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		<id>https://www.explainxkcd.com/wiki/index.php?action=history&amp;feed=atom&amp;title=Talk%3A3174%3A_Bridge_Clearance</id>
		<title>Talk:3174: Bridge Clearance - Revision history</title>
		<link rel="self" type="application/atom+xml" href="https://www.explainxkcd.com/wiki/index.php?action=history&amp;feed=atom&amp;title=Talk%3A3174%3A_Bridge_Clearance"/>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;action=history"/>
		<updated>2026-04-20T12:02:18Z</updated>
		<subtitle>Revision history for this page on the wiki</subtitle>
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	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=406524&amp;oldid=prev</id>
		<title>Headphones the stickman at 19:40, 18 February 2026</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=406524&amp;oldid=prev"/>
				<updated>2026-02-18T19:40:57Z</updated>
		
		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr style=&quot;vertical-align: top;&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 19:40, 18 February 2026&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l52&quot; &gt;Line 52:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 52:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;There's a website with videos of crashes under 11' 8&amp;quot; bridges:&amp;#160; https://11foot8.com/.&amp;#160; [[User:Dbwiddis|Dbwiddis]] ([[User talk:Dbwiddis|talk]]) 18:22, 1 December 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;There's a website with videos of crashes under 11' 8&amp;quot; bridges:&amp;#160; https://11foot8.com/.&amp;#160; [[User:Dbwiddis|Dbwiddis]] ([[User talk:Dbwiddis|talk]]) 18:22, 1 December 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;my friend drives a 47 billion light-year tall truck, this sign is very useful, okay? [[User:Headphones the stickman|Headphones the stickman]] ([[User talk:Headphones the stickman|talk]]) 19:40, 18 February 2026 (UTC)&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Headphones the stickman</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=406098&amp;oldid=prev</id>
		<title>DollarStoreBa'al: Clearly meant to be this.</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=406098&amp;oldid=prev"/>
				<updated>2026-02-12T19:08:39Z</updated>
		
		<summary type="html">&lt;p&gt;Clearly meant to be this.&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr style=&quot;vertical-align: top;&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 19:08, 12 February 2026&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l14&quot; &gt;Line 14:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 14:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;While all of the Tropics are potentially directly under the Moon, note that at any given moment the patch of Earth directly under the moon is a circle about 27.86 km (17.29 miles) in radius. (Proof: Consider the point on earth directly underneath the center of the moon and go 27.86 km in any direction. Your plumb line will then be moved 1/4 of a degree, and so it will miss the moon has a visual diameter of 0.5 degrees.) The same is true for the sun which has have an angular size of 0.5 degrees. Thus on any given day only a strip of the tropics about 55.4 km wide is underneath the moon in this sense and a similar strip exists for points under the sun. Note that it is only under the moon or sun for at most 2 minutes so the sign update must be done quickly. &amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;While all of the Tropics are potentially directly under the Moon, note that at any given moment the patch of Earth directly under the moon is a circle about 27.86 km (17.29 miles) in radius. (Proof: Consider the point on earth directly underneath the center of the moon and go 27.86 km in any direction. Your plumb line will then be moved 1/4 of a degree, and so it will miss the moon has a visual diameter of 0.5 degrees.) The same is true for the sun which has have an angular size of 0.5 degrees. Thus on any given day only a strip of the tropics about 55.4 km wide is underneath the moon in this sense and a similar strip exists for points under the sun. Note that it is only under the moon or sun for at most 2 minutes so the sign update must be done quickly. &amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;ISS also has an angular diameter of 0.5 degrees but it is much closer and moves quickly across the field of view so that it is passing over a path about 100 meters wide at a speed of about 8 km/s, leaving insufficient time to update the sign. &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;[[citation needed]] &lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;ISS also has an angular diameter of 0.5 degrees but it is much closer and moves quickly across the field of view so that it is passing over a path about 100 meters wide at a speed of about 8 km/s, leaving insufficient time to update the sign.&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;{{cn}}&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;[[User:DanLoeb|Dan Loeb]]&amp;#160; ([[User talk:DanLoeb|talk]]) 19:02 December 2025 EST&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;[[User:DanLoeb|Dan Loeb]]&amp;#160; ([[User talk:DanLoeb|talk]]) 19:02 December 2025 EST&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>DollarStoreBa'al</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=401218&amp;oldid=prev</id>
		<title>Danloeb at 00:03, 10 December 2025</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=401218&amp;oldid=prev"/>
				<updated>2025-12-10T00:03:05Z</updated>
		
		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr style=&quot;vertical-align: top;&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 00:03, 10 December 2025&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l15&quot; &gt;Line 15:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 15:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;ISS also has an angular diameter of 0.5 degrees but it is much closer and moves quickly across the field of view so that it is passing over a path about 100 meters wide at a speed of about 8 km/s, leaving insufficient time to update the sign. [[citation needed]] &amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;ISS also has an angular diameter of 0.5 degrees but it is much closer and moves quickly across the field of view so that it is passing over a path about 100 meters wide at a speed of about 8 km/s, leaving insufficient time to update the sign. [[citation needed]] &amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;[[User:DanLoeb|Dan Loeb]]&amp;#160; ([[User talk:DanLoeb|talk]]) 19:02 December 2025 EST&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;When I first read the title text I thought it was talking about the tide's effect on the height of the bridge. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 03:55, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;When I first read the title text I thought it was talking about the tide's effect on the height of the bridge. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 03:55, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Danloeb</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=401217&amp;oldid=prev</id>
		<title>2601:45:4100:5490:9801:965:E34D:2B5C: Most of the tropics are not 'under&quot; the moon on any given day. Also figures for ISS and Sun</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=401217&amp;oldid=prev"/>
				<updated>2025-12-09T23:59:30Z</updated>
		
		<summary type="html">&lt;p&gt;Most of the tropics are not &amp;#039;under&amp;quot; the moon on any given day. Also figures for ISS and Sun&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr style=&quot;vertical-align: top;&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 23:59, 9 December 2025&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l11&quot; &gt;Line 11:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 11:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:And clearances of GSOs (there will be locations where sufficiently geo''stationary'' satellites are pretty much perpetual, though mere geo''synchronous'' ones may have daily (or twice-daily, on the crux of the figure-of-8 ground track) 'exposure') are so much greater than what the LEO ones would.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:And clearances of GSOs (there will be locations where sufficiently geo''stationary'' satellites are pretty much perpetual, though mere geo''synchronous'' ones may have daily (or twice-daily, on the crux of the figure-of-8 ground track) 'exposure') are so much greater than what the LEO ones would.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:A particular favourite of the Russian civil/military programmes are ''highly'' eccentric (and oblique) to service the kind of latitudes they want more loiter (slow, and far away) ''or'' passage (near, but rapid) over, often in teams of craft spread across the track to pass coverage over to another when one of them zooms on out of the desired 'sweet spot'... &amp;quot;Tundra Orbits&amp;quot;, I think it is? So accounting for them might involve vastly varying heights (though usually similar, overhead to overhead, barring any ascending-/descending-track differences) over a greater-than-average spread of latitudes (but still less than pure 90°-polar would, which is potentially over everywhere at some time or another). [[Special:Contributions/82.132.237.174|82.132.237.174]] 14:06, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:A particular favourite of the Russian civil/military programmes are ''highly'' eccentric (and oblique) to service the kind of latitudes they want more loiter (slow, and far away) ''or'' passage (near, but rapid) over, often in teams of craft spread across the track to pass coverage over to another when one of them zooms on out of the desired 'sweet spot'... &amp;quot;Tundra Orbits&amp;quot;, I think it is? So accounting for them might involve vastly varying heights (though usually similar, overhead to overhead, barring any ascending-/descending-track differences) over a greater-than-average spread of latitudes (but still less than pure 90°-polar would, which is potentially over everywhere at some time or another). [[Special:Contributions/82.132.237.174|82.132.237.174]] 14:06, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;While all of the Tropics are potentially directly under the Moon, note that at any given moment the patch of Earth directly under the moon is a circle about 27.86 km (17.29 miles) in radius. (Proof: Consider the point on earth directly underneath the center of the moon and go 27.86 km in any direction. Your plumb line will then be moved 1/4 of a degree, and so it will miss the moon has a visual diameter of 0.5 degrees.) The same is true for the sun which has have an angular size of 0.5 degrees. Thus on any given day only a strip of the tropics about 55.4 km wide is underneath the moon in this sense and a similar strip exists for points under the sun. Note that it is only under the moon or sun for at most 2 minutes so the sign update must be done quickly. &lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;ISS also has an angular diameter of 0.5 degrees but it is much closer and moves quickly across the field of view so that it is passing over a path about 100 meters wide at a speed of about 8 km/s, leaving insufficient time to update the sign. [[citation needed]] &lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;When I first read the title text I thought it was talking about the tide's effect on the height of the bridge. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 03:55, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;When I first read the title text I thought it was talking about the tide's effect on the height of the bridge. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 03:55, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>2601:45:4100:5490:9801:965:E34D:2B5C</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=400988&amp;oldid=prev</id>
		<title>82.13.184.33 at 09:40, 8 December 2025</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=400988&amp;oldid=prev"/>
				<updated>2025-12-08T09:40:41Z</updated>
		
		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr style=&quot;vertical-align: top;&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 09:40, 8 December 2025&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l43&quot; &gt;Line 43:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 43:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:That aside, superluminal movement/communication ''could'' be achieved by carefully coordinated 'predictive' temporary connectivity, a whole universe-spanning disc of free-floating components that link/unlink as required to 'at that moment' (by any given frame-of-reference) the vehicle/barrier-support-pole is as actually as high as it is expected to be.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:That aside, superluminal movement/communication ''could'' be achieved by carefully coordinated 'predictive' temporary connectivity, a whole universe-spanning disc of free-floating components that link/unlink as required to 'at that moment' (by any given frame-of-reference) the vehicle/barrier-support-pole is as actually as high as it is expected to be.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:Already, we need to have had the normal 'upper limit bar' variously applied/unapplied ''more than 14 billion years ago'', in synch with how our planet's road infrastructure ''and'' its moon are precisely to be positioned, when even the latter won't actually start to exist (to eventually cause such a headache to the former) for almost 10 billion years. So you've already got to have worked that little problem out ahead of time, and thus increasingly less prescient installations perhaps all across half the cosmos. Which is a good trick, if you can do it! [[Special:Contributions/78.144.255.82|78.144.255.82]] 18:32, 30 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:Already, we need to have had the normal 'upper limit bar' variously applied/unapplied ''more than 14 billion years ago'', in synch with how our planet's road infrastructure ''and'' its moon are precisely to be positioned, when even the latter won't actually start to exist (to eventually cause such a headache to the former) for almost 10 billion years. So you've already got to have worked that little problem out ahead of time, and thus increasingly less prescient installations perhaps all across half the cosmos. Which is a good trick, if you can do it! [[Special:Contributions/78.144.255.82|78.144.255.82]] 18:32, 30 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;I added height that would require permit. But wasn't able to find at which height permit will definitely never be granted, maybe because no government actually ever made such statements, but not sure. --[[User:Trimutius|Trimutius]] ([[User talk:Trimutius|talk]]) 13:08, 1 December 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;I added height that would require permit. But wasn't able to find at which height permit will definitely never be granted, maybe because no government actually ever made such statements, but not sure. --[[User:Trimutius|Trimutius]] ([[User talk:Trimutius|talk]]) 13:08, 1 December 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;There's a website with videos of crashes under 11' 8&amp;quot; bridges:&amp;#160; https://11foot8.com/.&amp;#160; [[User:Dbwiddis|Dbwiddis]] ([[User talk:Dbwiddis|talk]]) 18:22, 1 December 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;There's a website with videos of crashes under 11' 8&amp;quot; bridges:&amp;#160; https://11foot8.com/.&amp;#160; [[User:Dbwiddis|Dbwiddis]] ([[User talk:Dbwiddis|talk]]) 18:22, 1 December 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>82.13.184.33</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=400987&amp;oldid=prev</id>
		<title>82.13.184.33 at 09:38, 8 December 2025</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=400987&amp;oldid=prev"/>
				<updated>2025-12-08T09:38:37Z</updated>
		
		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr style=&quot;vertical-align: top;&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 09:38, 8 December 2025&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l32&quot; &gt;Line 32:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 32:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;Hello, If I may, I was thinking that there is an implied sacrificial bar on the ~46b light year sign, as the sign post does not stop at the sign, but continues on out of the panel. This could also add context as to why it is so expensive for the moon to cross over the road, as the highway department would need to very quickly replace the sacrificial bar with a much lower one, only to put the taller one back up a couple minutes or even seconds later. [[User:Nvidietha|Nvidietha]] ([[User talk:Nvidietha|talk]]) 19:04, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;Hello, If I may, I was thinking that there is an implied sacrificial bar on the ~46b light year sign, as the sign post does not stop at the sign, but continues on out of the panel. This could also add context as to why it is so expensive for the moon to cross over the road, as the highway department would need to very quickly replace the sacrificial bar with a much lower one, only to put the taller one back up a couple minutes or even seconds later. [[User:Nvidietha|Nvidietha]] ([[User talk:Nvidietha|talk]]) 19:04, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;: What would happen to a 45-million light-year bar attached to a rotating surface such as earth? Given that points further from the centre would be rotating quicker, wouldn't the points near the end be at and above the speed of light? Would the act of extending it and expending earth's momentum on rotating it and spend all of the speed which allows the end to approach C? What if it materialised instead of extended? As far as i can tell, the Federal Road Body does not have the budget to break the laws of the universe. [[Special:Contributions/92.40.216.156|92.40.216.156]] 21:25, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;: What would happen to a 45-million light-year bar attached to a rotating surface such as earth? Given that points further from the centre would be rotating quicker, wouldn't the points near the end be at and above the speed of light? Would the act of extending it and expending earth's momentum on rotating it and spend all of the speed which allows the end to approach C? What if it materialised instead of extended? As far as i can tell, the Federal Road Body does not have the budget to break the laws of the universe. [[Special:Contributions/92.40.216.156|92.40.216.156]] 21:25, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:: Just taking Earth's rotation into account, the tip would be traveling (length of pole)×2pi per day. Assuming I didn't mess up some units with my napkin math, the tip will be going the speed of light at a length of about 25 AU, which is effectively microscopic on any scale worth measuring in light years. [[Special:Contributions/209.188.63.98|209.188.63.98]] 05:23, 30 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:: Just taking Earth's rotation into account, the tip would be traveling (length of pole)×2pi per day. Assuming I didn't mess up some units with my napkin math, the tip will be going the speed of light at a length of about 25 AU, which is effectively microscopic on any scale worth measuring in light years. [[Special:Contributions/209.188.63.98|209.188.63.98]] 05:23, 30 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l39&quot; &gt;Line 39:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 38:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;: My thought is that, if one maintains a maximally-strict definition of &amp;quot;directly overhead&amp;quot;, the need for such changes would, in actuality, be vanishingly small. Without attempting to crunch numbers, I imagine that, in the context of deep space (and assuming that deep space is finite), a cylinder 2 m in diameter, stretching from the earth's surface, would disappear into the void and hit almost nothing. [[Special:Contributions/205.175.118.102|205.175.118.102]] 22:29, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;: My thought is that, if one maintains a maximally-strict definition of &amp;quot;directly overhead&amp;quot;, the need for such changes would, in actuality, be vanishingly small. Without attempting to crunch numbers, I imagine that, in the context of deep space (and assuming that deep space is finite), a cylinder 2 m in diameter, stretching from the earth's surface, would disappear into the void and hit almost nothing. [[Special:Contributions/205.175.118.102|205.175.118.102]] 22:29, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:: Has anyone yet estimated the average height of overhead cosmic whatever above the Earth's surface? Seems like a topic that someone would have already looked into, and could be used here. I agree though, I think it'd be more likely for a 2m cross-section to hit a &amp;quot;ceiling&amp;quot; at the edge of the observable universe rather than a star or planet. That being said, there are a lot of stars and planets. [[User:R128|R128]] ([[User talk:R128|talk]]) 16:28, 1 December 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:: Has anyone yet estimated the average height of overhead cosmic whatever above the Earth's surface? Seems like a topic that someone would have already looked into, and could be used here. I agree though, I think it'd be more likely for a 2m cross-section to hit a &amp;quot;ceiling&amp;quot; at the edge of the observable universe rather than a star or planet. That being said, there are a lot of stars and planets. [[User:R128|R128]] ([[User talk:R128|talk]]) 16:28, 1 December 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;This ignores the relativistic limits.&amp;#160; At a height of 1/(2 pi cos(latitude)) light days, the top of your vehicle would be traveling at&amp;#160; light speed.&amp;#160; And that is just from the rotation of the earth.&amp;#160; In the Boston area, that works out to about 18.3 trillion feet.&amp;#160; --[[User:Divad27182|Divad27182]] ([[User talk:Divad27182|talk]]) 11:56, 30 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;This ignores the relativistic limits.&amp;#160; At a height of 1/(2 pi cos(latitude)) light days, the top of your vehicle would be traveling at&amp;#160; light speed.&amp;#160; And that is just from the rotation of the earth.&amp;#160; In the Boston area, that works out to about 18.3 trillion feet.&amp;#160; --[[User:Divad27182|Divad27182]] ([[User talk:Divad27182|talk]]) 11:56, 30 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>82.13.184.33</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=400986&amp;oldid=prev</id>
		<title>82.13.184.33 at 09:36, 8 December 2025</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=400986&amp;oldid=prev"/>
				<updated>2025-12-08T09:36:27Z</updated>
		
		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 09:36, 8 December 2025&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l18&quot; &gt;Line 18:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 18:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&amp;gt; ''clearance of 10 feet and 6 inches, which is a realistic clearance''..... Anything less than 13'6&amp;quot; (in the US) will get hit frequently. Yes, we know some bridges that get hit frequently.&amp;#160; --[[User:PRR|PRR]] ([[User talk:PRR|talk]]) 06:42, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&amp;gt; ''clearance of 10 feet and 6 inches, which is a realistic clearance''..... Anything less than 13'6&amp;quot; (in the US) will get hit frequently. Yes, we know some bridges that get hit frequently.&amp;#160; --[[User:PRR|PRR]] ([[User talk:PRR|talk]]) 06:42, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;:&lt;/del&gt;: It says realistic, not common. {{w|Storrow Drive}}, which should be very familiar to Randall, has a clearance of just 10 feet. --[[User:Coconut Galaxy|Coconut Galaxy]] ([[User talk:Coconut Galaxy|talk]]) 07:08, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;: It says realistic, not common. {{w|Storrow Drive}}, which should be very familiar to Randall, has a clearance of just 10 feet. --[[User:Coconut Galaxy|Coconut Galaxy]] ([[User talk:Coconut Galaxy|talk]]) 07:08, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;:&lt;/del&gt;:: Memorial Drive, at the so-called Harvard Bridge, right near MIT, has a clearance of 9 feet 0 inches. Large commercial traffic is not allowed on those two roads. Somehow big trucks go there regardless. MIT students sleeping in the nearby dorm, occasionally awaken to a loud noise. They phone MIT Campus Patrol, say, &amp;quot;Truck trap,&amp;quot; and return to slumber. [[Special:Contributions/173.188.194.233|173.188.194.233]] 15:10, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:: Memorial Drive, at the so-called Harvard Bridge, right near MIT, has a clearance of 9 feet 0 inches. Large commercial traffic is not allowed on those two roads. Somehow big trucks go there regardless. MIT students sleeping in the nearby dorm, occasionally awaken to a loud noise. They phone MIT Campus Patrol, say, &amp;quot;Truck trap,&amp;quot; and return to slumber. [[Special:Contributions/173.188.194.233|173.188.194.233]] 15:10, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;:&lt;/del&gt;: The current standard for bridge heights was established in 1956, when the US Interstate Highway system came into being. The minimum height was originally 14 feet (4.3 m), it was promptly (by 1960) raised to 16 feet (4.9 m); the &amp;lt;del&amp;gt;War&amp;lt;/del&amp;gt; Defense Department had demanded 17 feet (5.2 m). Highways built before the Interstate highway system set the standard (such as Storrow Drive, 1950) had lower clearances. The Merritt Parkway in Connecticut, a pioneering controlled-access highway built in the late 1930s, had a minimum bridge height of 11 feet (3.4 m); some of those clearances today are, or approach, 10 feet six inches (3.2 m). Surviving low-clearance bridges tend to be covered bridges over streams, and railway bridges over secondary roads, all built in the 19th and early 20th centuries. Trucks designed specifically (as they were, IIRC) to haul goods over the Interstate system will struggle on these older constructs. [[Special:Contributions/2605:59C8:160:DB08:E8F0:A309:4673:6AEF|2605:59C8:160:DB08:E8F0:A309:4673:6AEF]] 16:04, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;: The current standard for bridge heights was established in 1956, when the US Interstate Highway system came into being. The minimum height was originally 14 feet (4.3 m), it was promptly (by 1960) raised to 16 feet (4.9 m); the &amp;lt;del&amp;gt;War&amp;lt;/del&amp;gt; Defense Department had demanded 17 feet (5.2 m). Highways built before the Interstate highway system set the standard (such as Storrow Drive, 1950) had lower clearances. The Merritt Parkway in Connecticut, a pioneering controlled-access highway built in the late 1930s, had a minimum bridge height of 11 feet (3.4 m); some of those clearances today are, or approach, 10 feet six inches (3.2 m). Surviving low-clearance bridges tend to be covered bridges over streams, and railway bridges over secondary roads, all built in the 19th and early 20th centuries. Trucks designed specifically (as they were, IIRC) to haul goods over the Interstate system will struggle on these older constructs. [[Special:Contributions/2605:59C8:160:DB08:E8F0:A309:4673:6AEF|2605:59C8:160:DB08:E8F0:A309:4673:6AEF]] 16:04, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;:&lt;/del&gt;:Plenty of bridges in the UK get Bridge Strikes from trucks (despite copious warnings), and even the occasional double-decker bus that the driver gets wrong (wrong route, perhaps on a Not In Service drive to/from the depot, and forgotten what he's driving, hopefully nobody's riding above). Almost any city (and many rural locations) will probably know at least one local railway (or canal!) bridge that has massive amounts of face-protection (painted with warning stripes, words and height details, all the round warning signs, probably a 'jangly chain-bar' roof scraper and/or photoelectric warning-sign illuminator in the last stretch before it - and ''still'' visible scraping/denting on the add-on face-protection).&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:Plenty of bridges in the UK get Bridge Strikes from trucks (despite copious warnings), and even the occasional double-decker bus that the driver gets wrong (wrong route, perhaps on a Not In Service drive to/from the depot, and forgotten what he's driving, hopefully nobody's riding above). Almost any city (and many rural locations) will probably know at least one local railway (or canal!) bridge that has massive amounts of face-protection (painted with warning stripes, words and height details, all the round warning signs, probably a 'jangly chain-bar' roof scraper and/or photoelectric warning-sign illuminator in the last stretch before it - and ''still'' visible scraping/denting on the add-on face-protection).&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;:&lt;/del&gt;:Not sure if it's the lowest, vehiclewise, but for the UK I found https://www.youtube.com/watch?v=Vy9PmSRwG-k (going by the video thumbnail only) as a bridge that (non-SUV!) cars can just about use. But most people couldn't even walk or ride a bike under it, without ducking. Though at least you'd be high enough in any lorry cab to ''know'' it's a barrier to your vehicle. (Well, you'd have missed/disbelieved the signage, but basically be heading at a more obvious 'wall'.) [[Special:Contributions/82.132.237.174|82.132.237.174]] 16:16, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:Not sure if it's the lowest, vehiclewise, but for the UK I found https://www.youtube.com/watch?v=Vy9PmSRwG-k (going by the video thumbnail only) as a bridge that (non-SUV!) cars can just about use. But most people couldn't even walk or ride a bike under it, without ducking. Though at least you'd be high enough in any lorry cab to ''know'' it's a barrier to your vehicle. (Well, you'd have missed/disbelieved the signage, but basically be heading at a more obvious 'wall'.) [[Special:Contributions/82.132.237.174|82.132.237.174]] 16:16, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;:&lt;/del&gt;:: Try [https://www.google.co.uk/maps/@55.9486871,-4.1246238,3a,15y,159.97h,91.04t/data=!3m7!1e1!3m5!1sTzKuejjwGJ6h-bbUb5rVbg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D-1.037973936125013%26panoid%3DTzKuejjwGJ6h-bbUb5rVbg%26yaw%3D159.96810709182384!7i13312!8i6656?hl=en&amp;amp;entry=ttu&amp;amp;g_ep=EgoyMDI1MTEyMy4xIKXMDSoASAFQAw%3D%3D this one] in Scotland, at 4 feet 9 inches (3.2 m). [[Special:Contributions/2605:59C8:160:DB08:E8F0:A309:4673:6AEF|2605:59C8:160:DB08:E8F0:A309:4673:6AEF]] 19:48, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:: Try [https://www.google.co.uk/maps/@55.9486871,-4.1246238,3a,15y,159.97h,91.04t/data=!3m7!1e1!3m5!1sTzKuejjwGJ6h-bbUb5rVbg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D-1.037973936125013%26panoid%3DTzKuejjwGJ6h-bbUb5rVbg%26yaw%3D159.96810709182384!7i13312!8i6656?hl=en&amp;amp;entry=ttu&amp;amp;g_ep=EgoyMDI1MTEyMy4xIKXMDSoASAFQAw%3D%3D this one] in Scotland, at 4 feet 9 inches (3.2 m). [[Special:Contributions/2605:59C8:160:DB08:E8F0:A309:4673:6AEF|2605:59C8:160:DB08:E8F0:A309:4673:6AEF]] 19:48, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;:&lt;/del&gt;:::I don't know what that sign says, or how smalle Scotttish feet are, but 4`9 is slightly under 1.5m. :D --[[Special:Contributions/88.65.244.212|88.65.244.212]] 22:17, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:::I don't know what that sign says, or how smalle Scotttish feet are, but 4`9 is slightly under 1.5m. :D --[[Special:Contributions/88.65.244.212|88.65.244.212]] 22:17, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;:&lt;/del&gt;:::Depending on which Stretview shots (varied examples, seemingly, by time), you also get it as 4'6&amp;quot; and 1.3m warnings (if exactly that in Ft+In, which it might not be, should basically be 1m 37⅙cm, so probably was rounded down to 1.3m, even if the true value was also rounded down to get 4'6&amp;quot;, which is better than being rounded ''up''). The 4'9&amp;quot; might therefore have been a typo/thinko/printo on that version of the non-metric signage, or an inadvertant round-''up'' from the real measurement.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:::Depending on which Stretview shots (varied examples, seemingly, by time), you also get it as 4'6&amp;quot; and 1.3m warnings (if exactly that in Ft+In, which it might not be, should basically be 1m 37⅙cm, so probably was rounded down to 1.3m, even if the true value was also rounded down to get 4'6&amp;quot;, which is better than being rounded ''up''). The 4'9&amp;quot; might therefore have been a typo/thinko/printo on that version of the non-metric signage, or an inadvertant round-''up'' from the real measurement.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;:&lt;/del&gt;:::It looks like the signs on the bridge itself are accurate enough (in a downward-rounding direction), at least in the various versions I've discerned that are not either blurred by the StreetView process or obscured by the vegetation trailing down from above. [[Special:Contributions/78.144.255.82|78.144.255.82]] 22:52, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:::It looks like the signs on the bridge itself are accurate enough (in a downward-rounding direction), at least in the various versions I've discerned that are not either blurred by the StreetView process or obscured by the vegetation trailing down from above. [[Special:Contributions/78.144.255.82|78.144.255.82]] 22:52, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;:&lt;/del&gt;:::: It was 1.4 m, not 3.2. I erred. [[Special:Contributions/205.175.118.102|205.175.118.102]] 00:23, 30 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:::: It was 1.4 m, not 3.2. I erred. [[Special:Contributions/205.175.118.102|205.175.118.102]] 00:23, 30 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;Would expect that those in charge of the airspace would object to vehicles passing through. [[Special:Contributions/64.114.211.61|64.114.211.61]] 17:57, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;Would expect that those in charge of the airspace would object to vehicles passing through. [[Special:Contributions/64.114.211.61|64.114.211.61]] 17:57, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>82.13.184.33</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=392914&amp;oldid=prev</id>
		<title>Dbwiddis at 18:22, 1 December 2025</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=392914&amp;oldid=prev"/>
				<updated>2025-12-01T18:22:49Z</updated>
		
		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 18:22, 1 December 2025&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l49&quot; &gt;Line 49:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 49:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;I added height that would require permit. But wasn't able to find at which height permit will definitely never be granted, maybe because no government actually ever made such statements, but not sure. --[[User:Trimutius|Trimutius]] ([[User talk:Trimutius|talk]]) 13:08, 1 December 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;I added height that would require permit. But wasn't able to find at which height permit will definitely never be granted, maybe because no government actually ever made such statements, but not sure. --[[User:Trimutius|Trimutius]] ([[User talk:Trimutius|talk]]) 13:08, 1 December 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;There's a website with videos of crashes under 11' 8&amp;quot; bridges:&amp;#160; https://11foot8.com/.&amp;#160; [[User:Dbwiddis|Dbwiddis]] ([[User talk:Dbwiddis|talk]]) 18:22, 1 December 2025 (UTC)&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Dbwiddis</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=392909&amp;oldid=prev</id>
		<title>R128 at 16:28, 1 December 2025</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=392909&amp;oldid=prev"/>
				<updated>2025-12-01T16:28:19Z</updated>
		
		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 16:28, 1 December 2025&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l38&quot; &gt;Line 38:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 38:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;Would the presence of stuff deeper in space like stars and asteroids not warrant a constantly-changing number as the earth rotates such that the road intersects different ones?&amp;#160; Currently, if a car with a 10-thousand light-year thing atop following the rotation of earth would likely be constantly hitting various space things as it rotates to follow the earth. [[Special:Contributions/92.40.216.156|92.40.216.156]] 21:17, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;Would the presence of stuff deeper in space like stars and asteroids not warrant a constantly-changing number as the earth rotates such that the road intersects different ones?&amp;#160; Currently, if a car with a 10-thousand light-year thing atop following the rotation of earth would likely be constantly hitting various space things as it rotates to follow the earth. [[Special:Contributions/92.40.216.156|92.40.216.156]] 21:17, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;: My thought is that, if one maintains a maximally-strict definition of &amp;quot;directly overhead&amp;quot;, the need for such changes would, in actuality, be vanishingly small. Without attempting to crunch numbers, I imagine that, in the context of deep space (and assuming that deep space is finite), a cylinder 2 m in diameter, stretching from the earth's surface, would disappear into the void and hit almost nothing. [[Special:Contributions/205.175.118.102|205.175.118.102]] 22:29, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;: My thought is that, if one maintains a maximally-strict definition of &amp;quot;directly overhead&amp;quot;, the need for such changes would, in actuality, be vanishingly small. Without attempting to crunch numbers, I imagine that, in the context of deep space (and assuming that deep space is finite), a cylinder 2 m in diameter, stretching from the earth's surface, would disappear into the void and hit almost nothing. [[Special:Contributions/205.175.118.102|205.175.118.102]] 22:29, 29 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;:: Has anyone yet estimated the average height of overhead cosmic whatever above the Earth's surface? Seems like a topic that someone would have already looked into, and could be used here. I agree though, I think it'd be more likely for a 2m cross-section to hit a &amp;quot;ceiling&amp;quot; at the edge of the observable universe rather than a star or planet. That being said, there are a lot of stars and planets. [[User:R128|R128]] ([[User talk:R128|talk]]) 16:28, 1 December 2025 (UTC)&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>R128</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=392904&amp;oldid=prev</id>
		<title>Trimutius: A bit of a comment about my latest change</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:3174:_Bridge_Clearance&amp;diff=392904&amp;oldid=prev"/>
				<updated>2025-12-01T13:08:07Z</updated>
		
		<summary type="html">&lt;p&gt;A bit of a comment about my latest change&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 13:08, 1 December 2025&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l45&quot; &gt;Line 45:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 45:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:That aside, superluminal movement/communication ''could'' be achieved by carefully coordinated 'predictive' temporary connectivity, a whole universe-spanning disc of free-floating components that link/unlink as required to 'at that moment' (by any given frame-of-reference) the vehicle/barrier-support-pole is as actually as high as it is expected to be.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:That aside, superluminal movement/communication ''could'' be achieved by carefully coordinated 'predictive' temporary connectivity, a whole universe-spanning disc of free-floating components that link/unlink as required to 'at that moment' (by any given frame-of-reference) the vehicle/barrier-support-pole is as actually as high as it is expected to be.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:Already, we need to have had the normal 'upper limit bar' variously applied/unapplied ''more than 14 billion years ago'', in synch with how our planet's road infrastructure ''and'' its moon are precisely to be positioned, when even the latter won't actually start to exist (to eventually cause such a headache to the former) for almost 10 billion years. So you've already got to have worked that little problem out ahead of time, and thus increasingly less prescient installations perhaps all across half the cosmos. Which is a good trick, if you can do it! [[Special:Contributions/78.144.255.82|78.144.255.82]] 18:32, 30 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;:Already, we need to have had the normal 'upper limit bar' variously applied/unapplied ''more than 14 billion years ago'', in synch with how our planet's road infrastructure ''and'' its moon are precisely to be positioned, when even the latter won't actually start to exist (to eventually cause such a headache to the former) for almost 10 billion years. So you've already got to have worked that little problem out ahead of time, and thus increasingly less prescient installations perhaps all across half the cosmos. Which is a good trick, if you can do it! [[Special:Contributions/78.144.255.82|78.144.255.82]] 18:32, 30 November 2025 (UTC)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;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;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;I added height that would require permit. But wasn't able to find at which height permit will definitely never be granted, maybe because no government actually ever made such statements, but not sure. --[[User:Trimutius|Trimutius]] ([[User talk:Trimutius|talk]]) 13:08, 1 December 2025 (UTC)&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Trimutius</name></author>	</entry>

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