https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=130.225.98.201&feedformat=atomexplain xkcd - User contributions [en]2024-03-29T00:24:51ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=Talk:1279:_Reverse_Identity_Theft&diff=50824Talk:1279: Reverse Identity Theft2013-10-18T09:04:57Z<p>130.225.98.201: +</p>
<hr />
<div>My first attempt at an explanation. I have actually received emails designed for someone else because we had the same name and the sender missed a crucial difference between my email address and the intended recipient. [[User:Grahame|Grahame]] ([[User talk:Grahame|talk]]) 05:39, 18 October 2013 (UTC)Grahame<br />
<br />
AFAIK if you have adress name@gmail.com, then gmail delivers all mails in shape name+anything@gmail.com to your box. So the trick is to make address like J@gmail.com, then heavily use J+Brown@gmail.com to the point, that other people catch up an for example Joe Smith instead correct Smith@gmail.com will write J+Smith@gmail.com - which would end in your mailbox then. {{unsigned ip|89.176.232.253}}<br />
<br />
:Good explanation, except gmail only allowes usernames between 6 and 30 characters (and doesn't allow + in username). I would assume that this was true even before this strip and it's not so hard to verify, so Randal probably speaks about addresses like JoeSmith@gmail.com being mistakenly used by other Joe Smiths. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 08:55, 18 October 2013 (UTC)<br />
<br />
I don't get this. When you're creating an account, every e-mail service provider checks to see if the username is available, and only lets you create an account if your username's unique. This kind of issue can happen if you then go around and enter a wrong e-mail ID whenever you sign up for something, or if the company automatically assumes an e-mail ID without asking you (I don't think the latter happens). It shouldn't matter if a provider (GMail for instance) ignores everything after a certain character (+) while determining recepient, or even if it ignores an entire character (.) - all this should've been taken care of when you signed up in the first place. [[Special:Contributions/220.224.246.97|220.224.246.97]] 08:50, 18 October 2013 (UTC)<br />
<br />
:Exactly, it's about entering wrong e-mail ID. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 08:55, 18 October 2013 (UTC)<br />
<br />
I'm pretty sure the "+" in the comic refers to a simple concatenation of first initial and last name (e.g., <code>rmunroe@gmail.com</code>), not a literal <code>+</code> character (as in <code>r+munroe@gmail.com</code>). [[Special:Contributions/130.225.98.201|130.225.98.201]] 09:04, 18 October 2013 (UTC)</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1276:_Angular_Size&diff=504251276: Angular Size2013-10-11T15:53:55Z<p>130.225.98.201: /* Explanation */ more link fixes</p>
<hr />
<div>{{comic<br />
| number = 1276<br />
| date = October 11, 2013<br />
| title = Angular Size<br />
| image = angular size.png<br />
| titletext = If the celestial sphere were mapped to the Earth's surface, astronomy would get a LOT easier; you'd just need a magnifying glass.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete}}<br />
This comic is a comparison of the sizes of celestial objects when they are measured on earth's surface as shown under the title, and the sizes of everyday objects actually on earth. London's {{w|M25 motorway}} is around 60 km (35 miles) across, a {{w|soccer field}} is about 100 meters long, a {{w|Table tennis table|ping pong table}} is 274 centimeters long, a {{w|laptop}} is about 35 centimeters across (this one resembles an [http://www.apple.com/macbook-pro/ Apple MacBook Pro], the {{w|tilde}} symbol on a keyboard is about 5 millimeters long, and a cell of ''{{w|Escherichia coli|E. coli}}'' is about 2 micrometers long.<br />
<br />
A simple {{w|Intercept theorem|formula}} can be used to find the size on earth of a celestial object when the size of and distance to the object is known. This is done by taking the radius of the earth, multiplying by the diameter of the object, and dividing by the distance to the object from the center of the earth.<br />
<br />
The space objects referenced in the panels are:<br />
<br />
* The {{w|Sun}} and the {{w|Moon}} have approximately the same size (around 0.5 degrees of arc) when seen from the Earth.<br />
<br />
* {{w|Mercury (planet)|Mercury}}, {{w|Venus}}, {{w|Mars}}, {{w|Jupiter}}, {{w|Saturn}}, {{w|Uranus}}, and {{w|Neptune}} are the other planets of the {{w|Solar System}}.<br />
<br />
* {{w|Io (moon)|Io}}, {{w|Europa (moon)|Europa}}, {{w|Ganymede (moon)|Ganymede}}, and {{w|Callisto (moon)|Callisto}} are the main moons of Jupiter; {{w|Titan (moon)|Titan}} is the largest moon of Saturn; and {{w|Triton (moon)|Triton}} is the largest moon of Neptune. {{w|Ceres (dwarf planet)|Ceres}} and {{w|Pluto}} are {{w|dwarf planet}}s.<br />
<br />
* {{w|Phobos (moon)|Phobos}} and {{w|Deimos (moon)|Deimos}} are the moons of Mars. {{w|Eris (dwarf planet)|Eris}} is another dwarf planet. {{w|R Doradus}} and {{w|Betelgeuse}} are giant stars, respectively around 180 and 640 light-years away.<br />
<br />
* {{w|4942 Munroe}} is an asteroid [http://blog.xkcd.com/2013/09/30/asteroid-4942-munroe/ named] after xkcd author [[Randall]] Munroe. {{w|Proxima Centauri}}, {{W|Alpha Centauri|Alpha Centauri AB}}, {{w|Barnard's star}} and {{w|Sirius}} are nearby stars (all within 10 light-years from the Sun).<br />
<br />
* {{w|HD 189733 b}}, {{w|Gliese 581 b}}, {{w|Gliese 667 Cc}}, {{w|82 G. Eridani#Planetary_system|HD 20794 c}}, {{w|Tau Ceti#Planets|Tau Ceti c}}, and {{w|KOI-1686.01}} are {{w|extrasolar planet}}s; the parenthetical names are references to the comic [[1253: Exoplanet Names]].<br />
<br />
* {{w|Voyager 1}} and {{w|Voyager 2|2}} are space probes launched in 1977, and currently around 125 and 100 {{w|astronomical unit}}s away, respectively.<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Astronomy]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1276:_Angular_Size&diff=504231276: Angular Size2013-10-11T15:52:04Z<p>130.225.98.201: /* Explanation */ link fixes</p>
<hr />
<div>{{comic<br />
| number = 1276<br />
| date = October 11, 2013<br />
| title = Angular Size<br />
| image = angular size.png<br />
| titletext = If the celestial sphere were mapped to the Earth's surface, astronomy would get a LOT easier; you'd just need a magnifying glass.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete}}<br />
This comic is a comparison of the sizes of celestial objects when they are measured on earth's surface as shown under the title, and the sizes of everyday objects actually on earth. London's {{w|M25 motorway}} is around 60 km (35 miles) across, a {{w|soccer field}} is about 100 meters long, a {{w|Table tennis table|ping pong table}} is 274 centimeters long, a {{w|laptop}} is about 35 centimeters across (this one resembles an [http://www.apple.com/macbook-pro/ Apple MacBook Pro], the {{w|tilde}} symbol on a keyboard is about 5 millimeters long, and a cell of ''{{w|Escherichia coli|E. coli}}'' is about 2 micrometers long.<br />
<br />
A simple {{w|Intercept theorem|formula}} can be used to find the size on earth of a celestial object when the size of and distance to the object is known. This is done by taking the radius of the earth, multiplying by the diameter of the object, and dividing by the distance to the object from the center of the earth.<br />
<br />
The space objects referenced in the panels are:<br />
<br />
* The {{w|Sun}} and the {{w|Moon}} have approximately the same size (around 0.5 degrees of arc) when seen from the Earth.<br />
<br />
* {{w|Mercury (planet)|Mercury}}, {{w|Venus}}, {{w|Mars}}, {{w|Jupiter}}, {{w|Saturn}}, {{w|Uranus}}, and {{w|Neptune}} are the other planets of the {{w|Solar System}}.<br />
<br />
* {{w|Io (moon)|Io}}, {{w|Europa (moon)|Europa}}, {{w|Ganymede (moon)|Ganymede}}, and {{w|Callisto (moon)|Callisto}} are the main moons of Jupiter; {{w|Titan (moon)|Titan}} is the largest moon of Saturn; and {{w|Triton (moon)|Triton}} is the largest moon of Neptune. {{w|Ceres (dwarf planet)|Ceres}} and {{w|Pluto}} are {{w|dwarf planet}}s.<br />
<br />
* {{w|Phobos}} and {{w|Deimos}} are the moons of Mars. {{w|Eris (dwarf planet)|Eris}} is another dwarf planet. {{w|R Doradus}} and {{w|Betelgeuse}} are giant stars, respectively around 180 and 640 light-years away.<br />
<br />
* {{w|4942 Munroe}} is an asteroid [http://blog.xkcd.com/2013/09/30/asteroid-4942-munroe/ named] after xkcd author [[Randall]] Munroe. {{w|Proxima Centauri}}, {{W|Alpha Centauri|Alpha Centauri AB}}, {{w|Barnard's star}} and {{w|Sirius}} are nearby stars (all within 10 light-years from the Sun).<br />
<br />
* {{w|HD 189733 b}}, {{w|Gliese 581 b}}, {{w|Gliese 667 Cc}}, {{w|82 G. Eridani#Planetary_system|HD 20794 c}}, {{w|Tau Ceti#Planets|Tau Ceti c}}, and {{w|KOI-1686.01}} are {{w|extrasolar planet}}s; the parenthetical names are references to the comic [[1253: Exoplanet Names]].<br />
<br />
* {{w|Voyager 1}} and {{w|Voyager 2|2}} are space probes launched in 1977, and currently around 125 and 100 {{w|astronomical unit}}s away, respectively.<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Astronomy]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1276:_Angular_Size&diff=504221276: Angular Size2013-10-11T15:43:59Z<p>130.225.98.201: /* Explanation */ Voyagers</p>
<hr />
<div>{{comic<br />
| number = 1276<br />
| date = October 11, 2013<br />
| title = Angular Size<br />
| image = angular size.png<br />
| titletext = If the celestial sphere were mapped to the Earth's surface, astronomy would get a LOT easier; you'd just need a magnifying glass.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete}}<br />
This comic is a comparison of the sizes of celestial objects when they are measured on earth's surface as shown under the title, and the sizes of everyday objects actually on earth. London's {{w|M25 motorway}} is around 60 km (35 miles) across, a {{w|soccer field}} is about 100 meters long, a {{w|Table tennis table|ping pong table}} is 274 centimeters long, a {{w|laptop}} is about 35 centimeters across (this one resembles an [http://www.apple.com/macbook-pro/ Apple MacBook Pro], the {{w|tilde}} symbol on a keyboard is about 5 millimeters long, and a cell of ''{{w|Escherichia coli|E. coli}}'' is about 2 micrometers long.<br />
<br />
A simple {{w|Intercept theorem|formula}} can be used to find the size on earth of a celestial object when the size of and distance to the object is known. This is done by taking the radius of the earth, multiplying by the diameter of the object, and dividing by the distance to the object from the center of the earth.<br />
<br />
The space objects referenced in the panels are:<br />
<br />
* The {{w|Sun}} and the {{w|Moon}} have approximately the same size (around 0.5 degrees of arc) when seen from the Earth.<br />
<br />
* {{w|Mercury (planet)|Mercury}}, {{w|Venus}}, {{w|Mars}}, {{w|Jupiter}}, {{w|Saturn}}, {{w|Uranus}}, and {{w|Neptune}} are the other planets of the {{w|Solar System}}.<br />
<br />
* {{w|Io (moon)|Io}}, {{w|Europa (moon)|Europa}}, {{w|Ganymede}}, and {{w|Calisto}} are the main moons of Jupiter; {{w|Titan (moon)|Titan}} is the largest moon of Saturn; and {{w|Triton (moon)|Triton}} is the largest moon of Neptune. {{w|Ceres (dwarf planet)|Ceres}} and {{w|Pluto (dwarf planet)|Pluto}} are {{w|dwarf planet}}s.<br />
<br />
* {{w|Phobos}} and {{w|Deimos}} are the moons of Mars. {{w|Eris (dwarf planet)|Eris}} is another dwarf planet. {{w|R Doradus}} and {{w|Betelgeuse}} are giant stars, respectively around 180 and 640 light-years away.<br />
<br />
* {{w|4942 Munroe}} is an asteroid [http://blog.xkcd.com/2013/09/30/asteroid-4942-munroe/ named] after xkcd author [[Randall]] Munroe. {{w|Proxima Centauri}}, {{W|Alpha Centauri|Alpha Centauri AB}}, {{w|Barnard's star}} and {{w|Sirius}} are nearby stars (all within 10 light-years from the Sun).<br />
<br />
* {{w|HD 189733 b}}, {{w|Gliese 581 b}}, {{w|Gliese 667 Cc}}, {{w|82 G. Eridani#Planetary_system|HD 20794 c}}, {{w|Tau Ceti#Planets|Tau Ceti c}}, and {{w|KOI-1686.01}} are {{w|extrasolar planet}}s; the parenthetical names are references to the comic [[1253: Exoplanet Names]].<br />
<br />
* {{w|Voyager 1}} and {{w|Voyager 2|2}} are space probes launched in 1977, and currently around 125 and 100 {{w|astronomical unit}}s away, respectively.<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Astronomy]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1276:_Angular_Size&diff=504211276: Angular Size2013-10-11T15:37:45Z<p>130.225.98.201: /* Explanation */ more</p>
<hr />
<div>{{comic<br />
| number = 1276<br />
| date = October 11, 2013<br />
| title = Angular Size<br />
| image = angular size.png<br />
| titletext = If the celestial sphere were mapped to the Earth's surface, astronomy would get a LOT easier; you'd just need a magnifying glass.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete}}<br />
This comic is a comparison of the sizes of celestial objects when they are measured on earth's surface as shown under the title, and the sizes of everyday objects actually on earth. London's {{w|M25 motorway}} is around 60 km (35 miles) across, a {{w|soccer field}} is about 100 meters long, a {{w|Table tennis table|ping pong table}} is 274 centimeters long, a {{w|laptop}} is about 35 centimeters across (this one resembles an [http://www.apple.com/macbook-pro/ Apple MacBook Pro], the {{w|tilde}} symbol on a keyboard is about 5 millimeters long, and a cell of ''{{w|Escherichia coli|E. coli}}'' is about 2 micrometers long.<br />
<br />
A simple {{w|Intercept theorem|formula}} can be used to find the size on earth of a celestial object when the size of and distance to the object is known. This is done by taking the radius of the earth, multiplying by the diameter of the object, and dividing by the distance to the object from the center of the earth.<br />
<br />
The astronomical objects referenced in the panels are:<br />
<br />
* The {{w|Sun}} and the {{w|Moon}} have approximately the same size (around 0.5 degrees of arc) when seen from the Earth.<br />
<br />
* {{w|Mercury (planet)|Mercury}}, {{w|Venus}}, {{w|Mars}}, {{w|Jupiter}}, {{w|Saturn}}, {{w|Uranus}}, and {{w|Neptune}} are the other planets of the {{w|Solar System}}.<br />
<br />
* {{w|Io (moon)|Io}}, {{w|Europa (moon)|Europa}}, {{w|Ganymede}}, and {{w|Calisto}} are the main moons of Jupiter; {{w|Titan (moon)|Titan}} is the largest moon of Saturn; and {{w|Triton (moon)|Triton}} is the largest moon of Neptune. {{w|Ceres (dwarf planet)|Ceres}} and {{w|Pluto (dwarf planet)|Pluto}} are {{w|dwarf planet}}s.<br />
<br />
* {{w|Phobos}} and {{w|Deimos}} are the moons of Mars. {{w|Eris (dwarf planet)|Eris}} is another dwarf planet. {{w|R Doradus}} and {{w|Betelgeuse}} are giant stars, respectively around 180 and 640 light-years away.<br />
<br />
* {{w|4942 Munroe}} is an asteroid [http://blog.xkcd.com/2013/09/30/asteroid-4942-munroe/ named] after xkcd author [[Randall]] Munroe. {{w|Proxima Centauri}}, {{W|Alpha Centauri|Alpha Centauri AB}}, {{w|Barnard's star}} and {{w|Sirius}} are nearby stars (all within 10 light-years from the Sun).<br />
<br />
* {{w|HD 189733 b}}, {{w|Gliese 581 b}}, {{w|Gliese 667 Cc}}, {{w|82 G. Eridani#Planetary_system|HD 20794 c}}, {{w|Tau Ceti#Planets|Tau Ceti c}}, and {{w|KOI-1686.01}} are {{w|extrasolar planet}}s; the parenthetical names are references to the comic [[1253: Exoplanet Names]].<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Astronomy]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1276:_Angular_Size&diff=504181276: Angular Size2013-10-11T13:45:17Z<p>130.225.98.201: /* Explanation */ another panel</p>
<hr />
<div>{{comic<br />
| number = 1276<br />
| date = October 11, 2013<br />
| title = Angular Size<br />
| image = angular size.png<br />
| titletext = If the celestial sphere were mapped to the Earth's surface, astronomy would get a LOT easier; you'd just need a magnifying glass.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete}}<br />
This comic is a comparison of the sizes of celestial objects when they are measured on earth's surface as shown under the title, and the sizes of everyday objects actually on earth. London's {{w|M25 motorway}} is around 60 km (35 miles) across, a {{w|soccer field}} is about 100 meters long, a {{w|Table tennis table|ping pong table}} is 274 centimeters long, a {{w|laptop}} is about 35 centimeters across (this one resembles an [http://www.apple.com/macbook-pro/ Apple MacBook Pro], the {{w|tilde}} symbol on a keyboard is about 5 millimeters long, and a cell of ''{{w|Escherichia coli|E. coli}}'' is about 2 micrometers long.<br />
<br />
A simple {{w|Intercept theorem|formula}} can be used to find the size on earth of a celestial object when the size of and distance to the object is known. This is done by taking the radius of the earth, multiplying by the diameter of the object, and dividing by the distance to the object from the center of the earth.<br />
<br />
The astronomical objects referenced in the panels are:<br />
<br />
* The {{w|Sun}} and the {{w|Moon}} have approximately the same size (around 0.5 degrees of arc) when seen from the Earth.<br />
<br />
* {{w|Mercury (planet)|Mercury}}, {{w|Venus}}, {{w|Mars}}, {{w|Jupiter}}, {{w|Saturn}}, {{w|Uranus}}, and {{w|Neptune}} are the other planets of the {{w|Solar System}}.<br />
<br />
* {{w|Io (moon)|Io}}, {{w|Europa (moon)|Europa}}, {{w|Ganymede}}, and {{w|Calisto}} are the main moons of Jupiter; {{w|Titan (moon)|Titan}} is the largest moon of Saturn; and {{w|Triton (moon)|Triton}} is the largest moon of Neptune. {{w|Ceres (dwarf planet)|Ceres}} and {{w|Pluto (dwarf planet)|Pluto}} are {{w|dwarf planet}}s.<br />
<br />
* {{w|Phobos}} and {{w|Deimos}} are the moons of Mars. {{w|Eris (dwarf planet)|Eris}} is another dwarf planet. {{w|R Doradus}} and {{w|Betelgeuse}} are giant stars, respectively around 180 and 640 light years away.<br />
<br />
* {{w|4942 Munroe}} is an asteroid [http://blog.xkcd.com/2013/09/30/asteroid-4942-munroe/ named] after xkcd author [[Randall]] Munroe. {{w|Proxima Centauri}}, {{W|Alpha Centauri|Alpha Centauri AB}}, {{w|Barnard's star}} and {{w|Sirius}} are nearby stars (all within 10 light years from the Sun).<br />
<br />
* ...<br />
<br />
The parenthetical planet names in the "tilde" panel are references to the comic [[1253|Exoplanet Names]].<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Astronomy]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1276:_Angular_Size&diff=504161276: Angular Size2013-10-11T13:03:54Z<p>130.225.98.201: /* Explanation */ another panel</p>
<hr />
<div>{{comic<br />
| number = 1276<br />
| date = October 11, 2013<br />
| title = Angular Size<br />
| image = angular size.png<br />
| titletext = If the celestial sphere were mapped to the Earth's surface, astronomy would get a LOT easier; you'd just need a magnifying glass.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete}}<br />
This comic is a comparison of the sizes of celestial objects when they are measured on earth's surface as shown under the title, and the sizes of everyday objects actually on earth. London's {{w|M25 motorway}} is around 60 km (35 miles) across, a {{w|soccer field}} is about 100 meters long, a {{w|Table tennis table|ping pong table}} is 274 centimeters long, a {{w|laptop}} is about 35 centimeters across (this one resembles an [http://www.apple.com/macbook-pro/ Apple MacBook Pro], the {{w|tilde}} symbol on a keyboard is about 5 millimeters long, and a cell of ''{{w|Escherichia coli|E. coli}}'' is about 2 micrometers long.<br />
<br />
A simple {{w|Intercept theorem|formula}} can be used to find the size on earth of a celestial object when the size of and distance to the object is known. This is done by taking the radius of the earth, multiplying by the diameter of the object, and dividing by the distance to the object from the center of the earth.<br />
<br />
The astronomical objects referenced in the panels are:<br />
<br />
* The {{w|Sun}} and the {{w|Moon}} have approximately the same size (around 0.5 degrees of arc) when seen from the Earth.<br />
<br />
* {{w|Mercury (planet)|Mercury}}, {{w|Venus}}, {{w|Mars}}, {{w|Jupiter}}, {{w|Saturn}}, {{w|Uranus}}, and {{w|Neptune}} are the other planets of the {{w|Solar System}}.<br />
<br />
* {{w|Io (moon)|Io}}, {{w|Europa (moon)|Europa}}, {{w|Ganymede}}, and {{w|Calisto}} are the main moons of Jupiter; {{w|Titan (moon)|Titan}} is the largest moon of Saturn; and {{w|Triton (moon)|Triton}} is the largest moon of Neptune. {{w|Ceres (dwarf planet)|Ceres}} and {{w|Pluto (dwarf planet)|Pluto}} are {{w|dwarf planet}}s.<br />
<br />
* {{w|Phobos}} and {{w|Deimos}} are the moons of Mars. {{w|Eris (dwarf planet)|Eris}} is another dwarf planet. {{w|R Doradus}} and {{w|Betelgeuse}} are giant stars, respectively around 180 and 640 light years away.<br />
<br />
* {{w|4942 Munroe}} is an asteroid [http://blog.xkcd.com/2013/09/30/asteroid-4942-munroe/ named] after xkcd author [[Randall]] Munroe.<br />
<br />
* ...<br />
<br />
The parenthetical planet names in the "tilde" panel are references to the comic [[1253|Exoplanet Names]].<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Astronomy]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1276:_Angular_Size&diff=504151276: Angular Size2013-10-11T12:54:52Z<p>130.225.98.201: start wikirefs for the other astronomical objects</p>
<hr />
<div>{{comic<br />
| number = 1276<br />
| date = October 11, 2013<br />
| title = Angular Size<br />
| image = angular size.png<br />
| titletext = If the celestial sphere were mapped to the Earth's surface, astronomy would get a LOT easier; you'd just need a magnifying glass.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete}}<br />
This comic is a comparison of the sizes of celestial objects when they are measured on earth's surface as shown under the title, and the sizes of everyday objects actually on earth. London's {{w|M25 motorway}} is around 60 km (35 miles) across, a {{w|soccer field}} is about 100 meters long, a {{w|Table tennis table|ping pong table}} is 274 centimeters long, a {{w|laptop}} is about 35 centimeters across (this one resembles an [http://www.apple.com/macbook-pro/ Apple MacBook Pro], the {{w|tilde}} symbol on a keyboard is about 5 millimeters long, and a cell of ''{{w|Escherichia coli|E. coli}}'' is about 2 micrometers long.<br />
<br />
A simple {{w|Intercept theorem|formula}} can be used to find the size on earth of a celestial object when the size of and distance to the object is known. This is done by taking the radius of the earth, multiplying by the diameter of the object, and dividing by the distance to the object from the center of the earth.<br />
<br />
The astronomical objects referenced in the panels are:<br />
<br />
* The {{w|Sun}} and the {{w|Moon}} have approximately the same size (around 0.5 degrees of arc) when seen from the Earth.<br />
<br />
* {{w|Mercury (planet)|Mercury}}, {{w|Venus}}, {{w|Mars}}, {{w|Jupiter}}, {{w|Saturn}}, {{w|Uranus}}, and {{w|Neptune}} are the other planets of the {{w|Solar System}}.<br />
<br />
* {{w|Io (moon)|Io}}, {{w|Europa (moon)|Europa}}, {{w|Ganymede}}, and {{w|Calisto}} are the main moons of Jupiter; {{w|Titan (moon)|Titan}} is the largest moon of Saturn; and {{w|Triton (moon)|Triton}} is the largest moon of Neptune. {{w|Ceres (dwarf planet)|Ceres}} and {{w|Pluto (dwarf planet)|Pluto}} are {{w|dwarf planet}}s.<br />
<br />
* ...<br />
<br />
* {{w|4942 Munroe}} is an asteroid [http://blog.xkcd.com/2013/09/30/asteroid-4942-munroe/ named] after xkcd author [[Randall]] Munroe.<br />
<br />
The parenthetical planet names in the "tilde" panel are references to the comic [[1253|Exoplanet Names]].<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Astronomy]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1276:_Angular_Size&diff=504011276: Angular Size2013-10-11T11:24:22Z<p>130.225.98.201: tweak</p>
<hr />
<div>{{comic<br />
| number = 1276<br />
| date = October 11, 2013<br />
| title = Angular Size<br />
| image = angular size.png<br />
| titletext = If the celestial sphere were mapped to the Earth's surface, astronomy would get a LOT easier; you'd just need a magnifying glass.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete}}<br />
This comic is a comparison of the sizes of celestial objects when they are measured on earth's surface as shown under the title, and the sizes of everyday objects actually on earth. London's {{w|M25 motorway}} is around 60 km (35 miles) across, a {{w|soccer field}} is about 100 meters long, a {{w|Table tennis table|ping pong table}} is 274 centimeters long, a {{w|laptop}} is about 35 centimeters across (this one resembles an [http://www.apple.com/macbook-pro/ Apple MacBook Pro], the {{w|tilde}} symbol on a keyboard is about 5 millimeters long, and a cell of ''{{w|Escherichia coli|E. coli}}'' is about 2 micrometers long.<br />
<br />
A simple formula can be used to find the size on earth of a celestial object when the size of and distance to the object is known. This is done by taking the radius of the earth, multiplying by the diameter of the object, and dividing by the distance to the object from the center of the earth.<br />
<br />
{{w|4942 Munroe}} is an asteroid [http://blog.xkcd.com/2013/09/30/asteroid-4942-munroe/ named] for xkcd author Randall Munroe.<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Astronomy]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1276:_Angular_Size&diff=503991276: Angular Size2013-10-11T11:20:04Z<p>130.225.98.201: /* Explanation */ linking tweaks</p>
<hr />
<div>{{comic<br />
| number = 1276<br />
| date = October 11, 2013<br />
| title = Angular Size<br />
| image = angular size.png<br />
| titletext = If the celestial sphere were mapped to the Earth's surface, astronomy would get a LOT easier; you'd just need a magnifying glass.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete}}<br />
This comic is a comparison of the sizes of celestial objects when they are measured on earth's surface as shown under the title, and the sizes of everyday objects actually on earth. London's {{w|M25 motorway}} is around 50 km (30 miles) across, a {{w|soccer field}} is about 100 meters long, a {{w|Table tennis table|ping pong table}} is 274 centimeters long, a {{w|laptop}} is about 35 centimeters across (this one resembles an [http://www.apple.com/macbook-pro/ Apple MacBook Pro], the {{w|tilde}} symbol on a keyboard is about 5 millimeters long, and a cell of ''{{w|Escherichia coli|E. coli}}'' is about 2 micrometers long.<br />
<br />
A simple formula can be used to find the size on earth of a celestial object when the size of and distance to the object is known. This is done by taking the radius of the earth, multiplying by the diameter of the object, and dividing by the distance to the object from the center of the earth.<br />
<br />
{{w|4942 Munroe}} is an asteroid [http://blog.xkcd.com/2013/09/30/asteroid-4942-munroe/ named] for xkcd author Randall Munroe.<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Astronomy]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1275:_int(pi)&diff=502731275: int(pi)2013-10-09T15:52:41Z<p>130.225.98.201: /* Explanation */ slightly better example, avoiding precision complication</p>
<hr />
<div>{{comic<br />
| number = 1275<br />
| date = October 9, 2013<br />
| title = int(pi)<br />
| image = int pi.png<br />
| titletext = If replacing all the '3's doesn't fix your code, remove the 4s, too, with 'ceiling(pi) / floor(pi) * pi * r^floor(pi)'. Mmm, floor pie.<br />
}}<br />
<br />
==Explanation==<br />
<br />
This comic tells a simple, deadpan joke: that the number "{{w|3 (number)|3}}" is cursed and thus should not be used in programming. [[Randall]] recommends that programmers instead use <code>int(pi)</code>, which means the {{w|integer}} part of {{w|pi}}, without the {{w|fractional part}}. Pi, an {{w|irrational number}}, has a value starting <code>3.14159...</code>, making <code>int(pi)</code> equal to 3.<br />
<br />
In the title text, Randall takes the joke a step further, suggesting the usage of {{w|floor and ceiling functions}}: <code>ceiling(pi)</code> would be pi rounded ''up'' to the next integer, which is {{w|4 (number)|4}}; and <code>floor(pi)</code> is pi rounded ''down'' to the next integer, which is 3. (Note that <code>int(n)</code> and <code>floor(n)</code> have the same value when <code>n</code> is greater or equal to zero. For values less than zero, <code>int(n)</code> is equal to <code>ceiling(n)</code>. And the function <code>round(n)</code> will either be equal to <code>floor(n)</code> or <code>ceiling(n)</code>.)<br />
<br />
The joke here plays off of the fact that the intricacies of programming are endlessly confusing, and that [[292|novice programmers are often told to simply not do certain things without any explanation]]. This includes, in particular, a general proscription against "{{w|Magic number (programming)#Unnamed numerical constants|magic numbers}}" in the code. A new coder often has no way of knowing when a number can be legitimately written literally, and when it should be introduced as a named constant, or even as a constant expression, such as <code>2^16-1</code> rather than <code>65535</code>. Randall takes this to an extreme here by suggesting that certain numbers could be inherently problematic, but the general idea is perfectly believable.<br />
<br />
The formula in the comic is for the {{w|Sphere#Enclosed_volume|volume of a sphere}}: 4/3*pi*r^3.<br />
<br />
<i>Mmm... Floor pie.</i> is a reference to Homer Simpson [http://www.youtube.com/watch?v=GnjzmdxTXGQ]<br />
<br />
See also {{w|Cargo cult programming}}.<br />
<br />
==Transcript==<br />
:volume(r) = (4/int(pi))*pi*r^int(pi)<br />
:Programming Tip: The number "3" is cursed. Avoid it.<br />
<br />
<br />
{{comic discussion}}<br />
[[Category:Programming]]<br />
[[Category:Math]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1275:_int(pi)&diff=502721275: int(pi)2013-10-09T15:43:17Z<p>130.225.98.201: tweak explanation, mention magic numbers</p>
<hr />
<div>{{comic<br />
| number = 1275<br />
| date = October 9, 2013<br />
| title = int(pi)<br />
| image = int pi.png<br />
| titletext = If replacing all the '3's doesn't fix your code, remove the 4s, too, with 'ceiling(pi) / floor(pi) * pi * r^floor(pi)'. Mmm, floor pie.<br />
}}<br />
<br />
==Explanation==<br />
<br />
This comic tells a simple, deadpan joke: that the number "{{w|3 (number)|3}}" is cursed and thus should not be used in programming. [[Randall]] recommends that programmers instead use <code>int(pi)</code>, which means the {{w|integer}} part of {{w|pi}}, without the {{w|fractional part}}. Pi, an {{w|irrational number}}, has a value starting <code>3.14159...</code>, making <code>int(pi)</code> equal to 3.<br />
<br />
In the title text, Randall takes the joke a step further, suggesting the usage of {{w|floor and ceiling functions}}: <code>ceiling(pi)</code> would be pi rounded ''up'' to the next integer, which is {{w|4 (number)|4}}; and <code>floor(pi)</code> is pi rounded ''down'' to the next integer, which is 3. (Note that <code>int(n)</code> and <code>floor(n)</code> have the same value when <code>n</code> is greater or equal to zero. For values less than zero, <code>int(n)</code> is equal to <code>ceiling(n)</code>. And the function <code>round(n)</code> will either be equal to <code>floor(n)</code> or <code>ceiling(n)</code>.)<br />
<br />
The joke here plays off of the fact that the intricacies of programming are endlessly confusing, and that [[292|novice programmers are often told to simply not do certain things without any explanation]]. This includes, in particular, a general proscription against "{{w|Magic number (programming)#Unnamed numerical constants|magic numbers}}" in the code. A new coder often has no way of knowing when a number can be legitimately written literally, and when it should be introduced as a named constant, or even as a constant expression, such as <code>sqrt(pi)</code> rather than <code>1.7724538509055159</code>. Randall takes this to an extreme here by suggesting that certain numbers could be inherently problematic, but the general idea is perfectly believable.<br />
<br />
The formula in the comic is for the {{w|Sphere#Enclosed_volume|volume of a sphere}}: 4/3*pi*r^3.<br />
<br />
<i>Mmm... Floor pie.</i> is a reference to Homer Simpson [http://www.youtube.com/watch?v=GnjzmdxTXGQ]<br />
<br />
See also {{w|Cargo cult programming}}.<br />
==Transcript==<br />
:volume(r) = (4/int(pi))*pi*r^int(pi)<br />
:Programming Tip: The number "3" is cursed. Avoid it.<br />
<br />
<br />
{{comic discussion}}<br />
[[Category:Programming]]<br />
[[Category:Math]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1259:_Bee_Orchid&diff=483881259: Bee Orchid2013-09-03T09:54:32Z<p>130.225.98.201: /* Explanation */ another wikilink</p>
<hr />
<div>{{comic<br />
| number = 1259<br />
| date = September 2, 2013<br />
| title = Bee Orchid<br />
| image = bee orchid.png<br />
| titletext = In sixty million years aliens will know humans only by a fuzzy clip of a woman in an Axe commercial.<br />
}}<br />
<br />
==Explanation==<br />
Megan is explaining the evolutionary [http://www.pbs.org/wgbh/evolution/library/01/1/l_011_02.html phenomenon] of mimicry of female insects which fools male insects into trying to mate with the flower ({{w|pseudocopulation}}). This causes the pollen of the flower to stick to the male bee, who may make the same mistake with another flower, allowing for pollination. <br />
<br />
This particular orchid mimicked the solitary bee ''{{w|Eucera}}'', which now only pollinates it in the Mediterranean (the bee isn't really extinct yet). This may eventually lead to the extinction of the orchid due to lack of reproduction. In most areas where it grows, the orchid is using a method of {{w|self-pollination}}, which can be detrimental to the genetic vitality of the species as it is a form of in-breeding.<br />
<br />
Photographs of ''{{w|Ophrys apifera}}'':<br />
<br />
[[File:Ophrys apifera flower1.jpg | x250px]] [[File:Bee orchids, Aller Brook Local Nature Reserve - geograph.org.uk - 833516.jpg | x250px]]<br />
<br />
Female ''Eucera (Synhaolonia)'' guarding nests (left) and male ''Eucera'' (right):<br />
<br />
[[File:Synhalonia_nest_1.jpg | x200px]] [[File:Apidae - Eucera sp. (male).JPG | x200px]]<br />
<br />
The title text makes the assumption that, in sixty million years, much like the ''Eucera'' has today, humans will become nearly or completely extinct, and the only remaining records for other forms of life to identify them by would be commercials for the {{w|Axe (brand)|Axe}} line of male grooming products (ads which, like the orchid, present an idealized female form to deceptively attract males).<br />
<br />
==Transcript==<br />
:[Megan and Beret Guy are walking through woods.]<br />
:Megan: There are these orchids whose flowers look like female bees. When males try to mate with them, they transfer pollen.<br />
:Megan, crouching near a flower: This orchid -- ''Ophrys apifera'' -- makes flowers, but no bees land on them because the bee it mimics went extinct long ago.<br />
:Megan: Without its partner, the orchid as resorted to self-pollinating, a last-ditch genetic strategy that only delays the inevitable. Nothing of the bee remains, but we know it existed from the shape of the flower.<br />
:[They continue walking.]<br />
:Megan: Its an idea of what the female bee looked like to the male bee...<br />
:Megan: ...as interpreted by a plant.<br />
:Beret Guy: Wow, so...<br />
:[painting of an orchid]<br />
:Beret Guy: ... The only memory of the bee is a painting.<br />
:Beret Guy [text in corner of painting, like an artist's signature]: By a dying flower.<br />
:[Beret Guy runs back to the flower and sits down]: I'll remember your bee, orchid. I'll remember you.<br />
:[Beret Guy runs in the direction of Megan, out of frame.]<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Beret Guy]]<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Comics with color]]<br />
[[Category:Biology]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=Talk:1259:_Bee_Orchid&diff=48387Talk:1259: Bee Orchid2013-09-03T08:52:30Z<p>130.225.98.201: r</p>
<hr />
<div>[[First]]! The act of telling someone not to jinx something causes the jinx you're trying to prevent. [[User:gijobarts|gijobarts]] ([[User Talk:gijobarts|talk]]) 07:02, 2 September 2013 (UTC)<br />
<br />
I had thought all the worker bees were female, and all the male "drones" stayed in the hives. The Wikipedia says that isn't true for all species. [[User:gijobarts|gijobarts]] ([[User Talk:gijobarts|talk]]) 07:15, 2 September 2013 (UTC)<br />
<br />
[https://en.wikipedia.org/w/index.php?title=Ophrys_apifera&oldid=571187022#Reproduction Wikipedia on the reproduction of Ophrys apifera]:<br />
:It is the only species of the genus Ophrys which preferentially practice self-pollination. The flowers are almost exclusively self-pollinating in the northern ranges of the plant's distribution, but pollination by the solitary bee Eucera occurs in the Mediterranean area. In this case the plant attracts these insects by producing a scent that mimics the scent of the female bee. In addition, the lip acts as a decoy as the male bee confuses it with a female. Pollen transfer occurs during the ensuing pseudocopulation.<br />
:Bees in the past have promoted the evolution of bee orchids. Male bees, over many generations of cumulative orchid evolution, have built up the bee-like shape through trying to copulate with flowers, and hence carrying pollen.<br />
[[User:gijobarts|gijobarts]] ([[User Talk:gijobarts|talk]]) 07:36, 2 September 2013 (UTC)<br />
<br />
:A colony of ophrys apifera was discovered a few months ago.[http://www.elperiodic.com/torrent/noticias/254352_serra-perenxisa-disfruta-categoria-microrreserva-flora.html (Spanish)]. Probably not related.<br />
:[http://www.nguoiduatin.vn/nhung-ky-hoa-di-thao-quai-la-nhat-the-gioi-a98176.html This page (Vietnamese)] has an excellent photo of an ophrys apifera, along with other strange-looking plants. You can see how it looks like bees in that photo. [[User:gijobarts|gijobarts]] ([[User Talk:gijobarts|talk]]) 07:50, 2 September 2013 (UTC)<br />
<br />
Was there once another bee that pollinated it in more areas, or did the eucera once populate more of the world, or has the flower expanded where the bee has not followed? [[User:gijobarts|gijobarts]] ([[User Talk:gijobarts|talk]]) 08:47, 2 September 2013 (UTC)<br />
:Eucera is common all over Europe. But only the Southern bees recognize the plant. It may be the northern plants started selecting for a different bee that went extinct, or Eucera got ahead of the arms race in Europe or that self-pollination is more effective for now or some other reason entirely. [[Special:Contributions/96.251.85.48|96.251.85.48]] 15:41, 2 September 2013 (UTC)<br />
<br />
The Axe body spray gag is particularly relevant, since the ad's depiction of a woman, like the flower, is another imitation of real females of a species meant to draw males of the species through deception. [[User:Nick Douglas|Nick Douglas]] ([[User talk:Nick Douglas|talk]]) 17:50, 2 September 2013 (UTC)<br />
:You are right, and the title text is still too descriptive. Give us a try.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 18:29, 2 September 2013 (UTC)<br />
<br />
Note that (as doubtless mentioned in the linked-to Wikipedia article, "Axe" is known as "Lynx" in the UK (at least). The same style of marketing campaign, however, with the partially homogonised Anglo-American (or even Worldwide) cultural references fighting it out with local variations in sensibilities and advertising law/regulation. Meaning that besides alternate product-shots and (sometimes) voiceovers, they do tend to have similar/identical action composition in their ads.<br />
<br />
Also, self-pollination is being described as "a form of in-breeding". I think making that "the ultimate form of in-breeding", or similar, would be more accurate. In-breeding generally is used to describe more marginal or "just beyond the limit" forms of incests (e.g. close cousins, in human cultures), up until sibling or parent/child genetic re-mixing, but only full parthenogenisis seems to be more 'extreme' (although arguably less dangerous, through its long-time 'practice', rather than being a step ''back'' from the more beneficial sexual reproduction methods that the self-fertilising organism generally will have had to make, like in this case). [[Special:Contributions/178.106.190.241|178.106.190.241]] 23:29, 2 September 2013 (UTC)<br />
<br />
This is the most touching cartoon he's ever done. [[Special:Contributions/72.10.216.205|72.10.216.205]] 02:35, 3 September 2013 (UTC)<br />
I have to agree with you there. [[Special:Contributions/115.70.105.180|115.70.105.180]] 07:41, 3 September 2013 (UTC)<br />
: Well, right up there with [[695: Spirit]], anyway. [[Special:Contributions/130.225.98.201|130.225.98.201]] 08:52, 3 September 2013 (UTC)</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1259:_Bee_Orchid&diff=483441259: Bee Orchid2013-09-02T16:32:18Z<p>130.225.98.201: formatting</p>
<hr />
<div>{{comic<br />
| number = 1259<br />
| date = September 2, 2013<br />
| title = Bee Orchid<br />
| image = bee orchid.png<br />
| titletext = In sixty million years aliens will know humans only by a fuzzy clip of a woman in an Axe commercial.<br />
}}<br />
<br />
==Explanation==<br />
Megan is explaining the evolutionary [http://www.pbs.org/wgbh/evolution/library/01/1/l_011_02.html phenomenon] of mimicry of female insects which fools male insects into trying to mate with the flower ({{w|pseudocopulation}}). This causes the pollen of the flower to stick to the male bee, who may make the same mistake with another flower, allowing for pollination. <br />
<br />
This particular orchid mimicked the solitary bee ''{{w|Eucera}}'', which now only pollinates it in the Mediterranean (the bee isn't really extinct yet). This may eventually lead to the extinction of the orchid due to lack of reproduction. In most areas where it grows, the orchid is using a method of {{w|self-pollination}}, which can be detrimental to the genetic vitality of the species as it is a form of in-breeding.<br />
<br />
Photographs of ''Ophrys apifera'':<br />
<br />
[[File:Ophrys apifera flower1.jpg | x250px]] [[File:Bee orchids, Aller Brook Local Nature Reserve - geograph.org.uk - 833516.jpg | x250px]]<br />
<br />
Female ''Eucera (Synhaolonia)'' guarding nests (left) and male ''Eucera'' (right):<br />
<br />
[[File:Synhalonia_nest_1.jpg | x200px]] [[File:Apidae - Eucera sp. (male).JPG | x200px]]<br />
<br />
The title text makes the assumption that, in sixty million years, much like the ''Eucera'' has today, humans will become nearly or completely extinct, and the only remaining records for other forms of life to identify them by would be commercials for the {{w|Axe (brand)|Axe}} line of male grooming products.<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
:[Megan and Beret Guy are walking through woods.]<br />
:Megan: There are these orchids whose flowers look like female bees. When males try to mate with them, they transfer pollen.<br />
:Megan, crouching near a flower: This orchid -- ''Ophrys apifera'' -- makes flowers, but no bees land on them because the bee it mimics went extinct long ago.<br />
:Megan: Without its partner, the orchid as resorted to self-pollinating, a last-ditch genetic strategy that only delays the inevitable. Nothing of the bee remains, but we know it existed from the shape of the flower.<br />
:[They continue walking.]<br />
:Megan: Its an idea of what the female bee looked like to the male bee...<br />
:Megan: ...as interpreted by a plant.<br />
:Beret Guy: Wow, so...<br />
:[painting of an orchid]<br />
:Beret Guy: ... The only memory of the bee is a painting.<br />
:Beret Guy [text in corner of painting, like an artist's signature]: By a dying flower.<br />
:[Beret Guy runs back to the flower and sits down]: I'll remember your bee, orchid. I'll remember you.<br />
:[Beret Guy runs in the direction of Megan, out of frame.]<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Beret Guy]]<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Comics with color]]<br />
[[Category:Biology]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1255:_Columbus&diff=473701255: Columbus2013-08-23T06:58:16Z<p>130.225.98.201: /* Explanation */ link earendil, too</p>
<hr />
<div>{{comic<br />
| number = 1255<br />
| date = August 23, 2013<br />
| title = Columbus<br />
| image = columbus.png<br />
| titletext = And thus was smallpox introduced into the previously Undying Lands.<br />
}}<br />
<br />
==Explanation==<br />
In the comic, [[White Hat]] tells children that Christopher Columbus knew the world was round, but that others believed it to be flat. It is widely believed that Columbus had difficulty getting sponsorship because potential backers believed the world was flat. However, this is a false narrative known as the {{w|Myth of the Flat Earth}}. Educated people in Columbus's time knew the world was round. He had difficulty getting sponsorship for various other reasons, including disagreements about the distance to Asia. Columbus estimated a lower distance than his contemporaries. In fact, as noted at {{w|Christopher Columbus#Geographical_considerations}}, Columbus was wrong about this.<br />
<br />
As White Hat begins his explanation, Megan objects, though not explaining why. White Hat continues, so Megan interrupts, saying that Columbus sailed above the waves to {{w|Valinor}} and the {{w|Undying Lands}}. Megan's story is an allusion to the {{w|Silmarillion}}, by {{w|J. R. R. Tolkien}}, part of {{w|The Lord of the Rings}} saga. Specifically, she references {{w|Eärendil|Eärendil the Mariner}}, the only mortal sailor to reach the Undying Lands, home of the Valar, and later gifted with one of the titular {{w|Silmaril}}s.<br />
<br />
The title text refers to the {{w|Smallpox#Human_history|transfer of small pox}} to North America by Europeans.<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
<!-- Include any categories below this line. --></div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1255:_Columbus&diff=473691255: Columbus2013-08-23T06:55:50Z<p>130.225.98.201: /* Explanation */ wikilink silmaril</p>
<hr />
<div>{{comic<br />
| number = 1255<br />
| date = August 23, 2013<br />
| title = Columbus<br />
| image = columbus.png<br />
| titletext = And thus was smallpox introduced into the previously Undying Lands.<br />
}}<br />
<br />
==Explanation==<br />
In the comic, [[White Hat]] tells children that Christopher Columbus knew the world was round, but that others believed it to be flat. It is widely believed that Columbus had difficulty getting sponsorship because potential backers believed the world was flat. However, this is a false narrative known as the {{w|Myth of the Flat Earth}}. Educated people in Columbus's time knew the world was round. He had difficulty getting sponsorship for various other reasons, including disagreements about the distance to Asia. Columbus estimated a lower distance than his contemporaries. In fact, as noted at {{w|Christopher Columbus#Geographical_considerations}}, Columbus was wrong about this.<br />
<br />
As White Hat begins his explanation, Megan objects, though not explaining why. White Hat continues, so Megan interrupts, saying that Columbus sailed above the waves to {{w|Valinor}} and the {{w|Undying Lands}}. Megan's story is an allusion to the {{w|Silmarillion}}, by {{w|J. R. R. Tolkien}}, part of {{w|The Lord of the Rings}} saga. Specifically, she references Eärendil the Mariner, the only mortal sailor to reach the Undying Lands, home of the Valar, and later gifted with one of the titular {{w|Silmaril}}s.<br />
<br />
The title text refers to the {{w|Smallpox#Human_history|transfer of small pox}} to North America by Europeans.<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
<!-- Include any categories below this line. --></div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1239:_Social_Media&diff=443041239: Social Media2013-07-19T11:00:58Z<p>130.225.98.201: /* Explanation */ linking, caps</p>
<hr />
<div>{{comic<br />
| number = 1239<br />
| date = July 17,2013<br />
| title = Social Media<br />
| image = social_media.png<br />
| titletext = The social media reaction to this asteroid announcement has been sharply negative. Care to respond?<br />
}}<br />
<br />
==Explanation==<br />
This comic parodies how people tend to focus on social networking. Specifically in the case of revolutions, social media is given a lot of weight, even in countries with limited internet access. A direct parallel is made to the so-called {{w|Twitter Revolution}}s.<br />
<br />
On {{w|Twitter}} you can send text messages at a maximum of 140 characters. This means that there could be not much content at a single post, but often many people ''follow'' the people doing this ''tweets''. People who are not on social media tend to react like [[Cueball]] and come to the conclusion that twitter makes press coverage more stupid, just because those messages lack of many essentials. Cueball is also surprised about the stupidity of trying to link social media to the orbit of the asteroid – social media obviously have no impact on the orbit of any space objects; those are entirely driving by physics and gravitational mechanics, and are not influenced by opinions on any media.<br />
<br />
The title text continues the joke. The negativity on Twitter concerning an earth bound asteroid has nothing to do with Twitter but rather with the negativity of wiping out life on earth in general. Again, undue weight is given to social media.<br />
<br />
==Transcript==<br />
:[Cueball at a press conference]<br />
:Cueball: NASA has confirmed that the asteroid is heading directly for us.<br />
:Cueball: ...Yes, a question?<br />
<br />
:Audience member 1: What role has social media played in this asteroid's orbit?<br />
<br />
:Cueball: *''sigh''*<br />
<br />
:Audience member 1: Has twitter changed the way we respond to asteroid threats?<br />
:Cueball: Well, it's made the press conference questions stupider.<br />
:Audience member 2: Fascinating!<br />
:Audience member 3: What about Facebook?<br />
<br />
==Trivia==<br />
The comic may also parody an actual interview [http://www.slate.com/blogs/future_tense/2013/02/12/deb_feyerick_to_bill_nye_is_asteroid_2012_da14_connected_to_global_warming.html Is asteroid 2012_DA14 connected to global warming] in which {{w|Bill Nye}} was asked if the approaching asteroid {{w|2012_DA14}} was a result of global warming.<br />
<br />
{{comic discussion}}<br />
<!-- Include any categories below this line. --><br />
<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Social networking]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1237:_QR_Code&diff=435561237: QR Code2013-07-12T07:30:14Z<p>130.225.98.201: /* Explanation */ partial rv self: xkcd self-link already covered in transcript</p>
<hr />
<div>{{comic<br />
| number = 1237<br />
| date = July 12, 2013<br />
| title = QR Code<br />
| image = qr code.png<br />
| titletext = Remember, the installer is watching the camera for the checksum it generated, so you have to scan it using your own phone.<br />
}}<br />
<br />
==Explanation==<br />
{{W|QR code}}s are a type of 2D barcode that can be scanned using mobile app on a smartphone. This comic illustrates a user installing a new mobile application that requires the smartphone to scan a QR code on its own screen. Even with two mirrors or a front-facing camera and mirror, most smartphones would be unable to simultaneously display the camera feed for the QR scanner and the QR code itself.<br />
<br />
Incidentally, the QR code in the comic contains a link to a nearly identical image with a slightly changed caption that reads "How to trap a webcomic reader in an infinite loop".<br />
<br />
==Transcript==<br />
:To continue installing,<br />
:[image of a QR code with link to http://xkcd.com/1237/scan/]<br />
:scan this code.<br />
:12<br />
:seconds remaining<br />
:How to freak out a mobile app user<br />
{{comic discussion}}</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1237:_QR_Code&diff=435551237: QR Code2013-07-12T07:29:27Z<p>130.225.98.201: /* Explanation */ linking</p>
<hr />
<div>{{comic<br />
| number = 1237<br />
| date = July 12, 2013<br />
| title = QR Code<br />
| image = qr code.png<br />
| titletext = Remember, the installer is watching the camera for the checksum it generated, so you have to scan it using your own phone.<br />
}}<br />
<br />
==Explanation==<br />
{{W|QR code}}s are a type of 2D barcode that can be scanned using mobile app on a smartphone. This comic illustrates a user installing a new mobile application that requires the smartphone to scan a QR code on its own screen. Even with two mirrors or a front-facing camera and mirror, most smartphones would be unable to simultaneously display the camera feed for the QR scanner and the QR code itself.<br />
<br />
Incidentally, the QR code in the comic contains a [http://xkcd.com/1237/scan/ link] to a nearly identical image with a slightly changed caption that reads "How to trap a webcomic reader in an infinite loop".<br />
<br />
==Transcript==<br />
:To continue installing,<br />
:[image of a QR code with link to http://xkcd.com/1237/scan/]<br />
:scan this code.<br />
:12<br />
:seconds remaining<br />
:How to freak out a mobile app user<br />
{{comic discussion}}</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1211:_Birds_and_Dinosaurs&diff=372621211: Birds and Dinosaurs2013-05-13T15:36:30Z<p>130.225.98.201: wikilink for ''F. peregrinus''; misc formatting tweaks</p>
<hr />
<div>{{comic<br />
| number = 1211<br />
| date = May 13, 2013<br />
| title = Birds and Dinosaurs<br />
| image = birds and dinosaurs.png<br />
| titletext = Sure, T. rex is closer in height to Stegosaurus than a sparrow. But that doesn't tell you much; 'Dinosaur Comics' author Ryan North is closer in height to certain dinosaurs than to the average human.<br />
}}<br />
<br />
==Explanation==<br />
{{w|Bird}}s are commonly considered to be a separate {{w|class (biology)|class}} of {{w|tetrapods}}. However, this classification is false according to {{w|phylogenetic taxonomy}}. Taking into account that birds developed around {{w|Late Jurassic|150 mio. years ago}} out of small {{w|theropod}} dinosaurs, birds are indeed the last representatives of the {{w|Archosauria|dinosaur clade}}. (This premise appeared also in comic [[867]].)<br />
<br />
This relation between birds and dinosaurs is depicted in the comic in a {{w|cladogram}} which shows that ''{{w|Tyrannosaurus rex}}'' is closer related to the common {{w|sparrow}} than to ''{{w|Stegosaurus}}''. Not only do the former share a phylogenetic branch, but ''T. rex'' also lived around 80 mio. years ''after'' ''Stegosaurus''. (In popular culture, the concurrence of both species is a widespread error.) ''T. rex'' is also much more alike to modern birds than to other dinosaurs in terms of physiognomy.<br />
<br />
The comic draws the conclusion that if birds must in fact be considered modern dinosaurs, the hunting practice of birds of prey (specifically, the {{w|Peregrine Falcon}}) is consequently a dinosaur fight. For an inveterate dinosaur aficionado like [[Randall]], this fact must make the modern world much more attractive.<br />
<br />
The line "This is a good world." could also possibly refer to a [http://www.youtube.com/watch?v=znxFrgql5dc famous scene] from the {{w|Serenity (Firefly episode)|pilot episode}} of the television series ''{{w|Firefly}}'' featuring two plastic dinosaurs in a somewhat philosophic dialogue. Randall is known to be a {{w|Browncoat}}, i.e., a fan of the series.<br />
<br />
The title text is a sidesweep to the webcomic [http://www.qwantz.com Dinosaur Comics] drawn by Ryan North, who stands 6" 6' (198 cm) tall. The title text of the May 13th Dinosaur Comics also refers to Randall and XKCD.<br />
<br />
==Transcript==<br />
:By any reasonable definition, ''T. rex'' is more closely related to sparrows than to ''Stegosaurus''.<br />
:[Diagram showing that ''Stegosaurus'' came earlier than ''T. rex'', along with it showing that ''T. rex'' came closer in time to sparrows. Evaluation criteria "separation by time", "phylogenetic distance" and "physical similarity" are highlighted in red.]<br />
:Birds aren't ''descended'' from dinosaurs, they ''are'' dinosaurs.<br />
:Which means that the fastest animal alive today is a small carnivorous dinosaur, ''Falco peregrinus''.<br />
:[A picture of two birds is shown.]<br />
:It preys mainly on other dinosaurs, which it strikes and kills in midair with its claws.<br />
:[In red:] This is a good world.<br />
<br />
{{comic discussion}}<br />
[[Category:Comics with color]]<br />
[[Category:Charts]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1209:_Encoding&diff=367931209: Encoding2013-05-10T06:53:40Z<p>130.225.98.201: /* Explanation */ minor fixes</p>
<hr />
<div>{{comic<br />
| number = 1209<br />
| date = May 8, 2013<br />
| title = Encoding<br />
| image = encoding.png<br />
| titletext = I don't see how; the C0 block is right there at the beginning.<br />
}}<br />
<br />
==Explanation==<br />
[[Cueball]] and [[Megan]] hired a skywriter to write some text provided in Unicode. {{w|Skywriting}} is using an airplane to write words in the sky with controlled releases of smoke. {{w|Unicode}} is a standard for encoding text which supports an incredible variety of characters and modifiers. An {{w|interrobang}} is a combination question mark and exclamation mark. A {{w|diacritic}} is any symbol added to a character, usually an accent mark being added to a letter. In Unicode, {{w|Combining character|combining diacritics}} are represented as separate characters, but are rendered graphically as modifications to the previous one. The request appears to be particularly strange, given that diacritics are supposed to go over ''letters'' and not punctuation marks.<br />
<br />
Apparently the skywriter got so confused about their instructions that he not only rendered the text incorrectly, but also lost control of the plane. The skywriter's errors and the phrase "Unicode support" play off the common issue of {{w|Mojibake|software rendering Unicode symbols incorrectly}}.<br />
<br />
The tooltip refers to the {{w|C0 and C1 control codes|C0 Block}}, the name for the first 32 character codes in either the ASCII or Unicode encodings, traditionally called "control characters". It is likely that Cueball is wondering how the plane could have lost control when the control characters are easily found.<br />
<br />
==Transcript==<br />
:[Cueball and Megan are holding two-way radios.]<br />
:Cueball talking into radio: "No, the combining diacritics go ''over'' the interrobang!"<br />
:Megan, with radio lowered: "Oh jeez, I think he's lost control."<br />
:The skywriter we hired has terrible Unicode support.<br />
<br />
{{comic discussion}}<br />
[[category:Comics featuring Cueball]]<br />
[[category:Comics featuring Megan]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1209:_Encoding&diff=366541209: Encoding2013-05-08T09:03:10Z<p>130.225.98.201: /* Explanation */ more detailed explanation + wikilinks</p>
<hr />
<div>{{comic<br />
| number = 1209<br />
| date = May 8, 2013<br />
| title = Encoding<br />
| image = encoding.png<br />
| titletext = I don't see how; the C0 block is right there at the beginning.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete}}<br />
[[Cueball]] and [[Megan]] hired a skywriter to write a text provided in Unicode. {{w|Skywriting}} is using a airplane to write words in the sky with controlled releases of smoke. {{w|Unicode}} is a standard for encoding text which supports an incredible variety of characters and modifiers. An {{w|interrobang}} is a combination question mark and exclamation mark. A {{w|diacritic}} is any symbol added to a character, usually an accent mark being added to a letter. In Unicode, {{w|Combining character|combining diacritics}} are represented as separate characters, but are rendered graphically as modifications to the previous one.<br />
<br />
Apparently the skywriter got so confused about their instructions that he not just rendered the text incorrectly, but lost control of the plane. The skywriter's errors and the phrase "Unicode support" play off the common issue of {{w|Mojibake|softwares rendering Unicode symbols incorrectly}}.<br />
<br />
The tooltip refers to the {{w|C0 and C1 control codes|C0 Block}}, the name for the first 32 character codes in either the ASCII or UNICODE encodings, traditionally called "control characters". It is likely that Cueball is wondering how the plane could have lost control when the control characters are easily found.<br />
<br />
==Transcript==<br />
:Cueball and Meagan are holding two-way radios.<br />
:Cueball talking into radio: "No, the combining diacritics go ''over'' the interrobang!<br />
:Meagan, with radio lowered: "Oh jeez, I think he's lost control."<br />
:The skywriter we hired has terrible Unicode support.<br />
<br />
{{comic discussion}}<br />
[[category:Comics featuring Cueball]]<br />
[[category:Comics featuring Megan]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1198:_Geologist&diff=333601198: Geologist2013-04-12T11:32:10Z<p>130.225.98.201: /* Explanation */ prize -> trophy, with WP link</p>
<hr />
<div>{{comic<br />
| number = 1198<br />
| date = April 12, 2013<br />
| title = Geologist<br />
| image = geologist.png<br />
| titletext = 'It seems like it's still alive, Professor.' 'Yeah, a big one like this can keep running around for a few billion years after you remove the head.'<br />
}}<br />
<br />
==Explanation==<br />
{{w|Geology}} is the study of the physical and chemical makeup of the Earth.<br />
<br />
Hunters, after killing an especially difficult or rare beast, sometimes remove its head and hang it up on a wall as a {{w|Trophy hunting|trophy}}. [[Cueball]], as a geologist, "kills the Earth" by shooting at it. He removes its "head" (actually just a chunk of rock) and hangs it up on his office wall.<br />
<br />
The title text is probably a reference to a chicken running around with its head cut off.<br />
<br />
==Transcript==<br />
:[Cueball is wearing earmuffs and goggles, armed with a gun and a pickaxe. There are rocks nearby. There is a van in the background labeled "Dept. of Geology".]<br />
<br />
:[Cueball shoots three holes in the ground.]<br />
:BLAM BLAM BLAM<br />
<br />
:[Cueball hacks away at the top of a nearby rock.]<br />
:Clink Clink<br />
<br />
:[Cueball in his office. Behind him on a wall is a rock, labeled "Earth" and "4,500,000,000 BCE - April 12, 2013".]<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]</div>130.225.98.201https://www.explainxkcd.com/wiki/index.php?title=1167:_Star_Trek_into_Darkness&diff=266751167: Star Trek into Darkness2013-01-30T11:46:26Z<p>130.225.98.201: /* Explanation */ fmt</p>
<hr />
<div>{{comic<br />
| number = 1167<br />
| date = January 29, 2013<br />
| title = Star Trek into Darkness<br />
| image = star_trek_into_darkness.png<br />
| titletext = Of course, factions immediately sprang up in favor of '~*~sTaR tReK iNtO dArKnEsS~*~', 'xX_StAr TrEk InTo DaRkNess_Xx', and 'Star Trek lnto Darkness' (that's a lowercase 'L').<br />
}}<br />
<br />
==Explanation==<br />
The talk page of a Wikipedia article is used to discuss changes to the article. Here, [[Randall]] is referring to a {{w|Talk:Star Trek into Darkness#Requested move|talk page discussion}} on the Wikipedia article about ''{{w|Star Trek Into Darkness}}'' (an upcoming Star Trek film) about whether to capitalize the word "into." Wikipedia is {{w|WP:LAME|no stranger}} to lengthy battles over such trivial topics.<br />
<br />
Cueball suggests a compromise, and changes the title so that every other letter is capitalized. This will probably not go over well.<br />
<br />
Megan's line of "They should have sent a poet." is a quote from the film ''{{w|Contact (film)|Contact}}''; the quote appears in other xkcd comics, such as [[482: Height]].<br />
<br />
==Transcript==<br />
:[Cueball staring at computer screen.]<br />
:Cueball: Oh, wow. Look at Wikipedia's Talk page for Star Trek into Darkness. I have a new favorite edit war.<br />
:Megan (off-panel): Oh?<br />
<br />
:Cueball: Forty ''thousand'' words of debate over whether to capitalize "into" in the movie's title. Still no consensus.<br />
:Megan: That's ''magnificent''.<br />
:Cueball: It's breathtaking.<br />
:Megan: They should have sent a poet.<br />
<br />
:Cueball: Well I'm making an executive decision. I hope both sides accept this as a fair compromise.<br />
<br />
:[A wikipedia page titled "~*~ StAr TrEk InTo DaRkNeSs ~*~"]<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Wikipedia]]</div>130.225.98.201