https://www.explainxkcd.com/wiki/index.php?title=Talk:620:_Wings&feed=atom&action=historyTalk:620: Wings - Revision history2024-03-28T19:27:33ZRevision history for this page on the wikiMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=Talk:620:_Wings&diff=220764&oldid=prevObscure xkcd reference at 13:47, 13 November 20212021-11-13T13:47:50Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Why is this not a thing you can do in amusement parks or places like that?[[Special:Contributions/141.101.104.44|141.101.104.44]] 17:00, 8 September 2016 (UTC)</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Why is this not a thing you can do in amusement parks or places like that?[[Special:Contributions/141.101.104.44|141.101.104.44]] 17:00, 8 September 2016 (UTC)</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">I think that the bridge to which Cueball attached his wings is inspiration for the bridge in [[Click and Drag]].--[[User:Obscure xkcd reference|Obscure xkcd reference]] ([[User talk:Obscure xkcd reference|talk]]) 13:47, 13 November 2021 (UTC)</ins></div></td></tr>
</table>Obscure xkcd referencehttps://www.explainxkcd.com/wiki/index.php?title=Talk:620:_Wings&diff=126393&oldid=prev141.101.104.44 at 17:00, 8 September 20162016-09-08T17:00:27Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>[[User:Weatherlawyer| I used Google News BEFORE it was clickbait]] ([[User talk:Weatherlawyer|talk]]) 01:21, 29 January 2015 (UTC)</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>[[User:Weatherlawyer| I used Google News BEFORE it was clickbait]] ([[User talk:Weatherlawyer|talk]]) 01:21, 29 January 2015 (UTC)</div></td></tr>
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</table>141.101.104.44https://www.explainxkcd.com/wiki/index.php?title=Talk:620:_Wings&diff=83698&oldid=prevWeatherlawyer at 01:21, 29 January 20152015-01-29T01:21:04Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>PS:  I largely adapted this [http://forums.xkcd.com/viewtopic.php?f=7&t=43578&hilit=620+wings&start=120#p1726506 my writeup on xkcd forums from 2009 when the comic was made].  [[User:Jimbob|Jimbob]] ([[User talk:Jimbob|talk]]) 05:44, 8 June 2013 (UTC)</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>PS:  I largely adapted this [http://forums.xkcd.com/viewtopic.php?f=7&t=43578&hilit=620+wings&start=120#p1726506 my writeup on xkcd forums from 2009 when the comic was made].  [[User:Jimbob|Jimbob]] ([[User talk:Jimbob|talk]]) 05:44, 8 June 2013 (UTC)</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">:That was the whole point of Blackhat's presence. He was there to make sure Rob (AKA Cueball) wasn't hurt.</ins></div></td></tr>
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</table>Weatherlawyerhttps://www.explainxkcd.com/wiki/index.php?title=Talk:620:_Wings&diff=39946&oldid=prevJimbob: Created page with "Cueball's physics has a mistake on this one (or at least assumes we've managed to heat the atmosphere of Titan to Earth's temperature). The temperature of Titan is roughly 1/..."2013-06-08T05:44:16Z<p>Created page with "Cueball's physics has a mistake on this one (or at least assumes we've managed to heat the atmosphere of Titan to Earth's temperature). The temperature of Titan is roughly 1/..."</p>
<p><b>New page</b></p><div>Cueball's physics has a mistake on this one (or at least assumes we've managed to heat the atmosphere of Titan to Earth's temperature). The temperature of Titan is roughly 1/3 the temperature of Earth on an absolute scale. Starting with the Ideal Gas Law, PV = NkT (k is Boltzmann's constant, N is # of molecules, P is pressure, V is volume, T is temperature), its easy to define the density of a gas, ρ as:<br />
<br />
ρ = m/V = (m P)/(N k T) = P (m/N) / (k T)<br />
<br />
Titan's atmosphere is 98.4% molecular nitrogen (N<sub>2</sub>) and on Earth only 78.1% molecular nitrogen (by volume), but for simplicity we'll assume 100% for both. The weight of one molecule of Nitrogen is (m/N) ~ 2 × 14 × 1.67x10<sup>-27</sup> (kg/molecule) (there are 28 nucleons per molecule with a mass of about 1.67x10^-27 kg. <br />
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The pressure on Titan is P<sub>Titan</sub>=146.7 kPa, and T<sub>Titan</sub> = 93.7 K, while on Earth P<sub>Earth</sub>=101.3 kPa and T<sub>Earth</sub> = 287 K. <br />
<br />
Plugging in numbers, we get ρ<sub>Titan</sub> = 5.3 kg/m<sup>3</sup> and ρ<sub>Earth</sub> = 1.2 kg/m<sup>3</sup> (note the measured surface density of air on Earth is 1.2 kg/m<sup>3</sup> at Earth's mean temperature even without the simplifying assumption of 100% N<sub>2</sub>). <br />
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Hence Titan's atmosphere is 4.4 = (5.3/1.2) times denser than Earth's (or 340% denser); not 50% denser as stated in the comic.<br />
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You will get the 50% denser if you assume the same planetary temperature on Titan as on Earth. Titan at 287 K would have a density of ρ<sub>Titan at 287K</sub> ~ 1.73 kg/m<sup>3</sup> which is about 50% greater than Earth's.<br />
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For the second calculation (panel 2), note {{w|Lift_(force)|lift}} is proportional to the density of air. If your action on Earth creates a lift of L<sub>0</sub> and you weigh W<sub>0</sub>, on Titan you'd have a lift of 4.4 L<sub>0</sub> (Cueball calculated 1.5 L<sub>0</sub>) due to the greater air density. Your weight would only be 0.14 W<sub>0</sub>, due to Titan's lower surface gravity. If lift balances weight, you would be able to fly on Titan, that is if 4.4 L<sub>0</sub> = 0.14 W<sub>0</sub>. That means to fly on Titan you need a lift on Earth of L<sub>0</sub> = 0.03 W<sub>0</sub>, that is 3% of your Earth weight. Substituting Cueball's Titan density you would get the critical value from the comic: L<sub>0</sub> = 0.14 W<sub>0</sub>/(1.5) = 9% W<sub>0</sub>. <br />
<br />
PS: I largely adapted this [http://forums.xkcd.com/viewtopic.php?f=7&t=43578&hilit=620+wings&start=120#p1726506 my writeup on xkcd forums from 2009 when the comic was made]. [[User:Jimbob|Jimbob]] ([[User talk:Jimbob|talk]]) 05:44, 8 June 2013 (UTC)</div>Jimbob