Some articles on nebulae, spiral, spiral nebulae:
... speculated (correctly) that the Milky Way was a flattened disk of stars, and that some of the nebulae visible in the night sky might be separate Milky Ways ... introduced the term "island Universe" for these distant nebulae ... Charles Messier compiled a catalog containing the 109 brightest nebulae (celestial objects with a nebulous appearance), later followed by a larger catalog of 5,000 nebulae ...
... Kant also conjectured that some of the nebulae visible in the night sky might be separate "galaxies" themselves, similar to our own ... Kant referred to both our Galaxy and the "extragalactic nebulae" as "island universes", a term still current up to the 1930s ... a new telescope and was able to distinguish between elliptical and spiral-shaped nebulae ...
... In the 1910s, Vesto Slipher (and later Carl Wilhelm Wirtz) interpreted the red shift of spiral nebulae as a Doppler shift that indicated they were receding from Earth ... to the difficulty of using these methods, they did not realize that the nebulae were actually galaxies outside our own Milky Way, nor did they speculate about the cosmological implications ... equations and proposed, on the basis of the recession of spiral nebulae, that the Universe began with the "explosion" of a "primeval atom"—which was later called the Big Bang ...
... in the 1910s, Vesto Slipher and later, Carl Wilhelm Wirtz, determined that most spiral nebulae (now correctly called spiral galaxies) were receding from Earth ... Wirtz observed a systematic redshift of nebulae, which was difficult to interpret in terms of a cosmology in which the Universe is filled more or less uniformly with stars ... They weren't aware of the cosmological implications, nor that the supposed nebulae were actually galaxies outside our own Milky Way ...
Famous quotes containing the word spiral:
“Year after year beheld the silent toil
That spread his lustrous coil;
Still as the spiral grew,
He left the past years dwelling for the new,
Stole with soft step its shining archway through,
Built up its idle door,
Stretched in his last-found home, and knew the old no more.”
—Oliver Wendell Holmes, Sr. (18091894)