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		<id>https://www.explainxkcd.com/wiki/index.php?title=3159:_Continents&amp;diff=389637</id>
		<title>3159: Continents</title>
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				<updated>2025-10-27T12:11:30Z</updated>
		
		<summary type="html">&lt;p&gt;2407:7000:B045:9500:E00E:5D26:A67:8092: year correction&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 3159&lt;br /&gt;
| date      = October 24, 2025&lt;br /&gt;
| title     = Continents&lt;br /&gt;
| image     = continents_2x.png&lt;br /&gt;
| imagesize = 276x430px&lt;br /&gt;
| noexpand  = true&lt;br /&gt;
| titletext = The inflection point was probably in late 1966 or 1967, so when Neil Armstrong flew to space on Gemini 8, plate tectonics was not widely accepted, but when he landed on the Moon three years later it was the mainstream consensus.&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
{{incomplete|This page was created by a TECTONIC PLATE-SIZED CONVEYOR BELT. Don't remove this notice too soon.}}&lt;br /&gt;
{{w|Plate tectonics}} is the theory that the Earth's crust consists of a number of large land masses that have been slowly moving for billions of years. The theory is built on the earlier idea of {{w|Plate_tectonics#Continental_drift|continental drift}}, which was first proposed in the early 20th century. It was controversial until the mid-1960s, when advances in technology such as {{w|Geophysical_imaging#Seismic_Methods|seismic imaging}} made the mechanism clear.&lt;br /&gt;
&lt;br /&gt;
In this comic, [[Randall]] observes that it is very weird how people could go to the Moon before proving plate tectonics on Earth, due to space being thought of usually as a mysterious place, while humans have been on Earth for many millions of years.&lt;br /&gt;
&lt;br /&gt;
Manned spaceflight officially began in 1961, when the {{w|Soviet Union}} launched {{w|Yuri Gagarin}} into space after several years of launching robotic and animal payloads. Randall finds it surprising that we achieved this before we had verified something fundamental about the world we live on. As it happens, the first satellite launches, {{w|Sputnik}} and {{w|Explorer 1}}, took place during (and participated in) the {{w|International Geophysical Year}}, a focused international effort to collaborate across political lines to study the Earth in 1957-58 (which also included the mapping of the {{w|Mid-Atlantic Ridge}}). In the present day, much of plate tectonics research depends on {{w|Satellite navigation|satellite tracking and navigation}}, such as {{w|GPS}} (initiated 1973, launched starting in 1978, operational since 1993), to monitor plate motions in ways that a human on the ground cannot sense. Other critical technologies include {{w|laser rangefinder|laser ranging}} (first invented in 1960) and improvements in {{w|gravimetry|gravimetrics}}, all in advancement around the same time and in the same context of the {{w|Space Race}}.&lt;br /&gt;
&lt;br /&gt;
The spacecraft depicted in the comic appear to be a stylized Gemini re-entry module and an Agena target vehicle. &amp;quot;Houston&amp;quot; is the call sign of mission control at the Lyndon B. Johnson Space Center (known as the Manned Space Center prior to 1973) in Houston, Texas.&lt;br /&gt;
&lt;br /&gt;
The title text points out that plate tectonics was finally validated between {{w|Neil Armstrong}}'s first and last space missions. His first flight was in 1966 on {{w|Gemini 8}}, and his second and last flight was in 1969 on {{w|Apollo 11}}, the first mission to land people on the Moon.&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
{{incomplete transcript|Don't remove this notice too soon.}}&lt;br /&gt;
&amp;lt;p&amp;gt;[Two spacecraft, a Gemini capsule and an Agena Target Vehicle with a loose tether connecting them, are in space over the Mediterranean with Italy in the background. A voice is emanating from the spacecraft]&amp;lt;/p&amp;gt;&lt;br /&gt;
Spacecraft: Houston, the view is superb. We can see the continents spread out below us, right where they've been since the earth formed.&lt;br /&gt;
&amp;lt;p&amp;gt;[Caption beneath panel:]&amp;lt;/p&amp;gt;&lt;br /&gt;
I still can't believe we developed spaceflight before we figured out that the continents moved.&lt;br /&gt;
&lt;br /&gt;
==Trivia==&lt;br /&gt;
The comic may be intended to show Gemini 8's mission, with Armstrong on board, to dock with the previously launched {{w|Agena target vehicle|target vehicle}}. However, severe control issues with that mission precluded many of the planned aims (including the experiments that involved a tethered connection). The mission that might at some point have looked most like this depiction was perhaps {{w|Gemini 11}}, also launched in 1966 but without Armstrong being on board.&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&amp;lt;noinclude&amp;gt;&lt;br /&gt;
[[Category:Space]]&lt;br /&gt;
[[Category:Geology]]&lt;br /&gt;
[[Category:Comics featuring real people]]&lt;/div&gt;</summary>
		<author><name>2407:7000:B045:9500:E00E:5D26:A67:8092</name></author>	</entry>

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