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View Full Version : San Juan Goosenecks Illusion



stefan
01-16-2006, 03:53 PM
Thought i would point out an interesting illusion that i accidentally discovered with a friend about 6 years ago or so.

i was showing him some photographs in Stokes' Geology of Utah. One shot was an b/w aerial view of the Goosenecks of the San Juan. Anyhow, we were sitting at a table across from each other with the book between us. I pointed to the river, he responded "What river?" I said "that river there, that's the San Juan river." He responded again, "I just don't see which river you're talking about." I was very confused for a moment, then i decided I better take a look at what HE was looking at.

The book was oriented so the right side up was in line with my view...basically he was looking at it upside down.

When i flipped it around and looked at it i realized why he wasn't seeing it.(see below)
unfortunately i never scanned the Stokes' image, since it is the best one that i have found. but i did manage to find this one on the internet and decided to post it in both orientations for you all to see. (adapted from someone)

maybe you've already seen this sort of phenomenon.
it's amazing how our brains can be tricked. :patch:

if you have the stokes book, take a look at it, it really is the best angle for this sort of thing.
then slowly rotate the book around and see if you can maintain the image upside down, before it snaps back.
once it snaps back, can you make it invert again? i can't.

Iceaxe
01-16-2006, 04:12 PM
Thats crazy..... I've never seen that before. I'm going to print out a picture and mess with it a little :nod:

rock_ski_cowboy
01-16-2006, 04:52 PM
I've noticed the same thing happens to me in in google earth all the time, canyons looking like ridges... mostly when looking at them from the directly overhead view.

Iceaxe
01-16-2006, 05:13 PM
The only other time I have noticed an optical illusion of this magnitude is in a night club at closing time......

.....ones turn into tens :getiton:

......and 12 hours later they have slowly return to a one again. And similar to the picture above, in the morning I have tried spinning them around several times but they still remain a one. :haha:

:popcorn:

stefan
01-16-2006, 05:44 PM
For a 666th post, shane, that was a very appropriate one! :naughty:

jumar
01-17-2006, 06:16 AM
That's really cool :haha:

cachehiker
01-17-2006, 09:25 AM
I've seen this effect on a black and white, overhead shot of the Sand Flats Recreation Area. About 2/3rds of it looked right, but Negro Bill looked like a ridge and not like a canyon at all.