Equant & Deferent
The ancient Greeks were pretty clever,
Worked out that the Earth was round
From shadows cast by poles at noon
And by the earth upon the Moon,
And how the sky was put together
Just from watching from the ground,
And some who guessed a central Sun
About which all the planets run.
But then along came Aristotle,
Then along came Ptolemy –
And they alone would set the tone
Till their mistakes were set in stone.
The hand is dead, but still can throttle,
Piously and solemnly,
Of any thought that might get out –
So hush the whisper, choke the doubt.
But still, but still,
The more we looked, the more we saw –
The though the heavens mostly draw
Upon the Ptolemaic law,
They sometimes would exert their will
That rubbed enquiring watchers raw.
You see, the ancient Greeks well knew
That crystal dome and ev’ry gem
That all the night, without a rest,
Would wheel above from East to West.
And like the stars, the planets, too –
Though slower, losing ground on them.
Except…well, that’s where trouble lies,
With yearly yet unruly skies.
Because they each would switch their motion,
With the stars, and overtaking !
Week by week, the Greeks would trace
The way the planets dance and race.
So Ptolemy proposed a notion,
Saved the universe from breaking –
Sure it was all fudge and spin,
But epicyles for the win !
But here’s the thing –
For all its complex shells and reels,
For all its windmills within wheels,
It somehow kinda always deals
With accurate positioning,
As though the sums would guide their heels.
So if the Greeks were badly off,
Well, spare that scoff – they did their best
With nothing but a pair of eyes
To theorise what they can’t test.
But did they ever pinch their gaze
And mutter at the tangled ways
In which the heavens spend their days ?
Did even Ptolemy have doubt
And long to hack the deadwood out ?
The Romans, though they changed the names
(So Krios now Aries, and Ares now Mars),
They kept the skies just as before,
For fourteen hundred years or more.
And though the planets’ little games
Were thought as written in the stars –
A monk proposed a new appraiser,
Slashing bunkum with his razor.
Simple answers, they’re what matter !
Less is more than meets the eye –
If two proposals have to fight,
The simplest one is often right.
And all those epicycles clatter
With a clean, efficient sky –
Forget the Church and ancient stuff,
Copernicus has had enough !
And yet, and yet,
Despite his perfect circles round
His central sun, we quickly found
Like Ptolemy’s, they ran aground,
Till Kepler and ellipses met –
And suddenly, the maths was sound.
Truth be told, Copernicus
Had little proof on which to base
His unbound Earth and steadfast Sun –
In faith alone, his planets spun.
But still the world must turn, and thus,
Young Galileo took his place –
Perhaps with fewer facts than hope,
But this time with a telescope.
And in the eyepiece, clear as night,
The moons of Jupiter were seen –
As though the planet gave them birth –
And not in orbit round the Earth !
And better yet, the startling sight
Of Venus phasing inbetween
A smaller full and larger new –
And then the revolution flew !
So here’s the thing –
With claims of modern matter dark,
And energy with unseen spark –
Has it the proof of string and quark ?
Or do they chase around a ring
To make the model fit the mark ?
And like Copernicus, they could be right,
Despite a lack of evidence.
Or like old Ptolemy, they could be wrong,
Yet strong in their defence –
His theory held up, truth to tell,
In matching observations well –
But oh, it was a complex hell !
So scientists, and heaven-gazers,
Never lose your sharpest razors !