Arrrrgh!

Dorothy and the Rear Admiral.

The Moon Illusion

Moonrise over Seattle. Notice how the moon
is the same size regardless of position when
captured on film.

I find the moon illusion to be fascinating. I'm not sure I can adequately explain why, but let me try. First, it is a universally experienced phenomenon. Frequently one will hear somebody exclaim in awe, "Look how big the moon is!" There seems to be some evidence that different people experience it to different degrees, but everyone experiences it. It's impossible to measure objectively because it's a pure perceptual phenomenon, which brings me to reason number two.

There are as many theories for what causes the moon illusion as there are people studying it. Some claim to be the final answer on the debate but are actually pretty bizarre. The best roundup of explanations I've seen is here, even though I don't agree with some of the analysis.

The third reason is that the correct explanation for the moon illusion seems to be some combination of optics, biology, and psychology. There is no widely accepted correct explanation for the moon illusion, but any seemingly simple problem that requires such disparate disciplines to contribute to a possible solution is inherently fascinating.

Last night was a full moon. We watched it come up over the horizon as we were winding down from our monday night volleyball session. I suggested to everybody that we try the experiment offered on the earlier link, namely

The moon illusion disappears (for most people) when they bend down and look at the moon between their legs. [Is it merely coincidence that this is the position used for "mooning"? Disregard that.] Or, if so inclined, one can view the moon by hanging from one's heels! At least two hypotheses have been proposed to account for this. (1) Familiar objects in the field of view may become useless as distance references because of their unfamiliar appearance when viewed upside-down. (2) The illusion may have something to do with our inner-ear's balance mechanism that tells us whether the head is upright or upside-down.

So there we all were, bending over, "mooning" the moon to look at it upside down through our legs, and it absolutely, positively works. Stand there and look at the moon on the horizon and it looks huge. Bend over and look at it through your legs and it looks tiny. If you have a good theory for why this works, I'd like to hear it. My personal theory is that the mind is less adept at interpreting visual cues when veiwing the world upside down, and thus you get a more raw "unprocessed" version of what the eye sees. The mind is so good at processing visual information and recognizing patterns that we have to trick it into not doing it in order to get a more objective view of the world around us.

What do you think?

Update (20 October): My friend asked a psychology instructor at CU, Joe Berta, about his take on the "mooning the moon" experiment, and this was his response:

This is an old test of one explanation for the moon illusion. Some
researchers have proposed that the moon illusion is affected by the relation of the angle of the eyes relative to the head relative to the moon. So, by changing this relationship the illusion can be changed. However, most perceptual researchers don't believe this theory.

The most convincing explanation is that the moon on the horizon is perceived by our brain to be further away than it is when higher in the sky. Since the moon is actually the same size on our retina, the brain figures it must be bigger and we see it as bigger. The horizon acts as cues to depth. So, maybe, by putting our heads upside down we are eliminating normal cues to depth perception.

The explanation(s) of the moon illusion, however, is far from settled. Put "moon illusion" into google and you will find an amazing number of explanations and criticisms of other explanations.

Comfort Text

Last weekend I re-read "Pawn of Prophecy" by David Eddings, book one of the Belgariad, a sweepingly epic coming of age high fantasy novel aimed at the teen demographic. I ate these books up when I first got into them. I was perhaps 14 at the time. Reading it again was like mom's home cooking, a favorite stuffed animal, and an old worn-in t-shirt all at the same time. My friend called it the textual equivalent of comfort food.

The books draw from all the elements and archetypes of classic mythology in the same way the star wars saga does. It begins with the farm-boy, introduces the wise and old Merlin/Gandalf type, and culminates with a quest into the den of evil itself. These story-telling elements are as old as stories themselves, but Eddings puts everything together with an engaging liveliness. His characters, while often stereotypical, or archetypical, are amusing and entertaining in their dialogue and relationships. And the author has a gift for pacing that leaves you wanting to read just the next chapter before putting the book down for the night, and then the next chapter, and so on.

Sunshine Canyon

I think I need to start a weekly column about my adventures riding up sunshine canyon. Something interesting always happens. One time, I saw a real live black bear. I always see deer every time I ride up it, and once was even followed/chased by a doe. Well, yesterday's ride brought even more craziness. Let me start at the beginning.

Sunshine Canyon is just west of Boulder. I frequently ride up it because I can leave from my house, get a good workout going up, see some awesome views, have a lot of fun going back down, be back home after an hour and a half, and something interesting always happens. It's a good ride because it's steep enough to make you work but not so steep that you feel like you're going to die (i.e. Flagstaff). As you begin the ascent and approach the first real switchback, there's a private tennis court on the left. In the nook of the switchback is a very distinctive house. Not too much of it is really visible from the road, but the roof sure is, and the roof is one of the most distinctive elements. If it were painted a jollier color you would think it's the kind of roof a smurf or an elf would live under. But it's just sort of a boring dark brown color. It consists of two separate roofs, really. Each one is a sort of curvy spindly thing. It really is a landmark of sunshine canyon. You can't miss it when you're going up.

Yesterday I was riding up and I passed the smurf house and didn't think much of it because I always see the smurf house. Not too much after that I saw a little yellow sign someone had planted next to the road that said "Open Studios" and had an arrow and a little open door symbol on it. Sounded interesting. I figured I'd check it out on the way down.

On the way down I killed my momentum and turned down the dirt road the sign pointed me to. I didn't realize at first that it was leading me to the smurf house. Turned out the current occupants are a retired judge and his artist wife. I pulled up and ditched my bike and was instantly greeted by the husband. He had huge bushy eyebrows. He said that he bets I've always wondered what the house was like on the inside and invited me into it. It was a 70's glam palace with orange shag carpeting and wood tile everywhere. Apparently it was designed and built by some famous architect. He showed me his wife's art that was hanging up around the house, all of it for sale, and told me about his late son, who was apparently an accomplished sculptor named Jefferson. One of the rooms was the "Jefferson Museum," with the son's original terra cotta and marble pieces spread around. Bronze reproductions of the originals were selling for $2000. I would have bought one, but unfortunately I couldn't carry it away on my bike.

The wife's work was mostly oil paintings, but there was a nice pastel of a sunflower that I liked. The two of them would have talked my ear off all day if I had let them. I think they were impressed that I had stopped at their show on my bike. There were a couple of other people there, but they seemed to be friends there to see her work. I think they were just excited to have someone new at their house. Maybe they get lonely up there in the canyon. Who knows. But now I can say that I've been to the smurf house. And it has shag.

Here's Mr. Bushy Eyebrows. I mean, The Honorable Bushy Eyebrows.

Chronicles of Thew

Over the past couple of years I did a few entries for my friend's site, Big Trendy. My entries were too few and far between, I know, but I still hope to contribute more in the future. Until then, you can read the ones I already did:

Episode One

Key West

In the Gulf of Mexico

Dry Tortugas

Michigan, Friends, and Family

Last weekend I went to Michigan. My reasons were twofold; to go to the combined birthday party of a couple of college friends and to see my parents. I've said it many times before, but it's worth repeating. I consider myself blessed with good fortune in so many ways, one of which is the great group of friends I've made in college. We've been through a fair bit of life together now, and it's nice having such a great group to count on. Sure, we don't necessarily see each other very often, or even talk to each other that frequently, but sporadically there will be a special occasion that brings most or some of us together, like, say, a wedding in Seattle, or a birthday bash in Michigan, or a New Years celebration in Colorado. These are the kinds of friends that when we do get together, in some ways it's like no time has passed at all. We can continue the old jokes and take comfort in the easy familiarity of each other's presence. Of course, in other ways it's like a lot of time has passed, such as meeting a friend's two-year-old son for the first time.

No matter how much time passes, I know we will continue to have a unique bond.

If any of you are reading this, I love you all.

I hope to have a picture of us all up here soon.

_____________________________________________________________

While I was home my dad and I did a 35 mile bike ride through apple orchard country. It was a nice, cool fall day, with a persistent threat of rain that was never made good. Riding through Michigan farm country, which starts not too far from the house I grew up in, made me realize that Michigan can really be beautiful sometimes. The whole countryside is much greener and lush than what I'm used to biking here in Colorado. Of course, there aren't any mountains in Michigan. I know I took it for granted growing up there. The suburb I grew up in straddled the boundary between the city of Grand Rapids and the farm country outside of it, leaning slightly towards the farm country. Growing up I witnessed the farm land develop into strip malls. This was sad for me at the time, in the sense that I lost one of our favorite fruit stands which was also a source of delicious blueberry milkshakes. I do so love blueberries. But I wasn't aware at any significant level of the implications, or the fact that there was still more farm country within a couple of miles. I wouldn't have appreciated it even if I did think about it. I simply took it for granted. Doesn't everybody live right next to sources of delicious fresh produce like apples, blueberries, strawberries, and sweet corn? I guess not.


The ride also took us next to somebody with a herd of llamas, I think, and somebody else with a herd of buffalo. The buffalo ranch had a sign out front advertising jerky. That had to be good stuff.

Below is a picture of my dad and I about to do the Michigan MS150 last year.