The Milky way and its perceived changes

By Raoul Lannoy posted 08-03-2022 11:19


In dutch Melkweg, in German Milchstrasse, in french Voie Lactée , in english Milky Way  !  A rather poetic name for a giant band of stars seen under clear skies. All those names (even in dutch!) refer to something that crosses the heavens, includes our Universe and turned out to be wrong!  It is not the entire Universe ! Up until Galileo, only one Moon (capital letter M) was known. Then many moons  were discovered around other planets . They got names and the word "moon" was kept to define them.

Once Edwin Hubble located the Andromeda cepheid much much further than within our Milky Way, those spiral and elliptical nebulae became island universes on their own, were defined as galaxies and our Milky Way become one galaxy among many  (or should we write "the Galaxy" with capital letter "G" to distinguish from the other galaxies). I still have publications referring  M31 to a nebula rather than a galaxy (written in the 60's).

Within every culture, there's a reluctance to change definitions and words because a major discovery was made even if it was wholeheartedly accepted !

Granted, M31 is far less poetic than the "Andromeda Galaxy" or "the Andromeda Spiral Nebula", but M31 is what we use among club members.

And then you can even show "planetary nebulae" in your telescope (they turn out to be neither a planet nor a nebula).

What's most fascinating is the scope of a discovery forcing us to redefine something  out there , rather than its previous definition . But if we know both the old and the new definition, it's something more to share with the public.

1 view