You know that illusion where the moon sometimes looks a lot bigger than usual? Cool, hold on to that please.
Stephen Hawking wastes no time in a Brief History of Time (I don't know if it's because he took the title very seriously or just because that's what terminally ill people tend to do).
In the fourth paragraph of the first Chapter (Our Picture of the Universe) I think Stephen Hawking is saying he thinks the Earth is, or could be, the center of the Universe.
He writes:
"Ptolemy’s model provided a reasonably accurate system for predicting the positions of heavenly bodies in the sky. But in order to predict these positions correctly, Ptolemy had to make an assumption that the moon followed a path that sometimes brought it twice as close to the earth as at other times. And that meant that the moon ought sometimes to appear twice as big as at other times! Ptolemy recognized this flaw, but nevertheless his model was generally, although not universally, accepted."
Ptolemy’s model by the way, was geocentric (Earth was the center, not the sun). Remember you answered yes, that you've seen the moon on nights when it looked much bigger and note that Stephen Hawking has never heard of or seen that, as he uses it as the reason why Ptolemy's Earth centered Universe doesn't make sense. It's also the only reason he uses.
Here's the preceding paragraph so you have full context (it can be skipped). I'll walk through the reasoning right after.
“Aristotle thought the earth was stationary and that the sun, the moon, the planets, and the stars moved in circular orbits about the earth. He believed this because he felt, for mystical reasons, that the earth was the center of the universe, and that circular motion was the most perfect. This idea was elaborated by Ptolemy in the second century A.D. into a complete cosmological model. The earth stood at the center, surrounded by eight spheres that carried the moon, the sun, the stars, and the five planets known at the time, Mercury, Venus, Mars, Jupiter, and Saturn. The planets themselves moved on smaller circles attached to their respective spheres in order to account for their rather complicated observed paths in the sky. The outermost sphere carried the so-called fixed stars, which always stay in the same positions relative to each other but which rotate together across the sky. What lay beyond the last sphere was never made very clear, but it certainly was not part of mankind’s observable universe.
Ptolemy’s model provided a reasonably accurate system for predicting the positions of heavenly bodies in the sky. But in order to predict these positions correctly, Ptolemy had to make an assumption that the moon followed a path that sometimes brought it twice as close to the earth as at other times. And that meant that the moon ought sometimes to appear twice as big as at other times! Ptolemy recognized this flaw, but nevertheless his model was generally, although not universally, accepted."
If you don't see it at all and it sounds stupid to you, you may very well be right, and I may very well learn the slightly disappointing reason why I always think everyone else is crazy. But here's how I see it anyway:
1. Ptolemy’s model provided a reasonably accurate system for predicting the positions of heavenly bodies in the sky.
2. But in order to predict these positions correctly [that required] ...
3. ...that the moon followed a path that sometimes brought it twice as close to the earth as at other times
4. And that meant that the moon ought sometimes to appear twice as big as at other times!
5. Ptolemy recognized this flaw...
Why does Stephen Hawking put an exclamation mark at the end of #4? And why does he refer to the moon needing to sometimes appear twice as big as a "flaw"?
A. It could be that he often went from the ramp to the van and back to the ramp, so he never really saw the moon.
B. Possibly one time a long time ago when he took his glasses off he put someone else's glasses back on by mistake because when he has his off, he doesn't see very well, which is why of course he wears glasses. From that day forward and for the rest of his life (because he didn't believe a person should buy a second pair of glasses) his whole world was blurry, but never knowing non-blurry he was just happy he could make out the top of stairs, and he never even noticed the moon...
C. Maybe Stephen Hawking wasn't a very observant person? Or even more troubling, maybe he is one of the first documented cases of someone with glasses whose handicap resents the sense of sight so much that his own subconscious, as a form of rebellion, alters the images his brain is processing including his ability to see the moon because he also resents his imprisonment in a chair which displays itself in his inability to see anything that doesn't look shackled - like balloons, and the moon....
D. Or the possibility I lean towards, is that just like you've seen the moon look bigger, and I've seen it look bigger, and my Mom sure as hell has seen it look bigger because she calls me ever damn time to tell me it's beautiful, and even mainstream science agrees it sometimes looks bigger, that most likely Stephen had heard of this (most likely of course he saw it just like everyone else does).
So if basically everyone sees the moon look twice as big sometimes, including Stephen, then why would he use it as the reason he thought Ptolemy was wrong? It would make no sense because it makes no sense. All of his lab partners would be coming up to him after they read the first page going "Hey Stephen, great book, loved your take on that time stuff, but umm...hey - do me a favor and look at the sky realy quick. Do you see like a really big white circle anywhere? No?...".
If he wanted to just say Ptolemy was wrong he would have said anything else, including that what Ptolemy didn't know was that the moon looking bigger was just an illusion, as modern science later learned.
No, instead he writes like he's confident no on in the world could ever think a bigger moon wasn't the silliest thing they ever heard. It would be like writing "Newton's biggest problem with his gravity theory was it didn't explain why people kept floating away and no one can stick to the ground!"
Some reasons why he wouldn't just come out and say it ... First, the people he loved, or at least those with power of attorney, would have wheeled him into a locked facility before he could say "Beautiful Mind". Then of course there's his career. Also, some people feel like certain things need to be kept hidden in such a way that only those ready to find it will. Something about being responsible, letting others kind of self-select when they are ready and able for more (If that seems dumb, because you think why would finding something out be hard, then please, don't read anything I write again, I just make things up and post whatever sounds the weirdest).
And that's how you know Stephen Hawking was not sold on the whole Sun model. Sorry, I know I'm using only reason and that it's not well respected, but the guys dead so it's all I got this time. I'm open to any other explanation that makes more sense (to me).
Totally unrelated question: anyone think Stephen Hawking wasn't his real name and that he created that name to represent his two greatest passions - His Love of owls, especially hawks, and of course his guilty obsession with the great writer Stephen King? I'm just saying...probably for some it's a lot more plausible than the other thing I was saying. At least go for one of 'em....
That was wordy, I am wordy, sorry.
Thanks,
Crazy 8's (or Bette Davis Eyes, or me, or you, or us, or not, or)
Thanks again. Nick.