The Moon.

Striking isn't it?

We've all seen it, the gigantic, ominous, orange orb floating near the horizon that we all crane our necks to catch as it hides behind tall buildings while we run about our busy nights. Many question how this is possible but few ever get a chance to answer that. 

In about 10 minutes or less I will try my best:


The Moon Illusion

So if you're curious about this you're in pretty good company - the first man to be puzzled by this was Aristotle way back in 400 B.C.

He figured it had something to do with the atmosphere considering you're seeing the moon through a lot more of the atmosphere when it's at the horizon:

Figure 3.14 - Artist's (my) depiction of possible atmospheric effects | NOT drawn to scale. At all.

He figured it was causing some sort of magnification but that wasn't true, although it did account for half of our illusion: the orange hue. Similar to the sun that looks like a delicious egg yolk close to the horizon the moon also looks more orange.


The Answers (maybe...)

Both objects
are exactly the
same size

There are two main explanations for the illusion.

The first is the Ponzo Illusion. Basically our brains through evolution over the years have developed several shortcuts. This one tells us that due to perspective, towards the horizon things are more far away (i.e as the lines converge).

Therefore, if two objects look exactly the same at the horizon and nearer to us, then the one near the horizon must be bigger. 



The second half of this explanation is the Ebbinghaus Illusion, more commonly known as "Wow, my car looks huge next to that smart car!". This one's pretty simple, when the moon is next to the horizon it's passing by other objects unlike when it's up in the sky, giving our brains a frame of reference and therefore enlarging the size of the Moon.


The p(i)lot twist!

Sounds pretty legitimate? I thought so too, UNTIL I read that the illusion is experienced even by airline pilots flying far enough that they don't have the same reference objects that we do.

What does this mean? Well it's just one of many unexplained scientific mysteries that continue to remind us of how complex and challenging nature can be.


Fun with Moon illusions

In closing I figured we all deserved a fun set of moon illusions rather than such difficult to understand and scary looking ones. My favorite is definitely the "moon painting".

Closing Video

Further Reading/Viewing:

http://youtu.be/RXkYjL_7jME
http://www.mnn.com/earth-matters/space/blogs/why-nobody-can-explain-the-moon-illusion