7 ms·
Humans can sense the polarization of light with the naked eye
- modeless 11y agoFascinating! Wikipedia has a great illustration of what it looks like, and now I can definitely see it in my LCD monitor. https://en.wikipedia.org/wiki/Haidinger's_brush https://en.wikipedia.org/wiki/Haidinger's_brush
- cjslep 11y ago> Haidinger's brush may also be seen by looking at a white area on many LCD flat panel computer screens (due to the polarization effect of the display), in which case it is often diagonal. Thanks for that, I thought there was something wrong with me when I saw my yellow bow-tie neither perfectly vertical nor horizontal.
- ridgeguy 11y agoUsed the white screen at http://www.ledr.com/colours/white.htm http://www.ledr.com/colours/white.htm Can see faint blue & yellow bow tie figures as the article describes on my laptop LCD. They change as I rotate the screen. Very interesting.
- throwaway_97 11y agoI cant see any bow ties :/
- throwaway_97 11y agoWait I think I do.. Can't say for sure but they look like two small yellow marbles stacked vertically. What can I say about the polarization of my lcd?
- tjohns 11y agoYup, that's them. It should look like this, only _much_ fainter: https://en.wikipedia.org/wiki/Haidinger's_brush https://en.wikipedia.org/wiki/Haidinger's_brush (The blue part is a bit harder to see than the yellow.)
- mikepurvis 11y agoThat's a helpful reference. I definitely see it on a 2014 rMBP.
- colordrops 11y agoMaybe it depends on the screen type. I can see it very clearly on my macbook LCD screen, but I can't see almost anything g on my Samsung S4 OLED screen.
- ars 11y ago> OLED screen. Right. I would not expect it with an OLED since that is not polarized.
- learnstats2 11y agoI came here to comment that Haidinger's brush is fainter than the light coming through from the Apple logo on the back of a Macbook screen ;-)
- whoopdedo 11y agoI'm having a hard time finding the orientation of my phone. I can see yellow artifacts but they're not coherent like on other LCDs. And when I look through polarized sunglasses there's no blocked angle. It must be using some alternative polarization even though it's a regular TFT screen. There's certainly a value in not having your phone screen dimmed by sunglasses.
- mikeiwin10 11y agothanks for sharing
- yoha 11y agoHackers News tend to prefer messages that contribute something new to the conversation. This is why users downvote most jokes and often even positive comments such as yours, that should have simply been an upvote of the post. However, you seem new (green user name), so that's understandable the first time.
- jwdunne 11y agoI like this. Familiarising newcomers to the community's ways as opposed to a blind downvote is a good way to welcome them. We must remember that these sorts of posts are acceptable on other discussion forums, news aggregates and 99% of social media as a whole. Many newcomers will be used to this freedom and may feel intimidated because their first post received a -- in karma, without knowing it's won as easily as it's lost. I, personally, comment very irregularly. I hold myself to a strict rule of only commenting when I feel I can add real value to the discussion - on a lot of subjects, experts way above my skill level do this so I do not comment.
- kleer001 11y agoSeems to me that someone could write a bot to chaperone newbs until they got to a certain level of community standards.
- jwdunne 11y agoIn true hacker spirit, we could use ML to find the reason and give a message like "It's probably because x". Not sure what algorithm we'd have to use but I'm interested now.
- mutagen 11y agoResearchers suspect that Vikings used this effect in combination with a 'sunstone' (Icelandic Spar) to navigate by the sun even when it was hidden by clouds. Article: http://news.discovery.com/earth/navigating-by-sunstone-and-a-sixth-sense.htm http://news.discovery.com/earth/navigating-by-sunstone-and-a... Paper: http://rspa.royalsocietypublishing.org/content/468/2139/671 http://rspa.royalsocietypublishing.org/content/468/2139/671
- evincarofautumn 11y agoHuh. I thought all humans could see polarisation. Further evidence that I should stop presuming other people are like me.
- bitJericho 11y agoI had no idea this was possible, and had never seen this effect. Of course I launch a blank screen on my phone and the effect is plain as day, I don't even have to tilt my head back and forth. Amazing!
- Raphmedia 11y agoI never thought some people couldn't. So, they are able to see pure white out of computer screens? That must be amazingly clear.
- deleted 11y ago[deleted]
- pjungwir 11y agoI've never understand the idea that in non-polarized light, the "amplitude" of the light wave points in all directions, whereas in polarized light it points in only one. The amplitude of a light wave doesn't literally mean something is oscillating up and down, right?? The amplitude is just the light's intensity. So what does it really mean for light to be polarized? And why do thin slits cause polarization?
- valvar 11y agoWouldn't amplitude just be the height of the wave, while "intensity" is dependent mostly on the frequency?
- ars 11y agoPhotons don't really have a height, so they don't really have an amplitude. What we call amplitude, and is also called intensity, is the number of photons.
- dools 11y agoWhat you're probably hearing is probability amplitude, which is the product of a wave function with its complex conjugate, rather than amplitude referring to wave intensity. If you're interested in this stuff, check out the 160 or so videos from leonard susskind on youtube on modern physics.
- abdullahkhalids 11y agoLight is an electromagnetic field: a wave-on-a-rope type thing except the rope is space. An electromagnetic field exerts a force on charged objects like electron, protons or even entire atoms and molecules. If you put an electron and shoot polarized light at it, it's movement will be consistent with the electric field going up and down in a particular plane. Analogously for unpolarized light. A thin slit cause polarization the same way only one plane of oscillation is possible for a rope passing through a slit. Except what is stopping the oscillations in 'bad' directions is the interaction between the electromagnetic field and atoms that make up the boundaries of the slit.
- jrapdx3 11y agoVery interesting. Didn't take too long before seeing faint yellowish blobs. The only problem was tilting my head too fast, made my neck joints creak. Slowing down was better, it didn't take more than modest offset (say 25 degrees) anyway once knowing what to look for. It worked differently on two computers. One is a fairly recent MS Surface Pro 2 tablet, the other an ancient Dell D630. The display on the Dell is TN, and not as blue as the IPS screen of the SP2. The effect was a little easier to evoke with the Dell, though its screen color made the yellow less distinct but the blue counter-color more visible. Occasionally I experience aura of migraine, in one form appearing as blobs of color moving around the visual field. (Not necessarily yellow, can be any color.) Maybe it's a reason I've never noticed the polarization effect before, the faint yellow/blue spots just got lost in the noise.
- dsrguru 11y agoTook me an hour but I got it! Staring at a solid background on my Nexus 5 on full brightness in a pitch black room did the trick. Horizontal linear oscillation was more noticeable for me than vertical for some reason, which meant holding my phone in landscape mode. The brush pattern is significantly fainter on my laptop than my phone, and I seem to lose the effect every few minutes when using my laptop. I've been able to bring it back by glancing back at my phone in landscape. This is really, really cool by the way.
- steve19 11y agoAfter an hour of staring at a white LCD screen,I think you will see whatever your brain wants you to see ;-)
- amelius 11y agoCouldn't it be the case that the human eye is just sensitive to the artifacts of a polarization filter?
- rcthompson 11y agoNot if it also works on polarized light in the sky.
- MichaelCrawford 11y agoI have long noticed this effect however I had no clue I was seeing polarization. I'm into photography. I had a dead-simple Pentax K-1000 SLR. Its only automation is a very basic light meter; I adjust the aperture and exposure until the needle is where I want it to be (ie. sometimes purposely over- or under-exposed). Three lenses, but with a polarizing filter for each. Mainly I use the polarizers to deepen the blue of the sky.
- spydum 11y agoSame here.. I have been on occasion caught staring off into a blank editor with white background and just assumed the yellow was some eye strain related thing. Also..totally agree and I do the same: Circular polarizer for camera can ineed make some cool cloud/sky photos without drastically affecting the rest of frame.
- benihana 11y ago>To see Haidinger’s brushes for yourself, look at a blank white portion of an LCD screen on a computer, tablet or phone. Holy crap, it worked! They're very very very faint, and if your monitor ins't clean, they're easy to miss. They appear right where you're looking at. If you imagine two lines coming out of your eyes at the screen, they show up right where the lines converge. Very faint and pale yellow, almost looks like a fading after-image. Only saw them when I rolled my head left and right / up and down. Imagine pointing one ear towards the floor and the other towards the ceiling - I oscillated between these two positions and saw it. It was harder to see when I unfocused my eyes like I was going to look at a 3D picture. Easier to see when focusing on the spot in the screen I'm looking at.
- deleted 11y ago[deleted]
- wcchandler 11y agoI wonder if this contributes to eye strain and brain fatigue.
- scoot 11y agoOh, wow, I got it without even trying just by rotating my laptop screen 90 degrees (portrait vs. landscape if that make sense.) with just a web browser on this HN page (no other white screen needed). I'm sure I've noticed this effect before, as I often stand my laptop on its edge on the floor like an open book when I'm not using it (easier to reach down and grab the body that way), but hadn't paid it much attention and had no idea of the cause. Retina MBP if that makes a difference.
- DEinspanjer 11y agoSo after a little owl-like head twisting, I was able to perceive the brush on both of my Dell 24" LCDs. However, I noticed something interesting. Even though they are fairly similar models with a year or two difference (U2410 vs 2408WFP), they have different polarizations. The U has a vertical brush/bowtie and the WFP has a horizontal brush. In the past, I have noticed that the brightness of the two is different and has been hard to match. If I drag an application between the two screens, it is almost impossible to tune either monitor so the display is uniform. Does the manufacturer explicitly determine the orientation of the polarization? Are there reasons for one versus the other? Reasons why a manufacturer might want to rotate it? I have noticed in the past that some dashboard or nav screens in cars are hard to see with my sunglasses while others aren't, and I know that is due to the orientation of their polarization because if I twist my head 90 degrees, the effect reverses. Fun stuff.
- TheAdamist 11y agoIf you have polarized sunglasses you should be able to verify those polarizations by rotating your sunglasses to see when the screens go black vs look normal.
- whoopdedo 11y agoSince 3D movies use polarized light, could this contribute to the nausea some people experience when watching them? Or is that just the fast movement (like video games) since nearly all 3D movies are action films. edit: I now remember that 3d movies are projected using radially polarized light. The article only describes linearly polarization. There's also spiral and azimuth. Polarized light is really complicated.
- fishanz 11y agoYeah; I'm curious if there is anything comparable to this for radial polarization.