explain xkcd - User contributions [en]

Talk:1716: Time Travel Thesis

2016-08-05T23:45:09Z

173.245.56.65:

'''''-BZZZZT!-''
You can skip this comic and discussion page. It doesn't turn out to be important.''' {{unsigned|172.68.59.18}}

Any possibility that future Megan actually uses time travel to assist present Megan to exit? [[User:Plm-qaz snr|Plm-qaz snr]] ([[User talk:Plm-qaz snr|talk]]) 07:52, 5 August 2016 (UTC)
:Yes for sure --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:51, 5 August 2016 (UTC)

I don't feel like it's ''mainsplaining'' and I don't think ''not have a bad problem that will make it so she will not go to 1812 today.'' is relevant (maybe an joke, but nothing to do with the comic). [[Special:Contributions/162.158.114.230|162.158.114.230]] 08:18, 5 August 2016 (UTC)
:I have deleted that part. Someone deleted mansplaining before I started my edit, and then by the time I was ready there was edit conflicts and it was reentered. I have decided not to do anything about it. He may have a point. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:51, 5 August 2016 (UTC)

Did someone really decide ''mansplaining'' was the right word to use here? Not only is it entirely inappropriate, but it's not exactly a well-known term, so it's liable to confuse people. [[Special:Contributions/162.158.142.147|162.158.142.147]] 08:28, 5 August 2016 (UTC)
:Yeah. Cueball's just trying to have a conversation, not trying to act like he knows more than her. If anything, she's being rude by not letting him finish what he was saying. Sure, I know more about computers than my dad, but I let him tell me about his new discoveries. I'm a music major, so I know more about music than a lot of people, but I still let them talk. She not only keeps interrupting him, but goes back in time to avoid the "boring" conversation altogether--and says it all right in front of him. We're not supposed to think she's a decent [person], unlike when Randall stood up for people who happened to have not learned something. [[User:Trlkly|Trlkly]] ([[User talk:Trlkly|talk]]) 09:17, 5 August 2016 (UTC)
::Well she does try to let him know that he do not have to ask if she knows it, just begin talking about it. It is annoying when people assume that just because they just read something no one else has read about it. And even worse if he doesn't understand that she has used years of he life studying the subject. And if he actually understand but continues that's just bad... --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:51, 5 August 2016 (UTC)
::I don't see why it has to be mansplaining - Cueball just learned about it and thinks its exciting, so he wants to tell others about it. And in most conversations between a noob and an expert, the noob usually needs a point reclarified (especially if the book they just read wasnt written by that expert.) FutureMegan knows this isnt the case though… [[Special:Contributions/108.162.221.87|108.162.221.87]] 12:20, 5 August 2016 (UTC)

I don't think the title text mentions a TimeTravel to 2010. Rather there was a party themed 2010 in the future (Like there are 90's and 80's themed parties nowadays)
--[[Special:Contributions/162.158.83.198|162.158.83.198]] 10:41, 5 August 2016 (UTC)
:Agree that has been corrected. No one know when the glasses broke but in that future no one probably uses them anymore. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:51, 5 August 2016 (UTC)

How did future Megan know that the conversation wasn't important if she didn't attend it in her past (in fact, no-one did or would)? A grandfather paradox. At best, she remembered to tell her past self, in which case it's still a bootstrap paradox (and an impressive feat of human memory, though Novikov self-consistency principle might hav helped her "randomly" remember). [[Special:Contributions/141.101.95.99|141.101.95.99]] 10:57, 5 August 2016 (UTC)
:Tried to add some more about that paradox and in general. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:51, 5 August 2016 (UTC)
:I added a little bit explaining what I think is a way for the comic to not be a paradox. While it does seem like the grandfather paradox at first glance, so long as the cause interrupting the conversation is preserved in the effect of the interruption, there's no logical problem (at least, that I've been able to think of). So long as the Megan who didn't have the conversation knows that it doesn't go anywhere and travels back in time to tell her younger self and preserve the loop, it can be easily sustained. [[User:Marcus4742|Marcus4742]] ([[User talk:Marcus4742|talk]]) 19:53, 5 August 2016 (UTC)
: The true question is not whether there is an unsustainable time loop but rather if she has any evidence to say that conversation doesn't go anywhere with certainty, assuming that the time travel follows a closed time-like curve, as cueball talks about, then, (like marcus said) megan stops the conversation then goes back in time to stop the conversation because of the fact she stopped the conversation in the first place, not because she had any knowledge that the conversation was important or not. Alternatively, if the time travel is more of an infinite universe type with branching pathways, then future megan could know the conversation doesn't lead anywhere because she either had it or because closed time-like curves are not in effect. But we're probably over analyzing this. [[User:Lackadaisical|Lackadaisical]] ([[User talk:Lackadaisical|talk]]) 20:56, 5 August 2016 (UTC)

Alright, anyone who is willing to make the claim that "Google Glass will probably become popular in the 2010's" is living in a fantasy world. I've edited it to make the far more accurate claim that it could be either because Glass became popular or because Glass was an esoteric piece of hardware that lived (and died) in the 2010's. [[Special:Contributions/172.68.34.122|172.68.34.122]] 15:21, 5 August 2016 (UTC)

Talk:1643: Degrees

2016-02-15T14:11:16Z

173.245.56.65: Created page with "Rankine is a good compromise. ~~~~"

Rankine is a good compromise. [[Special:Contributions/173.245.56.65|173.245.56.65]] 14:11, 15 February 2016 (UTC)

Talk:1627: Woosh

2016-01-08T10:32:09Z

173.245.56.65: Comment

Looking for a joke that isn't there sounds a lot like [http://xkcd.com/559 xkcd.com/559]. [[Special:Contributions/162.158.2.140|162.158.2.140]] 05:43, 8 January 2016 (UTC)
Woooosh! [[Special:Contributions/108.162.245.181|108.162.245.181]] 05:48, 8 January 2016 (UTC)

Woosh

'''Woof''' ''(Guess my bot still needs some work)'' [[Special:Contributions/162.158.153.131|162.158.153.131]] 08:41, 8 January 2016 (UTC)

If it was a joke video that was never meant to be real to begin with and the commenter didn't realize this, then woosh would actually make sense [[User:Figvh|Figvh]] ([[User talk:Figvh|talk]])

:Woosh[[Special:Contributions/173.245.56.65|173.245.56.65]] 10:32, 8 January 2016 (UTC)

Talk:1012: Wrong Superhero

2015-11-01T07:48:18Z

173.245.56.65:

Maybe they wanted to know what the plural form of mantis is, if more were to show up? Looks like a job for etymology man. [[User:Davidy22|Davidy22]][[User talk:Davidy22|<tt>(talk)</tt>]] 14:30, 30 October 2012 (UTC)

So what is the title text referring too? [[Special:Contributions/108.162.221.98|108.162.221.98]] 14:54, 6 April 2015 (UTC)

adam-ology make more sense than the other guesses[[Special:Contributions/173.245.56.65|173.245.56.65]] 07:48, 1 November 2015 (UTC)

603: Idiocracy

2015-08-05T01:59:27Z

173.245.56.65: /* Explanation */

{{comic
| number = 603
| date = June 29, 2009
| title = Idiocracy
| image = idiocracy.png
| titletext = People aren't going to change, for better or for worse. Technology's going to be so cool. All in all, the future will be okay! Except climate; we fucked that one up.
}}
==Explanation==
The title of this comic is a reference to the dystopian comedy ''{{w|Idiocracy}}''. The film postulates that over about 500 years, society will suffer from a massive decrease in intellectual potential. This development is attributed to the fact that people with a lower IQ are believed to be more fertile and thus better able to pass on their genes. The scientifical approach towards a negative correlation between intelligence and fertility is called {{w|dysgenics|intelligence dysgenics}}.

[[Cueball]] professes his approval for the theories represented in the film, and Domed Hat agrees with him, lamenting the gradual decay in intelligence and education. But in panel 3, Domed Hat suddenly reveals that all the "facts" he cited were wrong, and we learn that he doesn't support the dysgenic thesis at all. He turns to accuse Cueball of conceited self-righteousness (using religious zealots as an analogy), harshly condemning intelligence dysgenics as an excuse for feeling superior to the rest of society. Cueball's suggestion of {{w|Birth control movement in the United States|birth control}} for the unintelligent only furthers his attitude. Although it is not named, one thing at work here is the {{w|Dunning-Kruger effect}} — that stupid people don't realize they're stupid.

Domed Hat's punchline, playing on Cueball's birth control suggestion, is a direct insult: it would be better to reproduce with a stupid person than an elitist like Cueball.

It's pretty clear here that [[Randall]] is voicing his opinion through Domed Hat, and using Cueball as a straw man.

The title text reflects the opinion. It makes a few cheery comments on the future, but then finishes on a rather sour note about {{w|climate change}}.

==Transcript==
:[Cueball looking at a DVD cover. White Hat stands next to him.]
:Cueball: ''Idiocracy'' is so true.
:White Hat: I know, right? It used to be that the intelligent, upper classes had more children.

:White Hat: Sadly, the recent reversal of this trend has dragged IQ scores and average education steadily downward.
:Cueball: Depressing, huh?

:White Hat: Yeah, except ''everything I just said was wrong.''
:Cueball: Huh?
:White Hat: Wrong. False. The opposite of true.

:White Hat: You're like the religious zealots who are ''burdened'' by their superiority with the sad duty of decrying the ''obvious'' moral decay of each new generation.
:White Hat: And you're just as wrong.
:Cueball: But look at how popular—
:White Hat: More harm has been done by people panicked over societal decline than societal decline ever did.

:Cueball: Look — all we need is a program that limits breeding to—
:[White Hat is walking off panel.]
:White Hat: New theory: Stupid people reproduce more because the alternative is sleeping with ''you.''

{{comic discussion}}
[[Category:Comics featuring White Hat‏‎]]
[[Category:Comics featuring Cueball]]
[[Category:Biology]]

368: Bass

2015-08-04T13:30:22Z

173.245.56.65: /* Explanation */

{{comic
| number = 368
| date = January 9, 2008
| title = Bass
| image = bass.png
| titletext = And sometimes I use it to retaliate against the guy upstairs with the loud girlfriend and the elliptical dish.
}}

==Explanation==
[[Black Hat]] and [[Cueball]] are standing inside a room behind a window hearing an obnoxious car outside playing loud music with deep bass. Black Hat created a machine that is able to blow out the car's speakers (by playing the same soundwaves back at them, but with the {{w|Phase (waves)|phase}} slightly offset, the phase difference will set up a {{w|resonance}} in the car's speakers big enough for them to destroy themselves). In a stroke of evil, he then starts playing Shirley Ellis' ''{{w|The Name Game}}'' to show how annoying the man was acting. At the end Black Hat tops this by playing the song {{w|Macarena (song)|''Macarena''}}.

The title text refers to comic [[316: Loud Sex]], where an elliptical reflector is used to focus sound waves.

==Transcript==
:[Black Hat and Cueball are standing in a room with one window. Black Hat is pushing a box with an elliptical dish on top towards the window.]
:''THUMPA THUMPA''

:Cueball: The bass from that car is driving me nuts.
:Black Hat: Me too. Give me a hand here.

:[The dish is aimed out the window; Black Hat plugs the device into the wall.]
:Cueball: I'm afraid to ask.
:Black Hat: The system detects bass rhythms and floods the target with a phase-shifted replica signal.
:Black Hat: The resonance should blow out their speakers.

:[The side of a building. The dish of the device is visible through a window, emitting sound waves.]
:''THUMPA THUMPA''
:''BLAM''

:[Back in the room.]
:Black Hat: Speakers down. Now flip that red switch.
:[Cueball does so with a "click."]

:[Back to the outside view, more sound waves.]
:''SHIRLEY SHIRLEY BO BIRLEY BANANA FANNA FO FIRLEY''
:Cueball: You're horrifying.
:Black Hat: Okay, now throw the switch labeled "Macarena".

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Music]]

148: Mispronouncing

2015-08-04T00:30:16Z

173.245.56.65: /* Explanation */

{{comic
| number = 148
| date = August 25, 2006
| title = Mispronouncing
| image = mispronouncing.png
| titletext = 'My pal Emad does this all the time. 'Hey man, which way to the airpart?'
}}

==Explanation==
This is the sixth comic at the [[My Hobby]] series. [[Cueball]] is deliberately mispronouncing words while talking. It's just his hobby. Hobbies in the ''My Hobby'' series are generally annoying or weird, but with an element of cleverness. Here, Cueball persists in mispronouncing his words despite the second character's attempt to correct him.

In the title text, [[Randall]] explains that he got the idea for this comic from one of his friends.

Interestingly, when Randall started the xkcd blog in October 2006, 6 weeks after the publication of this comic, he named it "[[Blag]]", and has used that name in several other comics, such as [[181: Interblag|here]] and [[239: Blagofaire|here]].

==Transcript==
:Cueball: Yeah, did you see what he said on his wobsite?
:Friend: ...his what?
:Cueball: Wobsite.
:Friend: ... I think you mean "website."
:Cueball: Why don't you write about it in your blag?

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Language]]
[[Category:My Hobby]]

Talk:1382: Rocket Packs

2014-06-16T04:34:06Z

173.245.56.65: Created page with "I think long fall boots (from Portal) would probably help with this. ~~~~"

I think long fall boots (from Portal) would probably help with this.
[[Special:Contributions/173.245.56.65|173.245.56.65]] 04:34, 16 June 2014 (UTC)

1379: 4.5 Degrees

2014-06-09T05:34:42Z

173.245.56.65: Forgot to remove one line when I merged.

{{comic
| number = 1379
| date = June 9, 2014
| title = 4.5 Degrees
| image = 4_5_degrees.png
| titletext = The good news is that according to the latest IPCC report, if we enact aggressive emissions limits now, we could hold the warming to 2°C. That's only HALF an ice age unit, which is probably no big deal.
}}

==Explanation==
{{incomplete}}
This comic is a way to visualize the change in climate predicted by the IPCC over the next century. The prediction, 4-5 degrees, doesn't seem like a very large change, but Randall points out that 4.5°C is the difference between the last Ice Age and today, which is quite a substantial difference. So, to give context to the number, he measures the temperature in "Ice Age Units," or IAU. 1 IAU is defined as the change in average global temperature by 4.5 degrees on the Centigrade scale. The last ice age was 1 IAU colder than the average "modern" global temperature, and Randall's neighborhood was buried under an ice sheet. The predicted change by the year 2100 is +1 IAU, and while we don't know what its effects will be exactly, a change of +2 IAU created the "Hothouse Earth" of the early Cretaceous period. In short, while 4.5°C seems like a small change in temperature, it seems quite a lot bigger if you phrase it as "halfway to having palm trees at the poles."

The title text notes that even with aggressive emissions reduction, the temperature will still rise by half an IAU. While it says it's "probably no big deal," this is probably a joke, because even half of an Ice Age would be a lot of ice.

==Transcript==
{{incomplete transcript}}
:Without prompt, aggressive limits on CO2 emissions, the Earth will likely warm by an average of 4°-5°C by the century’s end.
:How big a change is that?
:In the coldest part of the last ice age, Earth’s average temperature was 4.5°C below the 20th century norm.
:Let’s call a 4.5°C difference one “ice age unit.”
:-2 IAU -1 IAU 0 where we are today +1 IAU +2 IAU
:Snowball earth (-4 IAU)
:20,000 years ago
:My neighborhood:
:Half a mile of ice
:Average during modern times
:My neighborhood:
:Cueball: Hi
:Where we’ll be in 86 years
:My neighborhood:
:?
:Cretaceous hothouse
:+200m sea level rise
:No glaciers
:Palm trees at the poles
:

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics with color]]

1379: 4.5 Degrees

2014-06-09T05:34:01Z

173.245.56.65: /* Explanation */

{{comic
| number = 1379
| date = June 9, 2014
| title = 4.5 Degrees
| image = 4_5_degrees.png
| titletext = The good news is that according to the latest IPCC report, if we enact aggressive emissions limits now, we could hold the warming to 2°C. That's only HALF an ice age unit, which is probably no big deal.
}}

==Explanation==
{{incomplete}}
This is a comic representing the effects of climate change, with the introduction of the Ice Age Unit (IAU). 1 IAU is defined as the change in average global temperature by 4.5 degrees on the Centigrade scale.

This comic is a way to visualize the change in climate predicted by the IPCC over the next century. The prediction, 4-5 degrees, doesn't seem like a very large change, but Randall points out that 4.5°C is the difference between the last Ice Age and today, which is quite a substantial difference. So, to give context to the number, he measures the temperature in "Ice Age Units," or IAU. 1 IAU is defined as the change in average global temperature by 4.5 degrees on the Centigrade scale. The last ice age was 1 IAU colder than the average "modern" global temperature, and Randall's neighborhood was buried under an ice sheet. The predicted change by the year 2100 is +1 IAU, and while we don't know what its effects will be exactly, a change of +2 IAU created the "Hothouse Earth" of the early Cretaceous period. In short, while 4.5°C seems like a small change in temperature, it seems quite a lot bigger if you phrase it as "halfway to having palm trees at the poles."

The title text notes that even with aggressive emissions reduction, the temperature will still rise by half an IAU. While it says it's "probably no big deal," this is probably a joke, because even half of an Ice Age would be a lot of ice.

==Transcript==
{{incomplete transcript}}
:Without prompt, aggressive limits on CO2 emissions, the Earth will likely warm by an average of 4°-5°C by the century’s end.
:How big a change is that?
:In the coldest part of the last ice age, Earth’s average temperature was 4.5°C below the 20th century norm.
:Let’s call a 4.5°C difference one “ice age unit.”
:-2 IAU -1 IAU 0 where we are today +1 IAU +2 IAU
:Snowball earth (-4 IAU)
:20,000 years ago
:My neighborhood:
:Half a mile of ice
:Average during modern times
:My neighborhood:
:Cueball: Hi
:Where we’ll be in 86 years
:My neighborhood:
:?
:Cretaceous hothouse
:+200m sea level rise
:No glaciers
:Palm trees at the poles
:

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics with color]]

Talk:1352: Cosmologist on a Tire Swing

2014-04-08T16:17:13Z

173.245.56.65:

See this TED talk for clue: http://www.ted.com/talks/allan_adams_the_discovery_that_could_rewrite_physics
[[Special:Contributions/108.162.218.101|108.162.218.101]] 07:54, 7 April 2014 (UTC)

The question "what lies outside our observable universe?" is pretty easily answered with a "the same stuff as inside it, we just can't observe it". The more poignant question is whether the universe as a whole (not just its observable part) has an edge and if so, what lies beyond it. --[[User:Koveras|Koveras]] ([[User talk:Koveras|talk]]) 08:09, 7 April 2014 (UTC)

:The parts of universe which are not observable due to speed of light looks the same as the ones we can observe, sure. Just bigger. But there is nothing in physics saying there can't be something even more "outside". In fact, some theories consider it probable. And what can be THERE? Anything. Dragons. Possibly literally. Unfortunately, according to current physic, we can't PROVE something outside exists, much less look at it. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 10:21, 7 April 2014 (UTC)

What's the setting of the first panel? Given the cosmological context, could it be a reference to the {{w|Wood between the Worlds}} from the ''Narnia'' series? [[Special:Contributions/108.162.219.29|108.162.219.29]] 10:57, 7 April 2014 (UTC)

The puddles/ponds in the first panel mirror "reality", is this a hint for parallel universe(s)? Escher sees three worlds in a pond. http://cache2.allpostersimages.com/p/LRG/7/779/1X5I000Z/poster/escher-m-c-drei-welten.jpg

Someone please rewrite my shunted in assertion about the aforementioned wood. There's a reason for the setting in the first panel, I just can't think of a better place to put it in the explanation.
[[Special:Contributions/108.162.244.6|108.162.244.6]] 11:43, 7 April 2014 (UTC)

The tire swing also evokes the cosmology field in itself; accepted theories keep changing like the swing, endlessly being replaced by the next one. [[User:Ralfoide|Ralfoide]] ([[User talk:Ralfoide|talk]]) 14:19, 7 April 2014 (UTC)

Seems to me Randall is referring to the the A and B theories of time. ''— [[User:Tbc|tbc]] ([[User talk:Tbc|talk]]) 14:24, 7 April 2014 (UTC)''
:Seems to me Randall is referring to Physics and not philosophy. {{unsigned|ExternalMonolog}}

It's possible the tire swing might also be a reference to the idea that the universe is "shaped like a doughnut". [[Special:Contributions/173.245.48.24|173.245.48.24]] 16:32, 7 April 2014 (UTC)

Maybe it's important to note that the cosmologist is also portrayed as somebody not serious, and also doing "silly" science? A jab at the state our most serious scientists are, because we know, in a way, so little? Not sure if that's the kind of thing you put here, but it's relevant. [[Special:Contributions/141.101.80.237|141.101.80.237]] 17:21, 7 April 2014 (UTC)
;Maybe some of our most "serious" scientists.

Randall seems to be referring directly to the discovery of dark energy and the perpetual acceleration it gives to the expansion of the universe. "Tire swing" girl directly addresses this when she speaks of her surprise that her momentum increases rather than decays.[[User:ExternalMonolog|ExternalMonolog]] ([[User talk:ExternalMonolog|talk]]) 00:18, 8 April 2014 (UTC)ExternalMonolog

Maybe I shouldn't be writing here, since I'm a new guy around and I'm not well versed in the ways of this wiki, but it seems to me that aside from all that you've said, the main point of the idea of "Cosmologist on a tire swing" seems to be a parody of the fact that not only does every simple person apears to have a definite explanation for those universal unanswered riddles, (even though "It might have! Or maybe not! We don't know!"), the scientific community also seems to 'swing' between answers constantly as they discovers new clues or evidence. And even though it would seem that having more knowledge would bring them closer to getting the one true answers, it only gets them more and more doubts and questions about the nature of, well, everything (hence the swing not stopping but accelerating). [[Special:Contributions/141.101.89.206|141.101.89.206]] 02:39, 8 April 2014 (UTC)

It'd be cool to have the link to the TED talk or something similar about the gravity wave detection and its potential multiverse-ish implications; it seems relevant to the explanation. [[Special:Contributions/108.162.244.6|108.162.244.6]] 04:54, 8 April 2014 (UTC)

{{w|Georges_Lemaître}} developed the big bang theory as a Catholic Priest, with the understanding that he would not investigate whether anything happened before that. It was a compromise that allowed the physical threory to work within the context of theology. This gave backing to a desire not to think about what happen before. [[Special:Contributions/173.245.56.65|173.245.56.65]] 16:17, 8 April 2014 (UTC)

Talk:1342: Ancient Stars

2014-03-14T15:21:47Z

173.245.56.65:

I knew this because Nick Cave's 2013 album *Push The Sky Away* includes the lyrics "Sirius is eight point six light years away / Arcturus is thirty seven / The past is the past and it's here to stay / Wikipedia is heaven". Obviously Randall has been listening to it! ;-) [[Special:Contributions/173.245.53.176|173.245.53.176]] 08:32, 14 March 2014 (UTC)

The comic is about people getting the distance to the stars wrong. Wikipedia - List of brightest stars claims a that total of 9110 stars are visible to the naked eye and they provide a list of the 91 brightest stars. Of these only 59 are greater than 100 ly and only 6 are greater than 1,000 ly. The farthest visible star is 3,200 ly away. When people think of the stars they correctly imagine the vast distances they spread out over. But when lay people observe or imagine the visible stars they grossly overestimate the distances. As implied in the title text, in a world of vast astronomical underestimations, this is one of the few overestimates. 99% of the visible stars are only dozens of ly away.[[User:ExternalMonolog|ExternalMonolog]] ([[User talk:ExternalMonolog|talk]]) 09:35, 14 March 2014 (UTC)ExternalMonolog

:People aren't overestimating the distance, they are underestimating the speed of light :-). The number of visible stars is the true overestimating. And even that ... the 9110 is number of INDIVIDUAL stars we can see. We can also see {{w|Andromeda Galaxy}}, 2.5 million light years away ... but we can't distinguish any of trillion stars it have from others, the galaxy as whole is less bright that any of those 91 brightest stars. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 11:04, 14 March 2014 (UTC)

In the comic, the lifespan of stars is also vastly underestimated. A thousand years is nothing when their age is generally counted in millions or billions of years. What is the probability a near-visible star died in the last thousand years and wouldn't that be a major astronomical event? [[User:Ralfoide|Ralfoide]] ([[User talk:Ralfoide|talk]]) 14:21, 14 March 2014 (UTC)
:In the comic, the lifespan of stars isn't even mentioned in passing. The history of supernovae is pretty well documented and goes back nearly 2000 years, so the light from those supernovae is probably not more than 2200 years old...[[Special:Contributions/173.245.56.65|173.245.56.65]] 15:21, 14 March 2014 (UTC)

1342: Ancient Stars

2014-03-14T15:19:33Z

173.245.56.65: /* Explanation */

{{comic
| number = 1342
| date = March 14, 2014
| title = Ancient Stars
| image = ancient_stars.png
| titletext = 'The light from those millions of stars you see is probably many thousands of years old' is a rare example of laypeople substantially OVERestimating astronomical numbers.
}}

==Explanation==
[[Cueball]] is making a common observation; many of the visible stars in the sky are so distant that it takes thousands years for light from that star to reach Earth. However, the brightest star, {{W|Sirius}}, also happens to be one of the nearest at a mere 8.6 {{W|Light-year|light-years}} distance (in other words, the light that was arriving from Sirius in 2014, when the comic was posted, was emitted some time around August 2005). The previous US president, {{W|George W. Bush}}, was in office from 2000 to 2008; as [[Megan]] notes, this isn't terribly impressive.

The title-text references the fact that most normal people have a hard time imagining the large scale of astronomical numbers (for example, the distance between astronomical bodies or the size of the Sun); they typically imagine them as many orders of magnitude smaller than they actually are (this is especially the case with {{W|Supernovas}} as Randall mentions in his What if [http://what-if.xkcd.com/73/ Lethal Neutrinos] - see the line with note 4).

In this case, however, they instead overestimate both the number of stars and their distance by quite a bit. It's frequently cited that about 5,000 - 10,000 stars are visible by the naked eye. The {{W|Bright Star Catalogue}} is a star catalogue that lists all stars of {{W|Apparent magnitude|stellar magnitude}} 6.5 or brighter, which is roughly every star visible to the naked eye from Earth. The catalog contains 9,110 objects, of which 9,096 are stars. To see most of these you need pretty good eyes and a very dark night. Also at any point on Earth you will of course only be able to see less than half of these as the rest are blocked by the Earth!

Wikipedia have a list of the {{W|Visible stars|91 brightest stars}}. Of these only 59 are more than 100 light years away and only 6 are more than 1,000 light years away. The farthest on this list, {{W|Eta Canis Majoris|Aludra}}, is "only" 3,200 light years away. (The star {{W|List of stars in Cassiopeia|V762 Cas}} in the {{W|Cassiopeia (constellation)|Cassiopeia constellation}} is listed as being 14818 light years away and still having an {{W|apparent magnitude}} of 5.87 - thus being within the 6.5 limit).

There are visible objects much further away, like the {{w|Andromeda Galaxy}} which is 2.5 million light years away and made up of billions of stars.

==Transcript==
:[Cueball pointing up into the night sky.]
:Cueball: Just think - the light from that star was emitted thousands of years ago. It could be long gone.
:Megan: That's Sirius. It's eight light-years away.
:Cueball: Oh.
:Cueball: Just think - the light from that star was emitted in the previous presidential administration.
:Megan: Mmm, doesn't pack quite the punch.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Astronomy]]