Editing 1733: Solar Spectrum
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==Explanation== | ==Explanation== | ||
− | [[ | + | {{incomplete|Someone knowing more about the Fraunhofer lines could maybe improve the [[#Table of spectrum|table]] (mainly the comments).}} |
− | This comic's release day was postponed from the scheduled Wednesday release to a [[:Category:Thursday comics|Thursday release]] because [[Randall]] noticed the extreme popularity of the previous comic on Monday: [[1732: Earth Temperature Timeline]]. Randall even explained this in the header text | + | This comic's release day was postponed from the scheduled Wednesday release to a [[:Category:Thursday comics|Thursday release]] because [[Randall]]] noticed the extreme popularity of the previous comic on Monday: [[1732: Earth Temperature Timeline]]. Randall even explained this in the header text, see [[1732#Popularity_of_comic|this trivia item]] from the previous comic. |
This comic depicts the {{w|Fraunhofer lines}}, i.e. the {{w|spectral lines}} seen when sunlight is split in a {{w|spectrometer}}. These appear as black gaps in the rainbow of light, caused by light being absorbed by {{w|Chemical element|elements}} in the {{w|Sun}}. The frequencies of light that an atom absorbs depend on the exact arrangement of electron orbitals around it - because each element has a different pattern of orbitals, each one has a distinctive pattern in the absorption spectrum. The chart shows most of the main lines in the visible spectrum and identifies the elements linked to them. | This comic depicts the {{w|Fraunhofer lines}}, i.e. the {{w|spectral lines}} seen when sunlight is split in a {{w|spectrometer}}. These appear as black gaps in the rainbow of light, caused by light being absorbed by {{w|Chemical element|elements}} in the {{w|Sun}}. The frequencies of light that an atom absorbs depend on the exact arrangement of electron orbitals around it - because each element has a different pattern of orbitals, each one has a distinctive pattern in the absorption spectrum. The chart shows most of the main lines in the visible spectrum and identifies the elements linked to them. | ||
− | The image of the Fraunhofer lines from Wikipedia is shown below in the section with a [[#Table of spectrum|table]] of these lines. Here it can be seen that all the lines that are labeled with elements are correctly labeled. Also all lines shown in the part of the spectrum included in the comic are included. Ten of the lines included are not labeled in the picture on Wikipedia (at least not with an element | + | The image of the Fraunhofer lines from Wikipedia is shown below in the section with a [[#Table of spectrum|table]] of these lines. Here it can be seen that all the lines that are labeled with elements are correctly labeled. Also all lines shown in the part of the spectrum included in the comic are included. Ten of the lines included are not labeled in the picture on Wikipedia (at least not with an element, two of the three "h" labels are not in the table on Wikipedia). Six of these also have no label in the comic. But the other four line's label ''Those giant sunglasses'' constitute the joke of the comic. There seem to be only one clear error in the comic and that is the fifth line labeled Sunglasses, the middle of the lines, which is actually a Hydrogen line (C in the picture below). But the line next to it to the right is one of those not labeled in either pictures and it seems likely that it was this line Randall meant to be a Sunglass line... |
All ten extra lines (including both the labeled and unlabeled ones) seem to correspond to the [http://astro.u-strasbg.fr/~koppen/discharge/silicon.jpg spectrum of silicon], and '''the joke then refers to the {{w|silicon dioxide}} (aka glass)''' used in the lenses of the Sun's sunglasses. Of course, this means that the glasses have been ionized and turned into plasma by the heat of the sun. | All ten extra lines (including both the labeled and unlabeled ones) seem to correspond to the [http://astro.u-strasbg.fr/~koppen/discharge/silicon.jpg spectrum of silicon], and '''the joke then refers to the {{w|silicon dioxide}} (aka glass)''' used in the lenses of the Sun's sunglasses. Of course, this means that the glasses have been ionized and turned into plasma by the heat of the sun. | ||
− | The idea of a sun with sunglasses is a reference to pictures/clipart of the sun wearing sunglasses, often used to denote good weather. Randall has specifically used this picture in | + | The idea of a sun with sunglasses is a reference to pictures/clipart of the sun wearing sunglasses, often used to denote good weather. But Randall has specifically used this picture in his [[what if?]] ''{{what if|115|Into the Sun}}'' in the fourth image. The title text of that image even references the fact that those sunglasses will block the light to Earth: |
− | + | :A partial solar eclipse is when the Earth moves across the part of the Sun blocked by its sunglasses. | |
− | |||
So this comic is a direct callback to this what if? post. | So this comic is a direct callback to this what if? post. | ||
− | |||
− | |||
There is another joke in drawing a sun with sunglasses because sunglasses are meant to protect your eyes from the sun, so what should they protect the Sun's eye from, Star light...? Also, any glasses worn by the sun, would they not become sun glasses? | There is another joke in drawing a sun with sunglasses because sunglasses are meant to protect your eyes from the sun, so what should they protect the Sun's eye from, Star light...? Also, any glasses worn by the sun, would they not become sun glasses? | ||
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===Table of spectrum=== | ===Table of spectrum=== | ||
:This is the official image for {{w|Fraunhofer lines}} (solar spectrum) on Wikipedia: | :This is the official image for {{w|Fraunhofer lines}} (solar spectrum) on Wikipedia: | ||
− | :[[File:Fraunhofer_lines_From_Wikipedia.png]] | + | :[[File:Fraunhofer_lines_From_Wikipedia.png|upright=.9]] |
:The graph is a typical spectral lines chart, with a long rainbow band (from {{w|ultraviolet}} to the left to {{w|infrared}} on the right both colors appearing black as they are not visible.) The black lines in it, indicating the traces of different elements. Noe that the comic only covers the visible part of this spectrum. | :The graph is a typical spectral lines chart, with a long rainbow band (from {{w|ultraviolet}} to the left to {{w|infrared}} on the right both colors appearing black as they are not visible.) The black lines in it, indicating the traces of different elements. Noe that the comic only covers the visible part of this spectrum. | ||
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|759.370 | |759.370 | ||
|N/A | |N/A | ||
− | |This line is outside | + | |This line is outside comics range. So are the two unlabeled lines shown in the spectrum in the picture above around 720 and 730 nm. There are also even more oxygen lines further out in the infrared part of the spectrum which is not even included in the picture above. |
|- | |- | ||
|None | |None | ||
Line 59: | Line 56: | ||
|690 | |690 | ||
|Those giant sunglasses 5 | |Those giant sunglasses 5 | ||
− | |This is the fifth of the five xkcd | + | |This is the fifth of the five xkcd sunglass lines. This line is not labeled in the picture above. Wavelength read off manually |
|- | |- | ||
|B | |B | ||
Line 65: | Line 62: | ||
|686.719 | |686.719 | ||
|Oxygen 2 | |Oxygen 2 | ||
− | |Agreement | + | |Agreement |
|- | |- | ||
|None | |None | ||
Line 71: | Line 68: | ||
|577 | |577 | ||
|Those giant sunglasses 4 | |Those giant sunglasses 4 | ||
− | |This is the fourth of the five xkcd | + | |This is the fourth of the five xkcd sunglass lines. This line is not labeled in the picture above. Wavelength read off manually. |
|- | |- | ||
|None | |None | ||
Line 77: | Line 74: | ||
|660 | |660 | ||
|Unlabeled | |Unlabeled | ||
− | |This line is not labeled | + | |This line is not labeled either in the comic or in the picture above. Wavelength read off manually. It seems like this one was supposed to be one of the sunglasses lines, and then by mistake the arrow points to the labeled line C below. |
|- | |- | ||
|C | |C | ||
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|656.281 | |656.281 | ||
|Those giant sunglasses 3 | |Those giant sunglasses 3 | ||
− | |This is the third of the five xkcd sunglass lines. This is actually the | + | |This is the third of the five xkcd sunglass lines. This is actually the {{w|Hα}} line belonging to the {{w|hydrogen}} {{w|Balmer series}}. Seems like a mistake, and more likely it was meant for the arrow to point to the unlabeled line mentioned here above. |
|- | |- | ||
|None | |None | ||
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|645 | |645 | ||
|Those giant sunglasses 2 | |Those giant sunglasses 2 | ||
− | |This is the second of the five xkcd | + | |This is the second of the five xkcd sunglass lines. This line is not labeled in the picture above. Wavelength read off manually. |
|- | |- | ||
|a | |a | ||
Line 95: | Line 92: | ||
|627.661 | |627.661 | ||
|Oxygen 1 | |Oxygen 1 | ||
− | |Agreement | + | |Agreement |
|- | |- | ||
|D<sub>1</sub> | |D<sub>1</sub> | ||
Line 101: | Line 98: | ||
|589.592 | |589.592 | ||
|Sodium 2 | |Sodium 2 | ||
− | |Agreement. There | + | |Agreement. There are only one label (Sodium) in the comic above these two close lines. |
|- | |- | ||
|D<sub>2</sub> | |D<sub>2</sub> | ||
Line 107: | Line 104: | ||
|588.995 | |588.995 | ||
|Sodium 1 | |Sodium 1 | ||
− | |Agreement. There | + | |Agreement. There are only one label (Sodium) in the comic above these two close lines. |
|- | |- | ||
|D<sub>3</sub> or d | |D<sub>3</sub> or d | ||
Line 113: | Line 110: | ||
|587.5618 | |587.5618 | ||
|N/A | |N/A | ||
− | |This line is so close to the nearest sodium line that only one line is visible, so | + | |This line is so close to the nearest sodium line that only one line is visible, so only one is shown, both in the comic and in the picture above. |
|- | |- | ||
|None | |None | ||
Line 119: | Line 116: | ||
|577 | |577 | ||
|Those giant sunglasses 1 | |Those giant sunglasses 1 | ||
− | |This is the first of the five xkcd | + | |This is the first of the five xkcd sunglass lines. This line is not labeled in the picture above. Wavelength read off manually. |
|- | |- | ||
|None | |None | ||
Line 125: | Line 122: | ||
|554 | |554 | ||
|Unlabeled | |Unlabeled | ||
− | |Agreement. This line is not labeled either in the comic or in the picture above. Wavelength | + | |Agreement. This line is not labeled either in the comic or in the picture above. Wavelength read off manually. |
|- | |- | ||
|None | |None | ||
Line 131: | Line 128: | ||
|549 | |549 | ||
|Unlabeled | |Unlabeled | ||
− | |Agreement. This line is not labeled either in the comic or in the picture above. Wavelength | + | |Agreement. This line is not labeled either in the comic or in the picture above. Wavelength read off manually. |
|- | |- | ||
|None | |None | ||
Line 137: | Line 134: | ||
|537 | |537 | ||
|Unlabeled | |Unlabeled | ||
− | |Agreement. This line is not labeled either in the comic or in the picture above. Wavelength | + | |Agreement. This line is not labeled either in the comic or in the picture above. Wavelength read off manually. |
|- | |- | ||
|E<sub>2</sub> | |E<sub>2</sub> | ||
Line 149: | Line 146: | ||
|518.362 | |518.362 | ||
|Magnesium 2 | |Magnesium 2 | ||
− | |Agreement. See | + | |Agreement. See b below. There are only one label (Magnesium) in the comic above these two close lines. |
|- | |- | ||
|b<sub>2</sub> | |b<sub>2</sub> | ||
Line 161: | Line 158: | ||
|516.891 | |516.891 | ||
|N/A | |N/A | ||
− | |This iron line and the next magnesium line are so close that only one is visible in the spectrum, so only one is shown, both in the comic and in the picture above. There is only one label for both visible lines showing them to be magnesium, even though there are four lines (this one is | + | |This iron line and the next magnesium line are so close that only one is visible in the spectrum, so only one is shown, both in the comic and in the picture above. There is only one label for both visible lines showing them to be magnesium, even though there are four lines one of which (this one is Iron). |
|- | |- | ||
|b<sub>4</sub> | |b<sub>4</sub> | ||
Line 167: | Line 164: | ||
|516.733 | |516.733 | ||
|Magnesium 1 | |Magnesium 1 | ||
− | |Agreement. See | + | |Agreement. See b above. There are only one label (Magnesium) in the comic above these two close lines. |
|- | |- | ||
|c | |c | ||
Line 179: | Line 176: | ||
|486.134 | |486.134 | ||
|Hydrogen 3 | |Hydrogen 3 | ||
− | |Agreement with | + | |Agreement with {{w|Hβ}}. |
|- | |- | ||
|h | |h | ||
Line 185: | Line 182: | ||
|476 | |476 | ||
|Unlabeled | |Unlabeled | ||
− | |Agreement. This line is also unlabeled in the table on Wikipedia. " | + | |Agreement. This line is also unlabeled in the table on Wikipedia. "h" is used between H and g below. The wavelength is manually read off from the image. |
|- | |- | ||
|d | |d | ||
Line 203: | Line 200: | ||
|434.047 | |434.047 | ||
|Hydrogen 2 | |Hydrogen 2 | ||
− | |Agreement with | + | |Agreement with {{w|Hγ}}. |
|- | |- | ||
|G | |G | ||
Line 221: | Line 218: | ||
|410.175 | |410.175 | ||
|Hydrogen 1 | |Hydrogen 1 | ||
− | |Agreement with | + | |Agreement with {{w|Hδ}}. |
|- | |- | ||
|H | |H |