Ptolemy's Shadows: Examining Our Astronomical Perception of Time

[saltydog]

I must say I have the utmost respect for modern Astronomy yet I am led to suspect we are still being misled by her. She is very deceptive you know: a flat-looking earth, wandering planets, sun and moon moving across the sky, other too. Is she still up to her old tricks as she was at the time of Ptolemy and before the Middle Ages?

I suspect so. Have we really advanced that much since then? How will she look to us in a 1000 years? Will men look back at us, our theories, in the same way as we look back to the Geocentric theory? Ptolemy's epicycles were "shadows" of what was really out there: his perception of what the world "looked like" from his vantage point. Later, men of greater intuition refined his image enabling us to shine a light on the real clockwork and we were humbled.

Sometimes I wonder if that is the same case with the Big Bang and the expansion of the Universe. Can it possibly be shadows of what's really out there, waiting to be illuminated?

Personally, I'm very optimistic something revolutionary will come out of the Sloan data; I look outside of my window and marvel at our non-linear world as I wait for a modern-day Kepler.

Edit: Oh yea, if I offend any practicing Astronomers in here I apologize for my insolence. I really do admire you all.

 

[Garth]

I must say I have the utmost respect for modern Astronomy yet I am led to suspect we are still being misled by her. She is very deceptive you know: a flat-looking earth, wandering planets, sun and moon moving across the sky, other too. Is she still up to her old tricks as she was at the time of Ptolemy and before the Middle Ages?

I suspect so. Have we really advanced that much since then? How will she look to us in a 1000 years? Will men look back at us, our theories, in the same way as we look back to the Geocentric theory? Ptolemy's epicycles were "shadows" of what was really out there: his perception of what the world "looked like" from his vantage point. Later, men of greater intuition refined his image enabling us to shine a light on the real clockwork and we were humbled.

We must remember what a good ‘scientific’ theory the Ptolemaic system was.
The continual addition of ‘epicycles’ was a geometric equivalent of the summing of circular functions in Fourier analysis. Add enough and you can make ‘the theory fit the data’ to whatever accuracy required, and so convincing too!
The fact that the earth/universe only looks flat and the present epicycles (inflation, exotic DM and DE) are not necessary will take some time to sink in…

Garth

 

[saltydog]

The continual addition of ‘epicycles’ was a geometric equivalent of the summing of circular functions in Fourier analysis. Add enough and you can make ‘the theory fit the data’ to whatever accuracy required, and so convincing too!
Garth

Hello Garth. But the planets really DONT go back and forwards across the sky. It only "looks" that way against the celestial sphere.

Correct me if I'm wrong but Ptolemy invented his epicycles to account for this retro-grade motion which was of course only a reflection of the real clockwork. Sure it accurately accounts for their "apparent" motion but fails to describe their "actual" motion. How might such an equilavent analogy be applied to the "apparent" expansion of the Universe if such would be the case? That is, what would the "real" motion look like if this is indeed of the same coin?

 

[selfAdjoint]

Hello Garth. But the planets really DONT go back and forwards across the sky. It only "looks" that way against the celestial sphere.

Correct me if I'm wrong but Ptolemy invented his epicycles to account for this retro-grade motion which was of course only a reflection of the real clockwork. Sure it accurately accounts for their "apparent" motion but fails to describe their "actual" motion. How might such an equilavent analogy be applied to the "apparent" expansion of the Universe if such would be the case? That is, what would the "real" motion look like if this is indeed of the same coin?

But what is "really"? Admittedly our accelerated frame at the Earth's surface is not inertial, but in the spirit of the equivalence pronciplal we can attribute the signs of our acceleration to forces and then say the sun and the planets DO go around us! And if we can then get a suitable approximation to their motions through epicycles, well and good. How do you think we predict the motion of the Moon?

Actually the failing of the epicyclists was not geocentrism but the fixation on uniform circular motion. It was Kepler's rejection of that which broke the log jam.