Great Debate (astronomy) | Hacker News Reader

Great Debate (astronomy)

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62 pointsgilad9 comments

Later Hubble sent Shapley a letter that changed his mind in one fell swoop: "Here is the letter that destroyed my universe." He became a great mapper of galaxies and superclusters. Bravo.

Then in 1946 he was called up by the House Un-American Activities Committee for suspicious associations:

> HUAC committee chairman John E. Rankin commented, "I have never seen a witness treat a committee with more contempt" and considered contempt of Congress charges. Shapley accused HUAC of "Gestapo methods" and advocated for its abolition for making "civic cowards of many citizens" by pursuing the "bogey of political radicalism."

Bravo again Dr. Shapley.

It puts into perspective just how much our understanding of the universe has grown in the last 100 years. Of course, this is true for all kinds of sciences, but still, this concrete example gives me goosebumps. Just 100 years ago, almost within one lifetime, top scientists were not sure whether there were galaxies other than Milkyway. And today, we are observing quasars from the beginning of the universe and gravity waves from colliding black holes.

Curtis's galaxy was centered on the Sun, while Shapley correctly placed the Sun in the outer regions of the galaxy

It seems pretty obvious, just from looking around a bit on a dark night, that most of the Milky Way is on one side of us. So why would any model put the sun at the center?

Why would you know that the sun is the same as the stars?

In 1920 though?

Simple observation isn't the most accurate though. Simple observation has planets going backwards in their paths in the sky. That was really confusing when simple observation led everyone to believe the Earth was at the center.

Whatever assumptions anyone makes today is on the shoulders of giants that preceded them.

I think people’s default assumptions place themselves at the center of the universe.

It's not wrong, and makes the maths easier ... as long as we're happy to shift our reference point when appropriate, it seems valid to me. The CoM of the local galactic cluster isn't particular useful as a reference and is no more valid a default.

One of my personal /bête noires/ is people who say "the Earth isn't the centre of the Universe" ... it's a valid choice.

/fight-me

I find it amusing that after the heliocentric debates in the middle ages, some ~500 years later we still struggled to admit that we are not the centre of everything. :-)

Primates...

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