Mantis shrimp eyes(ryanblakeley.net)
ryanblakeley.net
Mantis shrimp eyes
https://ryanblakeley.net/p/mantis-shrimp-eyes
22 comments
> Polarized light usually oscillates in a fixed plane, but that plane can sometimes rotate, so light travels along a twisting helix.
wait what? they can bend light? make it not travel in a straight line? color me skeptical
wait what? they can bend light? make it not travel in a straight line? color me skeptical
The text here would appear to be confusing about what circular polarization means. Circular (or more generally, elliptical) polarization doesn't mean the light doesn't travel in a straight line.
Rather it means that the oscillations in the electrical (or equivalently, magnetic) field that the light consists of rotate around the axis that is the light's direction of travel, rather than staying in one fixed plane. The direction of travel stays constant though.
You might want to see the Wikipedia articles: https://en.wikipedia.org/wiki/Circular_polarization https://en.wikipedia.org/wiki/Elliptical_polarization
One way to think about this is to pick x and y directions perpendicular to the light's path of travel, and break down the light's oscillations into x and y components. Linear polarization occurs when these components are in phase with each other, and elliptical polarization occurs when they're not. When they're perfectly one quarter turn out of phase, you get circular polarization.
Rather it means that the oscillations in the electrical (or equivalently, magnetic) field that the light consists of rotate around the axis that is the light's direction of travel, rather than staying in one fixed plane. The direction of travel stays constant though.
You might want to see the Wikipedia articles: https://en.wikipedia.org/wiki/Circular_polarization https://en.wikipedia.org/wiki/Elliptical_polarization
One way to think about this is to pick x and y directions perpendicular to the light's path of travel, and break down the light's oscillations into x and y components. Linear polarization occurs when these components are in phase with each other, and elliptical polarization occurs when they're not. When they're perfectly one quarter turn out of phase, you get circular polarization.
ahh this makes sense. i was thinking of light as a stream of particles but this is about light-as-a-wave
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its easy to make light follow a bend. thats how fiber optic cables work
except theres nothing to bounce off of
I for one welcome our new mantis shrimp overlords.
Obligatory Oatmeal comic about the Mantis Shrimp:
https://theoatmeal.com/comics/mantis_shrimp
https://theoatmeal.com/comics/mantis_shrimp
Obligatory Ze Frank vid: https://www.youtube.com/watch?v=F5FEj9U-CJM
The Oatmeal claims that, "the mantis shrimp sees a thermonuclear bomb of light and beauty." This piece contradicts that claim:
"Mantis shrimp have twelve photoreceptor classes. Humans have three. We derive a spectrum of colors through comparisons between our three classes; this is called the opponent process or opponency. Mantis shrimp do not do this. They collapse the spectrum into just twelve colors."
The Oatmeal claims that, "the mantis shrimp sees a thermonuclear bomb of light and beauty." This piece contradicts that claim:
"Mantis shrimp have twelve photoreceptor classes. Humans have three. We derive a spectrum of colors through comparisons between our three classes; this is called the opponent process or opponency. Mantis shrimp do not do this. They collapse the spectrum into just twelve colors."
Ya, that's a lovely comic, but it appears to be a misconception. That comic is actually specifically called out in the book on page 107.
It's more like a 12 color lookup table.
> Every kind of red stimulates the bottom receptor of row 3. All shades of violet stimulate the top receptor on row 1
That's based on an experiment where they were trained to attack colored lights for a reward.
The comic also says they have 16 color receptors, but the other 4 (2 in the midband and 2 in the hemispheres), as far as anyone knows, aren't involved in color vision.
It's more like a 12 color lookup table.
> Every kind of red stimulates the bottom receptor of row 3. All shades of violet stimulate the top receptor on row 1
That's based on an experiment where they were trained to attack colored lights for a reward.
The comic also says they have 16 color receptors, but the other 4 (2 in the midband and 2 in the hemispheres), as far as anyone knows, aren't involved in color vision.
Would they be able to distinguish between a light that is pure orange (a single 600nm wave length) and a light that is a mix of red and yellow that gives humans the perception of orange?
If so, I think that's still kind of a cool thing to think about.
If so, I think that's still kind of a cool thing to think about.
It is my understanding that a mix of red and yellow frequencies would trigger the corresponding yellow and red-sensitive receptors, if it has them, but not orange.
That's my impression as well.
It's an interesting question. If you want to read more, the two researchers quoted in the book that I was summarizing are Justin Marshal and Mike Land. Each has a handful of papers that are cited in the bibliography.
It's an interesting question. If you want to read more, the two researchers quoted in the book that I was summarizing are Justin Marshal and Mike Land. Each has a handful of papers that are cited in the bibliography.
They actually do some comparison between colors, but it's implemented in a weird, alien way.
Instead of co-located and connected cones for different colors, they drag their eyes across a scene, so the comparison can happen across time instead, like a push broom sensor.
Instead of co-located and connected cones for different colors, they drag their eyes across a scene, so the comparison can happen across time instead, like a push broom sensor.
I’d forgotten about Ze. Wow, what a wild ride his 365 day vlogging experiment was. It was the first and most precious thing I did everyday for almost a year.
His History of Mens Underwear video was one of the best: https://www.youtube.com/watch?v=LNRX8kfGgYg
That's a good one, thanks. I actually started watching The Show from the beginning, but I don't know if I'll make it all the way through.
Also https://radiolab.org/episodes/211119-colors
Also of interest, mantis shrimp are edible and quite delicious.
Also of interest, mantis shrimp are edible and quite delicious.
Delicious too
https://www.nature.com/articles/166958b0