Before Hubble's findings, what state of scientific understanding characterized the Andromeda Nebula?

Answer

It was in scientific limbo, debated as a close gas cloud or an 'island universe'

Prior to Hubble's measurements, astronomers debated whether Andromeda was a relatively small cluster of stars within the Milky Way or an entirely separate, distant star system, referred to as an 'island universe'.

Before Hubble's findings, what state of scientific understanding characterized the Andromeda Nebula?
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