Talk:1145: Sky Color

I think most explanations of the the mirror issue overlook an even simpler explanation -- Things appear to be flipped such that left and right are reversed. However, that is only because you are used to things, such as people, rotating about a vertical axis, with top and bottom staying in the same position. If a clone of you stood on its head and you faced each other, your right arms would be on the same side (e.g. "closer to the door"). Now, if you look in a mirror, it is the same as seeing the clone flipped top to bottom. 24.41.66.114 01:06, 6 September 2013 (UTC)

I have read that when you are in front of the mirror, the reason that it seems to reverse the horizontal or x-axis (left-right) view but not the vertical or y-axis view, is that the mirror actually reverses the z-axis front-back. The part nearest to the mirror reverses. Example, if you hold your right gloved hand in front of the mirror with the 5 fingers pointing to the mirror, the image that you see in front of the mirror is not similar to the left-hand glove, but it is the right glove turned inside-out. To test, wear a right latex glove, write something on it, then remove the glove, making the right glove inside out. If you can read what you had just wrote, it had reversed horizontally, but not vertically, assuming same frames of reference. 188.114.106.101 (talk) (please sign your comments with ~~~~)

Of course with vertical mirror vertical axis is selected: perceived switching of left and right (really close with far to mirror surface). When standing on horizontal mirror we will perceive switching bottom from top. --JakubNarebski (talk) 09:09, 10 December 2012 (UTC)

You're certainly correct, but I think that the original question is not really asking about text (or other things) which are perpendicular to the mirror, but rather text which is parallel to it (and thus the close vs. far doesn't come into it). For example, when reading signs in your rear view mirror or holding a book in front of your chest while looking in a mirror. I've added a little bit to the explanation to attempt to help clarify what's happening in that situation. I'm not sure if it really helps or not. KeithyIrwin (talk) 10:00, 10 December 2012 (UTC)

If the part you added was "mirrors don't reverse things, turning around does", then I think that that is the best description. If you can see text in a mirror, then that means that you have turned away from the text. And normally, humans turn around the z-axis. If, rather than turning away from a sign to look at a mirror on the opposite wall, you instead somersaulted backward into a handstand, then you would see the sign reversed vertically instead of horizontally. 108.162.249.76 22:33, 5 November 2017 (UTC)

Easier way to describe it: Imagine you hold a piece of glass. Write on the glass and hold it in front of the mirror, so that you can see both the original text and the mirrored text. Both versions of the text will look identical. So the mirror doesn't change anything. 62.220.2.194 11:10, 10 December 2012 (UTC)

Another way: draw a line between the real object and its reflection. Things are reflected around that line. If that line is going up & down (relative to your eyes), then things are reflected left/right (relative to your eyes). If that line is horizontal (again relative to your eyes), then things are reflected top/bottom. So it's not so much whether the mirror is horizontal or vertical, but rather what direction you are looking into the mirror (although that can be influenced a lot by the mirror's orientation).CityZen (talk) 04:17, 11 December 2012 (UTC)

I always wonder: Since the sky goes from red to blue to red and the optical spectrum goes from red to green to blue. How come the sky is never green?

Because of human color perception. You only perceive green in polychromatic light when said light is stronger in the middle wavelengths than the low or high wavelengths; in other words, you would need a process in the sky that removed both the high and low wavelengths from white light. As the sun sets, only the lower wavelengths are removed, so you perceive yellows and reds -- this perception of color is "one-sided", i.e. it is not interfered with by even longer wavelengths. By the way, sometimes you do see green briefly in the sky, it's called a Green Flash. --Prooffreader (talk) 16:41, 10 December 2012 (UTC)

I used to go outside after a rain storm during the day, and sometimes the sky would seem very green. The effect could last for hours. 76.122.5.96 12:15, 12 December 2012 (UTC)

The sky is green, at times. Growing up in the Upper Midwest (USA), I quickly learned that green sky means it's time to watch out for tornadoes. I don't know the actual connection between the two situations--I would guess from the previous comment that whatever atmospheric conditions create tornado conditions also "edit out" both high and low wavelengths, at least to a degree. 129.176.151.14 14:44, 12 December 2012 (UTC)

This sentence doesn't make sense: "(from "his" right to left instead of from "his" left to right)" Trek7553 (talk) 15:15, 10 December 2012 (UTC)

Repeat Character Watch: The girl has appeared previously in 842: Mark, 892: Null Hypothesis, 1058: Old-Timers, and 1104: Feathers (A similar looking character also appears in 635: Locke and Demosthenes but this is actually the character Valentine from the book Ender's Game). The mother is seen in comics 806: Tech Support and 813: One-Liners. lcarsos_a (talk) 18:12, 10 December 2012 (UTC)

About this edition: 1/(x^4) does not look like a root to me. IMHO the forth root of x would be more like x^(1/4) but it's not the formula from the comic. (I'm too lazy to try to type lambda). Lmpk (talk) 19:00, 10 December 2012 (UTC)

You are correct. It's been fixed. The editor that made that edit was probably confusing 1/x⁴ with x^1/4, the latter of which would indeed be the fourth root. lcarsos_a (talk) 19:53, 10 December 2012 (UTC)

This page, linked from the explanation says that "the most strongly scattered indigo and violet wavelengths stimulate the red cones slightly as well as the blue, which is why these colours appear blue with an added red tinge." -- this seems rather strange. Assuming the cones are simulated based on frequency/wavelength, ultra-blue colors shouldn't stimulate the red cones because the electromagnetic spectrum is linear, not circular, despite the appearance of similarity between violet and red. Or am I missing something? --Waldir (talk) 16:14, 11 December 2012 (UTC)

If you look at the response curve (middle of cited page) you'll see that red receptors have two peaks, one in the red wavelengths, and another (very tiny one) in the violet. That's why purple (which is red + blue) looks so similar to violet, and why the "color wheel" works. 207.225.239.130 21:59, 11 December 2012 (UTC)

PS: "first years" is an idiom. Wouldn't that be "first year students" to be proper English? 207.225.239.130 22:05, 11 December 2012 (UTC)

Idioms are "proper English" too. There is no doubt about what is meant here (or at least, I hope there isn't, but perhaps there are regional differences that mean some English speakers don't say "first years" to talk about students in their first year), and the register is not unduly colloquial for this kind of a site. 14:00, 12 December 2012 (UTC)

The easiest way to explain mirrors is: they don't change left and right, they change forward and backward. What is farther from the mirror appears farther in the mirror. If you look at yourself, your nose and the nose of your reflection are the closest parts of the body together (at least in a bathroom mirror :-)), so *if there were* another person standing where the mirror *simulates* it, that person would wave it's right arm when you wave your left. But in a "absolute reference frame", both image and original wave their arm nearest to the door. Interestingly automobile drivers don't make this error: if you see a car in the rear mirror blinking left you don't assume they want to turn right...

There was a hilarious Get Fuzzy strip where Rob tried to explain why the sky is blue to Satchel, but I can't find it. This one?98.174.41.183 00:49, 31 December 2012 (UTC) Yes that's the one. --Smartin (talk) 04:23, 1 January 2013 (UTC)

I would also just like to add that, as I understand it, the Sun puts out a lot more blue light than violet light, so it would make sense for blue to dominate. After green light, where the Sun's output peaks, the intensity of the light starts dropping dramatically. 71.104.183.59 (talk) (please sign your comments with ~~~~)

I don't think that woman is Megan. She looks like a black-haired version of Ponytail. 108.162.219.203 (talk) (please sign your comments with ~~~~)

Have to agree. Doesn't look like Megan. 108.162.210.177 23:53, 22 June 2015 (UTC)

The mirror explanation is convoluted. The question tricks you into thinking there's right/left symmetry being mixed up, when the symmetry is actually across the surface of the mirror. That's it. 108.162.215.94 01:41, 28 September 2014 (UTC)

Clifford Stoll, in his book "Cuckoo's Egg", reports being asked why the sky was blue in an oral examination by Astronomy professors. Every time he thought he'd explained in sufficient detail, they would say "go on…" until he'd been talking for an hour on the topic. AmbroseChapel (talk) 01:22, 4 September 2017 (UTC)

My quick explanation for the mirror thing is that a mirror doesn't show the world reversed, it shows it inside-out. AmbroseChapel (talk) 01:22, 4 September 2017 (UTC)

Don't know why there was relationship with "First year" and "Fresher" in GB-English, as it only actually mentions (US term) "Freshman". But, from personal experience:

• I was a "first year" in the first of 5(/6?) years in Primary (US: Elementary) School.
• On moving to Secondary School, I was a First Year again, for the first of a further five years (first year/form to third year/form in 'lower school', fourth and fifth year in 'upper school')
• Would have then been part of the 'lower sixth' and 'upper sixth' for the A-Levels, at the Secondary School (called a "High School", but clearly mismatches US-type "High Schools" from what I've learnt from US TV/films) but that had been phased out before I got to that age, so I instead went to the "Sixth Form College" for that Further Education. Apart from being in the "first year of the course", I don't think I was considered a "first year". (Also, I did a fresh one-year course not available at Secondary level, as I was doing the first of my other two-years, and then started the A-Level follow-up as I was doing the 2nd year of my other courses, so I was in my first and second years at one point.)
• In actual Higher Education, we were "Freshers"... though not sure that was used beyond the first term (we were so new that we were asking if you needed e-stamps for the e-mail, and many other pre-"Eternal September" things that happened mostly just in the September (maybe October too). I suppose the situation of "I'm in the first year (of my degree)" might have meant we were "first years" again, but I actually can't remember (four decades back!) apart from an obvious digit on the library card...

...for what it's worth. 141.101.99.144 22:52, 11 September 2024 (UTC)

Rewritten the "text reflected in a mirror" paragraphs to be more precise. Also of note (though is to much to add there) is a slightly different scenario, exemplified by the last time I went to get my hair cut. The barbers' chairs are lined up against a wall perpendicular to the front window, which prominently displays the business's prices (for Gents and Ladies basic haircuts, and it being slightly more for any lady) in a transparency overlay on the window, to be read from the outside. Which means that looking out of the window from the inside, the text is backwards (left-right reversed, because obviously the top of the text would be the top of the text either side of the window).
But sitting inside in a position (towards the rear of the 'shop' whereby the wall-mirrors reflect the windows), you can read the text 'normally' from the inside. This is because the mirrors still reflect 'in-out' to the mirror, but this 'in-out'ness corresponds to left-right for the window (from my vantage-point), so unreverses that reversal. That which is more left or more right to the mirror (i.e. things inside and things outside the window) are still positioned the same 'way' (the image of them is proportionally either nearer or further away from you, a mark on the outside of the window that is obscured by the fully opaque bits of writing is still 'beyond' the writing, you're not seeing it as if it's now this side of the window, as if having flipped the window through itself because of magical 'left-right' mirroring as far as the mirror is concerned).
That's only because the mirror is on the (perpendicular) wall. If it was on the also perpendicular-to-window ceiling (or floor) then the in-out-flip would be in your (and the window's) up-down perception, and the (reversed) writing would still have the start of the advertising text to the right and the end of the advertising text to the left, but now also the top of the actual text is at the bottom of the image of the text, and vice-versa. Which gives you the effect of 'strictly right way round text, but rotated upside-down'. (Or, if either the window-text was installed upside down or you made yourself do a hand-stand/similar, it would look exactly ok again in the reflection.
If there was a mirror on the back wall of this place, then you could have looked into that (facing further into the shop from wherever in the middle of it you stand, away from the window) and again see the window-text as normal, as you would if you looked through the window from the outside, at the mirrors on the back wall, to look at the text that (as well as being entirely the right way round in the initial view) continues to appear to be the right way round by looking at this reflection of the inside of the window. Here, you have made the window be reversed (in-out) by dint of the chosen viewpoint actually being on the wrong side of it and are using a mirror to flip the view of the window (the direction of interest being in-out of the mirror, the same direction as the mirror), so in-becomes-out-becomes-in and out-becomes-in-becomes-out. Therefore 'normal'. Again, everything explainable as the mirror flipping the in-and-out for itself, far more accurately than any attempt that involves left-and-right from the pure perspective of the mirror.
...but I didn't want to mention quite so much of that in the Explanation, and hope that what I did put there is more than sufficient to describe the situation (for the general reader) without having gone into this more practical and extended example. (Which is also why, when driving and looking in the rear-view mirror, I can read the couple of 'bumper stickers' (or whatever you'd call our UK equivalent) stuck inside the rear window the right way round. And I obviously know why I should be able to, but still makes me smile when see them and often still can't idly help trying to work out why I'm seeing a reversed sticker re-reversed again, and then almost instantly telling myself the exact same explanation.) But I also thought it might be interesting to put this deeper-dive here, for those who bother to read this bit. ;) 81.179.199.253 01:14, 8 February 2026 (UTC)