explain xkcd - User contributions [en]

2696: Precision vs Accuracy

2023-01-17T21:17:17Z

Bigbillybass.:

{{comic
| number = 10000000000000000
| date = November 9, 2022
| title = Precision vs Accuracy
| image = precision_vs_accuracy_2x.png
| imagesize = 501x462px
| noexpand = true
| titletext = 'Barack Obama is much less likely than the average cat to jump in and out of cardboard boxes for fun' is low precision, but I'm not sure about the accuracy.
}}

==Explanation==
{{incomplete|Created by BARACK OBAMA IN A CARDBOARD BOX. Further detail, sortable table? - PLEASE CHANGE THIS COMMENT WHEN EDITING THIS PAGE. Do NOT delete this tag too soon.}}
This comic parodies the difference between 'accuracy' and 'precision' with a table. {{w|Accuracy and precision}} are common concepts to be encountered in the scientific field and often students have issues with the differences between them. Accuracy concerns whether a statement is true, while precision concerns how detailed it is; it is possible for a statement to be one but not the other. The comic explores this concept by comparing {{w|Barack Obama}}, former President of the United States, with {{w|cat}}s. Confusingly, he measures different statistics of both Barack Obama and cats (sometimes measuring them in terms of cats) leaving the unwary reader even more confused.

Being precise is typical of calculations that roll out an excess of significant digits, often in the form of trailing decimals. Precision is lowered by using more rounded figures, or merely being comparative, but largely unaffected by whether the original values used were accurate or even correct. Accuracy is a cumulative function of the accuracy given to the intermediate values used for any calculation, and can be degraded by using figures that are themselves in some way inaccurate or imprecise. One part of confusion between the two is because being too precise usually decreases accuracy.

The numbers mentioned in the top row (high precision) of the table all use exactly the same digits, dictating that a full five digits of ''precision'' are used in them all. The most "valid" or correct value is a number that's very accurate and precise (see table). For the medium accuracy the number is an anagram of the 1st entry, giving a value that is reasonable but would be overly exact, whilst the low accuracy number is just a repeat of the first entry's digits with a shifted decimal but clearly at the wrong scale, as Randall could have shifted the decimal point one further place to the left to be closest to the true measurement. Instead, he replaces the thousands separator with the decimal point, perhaps for the visual pun.

The title text compares Obama's and cats' enjoyment of playing with cardboard boxes. While cats are known to do this,{{citation needed}} we don't know whether Obama does.

The day prior to the publication of this comic (November 8, 2022) was election day in the United States, so Randall may have been remembering Barack Obama's presidency at this time.

{| class="wikitable"
!Precision
!Accuracy
!Statement
!Explanation
|-
|High
|High
|Barack Obama was president for 70,128 hours
|This is the official length in hours of {{w|Barack Obama}}'s 8-year presidency, including 2 {{w|leap year|leap days}}. Obama served from January 20, 2009 through January 20, 2017, and his term officially began and ended at noon on those days. (There were three {{w|leap second|leap seconds}} during his presidency, though.)
|-
|High
|Medium
|Barack Obama weighs as much as 17.082 cats
|The accuracy would depend on the mass of the cats in question. Also a human's mass can vary by a few pounds in a small amount of time as meals are consumed, resources are used in metabolism and wastes are eliminated, and thus this may be overly precise due the margin of error in both the mass of cats and the mass of Mr. Obama. In 2016, Obama was [https://www.cnn.com/2016/03/08/politics/obama-medical-exam-loses-weight officially reported] to weigh 175 lb (79.3787 kg). [https://www.google.com/search?q=how+heavy+is+an+average+cat Google claims that an average cat weighs between 8.8 and 11 lbs], so this statement may be close to accurate.
|-
|High
|Low
|Barack Obama is 70.128 feet tall
|A highly precise (5 significant digits) measurement, but far from his actual height, published as 6'1".
The given value is more than an order of magnitude different from both him and {{w|Robert Wadlow|almost}} any other known human, whilst one of 7.0128 would ''only'' be about 15% off – still a low accuracy, but not outside the realms of possibility for an otherwise unknown person.
Coincidentally, Barack Obama is approximately 70 ''cat'' feet tall, using the paw size of a house cat to measure his height. Given the number of cat-related facts in the rest of the chart, this could be seen as rather appropriate.
|-
|Medium
|High
|Most cats have 4 legs
|Like many mammals, cats are quadrupeds, which means "four feet". Unless there is a genetic or other developmental issue, or an an injury that causes the loss of a limb, then cats generally have 4 legs.
|-
|Medium
|Medium
|Barack Obama is 6'1"
|While only as precise as the nearest inch, a common degree of rounding in that scale of measurement, that is the former president's published height.
[https://www.cnn.com/2016/03/08/politics/obama-medical-exam-loses-weight In 2016], Obama was said to have "grown" 0.5 inches in height, so there is a definite lack of consistency of exactly how tall he is. The examinations may have been made at different times of their respective days, with some spinal compression occurring all the time not laid in bed, and his current height is also not publicly recorded; several years of gradual aging could also reduce his posture slightly, or sustaining his fitness (since experiencing the travails of office) may counteract this to a greater or lesser effect.
|-
|Medium
|Low
|Barack Obama has 4 legs
|Barack Obama, being a mammal, does qualify as a {{w|tetrapod}}, but as a primate, his ancestors' forelimbs evolved into arms and hands. Like other humans, he does not generally use them for locomotion, but to manipulate his environment. Thus calling these limbs "legs" runs counter to normal definitions, and is inaccurate.

|-
|Low
|High
|Most cats have legs
|A true (high accuracy) statement without much information (low precision).
|-
|Low
|Medium
|Barack Obama has fewer legs than your cat
|Again, this will depend on the cat (not to mention whether or not you actually have a cat), but in general, true.
|-
|Low
|Low
|Barack Obama's cat has hundreds of legs
|This statement has low accuracy, as Barack Obama owns a four-legged dog named Sunny, but is not known to have owned a cat, much less one with more legs than normal. And cats tend not to have hundreds of legs.{{Citation needed}} It also has low precision, as "hundreds" could reasonably range from 200 to 900. (From a strict logician's point of view, this could however be considered a vacuously true statement.)
|-
|Low
|Unsure
|Barack Obama is much less likely than the average cat to jump in and out of cardboard boxes for fun
|Barack Obama has never publicly jumped in and out of cardboard boxes for fun,{{Citation needed}} but the possibility exists that he does so in private. Cats, on the other hand, are commonly known for jumping in and out of cardboard boxes for fun.
|}

==Transcript==
:[The comic shows a table with 3 rows and 3 columns. Each row and column has a label, and then nine statements are given for the 3x3 grid.]
:{| class="wikitable"
|-
| || High accuracy || Medium accuracy || Low accuracy
|-
| High precision
|Barack Obama was president for 70,128 hours||Barack Obama weighs as much as 17.082 cats||Barack Obama is 70.128 feet tall
|-
| Medium precision
|Most cats have 4 legs||Barack Obama is 6'1"||Barack Obama has 4 legs
|-
| Low precision
|Most cats have legs||Barack Obama has fewer legs than your cat||Barack Obama's cat has hundreds of legs
|}

{{comic discussion}}

[[Category:Charts]]
[[Category:Statistics]]
[[Category:Comics featuring real people]]
[[Category:Cats]]

2725: Sunspot Cycle

2023-01-17T16:30:00Z

Bigbillybass.:

{{comic
| number = 2725
| date = January 16, 2023
| title = Sunspot Cycle
| image = sunspot_cycle_2x.png
| imagesize = 740x503x
| noexpand = true
| titletext = Who can forget the early 2010s memes? 'You know you're a 90s kid if you remember the feeling of warm sunlight on your face.' 'Only 90s kids remember the dawn.'
}}

==Explanation==
{{incomplete|Created by a NINETIES KID WHO ATE THE SUN - PLEASE change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic is a reference to the {{w|solar cycle}}, which is a roughly 11-year cycle of changes in the Sun's activity from a period of minimal levels of various related phenomena ({{w|sunspots}}, solar radiation, ejecta, and solar flares) to one of maximum activity in these areas. As the cycle continues, the Sun returns to minimal activity and starts over. Without actually studying the Sun, however, there is no discernable difference to our daily lives here on Earth, and studying the Sun in enough detail is difficult due to its intrinsic and eye-damaging brightness whenever viewed directly.

This comics makes a joke that when the absolute number of sunspots appears to decrease it is not because they disappear, but because they get so crowded that they begin to merge, and thus the number of individual spots decreases whereas the area of the sun covered by sunspots continues to increase to near total 'darkness'. This causes there to be a completely dark Sun after 11 years, at which point any new sunspots are ''bright'' patches, and the next 11-year cycle repeats the process but accumulating bright spots until eventually it is all bright once more, giving a total bright/dark cycle of 22 years.

The curve showing the number of differentiable sunspots in this 22-year cycle would follow the curves for two whole cycles of our normal Sun, as the number of distinct spots (of either kind) decreases down to practically just one Sun-enveloping spot. The change in brightness over the cycle, however, repeats only over the full 22 years, darkening and then being made to shine bright once more as the other type of spot appears and begins to dominate once more.

Below is a graph showing the number of sunspots as a function of time from around 1965 to 2025. Periods where the sun is dark are shown with black under the curve, and in transition periods with lines of darkness getting closer together on the way to 'fully' dark area plus vals of light reinserting themselves in the lightening part of the cycle. Also for clarity the troughs are labeled with the sun being bright or dark. It is always when there are few spots that the sun is either completely free from spots and thus bright, or completely covered and thus dark. The maxima are always during the height of the transition between the two extremes, with a wide swathe of the time around the minima being mostly light or mostly dark, alternating at around a decade of each predominating.

At times, this closely synchronises with the calendar decades. From this curve it can be seen that the Sun was bright across the 1990s, but not in the dark 1980s or the dark time from around 2001 to 2014. This fact is mentioned in the title text (see below). Similarly the 1970s were mostly bright, after the largely dark 1960s, the width of the transition periods covering the marked decade-defining years in slightly offset ways compared to the neighbouring ones. After the darkness began around 2000, the shift was such that it finally got bright again around 2014, with darkness returning around 2024. This is because of the sunspot cycles being 11 years (making the illumination cycle 22 years) and eventually it no longer credibly meshes with the arbitrary decadal cut-offs.

All this would obviously be catastrophic if it happened in our version of the universe, as during a dark phase unsufficient light would be coming from the Sun, and the Earth could freeze if all the energy from the Sun was reduced. If the spots only affect light in the visible spectrum, then Earth would not freeze but plants would have trouble with photosynthesis and other natural processes would be interrupted. In our universe sunspots cool the area of the Sun where they appear, relative to the rest of the surface (50-75% of the nearly 6000K 'norm'), but they are far from being actually dark; [https://image.gsfc.nasa.gov/poetry/workbook/sunspot.html NASA says] that each sunspot on its own would glow orange, brighter than the Moon is when it is full (with a typically bright Sun illuminating it). So even in a completely sunspot-covered Sun, the Sun would still be brighter than the Moon ought to be, and far brighter than the dark-time Moon would become (possibly causing issues for nocturnal life, as well). It would be possible to see it (and see by it) even if the heat delivered were very low and even at noon it would seemn to be {{wiktionary|crepuscular}} by our normal expectations. See more in the title text explanation.

These problems are obviously not a serious threat in the reality of the comic, as the Sun is truly dark and yet people and natural systems have long survived these dark periods and adapted accordingly. This becomes clear in the title text where internet memes indicate that people lived fine through the dark periods, although they obviously did not 'properly' see the Sun, as kids, if they were born during the early start of a 'dark decade'.

The title text indicates the effect on internet memes that the special solar cycle has had. During the 2010s in our universe there were many '90s kid' memes. Those were also popular in this universe, but they reflect that the Earth had at that time been dark since the 2000s, and thus only those born in the 90s and before would remember dawn or the feeling of the warm sun on their faces.

This of course indicates that the Sun is actually dark and gives no warmth. Thus it is a mystery how life on Earth prevails, but given that there were kids from the 1990s that made memes twenty years after, life does work in this strange alternate universe.

==Transcript==
:[This comics shows two graphs, one also with several images of the Sun in different times in the solar cycle. The top graph is much larger than the bottom graph, and above them is a explanation of what the graphs shows:]
:Ever wonder why the sun disappears for about 10 years every other decade? This terrifying period of worldwide darkness is a natural consequence of the 11-year sunspot cycle:

:[A graph is shown with a label above the arrow on the Y-axis and a label written above the left part of the X-axis with an arrow pointing from it to the right (there is not arrow on the X-axis line). The graph shows a sine curve with a dashed line. It starts close to the bottom and then increases, then decreases before i finally slightly increases again. Above the dashed line are eight circles representing the sun with various levels of sunspots, with an arrow between each circle pointing to the next to the right. All circles are just above the dashed curve and the small arrows between them also follow the curvature of the line, so this string makes the same shape as the curve. along the eight representation of the sun there are five labels. The eight Suns will be described below with labels given when relevant.]
:Y-Axis: Sunspot number
:Y-Axis: Time

:[The first Sun's circle is completely white]

:[The second Sun's circle has a few sunspots. A label is written to the left of it:]
:Dark sunspots appear

:[The third Sun's circle has several sunspots. A label is written to the left of it:]
:Sunspot number rises

:[The fourth Sun's circle is half covered in sunspots.]

:[The fifth Sun's circle is mostly black with a few lines of white dots. Between the fourth and fifth circle is a label:]
:Number falls as sunspots merge.

:[The sixth Sun's circle is almost completely black with just a few small white spots. A label is written above it:]
:Sunspots envelop sun, Earth enters years of darkness.

:[The seventh Sun's circle is mostly black with a few light areas.]

:[The eighth Sun's circle is still mostly black but with some larger white areas. A label is written above and left of it:]
:Bright sunspots appear, cycle reverses.

:[Below is a second graph with a label written near the top of the Y-axis which is otherwise not labeled. The X-axis also has no label, but six years are written beneath at equal intervals. The graph shows a similar sine curve as the one above, but with almost five cycles shown. Also each cycle is not close to being a perfect sine curve, but has the property with a peak followed by a trough. The five troughs are labeled. The area beneath the curve alternates from being black and white when there is a trough, with the peak in between having several vertical lines, indicating transfer from black to white and vise versa. There are not same distance between peaks and there are also features on the graphs, for instance the two peaks in the middle has a drop, so they look like volcanoes. And the last full peak has a clear outlier year with many sunspots.]
:Label: History:
:X-axis labels: 1970 1980 1990 2000 2010 2020
:Through 1970-1980: Sun is bright
:Through 1980-1990: Sun is dark
:Through 1990-2000: Sun is bright
:Through 2000-2010: Sun is dark
:Through 2010-2020: Sun is bright

{{comic discussion}}

[[Category:Astronomy]]
[[Category:Timelines]]
[[Category:Line graphs]]
[[Category:Internet]]

2725: Sunspot Cycle

2023-01-17T16:28:49Z

Bigbillybass.:

{{comic
| number = 2725
| date = January 16, 2023
| title = Sunspot Cycle
| image = sunspot_cycle_2x.png
| imagesize = 740x503x
| noexpand = true
| titletext = Who can forget the early 2010s memes? 'You know you're a 90s kid if you remember the feeling of warm sunlight on your face.' 'Only 90s kids remember the dawn.'
}}

==Explanation==
{{incomplete|Created by a NINETIES KID WHO FELT SUN - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic is a reference to the {{w|solar cycle}}, which is a roughly 11-year cycle of changes in the Sun's activity from a period of minimal levels of various related phenomena ({{w|sunspots}}, solar radiation, ejecta, and solar flares) to one of maximum activity in these areas. As the cycle continues, the Sun returns to minimal activity and starts over. Without actually studying the Sun, however, there is no discernable difference to our daily lives here on Earth, and studying the Sun in enough detail is difficult due to its intrinsic and eye-damaging brightness whenever viewed directly.

This comics makes a joke that when the absolute number of sunspots appears to decrease it is not because they disappear, but because they get so crowded that they begin to merge, and thus the number of individual spots decreases whereas the area of the sun covered by sunspots continues to increase to near total 'darkness'. This causes there to be a completely dark Sun after 11 years, at which point any new sunspots are ''bright'' patches, and the next 11-year cycle repeats the process but accumulating bright spots until eventually it is all bright once more, giving a total bright/dark cycle of 22 years.

The curve showing the number of differentiable sunspots in this 22-year cycle would follow the curves for two whole cycles of our normal Sun, as the number of distinct spots (of either kind) decreases down to practically just one Sun-enveloping spot. The change in brightness over the cycle, however, repeats only over the full 22 years, darkening and then being made to shine bright once more as the other type of spot appears and begins to dominate once more.

Below is a graph showing the number of sunspots as a function of time from around 1965 to 2025. Periods where the sun is dark are shown with black under the curve, and in transition periods with lines of darkness getting closer together on the way to 'fully' dark area plus vals of light reinserting themselves in the lightening part of the cycle. Also for clarity the troughs are labeled with the sun being bright or dark. It is always when there are few spots that the sun is either completely free from spots and thus bright, or completely covered and thus dark. The maxima are always during the height of the transition between the two extremes, with a wide swathe of the time around the minima being mostly light or mostly dark, alternating at around a decade of each predominating.

At times, this closely synchronises with the calendar decades. From this curve it can be seen that the Sun was bright across the 1990s, but not in the dark 1980s or the dark time from around 2001 to 2014. This fact is mentioned in the title text (see below). Similarly the 1970s were mostly bright, after the largely dark 1960s, the width of the transition periods covering the marked decade-defining years in slightly offset ways compared to the neighbouring ones. After the darkness began around 2000, the shift was such that it finally got bright again around 2014, with darkness returning around 2024. This is because of the sunspot cycles being 11 years (making the illumination cycle 22 years) and eventually it no longer credibly meshes with the arbitrary decadal cut-offs.

All this would obviously be catastrophic if it happened in our version of the universe, as during a dark phase unsufficient light would be coming from the Sun, and the Earth could freeze if all the energy from the Sun was reduced. If the spots only affect light in the visible spectrum, then Earth would not freeze but plants would have trouble with photosynthesis and other natural processes would be interrupted. In our universe sunspots cool the area of the Sun where they appear, relative to the rest of the surface (50-75% of the nearly 6000K 'norm'), but they are far from being actually dark; [https://image.gsfc.nasa.gov/poetry/workbook/sunspot.html NASA says] that each sunspot on its own would glow orange, brighter than the Moon is when it is full (with a typically bright Sun illuminating it). So even in a completely sunspot-covered Sun, the Sun would still be brighter than the Moon ought to be, and far brighter than the dark-time Moon would become (possibly causing issues for nocturnal life, as well). It would be possible to see it (and see by it) even if the heat delivered were very low and even at noon it would seemn to be {{wiktionary|crepuscular}} by our normal expectations. See more in the title text explanation.

These problems are obviously not a serious threat in the reality of the comic, as the Sun is truly dark and yet people and natural systems have long survived these dark periods and adapted accordingly. This becomes clear in the title text where internet memes indicate that people lived fine through the dark periods, although they obviously did not 'properly' see the Sun, as kids, if they were born during the early start of a 'dark decade'.

The title text indicates the effect on internet memes that the special solar cycle has had. During the 2010s in our universe there were many '90s kid' memes. Those were also popular in this universe, but they reflect that the Earth had at that time been dark since the 2000s, and thus only those born in the 90s and before would remember dawn or the feeling of the warm sun on their faces.

This of course indicates that the Sun is actually dark and gives no warmth. Thus it is a mystery how life on Earth prevails, but given that there were kids from the 1990s that made memes twenty years after, life does work in this strange alternate universe.

==Transcript==
:[This comics shows two graphs, one also with several images of the Sun in different times in the solar cycle. The top graph is much larger than the bottom graph, and above them is a explanation of what the graphs shows:]
:Ever wonder why the sun disappears for about 10 years every other decade? This terrifying period of worldwide darkness is a natural consequence of the 11-year sunspot cycle:

:[A graph is shown with a label above the arrow on the Y-axis and a label written above the left part of the X-axis with an arrow pointing from it to the right (there is not arrow on the X-axis line). The graph shows a sine curve with a dashed line. It starts close to the bottom and then increases, then decreases before i finally slightly increases again. Above the dashed line are eight circles representing the sun with various levels of sunspots, with an arrow between each circle pointing to the next to the right. All circles are just above the dashed curve and the small arrows between them also follow the curvature of the line, so this string makes the same shape as the curve. along the eight representation of the sun there are five labels. The eight Suns will be described below with labels given when relevant.]
:Y-Axis: Sunspot number
:Y-Axis: Time

:[The first Sun's circle is completely white]

:[The second Sun's circle has a few sunspots. A label is written to the left of it:]
:Dark sunspots appear

:[The third Sun's circle has several sunspots. A label is written to the left of it:]
:Sunspot number rises

:[The fourth Sun's circle is half covered in sunspots.]

:[The fifth Sun's circle is mostly black with a few lines of white dots. Between the fourth and fifth circle is a label:]
:Number falls as sunspots merge.

:[The sixth Sun's circle is almost completely black with just a few small white spots. A label is written above it:]
:Sunspots envelop sun, Earth enters years of darkness.

:[The seventh Sun's circle is mostly black with a few light areas.]

:[The eighth Sun's circle is still mostly black but with some larger white areas. A label is written above and left of it:]
:Bright sunspots appear, cycle reverses.

:[Below is a second graph with a label written near the top of the Y-axis which is otherwise not labeled. The X-axis also has no label, but six years are written beneath at equal intervals. The graph shows a similar sine curve as the one above, but with almost five cycles shown. Also each cycle is not close to being a perfect sine curve, but has the property with a peak followed by a trough. The five troughs are labeled. The area beneath the curve alternates from being black and white when there is a trough, with the peak in between having several vertical lines, indicating transfer from black to white and vise versa. There are not same distance between peaks and there are also features on the graphs, for instance the two peaks in the middle has a drop, so they look like volcanoes. And the last full peak has a clear outlier year with many sunspots.]
:Label: History:
:X-axis labels: 1970 1980 1990 2000 2010 2020
:Through 1970-1980: Sun is bright
:Through 1980-1990: Sun is dark
:Through 1990-2000: Sun is bright
:Through 2000-2010: Sun is dark
:Through 2010-2020: Sun is bright

{{comic discussion}}

[[Category:Astronomy]]
[[Category:Timelines]]
[[Category:Line graphs]]
[[Category:Internet]]

2725: Sunspot Cycle

2023-01-17T16:28:16Z

Bigbillybass.:

{{comic
| number = 2725
| date = January 16, 2023
| title = Sunspot Cycle
| image = sunspot_cycle_2x.png
| imagesize = 740x50x
| noexpand = true
| titletext = Who can forget the early 2010s memes? 'You know you're a 90s kid if you remember the feeling of warm sunlight on your face.' 'Only 90s kids remember the dawn.'
}}

==Explanation==
{{incomplete|Created by a NINETIES KID WHO FELT SUN - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic is a reference to the {{w|solar cycle}}, which is a roughly 11-year cycle of changes in the Sun's activity from a period of minimal levels of various related phenomena ({{w|sunspots}}, solar radiation, ejecta, and solar flares) to one of maximum activity in these areas. As the cycle continues, the Sun returns to minimal activity and starts over. Without actually studying the Sun, however, there is no discernable difference to our daily lives here on Earth, and studying the Sun in enough detail is difficult due to its intrinsic and eye-damaging brightness whenever viewed directly.

This comics makes a joke that when the absolute number of sunspots appears to decrease it is not because they disappear, but because they get so crowded that they begin to merge, and thus the number of individual spots decreases whereas the area of the sun covered by sunspots continues to increase to near total 'darkness'. This causes there to be a completely dark Sun after 11 years, at which point any new sunspots are ''bright'' patches, and the next 11-year cycle repeats the process but accumulating bright spots until eventually it is all bright once more, giving a total bright/dark cycle of 22 years.

The curve showing the number of differentiable sunspots in this 22-year cycle would follow the curves for two whole cycles of our normal Sun, as the number of distinct spots (of either kind) decreases down to practically just one Sun-enveloping spot. The change in brightness over the cycle, however, repeats only over the full 22 years, darkening and then being made to shine bright once more as the other type of spot appears and begins to dominate once more.

Below is a graph showing the number of sunspots as a function of time from around 1965 to 2025. Periods where the sun is dark are shown with black under the curve, and in transition periods with lines of darkness getting closer together on the way to 'fully' dark area plus vals of light reinserting themselves in the lightening part of the cycle. Also for clarity the troughs are labeled with the sun being bright or dark. It is always when there are few spots that the sun is either completely free from spots and thus bright, or completely covered and thus dark. The maxima are always during the height of the transition between the two extremes, with a wide swathe of the time around the minima being mostly light or mostly dark, alternating at around a decade of each predominating.

At times, this closely synchronises with the calendar decades. From this curve it can be seen that the Sun was bright across the 1990s, but not in the dark 1980s or the dark time from around 2001 to 2014. This fact is mentioned in the title text (see below). Similarly the 1970s were mostly bright, after the largely dark 1960s, the width of the transition periods covering the marked decade-defining years in slightly offset ways compared to the neighbouring ones. After the darkness began around 2000, the shift was such that it finally got bright again around 2014, with darkness returning around 2024. This is because of the sunspot cycles being 11 years (making the illumination cycle 22 years) and eventually it no longer credibly meshes with the arbitrary decadal cut-offs.

All this would obviously be catastrophic if it happened in our version of the universe, as during a dark phase unsufficient light would be coming from the Sun, and the Earth could freeze if all the energy from the Sun was reduced. If the spots only affect light in the visible spectrum, then Earth would not freeze but plants would have trouble with photosynthesis and other natural processes would be interrupted. In our universe sunspots cool the area of the Sun where they appear, relative to the rest of the surface (50-75% of the nearly 6000K 'norm'), but they are far from being actually dark; [https://image.gsfc.nasa.gov/poetry/workbook/sunspot.html NASA says] that each sunspot on its own would glow orange, brighter than the Moon is when it is full (with a typically bright Sun illuminating it). So even in a completely sunspot-covered Sun, the Sun would still be brighter than the Moon ought to be, and far brighter than the dark-time Moon would become (possibly causing issues for nocturnal life, as well). It would be possible to see it (and see by it) even if the heat delivered were very low and even at noon it would seemn to be {{wiktionary|crepuscular}} by our normal expectations. See more in the title text explanation.

These problems are obviously not a serious threat in the reality of the comic, as the Sun is truly dark and yet people and natural systems have long survived these dark periods and adapted accordingly. This becomes clear in the title text where internet memes indicate that people lived fine through the dark periods, although they obviously did not 'properly' see the Sun, as kids, if they were born during the early start of a 'dark decade'.

The title text indicates the effect on internet memes that the special solar cycle has had. During the 2010s in our universe there were many '90s kid' memes. Those were also popular in this universe, but they reflect that the Earth had at that time been dark since the 2000s, and thus only those born in the 90s and before would remember dawn or the feeling of the warm sun on their faces.

This of course indicates that the Sun is actually dark and gives no warmth. Thus it is a mystery how life on Earth prevails, but given that there were kids from the 1990s that made memes twenty years after, life does work in this strange alternate universe.

==Transcript==
:[This comics shows two graphs, one also with several images of the Sun in different times in the solar cycle. The top graph is much larger than the bottom graph, and above them is a explanation of what the graphs shows:]
:Ever wonder why the sun disappears for about 10 years every other decade? This terrifying period of worldwide darkness is a natural consequence of the 11-year sunspot cycle:

:[A graph is shown with a label above the arrow on the Y-axis and a label written above the left part of the X-axis with an arrow pointing from it to the right (there is not arrow on the X-axis line). The graph shows a sine curve with a dashed line. It starts close to the bottom and then increases, then decreases before i finally slightly increases again. Above the dashed line are eight circles representing the sun with various levels of sunspots, with an arrow between each circle pointing to the next to the right. All circles are just above the dashed curve and the small arrows between them also follow the curvature of the line, so this string makes the same shape as the curve. along the eight representation of the sun there are five labels. The eight Suns will be described below with labels given when relevant.]
:Y-Axis: Sunspot number
:Y-Axis: Time

:[The first Sun's circle is completely white]

:[The second Sun's circle has a few sunspots. A label is written to the left of it:]
:Dark sunspots appear

:[The third Sun's circle has several sunspots. A label is written to the left of it:]
:Sunspot number rises

:[The fourth Sun's circle is half covered in sunspots.]

:[The fifth Sun's circle is mostly black with a few lines of white dots. Between the fourth and fifth circle is a label:]
:Number falls as sunspots merge.

:[The sixth Sun's circle is almost completely black with just a few small white spots. A label is written above it:]
:Sunspots envelop sun, Earth enters years of darkness.

:[The seventh Sun's circle is mostly black with a few light areas.]

:[The eighth Sun's circle is still mostly black but with some larger white areas. A label is written above and left of it:]
:Bright sunspots appear, cycle reverses.

:[Below is a second graph with a label written near the top of the Y-axis which is otherwise not labeled. The X-axis also has no label, but six years are written beneath at equal intervals. The graph shows a similar sine curve as the one above, but with almost five cycles shown. Also each cycle is not close to being a perfect sine curve, but has the property with a peak followed by a trough. The five troughs are labeled. The area beneath the curve alternates from being black and white when there is a trough, with the peak in between having several vertical lines, indicating transfer from black to white and vise versa. There are not same distance between peaks and there are also features on the graphs, for instance the two peaks in the middle has a drop, so they look like volcanoes. And the last full peak has a clear outlier year with many sunspots.]
:Label: History:
:X-axis labels: 1970 1980 1990 2000 2010 2020
:Through 1970-1980: Sun is bright
:Through 1980-1990: Sun is dark
:Through 1990-2000: Sun is bright
:Through 2000-2010: Sun is dark
:Through 2010-2020: Sun is bright

{{comic discussion}}

[[Category:Astronomy]]
[[Category:Timelines]]
[[Category:Line graphs]]
[[Category:Internet]]