid variable stars for the first time on astronomical photos of Andromeda. These were made using the 100-inch (2.5 m) Hooker telescope, and they enabled the distance of Great Andromeda Nebula to be determined. His measurement demonstrated conclusively that this feature was not a cluster of stars and gas within our own galaxy, but an entirely separate galaxy located a significant distance from the Milky Way [these results published in the offered paper]."--Wikipedia on M31 [++] "Although there was no clear consensus on the size of the Milky Way, Hubble's distance estimate placed the Andromeda Nebula approximately 900,000 light-years away. If Hubble was right, the Nebula clearly lay far beyond the borders of the Milky Way Galaxy (the largest estimates of its size put its diameter at around 300,000 light years). The Andromeda Nebula therefore had to be a galaxy and not a nebulous cloud or sparse star cluster within the Milky Way. Hubble s finds in the Andromeda Nebula and in other relatively nearby spiral nebulae swiftly convinced the great majority of astronomers that the universe in fact contains a myriad of galaxies. "--Britannica. Seller Inventory # ABE-1738508043123

Bibliographic Details

Title: "A Spiral Nebula as a Stellar System, ...
Publisher: University of Chicago Press
Publication Date: 1929
Binding: No Binding
Condition: Very Good