The Moon (Part 2)

Abu Loren wrote: Oh no, not THIS diagram again!

Yup, looks like you're gonna have to dodge it again!


Edited by Ron Webb - 31 October 2015 at 4:16pm

It's basic geometry.

But it's even simpler than that:
- You know that as things move toward the horizon they get farther away, right?
- And as they get farther away, they appear smaller, right?
Which one of those concepts is giving you trouble?

Abu Loren wrote: Ok from our perspective when the Sun 'rises' in the East and when it 'sets' in the West the Sun seems to be a lot larger than when it is overhead. Could it be that the Sun is further away when it is right above us? Meaning the Sun takes an 'Ohm' trajectory rather than a straight forward line?

No, it couldn't be.  In the first place, the sun is not larger when it sets than when it is overhead.  You can easily measure it using a pinhole camera.

More important, if it followed the trajectory you suggest, then people a few thousand miles to the west of you would see the sun as absolutely HUGE when it is overhead for them (and setting for you).  But they don't.

The sun and moon are both within a few percent of half a degree wide, for all observers, everywhere and all the time.  There is only one trajectory that can account for this: a circular orbit, with the earth at the centre, and with a diameter large enough to make differences in the observers' locations insignificant by comparison.

I don't know and nobody will ever know because we can't really test these things.

Sure we can.

Abu Loren wrote: Thank you! You've just explained perfectly the argument for a flat Earth.

I'm not even talking about the shape of the earth!

Just explain to me, according to your theory: if the moon moves closer to the earth as it sets in your location, then why doesn't it look bigger to people to the west of you, for whom it is still directly overhead?  Why is it always, everywhere, for everyone, half a degree wide?

You should have looked at the COMMENTS section as they will tell you about the problems with the article.

There are certain simplifying assumptions, and part of the exercise is to identify them.  There are no "problems" with the general approach.

Another problem is the fact that we cannot for sure know the exact or approximate distance of the stars mentioned.

We don't need to know the distance to the stars.  The distance to Regulus is mentioned (and they got it wrong!) just for interest's sake, but it doesn't enter into the calculations.

So it's a failed calculation on all counts.

It's a simplified calculation, which gives fairly good results for illustrative purposes.  You are welcome to improve on it if you wish.  That's what science is all about. 

The point is, we can measure it, even without sophisticated instruments.