Explain xkcd: It's 'cause you're dumb.
This comic plays on different meanings of the word "hottest". In the opening question, "Who are today's 10 hottest actors?" the word "hottest" would typically refer to an actor's popularity, success, demand or attractiveness. Cueball and Megan interpret the word "hottest" as asking them to the list the 10 actors who have the highest surface temperature, and we see them measuring "Justin's" (possibly referring to, Long, Theroux, or Timberlake or any of the several other Justins in show business) surface temperature using an infrared thermometer (the thermometer typically has a laser pointer to know the approximate location where the radiometric temperature comes from). The measured temperature of 81.5 is presumably reported in degrees Fahrenheit, corresponding to 27.5 °C. This temperature is below the average human internal body temperature of 98.6 °F/37 °C as skin is cooler; Megan also believes that another object (Justin's shirt) was also measured within the infrared thermometer field of view, lowering the reported measurement. With such a measurement of hotness, the hottest actor on any given day would probably be whoever is exercising, or sick with a fever. Or, an animal actor, of a species with a higher body temperature than humans. (Category:Films about birds)
Randall here excludes the fact that accurately deriving surface temperature from bright (radiance) temperature requires knowing the emissivity of the object. Since not all objects radiate with the same efficiency, two objects with the same surface temperature will emit different thermal radiance, but if emissivity is not taken into account they will report different surface temperatures.
The title-text references the temperatures of Hollywood's rising stars, this time interpreting stars as actual stars, not famous people. In this case, the star ξ Persei in the Perseus constellation (which is located in, and responsible for the fluorescence of, an object called the California Nebula), one of the hottest stars (35,000 kelvins, Sun: 5,800 K) visible to the naked eye. The star also has similar declination (+35° 47′) as the latitude of Hollywood (34° N) so it is literally rising there every night. They are shooting stars with a laser beam and mid-July is the start of the shooting stars known as the Perseids that appear in the Perseus constellation.
- Opening Question: Who are today's 10 hottest actors?
- [Cueball is holding a clipboard, taking notes, while Megan aims an infrared thermometer off screen.]
- Megan: 81.5, but I think it got part of his shirt. [Megan yells] HEY JUSTIN — HOLD STILL!
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- Closing: We grab an infrared thermometer and find out!
Could be Bieber... 04:42, 18 July 2014 (UTC)
- Good point. Sjrsimac (talk) 04:48, 18 July 2014 (UTC)
- More likely Timberlake.220.127.116.11 06:48, 18 July 2014 (UTC)Nix
- It's referring to Justin Theroux, currently in ninth place on IMDB's Most Popular Males list. (http://www.imdb.com/search/name?gender=male) Yeah, I have no idea who he is either. I feel old. 18.104.22.168 06:49, 18 July 2014 (UTC)
- The name of the comic is ACTORS, guys. Last I checked, Bieber is not an actor. 22.214.171.124 01:12, 20 July 2014 (UTC)
Do you think it's necessary to add that the temperature is in Fahrenheit, and that normal body temperature is around 98.6? The part about getting a bit of his shirt should also probably be explained in that context. 126.96.36.199 05:39, 18 July 2014 (UTC)
- Yeah, please do. Most Americans can't handle metric units, and I can't handle Fahrenheit. The only thing I can remember is that body temperature is around 100°F. --188.8.131.52 07:26, 18 July 2014 (UTC)
- Inserted Fahrenheit and Celcius into the explanation...
- Compared Suns temp. to Xi Persei, inserted link to films about birds (them being the hottest warm-blooded creatures I know of) Tier666 (talk) 08:03, 18 July 2014 (UTC)
I seem to recall several other comics making fun of these generic headlines of the form "The <n> <adjective> <nouns> you must see". I could only find one though: http://xkcd.com/1283/ --184.108.40.206 07:40, 18 July 2014 (UTC)
- http://www.xkcd.com/1307/ (Buzzfeed Christmas) has plenty of these. 220.127.116.11 08:58, 18 July 2014 (UTC)
Forget animals and "stars" with fevers: certainly the "hottest" objects involved in creating characters are the server farms behind CGI cartoon films! I can only imagine the heat load during final rendering. (Note: I stated "creating characters" akin to acting; to use movie-making in general, the hottest objects would be stage lighting, or the Sun during outdoor scenes.) --BigMal // 18.104.22.168 12:20, 18 July 2014 (UTC)
- Rendering is not acting. The computation of crowd behaviour, on the other hand, is. So question is how hot will became CPUs (or GPUs) of computers involved in computing the battles like in LOTR. -- Hkmaly (talk) 12:35, 18 July 2014 (UTC)
- I'm sure there are plenty of movies in which the sun is a character. There might also be special effects or a separate voice actor, but if the sun plays itself for some of the time, it might be considered an (uncredited) actor.  22.214.171.124 16:54, 18 July 2014 (UTC)
- For that matter isn't ξ Persei visible in some night-sky scenes, making it once again the hottest? 126.96.36.199 21:51, 18 July 2014 (UTC)
- Does it play a major role in any movie? Or are we lumping irrelevant background extras with actors? 188.8.131.52 04:16, 19 July 2014 (UTC)
I'm not sure there is misunderstanding about stars. I mean, the misunderstanding about the meaning of hot is enough to rank ξ Persei as hotter that any actress, including Kirsten Dunst (which is sexiest according to this list, my opinion is different). I'm also sure ξ Persei is more attractive if you measure the force in fixed distance of 10 meters from surface. -- Hkmaly (talk) 12:35, 18 July 2014 (UTC)
Anybody else suddenly notice that ξ looks a lot like the new name of the "Artist formerly known as Prince"? And thus miss the Astronomical reference entirely and wonder if his last name was now Persei?Seebert (talk) 20:38, 18 July 2014 (UTC)
- I don't understand any of what you just said, but "The artist formerly known as Prince" has been referring to himself as "Prince" for at least 13 years. That strange symbol was only his name from 1993 to 2000. NealCruco (talk) 01:27, 19 July 2014 (UTC)
The article says "They are shooting stars with a laser beam...", is this a typo, or a phrasing I don't understand? 184.108.40.206 21:51, 18 July 2014 (UTC)
- Using a laser beam to point out stars is common. See http://www.skyandtelescope.com/observing/some-pointers-on-the-use-of-laser-pointers/ . In movies, shooting refers to filming. 220.127.116.11 17:11, 21 July 2014 (UTC)
Incidentally, an IR thermometer is great for the kitchen -- the best way to heat a skillet to a consistent temperature for making perfect pancakes or stir-fry.
18.104.22.168 23:43, 18 July 2014 (UTC)
The fact that "ξ Per rises in Hollywood every night" is incorrect: the time of rise can be at any time of the day/night and it depends on the time of year. Moreover, the explanation using ξ Per's declination is incorrect: the stars with declination δ rise in a location with latitude φ if and only if |δ| < 90° - |φ|, so the given statement "star rises every night if (approximately) δ = φ" is only correct for |φ| < 45° (and so is incidentally correct in this case). 22.214.171.124
15:21, 19 July 2014 (UTC)