explain xkcd - User contributions [en]

1235: Settled

2013-07-08T12:29:23Z

174.88.153.125: /* Explanation */ minor typo

{{comic
| number = 1235
| date = July 8, 2013
| title = Settled.
| image = settled.png
| titletext = Well, we've really only settled the question of ghosts that emit or reflect visible light. Or move objects around. Or make any kind of sound. But that covers all the ones that appear in Ghostbusters, so I think we're good.
}}

==Explanation==
{{incomplete}}
In this comic, there is a timeline {{w|chart}} describing the percentage of people in the United States that have a {{w|Camera}} at every moment.
Most liley [[Randall_Munroe|Randall]] refers that today most people carry around cameras or camera-available devices such as {{w|Digital_camera|Digital Cameras}} or {{w|Smartphone|Smartphones}}.

The chart shows that after the 80's the percentage increases every year, almost reaching 100% by 2013. The text below the image states that "''We have conclusively settled the questions of {{w|Flying_saucer|Flying saucers}},Lake Monsters (probably referring to {{w|Loch_Ness_Monster|The Loch Ness Monster}}), {{w|Ghost|Ghosts}} and {{w|Bigfoot}}''" insinuating that as almost everyone carry a camera, those entities must have been seen by now (if they exist) or questions about them should be answered by now (if there are). Note that the comic does not say the entities exist or not, only that most questions should be answered given the high amount of image capturing devices people carry.

The title text declares an exception in the case of ghosts, by saying that questions should be answered about only those capturable by a camera (those visible, audible or that perform any kind of {{w|Telekinesis}}. The title text also makes a joke about the ghosts of "{{w|Ghostbusters}}", a popular series of TV, that featured highly visible ghosts often made of a slime sustance. The title text says that we are good with those not existing given their mischievous behavior.

==Transcript==
'''Settled'''

A timeline chart shows years in the x-axis starting from before 1980 until 2013.
The chart line describes the increasing in percentage of people carrying around Cameras.

In the last few years, with very little fanfare, we've conclusively settled the questions of flying saucers, lake monsters and Bigfoot.

{{comic discussion}}
[[Category:Comics with color]]
[[Category:Charts]]

Talk:1231: Habitable Zone

2013-06-29T16:28:37Z

174.88.153.125:

Even if you placed the mirror in Space, it would be incredibly obvious what is going on. I don't think this would work. [[Special:Contributions/96.251.85.48|96.251.85.48]] 06:56, 28 June 2013 (UTC)

:For this trick to work, the mirror would need to be placed AT LEAST two light years away and be at least 1AU big. Somehow I don't think this is worth it. Alternatively, you need more complicated optical system which would not only mirror Earth, but also create illusion it's further away. I still think such system would be more costly to build that ISS. Or ... well ... you could put an LCD display directly over the telescope. That's doable, cheap and as a bonus you can display planets from sci-fi there. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 08:44, 28 June 2013 (UTC)

::Under Hkmaly's initial proposal, the astronomer would have to make two observations, 4 years apart, in order to see the "other" telescope. [[User:Elsbree|Elsbree]] ([[User talk:Elsbree|talk]]) 07:13, 29 June 2013 (UTC)

Since when do we have terrestrial telescopes that can directly resolve exoplanets? I think we're still at the stage where we get excited by troughs in light curves EDIT: TIL that there are specific techniques for exactly that: {{w|Nulling interferometry}} and {{w|Vortex coronagraph}}s. Still, they may work for hot Jupiters, but don't think we can detect Goldilocks exoplanets from the ground yet; much less see oceans and visible weather. [[Special:Contributions/220.224.246.97|220.224.246.97]] 09:14, 28 June 2013 (UTC)

My first thought was that you need to point the mirror so that it's aimed perfectly at the Earth. Then, I realized that you can use a corner reflector so that the aim doesn't have to be precise at all. Then, I came to the following realization: what if a significant portion of the stars we see are simply reflections of our own solar system due to a massive prank done by aliens? [[Special:Contributions/174.88.153.125|174.88.153.125]] 15:22, 28 June 2013 (UTC)

:Or all of them? Of course including additional variable features like red shift. So [http://commons.wikimedia.org/wiki/File:Universum.jpg they were right!] Forever alone... --[[User:Kronf|Kronf]] ([[User talk:Kronf|talk]]) 16:31, 28 June 2013 (UTC)

:: Where would these aliens reside? Either we're pranking ourselves, or there are other stars. [[Special:Contributions/220.224.246.97|220.224.246.97]] 17:57, 28 June 2013 (UTC)

::: What if there's a mirage-like effect in space, that causes light rays to mirror back to us with some variability, maybe different sizes, shapes, colors, and the universe is actuallly quite small? I mean, other than light, do we seriously detect gravity and other stuff out there (other than the visible effects of those properties on other stuff we see)? [[Special:Contributions/189.5.110.148|189.5.110.148]] 06:17, 29 June 2013 (UTC)

:::: If the universe is curved spherically, something similar to this would actually happen. http://en.wikipedia.org/wiki/Shape_of_the_Universe [[Special:Contributions/174.88.153.125|174.88.153.125]] 16:28, 29 June 2013 (UTC)

Wouldn't reflected light make the mirror extremely bright and impossible to view directly?

: Depends on how far the aliens decide to put the mirror. Light gets weaker with distance, which is the same reason that distant stars (many of which are brighter than our sun) don't overwhelm us with light. Also...what if the sun is merely a reflection of something? [[Special:Contributions/174.88.153.125|174.88.153.125]] 16:28, 29 June 2013 (UTC)

Talk:1231: Habitable Zone

2013-06-28T15:23:48Z

174.88.153.125:

Talk:1231: Habitable Zone

2013-06-28T15:22:55Z

174.88.153.125: