# Why does the rising moon look so big?

A few years ago, artist Maki Naro drew a comic explaining why the Moon appears larger on the horizon than it does way up in the sky.

Recently, he got a helpful email from astronomy blogger Phil Plait. Turns out, the original comic was just a bit wrong and Phil Plait had a much more thorough explanation. So, like any good evidence-based comic artist, Naro drew a new version of the comic, featuring a only-sorta-creepy Phil Plait jumping out of the bushes to accost people with accurate astronomical information.

See the full comic

Check out this post on Phil Plait's Bad Astronomy blog, upon which the comic is based.

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1. David Forbes says:

A good way to convince people that the moon doesn’t shrink as it rises: Have them hold their thumb at arms length and measure the moon with it as the full moon is rising, then do the same a few hours later. They can make a pen mark on the thumb to be sure they don’t forget.

2. Rich Keller says:

I’m going to hold a transparent plastic thing at arm’s length at moonrise and mark the diameter of the moon on it. Then, when the moon is more overhead, I’ll compare its diameter to the marks I made.

Science!

3. Matt_B says:

See 5th panel — if the characters the same height (and from panels 3 & 7 they pretty much are), then they should measure the same number of parallel lines.  Unless they mean the drawings are the same size?

1. I believe the lines are meant to be convergent and not parallel, hence the optical illusion.

1. Matt_B says:

according to the rules of perspective drawing, lines convergent to an unseen point are meant to be parallel in 3D.  That is,  in the world of the comic, the girls are standing in front of an actual police line-up background with parallel lines.

4. davidsfp says:

” only-sorta-creepy Phil Plait”  The cartoon Phil or the real one?

5. garyg2 says:

Cool.

But I don’t get what Sir Clive Sinclair has to do with any of this…

1. Guest says:

Ha! I’ve always thought Phil, Richard Wiseman, and Jason Zimbler (formerly Ferguson on “Clarissa Explains it All”) look eerily alike :D

1. garyg2 says:

ooh yeah…. obviously an alien master race, stealthy infiltrating our… science.

6. But what about when someone holds a Coronita bottle and they convincingly look like a bonafide giant from a mythical land (or hold a tallboy Budweiser and look like a dwarf)? Even science can’t explain THAT.

7. I have seen this explanation proffered many, many times and it has never made sense to me.  The moon looks larger on the horizon because it’s light is passing through more/thicker atmosphere…..same way the moon appears warped and bendy when seen rising from space. I’ve seen the Bad Astronomer get several things wrong over the years.

1. Guest says:

The atmospheric lensing hypothesis is probably the oldest, and yet the most incorrect explanation. The problem with the lensing argument is that the moon really does not change size. At all. Do the quarter/thumb/pinky trick.

The atmosphere squishes the moon and affects its color, but it doesn’t magnify it.