Assertion: andromeda galaxy | /r/Synonym | the andromeda nebula
Facets:
value: in the 1920s
type: TEMPORAL
Source sentences:
text: In the 1920s, the Andromeda Galaxy was known as the Andromeda Nebula, and for a long time, astronomers thought it was a nebula inside our own galaxy.
text: The Andromeda Galaxy, for instance, was once referred to as the Andromeda Nebula (and spiral galaxies in general as "spiral nebulae") before the true nature of galaxies was confirmed in the early 20th century by Vesto Slipher, Edwin Hubble and others.