# DIY: Sun and Moon do not get smaller

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#### imasomebody

• 26
##### DIY: Sun and Moon do not get smaller
« on: March 01, 2009, 06:17:11 PM »
According to the FAQ:
Quote

A: It's a perspective effect. Really, the sun is just getting farther away; it looks like it's disappearing because everything gets smaller, and eventually disappears as it gets farther away.

Hold out your thumb straight out at moonrise, compare the size of the moon to your thumb.

Do the same when the moon is directly overhead.

The size does not change.

I can confirm this because I have looked at the moon in both cases using the same magnification on my telescope, and the moon takes up the exact same space.  If I am understanding this correctly, according to FET shouldn't they get smaller at rise/set?  A 32 mile wide object should seem a lot smaller when it's so much farther away.  A ginormous object that is really far away already wouldn't change much, if at all.

edit: BTW, if I'm doing my math right, at sunrise it should be ~7,000 miles away(4,000 miles of earth, then 3000 more miles), at mid day it should be 3000 miles away.  That's over a a 2:1 factor, yet their apparent size does not change(look at a radio tower 1 mile away, look at one 2 miles away, or put your hand one foot in front of your face, then stretch it all the way out, notice it takes up a much smaller area of your vision).  In RET, the moon is 236,000 miles away, a change 4000 miles is insignificant, representing a 1/59th change, and in fact if observed with photographs could probably be detected.
« Last Edit: March 01, 2009, 08:47:59 PM by imasomebody »

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#### imasomebody

• 26
##### Re: DIY: Sun and Moon do not get smaller
« Reply #1 on: March 02, 2009, 05:20:38 PM »
Odd how this easily accomplished test has no responses.  Nobody tried it yet?  We've been through a full cycle since I posted...

#### Ulrichomega

• 736
• Bring it Bishop.
##### Re: DIY: Sun and Moon do not get smaller
« Reply #2 on: March 03, 2009, 08:33:19 AM »
I remember in the old days, this test was being "done". No-one responded then either.

In other news, this is my first post here since '07.
I'm so tempted to put a scratch and sniff at the bottom of a pool and see what you do...

Avert your eyes, this is too awesome for them...

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#### bowler

• 871
##### Re: DIY: Sun and Moon do not get smaller
« Reply #3 on: March 03, 2009, 08:43:06 AM »
I tried this as well. Apparently the increase in scattering as the sun gets further way compensates exactly for the effect. For both the sun and the moon. Scary. This is trivially a load of rubbish because the atmosphere does not scatter light uniformly. The suns light does get scattered in the Earths atmosphere thats why the sky appears blue. Sometimes you just have to bang your head against a brick wall; who knows if you bang long enough you might start to believe it. That or huff a load of glue.

edit - good point, well made
« Last Edit: March 03, 2009, 08:52:48 AM by bowler »

#### Ulrichomega

• 736
• Bring it Bishop.
##### Re: DIY: Sun and Moon do not get smaller
« Reply #4 on: March 03, 2009, 08:49:45 AM »