explain xkcd - User contributions [en]

3036: Chess Zoo

2025-01-14T08:25:18Z

172.69.22.210: /* Explanation */

{{comic
| number = 3036
| date = January 10, 2025
| title = Chess Zoo
| before = [[#Explanation|↓ Skip to explanation ↓]]
| image = chess_zoo_2x.png
| imagesize = 740x1221px
| noexpand = true
| titletext = The zoo takes special care to keep kings separated from opposite-color pieces as part of their conservation program to prevent mating in captivity.
}}

==Explanation==
{{incomplete|Need to move the image in the trivia inside the explanation in a smooth way. It's not trivial, it's useful for the explanation.}}
{{w|Zoo|Zoos}} are large encampments where various animals live in small enclosures. They're generally used as public exhibitions for amusement and education and as safe spaces for rescued and endangered animals. Many modern zoos deliberately allow different types of animals to mingle and interact, finding that it promotes enrichment and well-being. Naturally, in such cases, the zoo needs to be designed so that incompatible species (such as predators and prey) aren't allowed to interact, and good designs will allow animals space for rest and privacy when needed.

[[Randall]] has here created a zoo for giant {{w|chess}} pieces, as if they were animals. He treats the different pieces as if they were different species and designs the enclosures to allow interactions between different species, but prevents the possibility of one piece capturing another (which is treated as analogous to one animal attacking another), as well as of escape. In the [[#Trivia|Trivia]] section a color version of the zoo shows where different types of pieces can move. The zoo is almost completely horizontally symmetrical from top to bottom with black pieces on the top and white pieces on the bottom. The only place that isn't completely symmetrical is the entrances to the bishop enclosures.

There are many subtle "jokes" in the image that play on how chess pieces move:
* Bishops can only move diagonally. Enclosures containing them do not have diagonal walls or corners which would allow them to slip out, and orthogonal portals into their enclosures are only one square wide and at least two squares long so that they can't get through. One bishop enclosure even has a portal open to the visiting people, letting it serve as a {{w|petting zoo}}. Opposing bishops can safely mingle as long as they are on opposite colors, since a bishop can never move to a square of the opposite color than the one on which it currently stands. This is enforced by these mingling enclosures only having two openings, each on opposite colored squares (i.e. an enclosure only has an opening for black pieces on white squares and one for white pieces on black squares).
* Knights move in an "L" shape (two squares along one orthogonal direction, then one more square in a perpendicular direction), leaping over other pieces and presumably walls. The walls of their enclosures have been designed to prevent escape by placing blocks where they would land if they leapt over the wall, or using double-thick walls. They can also be blocked by the same portals that block bishops, although they would need to be four blocks long instead of two.
* Rooks can only move along ranks and files. They have free roam of several enclosures, though diagonal walls are able to stop them, preventing them from accessing the center mingling bishops.
* Queens and kings can move along ranks and files as well as diagonally, so their enclosures must have the same precautions as would be required for both bishops and rooks.
* Pawns can only move forward (or diagonally forward when capturing), but upon reaching the final rank (the opponent's back rank), they are "promoted," becoming a knight, bishop, rook, or queen. The pawns are in a double-walled enclosure with no doors to prevent escape after promotion. It is unclear what would happen to the pawns after they are promoted. Would they remain in the "pawn" enclosure or moved to their new enclosure according to their new piece type is unclear. Also unclear is how the pawns would be repopulated if all of them were to be promoted, leaving the pawn enclosure devoid of pawns. It appears that the pawns promoting is part of the zoo's attractions as mentioned in the Banner for the black pawns' enclosure that says: SHH! PAWNS PROMOTING.
* A special feature of the enclosure, mentioned in the caption, is that there is at least one room for every type of pieces where other pieces cannot enter (except the king is always in a room with the queens). This means that even though some of the pieces can mingle with some of the other pieces they can also always retreat to a room where the other pieces cannot disturb them. For instance the top and bottom room with rooks can not be entered by any other type of pieces. In the two rooms right above and below the middle room, the bishops of the same color have their personal room. And also the two rooms to the right where black and white bishops co-exist on different colors, cannot be entered by any other type. (This is of course needed, since else there could be captures). The pawns have their own rooms top and bottom right. The knights have a separate room from which they can jump out to the rooms with either rooks or king/queens, but no other piece can enter their personal space to the left. And the king and his queens can retreat top or bottom left where the knights cannot enter. No piece can encounter all the others (even of the same color) but all pieces can meet at least one other type of pieces, the pawns though only after promotion. But they could not meet a king. This is similar to real zoos where separate enclosures are designed to be accessible only to one species (for example, through an opening too small for one of the species to pass through), allowing animals control over their interactions.

There are a couple of "interaction" areas that could have been built into the zoo design while preventing piece capture or escape but have not. There is no reason bishops and knights of the same color couldn't occupy the same enclosure, so long as there are adequate walls to prevent knights from escaping their enclosure. Additionally, it would be possible to allow visitor access to the white-bishop-on-black and black-bishop-on-white enclosure, as well as allow visitor access to the knight enclosures, however it is not apparent whether this is a priority of the zoo.

Every visitor of the zoo is depicted as centered on a single square occupied only by themselves, just like a chess piece. This could perhaps imply an entire chess board "world", where humans and chess pieces coexist as separate species, both aligned to the grid.

The title text contains a pun on the word 'mating'. The phrase "mating in captivity" is typically used to refer to animals in zoos copulating, hopefully producing offspring. This is typically done for species that are endangered (in hopes of reintroducing them to the wild, and in the meantime maintaining a healthy population of their own), but in the relatively safe and nurturing environment of the zoo could become problematic if allowed to happen without a certain degree of planning. In a conservation program, much thought may be put to how to avoid inbreeding, overpopulation and social stresses amongst the animals (as well as the problems of feeding and housing all the offspring), and so males and females may be given limited and highly curated access to each other, strictly according to the identified breeding requirements.

In the context of chess, "mating" means delivering an attack from which the opponent's king cannot escape, thereby winning the game. Unlike captive breeding programs, "mating" in in this sense, would presumably eliminate a piece (or an entire side), rather than creating additional animals, and therefore is undesirable. To prevent this from occurring, kings are not kept in the same enclosure as any piece of an opposing color. In fact, only opposing bishops on opposite colors are shown as unallied co-residents of an enclosure, in this zoo, thanks to their particular method of wall-free separation.

==Transcript==
:[A large panel is shown. It contains what appear to be a chessboard, but it is much larger than the usual 8x8=64 chess board squares. But it is divided into squares that are alternatingly white or gray. In the part shown 29x43 = 1247 squares are visible. Although for the outer rows and columns only less than half of each square there can be seen, so only 27x41 = 1107 squares are fully shown. On the "board" there are many details. Above the panel there is a large caption with a caption giving an explanation:]
:<big><big>Chess Zoo</big></big>
:<big>Designed to give different types of pieces their own enclosures while letting them interact as much as possible without allowing captures</big>

:[Upon the board there has been drawn an enclosure by drawing black squares on the white/gray squares. These black squares are smaller than the underlying squares but centered on the middle of their square. The outer parts of this enclosure covers 25x39 = 975 squares. It is not an entire rectangle of the black squares, but the top, the right side and bottom is a full line of 25, 39 and 25 black squares. The left line is only a normal line for the top and bottom 6 squares. Then for the next 12 rows (top or bottom), the "solid" line is moved one step in (to the right) and only on every second row is here a black square on the outer line. Above this there is a gap of 5 squares without black squares on either of the two left most squares (and 7 rows in a row with no black squares on the outer most line). This created a section inside the enclosure connected directly to the outside, but this part is still closed off, with black squares forming walls on this inner section, that closes it off from the rest of the enclosure.]

:[Inside this enclosure there are many other squares that have the black squares on top forming several rooms that are either closed of from other rooms or connected in some places. And on the white and gray squares that do not have black squares in top, there may bee drawn chess pieces or humans on them.]

:[The top part of the image has enclosures for black chess pieces and the bottom for white ones. Smaller black squares form enclosures around the chess pieces while the characters are outside of them. In the middle of the image, to the right, there are black and white bishops next to each other on squares of opposite colors. Humans are only on the outside of the enclosure, mainly above (eight) and below (six) with only three to the right. The the left people can stand either outside normal (three), or inside one of the indentations (two). But they can also walk into the open part and there are nine inside like this.]

:[Banner on top of smaller black squares on the top right, above an enclosure with a knight and four pawns:]
:Banner: ''Shh! Pawns promoting.''

:[Jill near the center, standing in front of Blondie and pointing forward:]
:Jill: Look, mommy! Bishops!

===Detailed description===
:[The humans outside the actual part of the enclosure are listed here, and the rooms they are looking into are also described:]

:[Top row from the left: Over the fifth black square a boy with what appears to be a cap. Next to him Hairbun. Two squares over Cueball. They look into the blacks King and Queens only section. There are four queens in this room and the king. One of the Queens are on her way down a hall to a room below, with a fifth queen and a knight. Over black square 14 there is another Cueball next to Hairy looking into the black rook only section. There are three rooks, one of which is moving in a hall to the room below. Over black square 19 is White Hat and two squares on Danish next to Ponytail looking into the black pawns only section, the two women over the banner. One of the pawns has promoted into a knight four others are still on their way to promote. This room has double thickness walls with two black squares all the way around.]

:[Down the right side from the top: To the right of black square 12 from the top another Cueball looking into the blacks bishops only section with three bishops, two on gray squares and one on a white square. To the right of black square 26 from the top another White Hat and another Hairy are looking into the white bishops only section with two bishops both on white squares. Above this room is a room with both white and black bishops, with the three white bishops on gray squares and the three black bishops on white squares.]

:[Bottom row from the right: Under the fourth black square from the right another Cueball looking into the White pawns only section, there are three pawns, none of them has promoted, bu their is also no banner- This room also has double thickness walls. Under the tenth black square to the 13th are four people in a row, from the right, another White Hat, another Hairy, another Hair Bun and another Cueball. They look into the white rooks only section. There are four rooks, one of them on the way into a hall towards the room above. Under the 21st black square from the right Megan is looking into the white King and Queens only section. There are three Queens with the King. A fourth queen is in a room above, where she is together with a knight.]

:[Up the left side from the bottom: The the left of black square three from the bottom another Hairy is looking into the white King and Queens only section. The seventh black square from the bottom it moved on space to the right. In the hole left there another Cueball is standing so he can see the passage where the white King and Queen can move into a room where also white knights can be, and there is one knight and one queen. To the left of outer wall 27 squares up, is Blondie, she is standing in the normal row left of the wall, but at a place where there is an indentation, so she is not next to the nearest black square. Se looks into the black knights only section with only one knight present. Four squares above her another Ponytail is standing in an indentation in the wall looking into the room where the black King and Queens can be together with the black knights, there is a queen and a knight. Four squares above this another Hairy is seen. He seems to have turned away from the wall walking to the left, so he is not looking into the black King and Queens only section behind him.]

:[The opening into the enclosure from the left to the end: Three squares in at the bottom over a black square one higher than the nearest another Megan walks to the right, next to her another Cueball walks the same way, he is not directly over a black square. And one further left below in one if the indentations another Ponytail. They are all above the white knights only section, with only one knight present. Above the first of the two Cueball's at the top of the opening in an indentation is Knit Cap looking into the black knights only section. At the bottom four squares further in than Ponytail is a person standing in an indentation with very large hair looking into a room where both white knights and rooks can be together, one of each is present. One further square in but two above him is another Blondie and next to her Jill pointing at the room with white and black bishops together, as she calls out. This room is the one where they are on their own color square, three white on white and three black on gray squares. Above them is the room where both black knight and black rooks can be together, with three knights and one rook. One square further in and one below them is another Cueball looking in to a section only accessible to white rooks next to the bishops room. There is one rook there. But below this part of the room it opens up and has both white rooks (3) and white bishops (5) with three bishops on white and two on gray squares. A similar room is above these last three persons with a black rook in the near part not accessible to bishops but then black rooks (1) and black bishops (3) can be together in the rest of that room. All bishops on gray squares.]

:[In total there are 9 Cueballs, 5 Hairys, 3 White Hats, 3 Ponytails, 2 Megans, 2 Hairbuns, 2 Blondies, 1 Knit Cap, 1 Danish, 1 Jill, 1 kid with a cap, 1 man with lots of hair, for a total of 31 humans.]

:[In total there are the following black pieces 1 king, 5 queens, 6 knights (one a promoted pawn), 5 rooks, 11 bishops and 4 pawns (together with the promoted knight). A total of 32 black pieces. There are the following white pieces: 1 king, 4 queens, 3 knights, 9 rooks, 13 bishops and 3 pawns for a total of 33 white pieces. 65 pieces in all. Similar number of each type of pieces as there are humans, 31, 32 and 33 for a total of 96 squares occupied by something that are "alive".]

===Visual-aspects-reliant representation of the comic===
:[Layout (H is a human; # is a smaller black square; chess pieces on the top half are black and below that white, unless otherwise noted):]
HH H HH H HH
#########################
# # #########
# Q Q # R ## ##
# K # R##P P##
H# #Q# Q##### ## P ##
### ### #R## P ##
## ###### # ## N ##
### # ##### # #########
H# Q # #### # ########
### N# ##### # #
# # R B # #
####### #### # B B#H
H # # N N## B R# #
### N # ## B# B #
# # ## # # # #
### # #N# ### ###B## ####
########### # B# B#
#H# # # # #R# # #
##B # B # [White bishops]
H HH B # B # [Black bishops]
HH H## B # B # [Left bishop: white, right bishop: black]
# #H# #H# # # B # B B#
########### R# # #
### # # # ### ## #### ###
# N# ## # #B # #
### # ##R R #B #H
# # ## R B # #H
####### R#### # B #
# # BB# #
###QN # N ##### B # #
# # #### # ########
### # ##### # #########
H## ###### # ## ##
### ### # ##P ##
# # # #####R## ##
# K Q# ## P P##
H# Q # RR ## ##
# Q # R #########
#########################
H HHHH H

==Trivia==
*User [[User:D5xtgr|D5xtgr]] made the [https://pasteboard.co/64VsBMA5af8l.png following depiction] of the board with colors showing which rooms the different pieces can enter by mixing colors.
**It was uploaded here with help, as D5xtgr could not at the time upload files:
[[File:3636 Chezz Zoo-with colors.png]]
*This is a version of xkcd 3036 "Chess Zoo" with partially-transparent coloured overlays illustrating the range of movement each piece has. Warm colours (red, brown, orange, yellow) are used for the black pieces, and cool colours (blue, teal , cyan, green) for the white pieces to show contrast. Because some regions are accessible to multiple pieces, these overlays overlap in places, producing colours that are combination or mixture of the originals.
**The text taken from the page where the original image was posted.
*Jake Ouellette made an [https://cadencecode.com/play/zooofchess interactive simulation of the chess zoo], which has several more jokes embedded in it.
{{comic discussion}}

[[Category:Large drawings]]
[[Category:Chess]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics featuring Blondie]]
[[Category:Comics featuring Jill]]
[[Category:Comics featuring Knit Cap]]
[[Category:Comics featuring Danish]]
[[Category:Multiple Cueballs]]

Talk:2853: Redshift

2023-11-12T06:57:24Z

172.69.22.210: ?

Does it make any sense to try and relate the two Z values to a more "normal" time? [[User:MAP|MAP]] ([[User talk:MAP|talk]]) 21:08, 10 November 2023 (UTC)

I have added exactly that, using `astropy.cosmology` for the calculations [[User:Juandesant|Juandesant]] ([[User talk:Juandesant|talk]]) 21:16, 10 November 2023 (UTC)

There is a big error in the current explanation, saying it means they were interested in this since the early universe, but that would only be true if the z value was much closer to 1. I'm not exactly sure as I haven't done the math, but with that many decimal places of zero's it is probably near enough history to be during their lifetime. So the joke isn't being interested in the early universe since the early universe, but rather so interested in it that they talk about other things with the same terminology.--[[Special:Contributions/172.70.126.142|172.70.126.142]] 21:18, 10 November 2023 (UTC)

Why aren't these values expressed in scientific notation? Separately, do they make sense logarithmically? [[User:JohnHawkinson|JohnHawkinson]] ([[User talk:JohnHawkinson|talk]]) 07:12, 11 November 2023 (UTC)
:Part of the joke is that the values are unwieldy to use compared to everyday language and units. The scientific notation would have lessened this. However they are given in a universal standard time instead of some solar system or human related units, so they generally should be clearly preferred. Sebastian --[[Special:Contributions/172.68.110.188|172.68.110.188]] 15:37, 11 November 2023 (UTC)

I feel like the Earth's gravitational field would affect the answer as z goes to zero? [[Special:Contributions/172.69.22.210|172.69.22.210]] 06:57, 12 November 2023 (UTC)

2599: Spacecraft Debris Odds Ratio

2023-11-04T03:50:04Z

172.69.22.210: /* Explanation */

{{comic
| number = 2599
| date = March 28, 2022
| title = Spacecraft Debris Odds Ratio
| image = spacecraft_debris_odds_ratio.png
| titletext = You say this daily walk will reduce my risk of death from cardiovascular disease by 30%, but also increase my risk of death by bear attack by 300%? That's a 280% increased! I'm not a sucker; I'm staying inside.
}}

==Explanation==
This comic is a misunderstanding of statistics very similar to that of [[1252: Increased Risk]]. It suggests that going outside for more than 5 hours per day significantly increases your risk of head injury from falling spacecraft, and advises to limit outside activity to avoid this risk.

The data are apparently based on a {{w|Monte Carlo Method|Monte Carlo simulation}}, a computational method that uses input values randomly drawn from a given distribution and which repeats that calculation many times; the distribution of the outputs is then analyzed. This method is used to determine the possible outcomes (and their respective probabilities) for a given scenario. Basically, instead of doing hard math to calculate the outcomes you let a computer repeat the scenario for a huge number of different input values and watch what happens.
In this case, the study might have consisted of defining the baseline probability of spacecraft debris falling from the sky in a given time frame (say, 1% every minute) as well as the probability that it is heavy enough to break through the roof (say, also 1%), translating this to the output of a random number generator (e.g. "1" means "space debris falls in direction of head and can break through the roof", 2-100 means "space debris falls in direction of head but can't go through a roof" and values 101-10000 mean "no danger from space debris"), adding another random number generator to simulate the distributions for "person is outside X hours of the day", then drawing numbers repeatedly from both distributions and calculating the outcome for each instance.

Doing a Monte Carlo simulation for a hypothetical and rare scenario like this can make sense: it is so rare for humans to be struck by spacecraft debris that an absurdly large sample size, involving tens of millions of participants over several decades, would be necessary to obtain significant experimental data.
However, the statistical analysis and presentation of the data is horribly misleading and sensationalizing. The comic essentially pokes fun at the way that data can be misrepresented and exaggerated using an example that people would realize is absurdly unlikely.

The results are presented not as an overall probability but rather as an {{w|Odds_ratio|odds ratio}} of the probabilities. The odds ratio is defined as p(A happens in presence of B)/p(A happens in absence of B), which here would be p(space debris head injury after Xh spent outside and 24-Xh inside)/p(space debris head injury after 24h spent inside). The resulting value tells you how much more likely an outcome becomes if you do (or have) A. E.g. the bottom line of the graph in the comic means that spending 11+ hours outside will make it 3 times as likely to get a head injury from space debris compared to not being outside at all.
However, while odds ratios can be useful they tend to hide the scale of a probability - e.g. 0.00000000002%/0.00000000001% = 2, the outcome became twice as likely but the probability only rose by 0.00000000001%. And since the odds of being hit in the head by (any part of) a falling spacecraft are [https://www.livescience.com/33511-falling-nasa-satellite-uars-risk.html astronomically ([[559: No Pun Intended |no pun intended]]) low to begin with], even quadrupling it still results in a negligible probability.

The choice of hour brackets instead of a linear time scale is suspicious. Monte Carlo simulations involve a huge number of computations; the scientists should have more than enough data to plot the odds ratio for every additional hour spent outside. Moreover, each hour bracket has a different size - why didn't they use a regular binning like e.g. 1-3, 4-6, 7-9, 10-12? One might suspect that they wanted to conceal inconsistencies and that the underlying data points by themselves don't look nearly as convincing.
Moreover, range-based groups of any kind should never be analyzed as if they were independent categories. Spending 5 hours outside is not intrinsically different from spending 1 hour outside - the 5-hour-mark (presumably) doesn't suddenly turn humans into space-debris magnets. The likelihood of space debris falling down at any given moment stays the same and the cumulative (i.e. summed-up) probability should increase at a constant rate. Instead of comparing every hour bracket to the same baseline reference, each should each be compared to the next-lowest value.

The error bars (the lines extending from the points in the graph) are HUGE compared to the effect they measured. Error bars define the range in which the true value might be - here, for 2-4 hours the true value could be an increase by 2, or a small DEcrease of the probability.

[[1429: Data|The data]] are shown on a [[1162: Log Scale|log scale]]. Logarithmic scales are used when you have both very small and very large values and want to depict their relative differences in a single plot without making the small values look like zero or cutting off the large values. The data shown here do not have huge differences - there is no good reason for using a log scale. However, the log scale is conveniently chosen to make the error bars look like they have the same length. They do not. The error bar for the last data point is actually twice as large as that for the first data point.

The title text continues the misuse of statistics by insinuating that a 30% decrease of cardiovascular disease resulting from going outside (and exercising) is outweighed by a simultaneous 300% increase of risk of being killed by a bear. As shown in [[1102: Fastest-Growing]], the percentage increase/decrease alone of something has little meaning; the context of the original size is needed to evaluate how impressive the change really is. And in this case, the probability of dying from a cardiovascular disease is much, MUCH higher than the probability of being attacked and killed by a bear, so the moderate decrease of the former has much more impact on one's overall life expectancy than even a huge increase of the latter (unless you live in an area that has many bears, in which case your best bet is to take appropriate precautions rather than to never go outside at all).

The "280% increase" of the title text is also an error, though perhaps not for reasons you might assume at first glance (the correct calculation is not "300% − 30% = 270%"). To "increase by 300%" means to add 300% on top of the original 100% (=400%, so multiplied by 4), while to "decrease by 30%" means to remove 30% from the original 100% (=70%, so multiplied by 0.7). Combining these (which is very very wrong!) would mean multiplying by both, for an overall change of 4.0 × 0.7 = 2.8, or 280%. However, this should be read as an increase ''to'' 280% of its old value, not ''by'' 280% (you started at 100% and added 180%). But this is a very, very wrong way of doing the math because these are probabilities of very different things with very different scales (if you threw out 30% of your dishware but in that same period also acquired 3 toothpicks on top of your original 1 toothpick, would you say that your kitchen stuff increased by 180%?). The correct way of combining the two probabilities would be to translate them onto the same scale - the overall chance of death - which would be done by multiplying each value with its probability of happening at all. For example, if the chance of dying from cardiovascular disease was 50% and the chance of being killed by a bear was 0.1%, the overall chance of dying from either would be the sum, 50.1%. Both probabilities are affected by going outside; the new chances are now 50%*0.7=35% and 0.1%*4=0.4% and the combined chance of dying from either is now 35.4% - a significant DEcrease from the original 50.1%.

The specific reference to falling spacecraft is likely inspired by events happening around the time of this comics release (March 2022). Around a month before this was posted, the head of the Russian space agency, {{w|Roscosmos}}, warned that sanctions against Russia (mostly those over the {{w|2022 Russian invasion of Ukraine}}) could result in the {{w|International Space Station}} crashing. Since the Russian section of the space station is the one that provides propulsion (although it is built to rely on the power generated by the other sections), this was taken seriously and as of when this was posted, {{w|NASA}} was trying to come up with alternative stabilization strategies in case the situation worsened. There was also a recent [https://www-uol-com-br.translate.goog/tilt/noticias/redacao/2022/03/17/parte-do-foguete-spacex-e-encontrada-por-morador-do-pr.htm?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=pt-BR&_x_tr_pto=wapp report] of some 600 kg space rocket debris found in Brazil.

==Transcript==
:[A chart is shown. Above the chart there is a heading, with a subheading below it:]
:Odds ratio for head injuries from falling spacecraft debris
:<small>(Monte Carlo Simulation)</small>

:[The chart is rectangular with the X-axis labels above the chart with numbers from 1 to 5. These are places over vertical lines. The first at 1 is black, the other four are light gray. There are three smaller light gray ticks between each set of lines, and one on either side of the first and last. The distance between lines gets smaller and smaller towards the right, probably logarithmic.]
:X-axis: 1 2 3 4 5

:[The Y-axis is not scaled; there are no ticks or lines. Instead it just gives five labels from top to bottom. Above those labels there is an arrow pointing to the top one with a label above explaining the axis.]
:Hours spent outdoors per day
:Y-axis:
::0 (ref)
::1
::2-4
::5-10
::11+

:[Aligned with each of these five divisions of the Y-axis there is a dot. The top one is placed on the solid line under 1 as a reference point. The other four dots all have long error bars, with the dots at the center of these. The second dot is a bit to the left of the solid line, with the error bar going almost to the left edge of the graph and halfway to the first light gray line to the right. The third dot is located halfway between the solid and the first light gray line with the error bar just crossing the solid line, and almost reaching the gray line. The fourth dot is about a third way between the first and second of the gray lines, with the error bar crossing both these lines. The fifth and last dot is just past the second gray line, with the error bar crossing both that, going more than half toward the first gray line, and also just past the third gray line. On the same height as the two bottom dots, there are asterisks just right of the edge of the graph.]
:<nowiki>*</nowiki>
:<nowiki>*</nowiki>

:[Below the panel there is a caption:]
:Our new study suggests that spending more than 5 hours outside significantly increases your risk of head injury from spacecraft debris, so try to limit outdoor activities to 4 hours or less.

==Trivia==
*In the [https://www.explainxkcd.com/wiki/images/archive/d/d5/20220329223238%21spacecraft_debris_odds_ratio.png original version] of the comic, the Y-axis label said "Hours spent outdoors", but the comic was later changed to specify "Hours spent outdoors ''per day''", which makes more sense. When the updated image was uploaded, it had a much larger size than normal, because Randall posted the same file for both the normal "double size" image and the "regular" size. This had happened before with [[2576: Control Group]], see that comic's [[2576: Control Group#Trivia|trivia section]]. This resulted in the problem that the comic broke the boundaries on [https://xkcd.com xkcd.com].
*This comic's title text ("That's a 280% increased") has a typo.

{{comic discussion}}

[[Category:Charts]]
[[Category:Statistics]]
[[Category:Space]]
[[Category:Animals]] 
[[Category:Comics edited after their publication]]

Talk:2845: Extinction Mechanisms

2023-10-24T10:30:51Z

172.69.22.210:

-Hello, I'm a Christian that has done research to be intellectually fulfiled, and I would just want to say that I did not know that paleontologists were having trouble with this problem. A general Christian solution is that Noah's Flood, combined with the aftermath being much cooler, was the cause of the dinosaur extinction. Also, before you hate on me, I'm not trying to correct anyone, or be offensive. I just thought I'd share my thoughts on this and add another theory to the mix. This is my second time posting a comment, so sorry if I did something wrong or something. Also, I know there's a comic that "debunks" this, but there seems to have been more evidence and research done since then. Also, the biggest help to me has been ''The Case for A Creator'' by Lee Strobel. [[User:Azerty99|Azerty99]] ([[User talk:Azerty99|talk]]) 15:17, 23 October 2023 (UTC)

:Reading a book (or even many books) is not research. Science means you're never absolutely sure about anything. You're only relatively certain until contradictory proof of the currently theory (or theories) exists. This is not a weakness, but exactly the strength of the scientific method. If you have significant and non-controvertible proof that men and dinosaurs existed at the same time, I'll tentatively accept your ideas. Until then, it's all just bunk. [[Special:Contributions/162.158.197.151|162.158.197.151]] 15:32, 23 October 2023 (UTC)

:Paleontologists are not having an issue with this. It is merely the premise for the comic. The available evidence vastly points to the extinction of the non avian dinosaurs ~66 million years ago. Of course the scientific community always welcomes new evidence to evaluate and see if it leads to a different conclusion or modification of the current consensus.

:It's a troll folks, treat it with the contempt it deserves. [[Special:Contributions/172.69.43.240|172.69.43.240]] 19:09, 23 October 2023 (UTC)

One obvious type of hole was not discussed. The Acme Portable Hole™ is an entirely different class of holes as extensively demonstrated in (this)[https://en.wikipedia.org/wiki/Wile_E._Coyote_and_the_Road_Runner] documentation.

-Ok, thanks for the comments in return! And thanks for not being extremely rude! Here's one article that shows several bio-organic materials that should have decayed if in the situations they were in for -66 million years. https://genesisapologetics.com/faqs/dinosaurs-lived-recently-and-died-in-noahs-flood/ Also, can I see the evidence shown in the second comic? I would like to see all this evidence. Also, I wasn't aware that scientific ideas shown in xkcd that were heavily implied to be true were false. That sounds a bit rude, but usually xkcd
gives funny interpretations of actual problems, like all the ones about COVID, or the Heartbleed Bug. Also, I'm not a troll. I'm willing to debate as long as people aren't saying things like "Science says" and equivocal stuff, and shows evidence instead of just giving vague statements. Thanks! [[User:Azerty99|Azerty99]] ([[User talk:Azerty99|talk]]) 22:25, 23 October 2023 (UTC)
:There's little disagreement that an asteroid striking the Yucatan around 66 mya caused or was a significant contributor to the extinction of the dinosaurs, but there are multiple (not necessarily mutually exclusive) hypotheses about what exact mechanisms had the biggest effects.
:It's like finding a body with nineteen bullet wounds. The detectives will have to piece together the evidence and come to tentative conclusions about what kind of gun was used, from how far away, whether the body was moved after the shooting, whether the victim died immediately or after some time, etc. But until someone finds something major that suggests otherwise, "death by shooting" is going to have to remain the working theory. [[Special:Contributions/172.69.247.41|172.69.247.41]] 23:09, 23 October 2023 (UTC)

-That analogy makes almost perfect sense, except there's a pretty big difference between finding 19 bullet holes in a man and concluding "death by shooting" and thinking that a meteor caused extinction because fossils were found in rocks that could be from the time that the meteor struck. Also, assuming that the mechanisms shown in the comic that are crossed out have been shown to not be possible, then what evidence is there that the meteor was the cause at all besides the correlation of the meteor impact and the extinction time? Does the correlation imply causation? Also, the theory of the meteor assumes the time of the extinction of the dinosaurs, which, while excepted by the majority of scientists, has been called into question.
:Ah, you figured it out. The extinction of the dinosaurs must have caused the meteor impact. The crossed-out mechanisms have '''not''' been ruled out; they're the leading hypotheses. That's the whole joke. Whoosh! There's plenty of evidence to conclude that the meteor was the cause of the mass extinctions. I don't see the need to provide you with them - they can be easily found. But you're not really interested in learning about evidence that could falsify your beliefs; you're fighting tooth and nail against anything that contradicts your preconceived conclusion. --[[Special:Contributions/172.69.34.140|172.69.34.140]] 07:25, 24 October 2023 (UTC)
:well dinosaur fossils are found below the cretaceous-paleogene boundary and not found above, so the major groups (excluding birds) most likely died out around that exact period; it contains a large amount of iridium, which is common in asteroids and there would be a low chance that there would be any other method to deposit iridium worldwide. its age can also be estimated using radiometric dating which puts it at around 66 mya (66.043 ± 0.011 mya to be exact) [[Special:Contributions/172.69.134.181|172.69.134.181]] 00:47, 24 October 2023 (UTC)
:XKCD is a webcomic that often derives humor from science. However, it is not a reliable source of information.{{Citation needed}} Consider the various "phone ideas" comics that present phones with "features" that are absurd or impossible. The "crossing out" of the hypotheses in the comic should not be taken as an indication that these hypotheses have been discredited. The comic presents the hypothesis that a meteor broke into pieces, all of equal volume, that struck each square meter of the Earth's surface, and hit each dinosaur individually. I'm reasonably confident that that is physically impossible, but the comic lists this hypothesis together with some of the current leading hypotheses and shows those leading hypotheses crossed-out and describing this alternative hypothesis as "obvious." There idea that this alternative hypothesis is in any way comparable to the others listed, or has any legitimacy, is absurd to the point of being laughable, and thus funny. Regarding the apparently preserved tissue found in summer fossils, I found this interesting link: [https://web.archive.org/web/20221202184025/https://www.uwstout.edu/about-us/news-center/researchers-identify-mechanisms-blood-vessel-preservation-t-rex-dinosaur Researchers identify mechanisms of blood vessel preservation in a T. rex dinosaur]--[[Special:Contributions/172.69.22.210|172.69.22.210]] 10:30, 24 October 2023 (UTC)

-While Noah's Flood was likely an actual event, it would not have been worldwide. Christianity originated in ancient Rome, which is near the Mediterranean Sea, and it is likely that after the last Ice Age, the sea levels rose, and the Atlantic Ocean flooded through what is now the Strait of Gibraltar, creating the Mediterranean Sea. Although this was not a worldwide flood, to the people living in the affected area, it would have seemed as such. [[User:Unknown User|Unknown User]] ([[User talk:Unknown User|talk]]) 01:00, 24 October 2023 (UTC)Unknown User

- Issues with Noah’s flood. 1. If it was worldwide and lasted 40 days, all the salty ocean water would have contaminated all fresh water on earth. This would have killed all fresh water fish within minutes or hours. Yet we have fresh water fish. Maybe in the millennia since fish have evolved the ability to survive in fresh water again? 2. The math shows that it would take 3-4 times the current amount of water to cover the earth worldwide. Where did all that water go? It’s not on earth now. We would be aware of that. The math ain’t mathing.

What the meteor does, looks like a cluster bomb. BTW does one like to do the math for the meteor falling apart into pieces of 1l and those being randomly distributed. What is the expected value of dinosaurs of various area sizes being hit? Sebastian --[[Special:Contributions/162.158.94.219|162.158.94.219]] 07:59, 24 October 2023 (UTC)