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It's amazing that barely a 100 years ago The Great Debate in astronomy was weather the Milky Way was the extent of the universe or things like Andromeda were th
by harywilke 3y ago
It's amazing that barely a 100 years ago The Great Debate in astronomy was weather the Milky Way was the extent of the universe or things like Andromeda were their own 'island universes'. In the 1920s, Edwin Hubble showed that Andromeda was far outside the Milky Way by measuring Cepheid variable stars. These are the same stars that we are measuring today in this debate.
https://en.wikipedia.org/wiki/Great_Debate_(astronomy) https://en.wikipedia.org/wiki/Great_Debate_(astronomy)
- chadcmulligan 3y agoAnd not much longer before that the discussion was how long would the sun last - 5,000 years or so was the estimate if it was a big ball of burning gas (source: A scientific American article I read, wish I could find it again, hoping someone here knows)
- yokoprime 3y agoI think it’s this one you’re referring to https://www.scientificamerican.com/article/experts-doubt-the-sun-is-actually-burning-coal/ https://www.scientificamerican.com/article/experts-doubt-the...
- chadcmulligan 3y agoThat's the one, thanks, I've been looking for it for ages