How big is our Milky Way galaxy?

[Magical Realist]

Keeping it all in perspective:

https://www.youtube.com/watch?v=MX3PIkbT...3RaflCI3Z0

[Zinjanthropos]

Great vid MR. Have read where people, have trouble comprehending the size of the universe. This should help.

[C C]

Keeping it all in perspective:

https://www.youtube.com/watch?v=MX3PIkbT...3RaflCI3Z0

The Milky Way is so large that before the 1920s, we thought it was the universe.{1} For awhile there was a stage of viewing the particular newly re-conceived nebulas (that were now other galaxies) as a "multiverse" situation (minus that label of today), before finally expanding the boundaries of the "universe" idea itself. In 1929, Edmond Hamilton wrote the serial that became the novel titled "Outside the Universe", which still reflected the momentum of the older belief (i.e., to depart the Milky Way was to leave our universe).

Not the first "multiverse" scenario, of course. When the geocentric and the heliocentric models each respectively fell aside, a grander plurality of worlds was interpreted as the case before "cosmos" was repeatedly elevated to a higher level.{2}

- - - footnotes - - -

{1} Dec. 30, 1924: Hubble Reveals We Are Not Alone: Astronomer Edwin Hubble announces that the spiral nebula Andromeda is actually a galaxy and that the Milky Way is just one of many galaxies in the universe.

Before Copernicus and Galileo, humans thought our world was the center of creation. Then (except for a few notable stragglers) we learned that the sun and planets did not revolve around the Earth, and we discovered that our sun — though the center of our solar system and vitally important to us — was not the center of the universe or even a major star in our galaxy.

But we still grandiosely thought our own dear Milky Way contained all or most of the stars in existence. We were about to be knocked off our egotistical little pedestal once again.


{2} Stars as Suns & The Plurality of Worlds: What is a world? In part, spurred on by Copernicus's ideas, the Dominican Friar Giordano Bruno published "On the Infinite Universe and Worlds", in 1584. [...] he suggested that Earth was one of many inhabited worlds ... and that the stars were suns, which had their own worlds.

As a result of shifting views of the universe the very idea of "world" (in Latin, Mundi) was changing. In the Aristotelian cosmos, the world was effectively synonymous with the Earth. The sphere of the world and the terrestrial realm were one in the same. Once Earth became one planet among many orbiting the sun, those planets became Earth like worlds. This new understanding of worlds is reflected in the title of "The Discovery of a World in the Moon" from the 1630's. As it took a long time for the Copernican model of the cosmos to win out over competing models, it took a considerable bit of time for ideas similar to Bruno's to come to fruition.

The increasing acceptance of Descartes theory of vortices in the later half of the 17th century brought with it the idea that the stars were like our sun and had their own planets orbiting around them. Bernard le Bovier de Fontenelle's popular 1686 book "Conversations on the plurality of worlds" broadly disseminated this notion, in a range of editions and translations.

[Zinjanthropos]

This has to go here

https://www.youtube.com/watch?v=JWVshkVF0SY