Comment by throw1002a | Hacker News Reader

Comment by throw1002a | Hacker News Reader

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I highly recommend (sci-fi author) Micheal Flynn's (long-ish) chronological timeline on the series of events that led the general consensus going from Ptolemaic system to heliocentrism:

* http://tofspot.blogspot.com/2013/10/the-great-ptolemaic-smac...

We tend view things in hindsight and judge people with our 20/20 view, when events really unfolded over a period of time, and so people made decisions with imperfect knowledge.

Two things that people forget or don't know: (a) Galileo was technically wrong, since he insisted on Copernicus' circular orbits, and it was Kepler that got it right (with elliptical orbits). And (b), it was not until 1806 that the Earth's motion was demonstrated through parallax (150+ years after Galileo died), at which point heliocentrism was more than simply an untested hypothesis.

Regarding (a) and (b) together: people when from Ptolemy to Kepler by the 1690s not because they had proof that it was true, but mainly because it made the answer easier. Ptolemy worked reasonably well mathematically at predicting orbits, it just took a damn long time.

Great points. For a quick summary I suggest reading the highest rated answer to this Physics SE question: https://physics.stackexchange.com/questions/26291/why-did-th.... The keypoint that most people fail to realize is that "Ironically, geocentrism persisted because the ancients were decent scientists and were unimpressed by (pre-Kepler) heliocentrism's failure to support itself with observational data."

"We tend view things in hindsight and judge people with our 20/20 view, when events really unfolded over a period of time, and so people made decisions with imperfect knowledge."

I think the same when people think Newton was crazy for pursuing alchemy. With hindsight it's clear that this wouldn't work but with the information he had at the time this was not so clear.

To be fair, the alchemists have accomplished virtually every one of their goals via a mixture of chemistry, particle physics, and electrical engineering invented by alchemists, their academic students, their students' students, etc (that is, from the academic tree rooted in the alchemists) --

- Life expectancies are soaring.

- Wounds that easily would've been fatal in 1850 are routinely survived by even the poor or middle class.

- Diseases of every variety are being tamed or eradicated.

- You can transmute elements, if you try hard.

- We've weaponized transmuting elements, at least two different ways.

- We've invented machines and materials that embody some human faculties, eg the ability to perform logic.

- We're making significant progress on artificial souls.

- We've created several varieties of artificial life.

I think people who regard the alchemists as failures are completely nuts and exactly the sort of people rebranding and marketing work on. Science is nothing but rebranded magic -- to the point if you substitute nouns with unfamiliar words, it sounds like magic out of a book. (Go on -- try explaining how cellphones accessing Wikipedia works at the level of electrons and photons with entirely new nouns in place of the familiar ones.)

For fun, we can even argue about if LIGO is actually just a successful version of the Michelson-Morley experiment and the detection of gravitational waves is also a confirmation of the existence of an aether. (It's obvious why M-M was a failure, given that it was trying to detect a much weaker effect with much less sensitive equipment.)

Also perhaps of some interest:

> Galileo's Daughter: A Historical Memoir of Science, Faith, and Love is a book by Dava Sobel. It is based on the surviving letters of Galileo Galilei's daughter, the nun Suor Maria Celeste, and explores the relationship between Galileo and his daughter. It was nominated for the 2000 Pulitzer Prize for Biography or Autobiography.[1]

* https://en.wikipedia.org/wiki/Galileo%27s_Daughter

Maybe we couldn't distinguish "the earth goes around the sun" from "the sun goes around the earth" until 1806, but we could tell that the other planets have the sun, rather than the earth, as their primary much earlier than that.

Isn't that the most important difference between the systems?

@namarie got it right. Per Part 3 in the series:

In the second episode, we saw a slew of new telescopic discoveries during 1610-1611; viz., the mountains on the moon, the Medicean stars, and (more decisively) the phases of Venus. Now the first two do not demonstrate geomobility, not do they undermine geostationarity. The first indicates that the moon is not incorruptible. But this is agreed to by theology, and it undermines only Aristotelian physics. The second indicates that some heavenly bodies -- Cosmo, Franco, Carlo, and Lonzo -- circle Jupiter and not the Earth. This bothers Aristotelian physicists, but not Tychonic astronomers. Only the phases of Venus KOs Old Man Ptolemy.

But eliminating Ptolemy does not prove Copernicus any more than eliminating Darwin would prove ID. There may be [and were!] other alternatives. When Ptolemy was ptossed, astronomers flocked... to the Tychonic and Ursine systems -- because none of the telescopic observations have so far established the motions of the Earth.

* http://tofspot.blogspot.com/2013/09/the-great-ptolemaic-smac...

In Part 2 Flynn outlines the seven major models in play:

* Heraclidean. Geo-heliocentric. Mercury and Venus circle the Sun; everything else circles the Earth.

* Ptolemaic. Geocentric, stationary Earth.

* Copernican. Heliocentric, pure circles with lots of epicycles.

* Gilbertian. Geocentric, rotating Earth. (proposed by William Gilbert in De magnete)

* Tychonic. Geo-heliocentric. Sun and Moon circle the Earth; everything else circles the Sun.

* Ursine. Tychonic, with rotating Earth.

* Keplerian. Heliocentric, with elliptical orbits.

* http://tofspot.blogspot.com/2013/08/the-great-ptolemaic-smac...

No, because there was a system (the Tychonic system IIRC) where the sun orbits the earth and the planets orbit the sun. It seems to have been popular at the time also.

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