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		<id>https://www.explainxkcd.com/wiki/index.php?title=3221:_Landscape_Features&amp;diff=408628</id>
		<title>3221: Landscape Features</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3221:_Landscape_Features&amp;diff=408628"/>
				<updated>2026-03-22T04:35:03Z</updated>
		
		<summary type="html">&lt;p&gt;Mirror Spock: consistency&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 3221&lt;br /&gt;
| date      = March 18, 2026&lt;br /&gt;
| title     = Landscape Features&lt;br /&gt;
| image     = landscape_features_2x.png&lt;br /&gt;
| imagesize = 537x454px&lt;br /&gt;
| noexpand  = true&lt;br /&gt;
| titletext = 'Well, there's speculation that it's due to a mantle hotspot.' --a geologist who's trying to cover up the fact that they didn't hear your question&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
This comic is a map of the United States, purporting to explain some of the most significant elements of the landscape in each region. For each area it names one major geological or human mechanism (plate tectonics, erosion, farming, etc.) which it claims is responsible for the majority of interesting formations and features.&lt;br /&gt;
&lt;br /&gt;
Many of these causes are summarized in a single word answer, which is overly-simplistic when trying to explain a complex landscape. A few phrases are longer, but still don't actually explain much, and some areas are just labeled &amp;quot;geology&amp;quot;, which while lacking in explanatory power, is often solely responsible for some of the most striking landscape features. &amp;quot;Geology&amp;quot; is in fact poor label here, since almost all of the other causes (volcanos, glacial erosion, plate tectonics, etc.) are all elements of geology.  Randall appears to default to &amp;quot;geology&amp;quot; as the cause in areas where the landscape is largely made of metamorphic or igneous rocks (mountainous areas) instead of some alteration of base rock features via volcanos, earthquakes, etc.  However, the actual landscapes in these areas do have specific causes, as shown by the fact that the Appalachians are labeled as &amp;quot;continents colliding&amp;quot; not &amp;quot;geology&amp;quot;.  Similar more detailed explanations could have been given for other areas, for instance {{w|Laramide_orogeny|&amp;quot;one continent sliding under another&amp;quot;}} for the Rocky Mountains compared to &amp;quot;continents colliding&amp;quot; for the Appalachians.&lt;br /&gt;
&lt;br /&gt;
The title text plays off the fact that a large part of geology is concerned with activity in the mantle, so explaining some geologic feature by saying &amp;quot;there's speculation that it's due to a mantle hotspot&amp;quot; does not give much information. The suggestion is that this would let a distracted geologist buy time while responding to a missed question. Many of Earth's seemingly out-of-place features (e.g., {{w|Hawaii hotspot}}, {{w|Iceland}}, the {{w|Snake River Plain}} in Idaho, etc.) form from such mantle hotspots, so it's an easy go-to explanation for many of the geological features people are often most curious about.  This idea was explored recently in [[3141: Mantle Model]].&lt;br /&gt;
&lt;br /&gt;
This map with subdivisions follows up on a number of prior maps representing supposed geographical splits of some conversational outcome or other, such as [[1407: Worst Hurricane]] and [[2108: Carbonated Beverage Language Map]].&lt;br /&gt;
&lt;br /&gt;
===Table of regions===&lt;br /&gt;
{| class=&amp;quot;wikitable sortable&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! Location&lt;br /&gt;
! Description&lt;br /&gt;
! Explanation&lt;br /&gt;
|-&lt;br /&gt;
| Adirondack Mountains&lt;br /&gt;
| ???&lt;br /&gt;
| The Adirondack Mountains are made of billion-year-old rock but were uplifted relatively recently, within the last 5–10 million years. They are still rising today despite being far from any plate boundary, forming a dome with no clear tectonic cause. &lt;br /&gt;
|-&lt;br /&gt;
| Most of northern conterminous U.S.&lt;br /&gt;
| glaciers&lt;br /&gt;
| During the {{w|Last Glacial Period}}, this area was covered by {{w|Laurentide Ice Sheet|an ice sheet}} that left its marks on the landscape, in the form of {{w|moraines}}, {{w|eskers}}, {{w|glacial erratics}}, etc. This is most notable in Wisconsin where bluffs were formed due to the glacier movement.&lt;br /&gt;
|-&lt;br /&gt;
| Appalachian Mountains&lt;br /&gt;
| continents colliding&lt;br /&gt;
| {{w|Geology of the Appalachians|The Appalachian Mountains formed roughly 480 to 300 million years ago}} through a series of continent-continent collisions, culminating in the assembly of the supercontinent Pangaea. The primary collision involved ancestral North America (Laurentia) crashing into Gondwana (Africa/South America), resulting in a Himalayan-scale mountain range.&lt;br /&gt;
|-&lt;br /&gt;
| Mississippi and Ohio River Basins&lt;br /&gt;
| rivers&lt;br /&gt;
| The {{w|Mississippi River}}'s geology has a complex, 70 million year history involving massive sediment deposition, glacial activity, and tectonic shifting. Formed mostly by melting glaciers ~12,000 years ago, it drains a vast, shifting basin, depositing millions of tons of sediment in a massive delta and creating a vast, shifting alluvial plain. The {{w|Ohio_River#Geology|Ohio River's geology}} is similar.&lt;br /&gt;
|-&lt;br /&gt;
| Southeastern U.S.&lt;br /&gt;
| farming&lt;br /&gt;
| Landscape changes from {{w|cotton production in the United States}}, due to the presence of the {{w|Black Belt (geological formation)|Black Belt}}.  From the perspective of landscape features, it would be more accurate to say that they were caused by &amp;quot;erosion&amp;quot; not &amp;quot;farming&amp;quot;.  The Atlantic Coastal Plain is made up of sediments and sedimentary rock eroded from the Appalachian Mountains over millions of years.  The relatively flat landscape and loose fertile soils make farming both easy and productive respectively.  Thus farming is a result of the landscape features, not a cause of them.&lt;br /&gt;
|-&lt;br /&gt;
| Southern Florida&lt;br /&gt;
| ongoing disputes between limestone and water&lt;br /&gt;
| Florida is a vast {{w|karst}} landscape formed by the dissolution of underground limestone and dolostone bedrock by acidic rainwater, resulting in a terrain characterized by sinkholes, springs, caverns, and disappearing streams. This soluble bedrock, formed from ancient marine deposits, covers much of the state, directly connecting surface water to the Floridian aquifer system.&lt;br /&gt;
|-&lt;br /&gt;
| Southern Missouri / Northern Arkansas&lt;br /&gt;
| geology&lt;br /&gt;
| The {{w|Ozark Mountains}}, which are composed primarily of ancient limestone and {{w|dolomite}}, form a rugged landscape characterized by hills, caves, and springs. Prolonged erosion of these soluble rocks has produced extensive karst features, including sinkholes and underground rivers.&lt;br /&gt;
|-&lt;br /&gt;
| {{w|Great Plains}}&lt;br /&gt;
| farming&lt;br /&gt;
| The lack of other major events left the terrain relatively level; as with the Southeastern U.S./Atlantic Seaboard (see above), the cause of the landscape here is erosion of the Rocky Mountains, with the sediments carried by rivers towards the Mississippi basin and creating a flat, even landscape. Areas were historically shaped by either herds of bison or indigenous agriculture, both limiting the growth of forests. &amp;quot;Farming&amp;quot; is likely a reference to the more recent mix of large-scale crop farming (especially staples like wheat and corn) and herding (bison replaced by cattle). European plowing techniques unsuited for the dry plains ultimately resulted in the {{w|Dust Bowl}}, a period of intense erosion and dust storms which reshaped the landscape, and as a response led to the {{w|Great Plains Shelterbelt}}.&lt;br /&gt;
|-&lt;br /&gt;
| Central Idaho / Yellowstone&lt;br /&gt;
| a supervolcano&lt;br /&gt;
| The {{w|Snake River Plain}} is an area of high-elevation flat plain in the otherwise contiguous Rocky Mountains. It was formed by the movement of the continental plate over the {{w|Yellowstone Hotspot}}.&lt;br /&gt;
|-&lt;br /&gt;
| American West surrounding Idaho / Yellowstone&lt;br /&gt;
| geology&lt;br /&gt;
| [[3162: Heart Mountain]]&lt;br /&gt;
|-&lt;br /&gt;
| Immediately off of West coast up to the Four Corners&lt;br /&gt;
| volcanoes&lt;br /&gt;
| A combination of various {{w|volcanic field}}s of different origins, including {{w|Cascade Volcanoes}} in the Pacific Northwest, {{w|Albuquerque volcanic field}} in New Mexico, {{w|San Francisco volcanic field}} in Arizona, and {{w|San Juan volcanic field}} in Colorado.&lt;br /&gt;
|-&lt;br /&gt;
| Eastern Washington&lt;br /&gt;
| megafloods&lt;br /&gt;
| Most likely a reference to the {{w|Missoula floods}} and the {{w|Bonneville flood}}, a series of floods caused by glacial ice dam failures causing massive lakes to flood large regions of present-day eastern Washington. These floods actually continued all the way to the Pacific Ocean, altering the shape of the {{w|Columbia River Gorge}} and flooding much of the {{w|Willamette River}} in western Oregon. The comic may have simplified these to avoid bisecting the adjacent zones along the coast.&lt;br /&gt;
|-&lt;br /&gt;
| West Coast&lt;br /&gt;
| a plate tectonic speedrun&lt;br /&gt;
| Most likely a reference to the significant tectonic activity on the western coast of the US, caused by the collisions of the {{w|Juan de Fuca plate}}, {{w|Pacific plate}}, and the {{w|North American plate}}, as part of the {{w|Ring of Fire}}.&lt;br /&gt;
|-&lt;br /&gt;
| Southwest Desert&lt;br /&gt;
| water and time&lt;br /&gt;
| The sedimentary rock layers exposed in the {{w|geology of the Grand Canyon area}} range in age from about 200 million to nearly 2 billion years old. Uplift of the region started about 75 million years ago during the mountain-building event creating the Rocky Mountains. The opening of the Gulf of California around 6 million years ago enabled a large river to cut its way northeast from the gulf. The new river captured the older drainage to form the ancestral Colorado River, which started to form the Grand Canyon. Wetter climates from ice ages starting 2 million years ago greatly increased excavation of the Grand Canyon, which was nearly as deep 1.2 million years ago as it is now.  &lt;br /&gt;
|-&lt;br /&gt;
| Northern Alaska&lt;br /&gt;
| geology&lt;br /&gt;
| Northern {{w|Geology of Alaska|Alaska geology}} is dominated by the Brooks Range (a major Paleozoic mountain belt) and the Arctic Slope sedimentary basin, containing rich Paleozoic-Mesozoic rock sequences. The region is part of the Arctic Alaska–Chukotka Microplate, shaped by Mesozoic tectonic shifts, including the Arctic Ocean opening and the Brooks Range uplift.&lt;br /&gt;
|-&lt;br /&gt;
| Aleutian Islands&lt;br /&gt;
| volcanoes&lt;br /&gt;
| The Aleutian Islands are a continuation of the Alaskan {{w|Aleutian Range}}, and form part of the {{w|Ring of Fire}}. Most of the islands in the chain bear signs of being formed by volcanoes, and many volcanic cones still exist on the islands today.&lt;br /&gt;
|-&lt;br /&gt;
| Southeast Alaska&lt;br /&gt;
| glaciers&lt;br /&gt;
| This part of Alaska (including {{w|Glacier Bay National Park and Preserve|Glacier Bay National Park and Preserve}}) and western Canada has many glaciers that are still carving the landscape.&lt;br /&gt;
|-&lt;br /&gt;
| Hawaiian island chain&lt;br /&gt;
| volcanoes&lt;br /&gt;
| Hawaii, including the {{w|Northwest Hawaiian Islands}}, and seamounts northwest of it were formed by a tectonic plate moving over a hotspot, with volcanoes erupting and forming land as it went. The entire chain can be seen [https://www.google.com/maps/@34.0555574,-176.5939317,4904085m/data=!3m1!1e3?entry=ttu&amp;amp;g_ep=EgoyMDI2MDMxNS4wIKXMDSoASAFQAw%3D%3D here]. Volcanic fog from the {{w|List of volcanoes in the Hawaiian–Emperor seamount chain|three active volcanoes on the Big Island}} can often be seen on neighboring islands.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Features of each state, alphabetically===&lt;br /&gt;
* Alabama: continents colliding, farming, rivers&lt;br /&gt;
* Alaska: geology, glaciers, volcanoes&lt;br /&gt;
* Arizona: water and time, volcanoes&lt;br /&gt;
* Arkansas: geology, farming, rivers&lt;br /&gt;
* California: a plate tectonics speedrun, volcanoes, water and time&lt;br /&gt;
* Colorado: volcanoes, geology, farming&lt;br /&gt;
* Connecticut: glaciers&lt;br /&gt;
* Delaware: farming&lt;br /&gt;
* District of Columbia: either farming or plates colliding&lt;br /&gt;
* Florida: farming, ongoing disputes between limestone and water&lt;br /&gt;
* Georgia: continents colliding, farming&lt;br /&gt;
* Hawaii: volcanoes&lt;br /&gt;
* Idaho: a super volcano, geology&lt;br /&gt;
* Illinois: glaciers, rivers&lt;br /&gt;
* Indiana: glaciers, rivers&lt;br /&gt;
* Iowa: glaciers, farming, rivers&lt;br /&gt;
* Kansas: farming&lt;br /&gt;
* Kentucky: rivers, continents colliding&lt;br /&gt;
* Louisiana: farming, rivers&lt;br /&gt;
* Maine: glaciers&lt;br /&gt;
* Maryland: plates colliding, farming&lt;br /&gt;
* Massachusetts: glaciers&lt;br /&gt;
* Michigan: glaciers&lt;br /&gt;
* Minnesota: glaciers, farming, rivers&lt;br /&gt;
* Mississippi: farming, rivers&lt;br /&gt;
* Missouri: farming, geology, rivers&lt;br /&gt;
* Montana: geology, glaciers&lt;br /&gt;
* Nebraska: farming&lt;br /&gt;
* Nevada: volcanoes, geology, water and time&lt;br /&gt;
* New Hampshire: glaciers&lt;br /&gt;
* New Jersey: glaciers, farming&lt;br /&gt;
* New Mexico: volcanoes, geology, water and time, farming&lt;br /&gt;
* New York: glaciers, ???, continents colliding&lt;br /&gt;
* North Carolina: continents colliding, farming&lt;br /&gt;
* North Dakota: glaciers, farming&lt;br /&gt;
* Ohio: glaciers, rivers&lt;br /&gt;
* Oklahoma: farming, geology&lt;br /&gt;
* Oregon: a plate tectonics speedrun, volcanoes, megafloods, a supervolcano, geology&lt;br /&gt;
* Pennsylvania: glaciers, rivers, continents colliding, farming&lt;br /&gt;
* Rhode Island: glaciers&lt;br /&gt;
* South Carolina: continents colliding, farming&lt;br /&gt;
* South Dakota: glaciers, farming&lt;br /&gt;
* Tennessee: continents colliding, rivers&lt;br /&gt;
* Texas: farming, geology, water and time&lt;br /&gt;
* Utah: geology, volcanoes&lt;br /&gt;
* Vermont: glaciers&lt;br /&gt;
* Virginia: continents colliding, farming&lt;br /&gt;
* Washington: megafloods, a plate tectonics speedrun&lt;br /&gt;
* West Virginia: rivers, continents colliding&lt;br /&gt;
* Wisconsin: glaciers, rivers&lt;br /&gt;
* Wyoming: a supervolcano, geology, farming&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:[A small panel showing Cueball pointing toward the left and Ponytail standing to his right overlaps the top of a much larger panel containing a map.]&lt;br /&gt;
:Cueball: What's up with this weird landscape?&lt;br /&gt;
:Ponytail: Oh, it was caused by ...&lt;br /&gt;
&lt;br /&gt;
:[The larger panel shows a map of the United States, with southern Canada, northern Mexico, and most of Cuba and the Bahamas visible as well. An inset at lower left shows Alaska along with part of northwest Canada, with a smaller inset showing Hawaii. International borders and coastlines are indicated in black, and state borders are indicated in gray. Red lines divide the United States into irregularly shaped zones (the red lines indicating zones do not cross into the neighboring countries, except in the Alaska inset), with each zone being labeled with red text. Each text label begins with &amp;quot;...&amp;quot; to indicate that it is the conclusion of Ponytail's sentence. The following are the labels used:]&lt;br /&gt;
:[Main map:]&lt;br /&gt;
:... a plate tectonics speedrun&lt;br /&gt;
:... volcanoes&lt;br /&gt;
:... megafloods&lt;br /&gt;
:... a supervolcano&lt;br /&gt;
:... geology&lt;br /&gt;
:... water and time&lt;br /&gt;
:... glaciers&lt;br /&gt;
:... rivers&lt;br /&gt;
:... continents colliding&lt;br /&gt;
:... ???&lt;br /&gt;
:... ongoing disputes between limestone and water&lt;br /&gt;
:[On the main map, the label &amp;quot;... glaciers&amp;quot; appears three times in various places in the same contiguous zone that runs from Washington state to Maine. The label &amp;quot;... farming&amp;quot; appears twice, representing two separate zones, one that runs from Montana to Louisiana and the other that runs from New Jersey to Mississippi. The label &amp;quot;... geology&amp;quot; appears twice on the main map, representing two separate zones, one that runs from Washington state to Texas and the other being a roughly circular region mostly in southern Missouri and northern Arkansas.]&lt;br /&gt;
:[Alaska inset:]&lt;br /&gt;
:... geology&lt;br /&gt;
:... volcanoes&lt;br /&gt;
:... glaciers&lt;br /&gt;
:[Hawaii inset:]&lt;br /&gt;
:... volcanoes&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&amp;lt;noinclude&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[Category:Comics with color]]&lt;br /&gt;
[[Category:US maps]]&lt;br /&gt;
[[Category:Comics featuring Cueball]]&lt;br /&gt;
[[Category:Comics featuring Ponytail]]&lt;br /&gt;
[[Category:Geology]]&lt;br /&gt;
[[Category:Volcanoes]]&lt;/div&gt;</summary>
		<author><name>Mirror Spock</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3221:_Landscape_Features&amp;diff=408627</id>
		<title>3221: Landscape Features</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3221:_Landscape_Features&amp;diff=408627"/>
				<updated>2026-03-22T04:32:15Z</updated>
		
		<summary type="html">&lt;p&gt;Mirror Spock: `&amp;amp;` ~~&amp;gt; `and`&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 3221&lt;br /&gt;
| date      = March 18, 2026&lt;br /&gt;
| title     = Landscape Features&lt;br /&gt;
| image     = landscape_features_2x.png&lt;br /&gt;
| imagesize = 537x454px&lt;br /&gt;
| noexpand  = true&lt;br /&gt;
| titletext = 'Well, there's speculation that it's due to a mantle hotspot.' --a geologist who's trying to cover up the fact that they didn't hear your question&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
This comic is a map of the United States, purporting to explain some of the most significant elements of the landscape in each region. For each area it names one major geological or human mechanism (plate tectonics, erosion, farming, etc.) which it claims is responsible for the majority of interesting formations and features.&lt;br /&gt;
&lt;br /&gt;
Many of these causes are summarized in a single word answer, which is overly-simplistic when trying to explain a complex landscape. A few phrases are longer, but still don't actually explain much, and some areas are just labeled &amp;quot;geology&amp;quot;, which while lacking in explanatory power, is often solely responsible for some of the most striking landscape features. &amp;quot;Geology&amp;quot; is in fact poor label here, since almost all of the other causes (volcanos, glacial erosion, plate tectonics, etc.) are all elements of geology.  Randall appears to default to &amp;quot;geology&amp;quot; as the cause in areas where the landscape is largely made of metamorphic or igneous rocks (mountainous areas) instead of some alteration of base rock features via volcanos, earthquakes, etc.  However, the actual landscapes in these areas do have specific causes, as shown by the fact that the Appalachians are labeled as &amp;quot;continents colliding&amp;quot; not &amp;quot;geology&amp;quot;.  Similar more detailed explanations could have been given for other areas, for instance {{w|Laramide_orogeny|&amp;quot;one continent sliding under another&amp;quot;}} for the Rocky Mountains compared to &amp;quot;continents colliding&amp;quot; for the Appalachians.&lt;br /&gt;
&lt;br /&gt;
The title text plays off the fact that a large part of geology is concerned with activity in the mantle, so explaining some geologic feature by saying &amp;quot;there's speculation that it's due to a mantle hotspot&amp;quot; does not give much information. The suggestion is that this would let a distracted geologist buy time while responding to a missed question. Many of Earth's seemingly out-of-place features (e.g., {{w|Hawaii hotspot}}, {{w|Iceland}}, the {{w|Snake River Plain}} in Idaho, etc.) form from such mantle hotspots, so it's an easy go-to explanation for many of the geological features people are often most curious about.  This idea was explored recently in [[3141: Mantle Model]].&lt;br /&gt;
&lt;br /&gt;
This map with subdivisions follows up on a number of prior maps representing supposed geographical splits of some conversational outcome or other, such as [[1407: Worst Hurricane]] and [[2108: Carbonated Beverage Language Map]].&lt;br /&gt;
&lt;br /&gt;
===Table of regions===&lt;br /&gt;
{| class=&amp;quot;wikitable sortable&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! Location&lt;br /&gt;
! Description&lt;br /&gt;
! Explanation&lt;br /&gt;
|-&lt;br /&gt;
| Adirondack Mountains&lt;br /&gt;
| ???&lt;br /&gt;
| The Adirondack Mountains are made of billion-year-old rock but were uplifted relatively recently, within the last 5–10 million years. They are still rising today despite being far from any plate boundary, forming a dome with no clear tectonic cause. &lt;br /&gt;
|-&lt;br /&gt;
| Most of northern conterminous U.S.&lt;br /&gt;
| glaciers&lt;br /&gt;
| During the {{w|Last Glacial Period}}, this area was covered by {{w|Laurentide Ice Sheet|an ice sheet}} that left its marks on the landscape, in the form of {{w|moraines}}, {{w|eskers}}, {{w|glacial erratics}}, etc. This is most notable in Wisconsin where bluffs were formed due to the glacier movement.&lt;br /&gt;
|-&lt;br /&gt;
| Appalachian Mountains&lt;br /&gt;
| continents colliding&lt;br /&gt;
| {{w|Geology of the Appalachians|The Appalachian Mountains formed roughly 480 to 300 million years ago}} through a series of continent-continent collisions, culminating in the assembly of the supercontinent Pangaea. The primary collision involved ancestral North America (Laurentia) crashing into Gondwana (Africa/South America), resulting in a Himalayan-scale mountain range.&lt;br /&gt;
|-&lt;br /&gt;
| Mississippi and Ohio River Basins&lt;br /&gt;
| rivers&lt;br /&gt;
| The {{w|Mississippi River}}'s geology has a complex, 70 million year history involving massive sediment deposition, glacial activity, and tectonic shifting. Formed mostly by melting glaciers ~12,000 years ago, it drains a vast, shifting basin, depositing millions of tons of sediment in a massive delta and creating a vast, shifting alluvial plain. The {{w|Ohio_River#Geology|Ohio River's geology}} is similar.&lt;br /&gt;
|-&lt;br /&gt;
| Southeastern U.S.&lt;br /&gt;
| farming&lt;br /&gt;
| Landscape changes from {{w|cotton production in the United States}}, due to the presence of the {{w|Black Belt (geological formation)|Black Belt}}.  From the perspective of landscape features, it would be more accurate to say that they were caused by &amp;quot;erosion&amp;quot; not &amp;quot;farming&amp;quot;.  The Atlantic Coastal Plain is made up of sediments and sedimentary rock eroded from the Appalachian Mountains over millions of years.  The relatively flat landscape and loose fertile soils make farming both easy and productive respectively.  Thus farming is a result of the landscape features, not a cause of them.&lt;br /&gt;
|-&lt;br /&gt;
| Southern Florida&lt;br /&gt;
| ongoing disputes between limestone and water&lt;br /&gt;
| Florida is a vast {{w|karst}} landscape formed by the dissolution of underground limestone and dolostone bedrock by acidic rainwater, resulting in a terrain characterized by sinkholes, springs, caverns, and disappearing streams. This soluble bedrock, formed from ancient marine deposits, covers much of the state, directly connecting surface water to the Floridian aquifer system.&lt;br /&gt;
|-&lt;br /&gt;
| Southern Missouri / Northern Arkansas&lt;br /&gt;
| geology&lt;br /&gt;
| The {{w|Ozark Mountains}}, which are composed primarily of ancient limestone and {{w|dolomite}}, form a rugged landscape characterized by hills, caves, and springs. Prolonged erosion of these soluble rocks has produced extensive karst features, including sinkholes and underground rivers.&lt;br /&gt;
|-&lt;br /&gt;
| {{w|Great Plains}}&lt;br /&gt;
| farming&lt;br /&gt;
| The lack of other major events left the terrain relatively level; as with the Southeastern U.S./Atlantic Seaboard (see above), the cause of the landscape here is erosion of the Rocky Mountains, with the sediments carried by rivers towards the Mississippi basin and creating a flat, even landscape. Areas were historically shaped by either herds of bison or indigenous agriculture, both limiting the growth of forests. &amp;quot;Farming&amp;quot; is likely a reference to the more recent mix of large-scale crop farming (especially staples like wheat and corn) and herding (bison replaced by cattle). European plowing techniques unsuited for the dry plains ultimately resulted in the {{w|Dust Bowl}}, a period of intense erosion and dust storms which reshaped the landscape, and as a response led to the {{w|Great Plains Shelterbelt}}.&lt;br /&gt;
|-&lt;br /&gt;
| Central Idaho / Yellowstone&lt;br /&gt;
| a supervolcano&lt;br /&gt;
| The {{w|Snake River Plain}} is an area of high-elevation flat plain in the otherwise contiguous Rocky Mountains. It was formed by the movement of the continental plate over the {{w|Yellowstone Hotspot}}.&lt;br /&gt;
|-&lt;br /&gt;
| American West surrounding Idaho / Yellowstone&lt;br /&gt;
| geology&lt;br /&gt;
| [[3162: Heart Mountain]]&lt;br /&gt;
|-&lt;br /&gt;
| Immediately off of West coast up to the Four Corners&lt;br /&gt;
| volcanoes&lt;br /&gt;
| A combination of various {{w|volcanic field}}s of different origins, including {{w|Cascade Volcanoes}} in the Pacific Northwest, {{w|Albuquerque volcanic field}} in New Mexico, {{w|San Francisco volcanic field}} in Arizona, and {{w|San Juan volcanic field}} in Colorado.&lt;br /&gt;
|-&lt;br /&gt;
| Eastern Washington&lt;br /&gt;
| megafloods&lt;br /&gt;
| Most likely a reference to the {{w|Missoula floods}} and the {{w|Bonneville flood}}, a series of floods caused by glacial ice dam failures causing massive lakes to flood large regions of present-day eastern Washington. These floods actually continued all the way to the Pacific Ocean, altering the shape of the {{w|Columbia River Gorge}} and flooding much of the {{w|Willamette River}} in western Oregon. The comic may have simplified these to avoid bisecting the adjacent zones along the coast.&lt;br /&gt;
|-&lt;br /&gt;
| West Coast&lt;br /&gt;
| a plate tectonic speedrun&lt;br /&gt;
| Most likely a reference to the significant tectonic activity on the western coast of the US, caused by the collisions of the {{w|Juan de Fuca plate}}, {{w|Pacific plate}}, and the {{w|North American plate}}, as part of the {{w|Ring of Fire}}.&lt;br /&gt;
|-&lt;br /&gt;
| Southwest Desert&lt;br /&gt;
| water and time&lt;br /&gt;
| The sedimentary rock layers exposed in the {{w|geology of the Grand Canyon area}} range in age from about 200 million to nearly 2 billion years old. Uplift of the region started about 75 million years ago during the mountain-building event creating the Rocky Mountains. The opening of the Gulf of California around 6 million years ago enabled a large river to cut its way northeast from the gulf. The new river captured the older drainage to form the ancestral Colorado River, which started to form the Grand Canyon. Wetter climates from ice ages starting 2 million years ago greatly increased excavation of the Grand Canyon, which was nearly as deep 1.2 million years ago as it is now.  &lt;br /&gt;
|-&lt;br /&gt;
| Northern Alaska&lt;br /&gt;
| geology&lt;br /&gt;
| Northern {{w|Geology of Alaska|Alaska geology}} is dominated by the Brooks Range (a major Paleozoic mountain belt) and the Arctic Slope sedimentary basin, containing rich Paleozoic-Mesozoic rock sequences. The region is part of the Arctic Alaska–Chukotka Microplate, shaped by Mesozoic tectonic shifts, including the Arctic Ocean opening and the Brooks Range uplift.&lt;br /&gt;
|-&lt;br /&gt;
| Aleutian Islands&lt;br /&gt;
| volcanoes&lt;br /&gt;
| The Aleutian Islands are a continuation of the Alaskan {{w|Aleutian Range}}, and form part of the {{w|Ring of Fire}}. Most of the islands in the chain bear signs of being formed by volcanoes, and many volcanic cones still exist on the islands today.&lt;br /&gt;
|-&lt;br /&gt;
| Southeast Alaska&lt;br /&gt;
| glaciers&lt;br /&gt;
| This part of Alaska (including {{w|Glacier Bay National Park and Preserve|Glacier Bay National Park and Preserve}}) and western Canada has many glaciers that are still carving the landscape.&lt;br /&gt;
|-&lt;br /&gt;
| Hawaiian island chain&lt;br /&gt;
| volcanoes&lt;br /&gt;
| Hawaii, including the {{w|Northwest Hawaiian Islands}}, and seamounts northwest of it were formed by a tectonic plate moving over a hotspot, with volcanoes erupting and forming land as it went. The entire chain can be seen [https://www.google.com/maps/@34.0555574,-176.5939317,4904085m/data=!3m1!1e3?entry=ttu&amp;amp;g_ep=EgoyMDI2MDMxNS4wIKXMDSoASAFQAw%3D%3D here]. Volcanic fog from the {{w|List of volcanoes in the Hawaiian–Emperor seamount chain|three active volcanoes on the Big Island}} can often be seen on neighboring islands.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Features of each state, alphabetically===&lt;br /&gt;
* Alabama: continents colliding, farming, rivers&lt;br /&gt;
* Alaska: geology, glaciers, volcanoes&lt;br /&gt;
* Arizona: water and time, volcanoes&lt;br /&gt;
* Arkansas: geology, farming, rivers&lt;br /&gt;
* California: a plate tectonics speedrun, volcanoes, water and time&lt;br /&gt;
* Colorado: volcanoes, geology, farming&lt;br /&gt;
* Connecticut: glaciers&lt;br /&gt;
* Delaware: farming&lt;br /&gt;
* District of Columbia: either farming or plates colliding&lt;br /&gt;
* Florida: farming, ongoing disputes between limestone and water&lt;br /&gt;
* Georgia: continents colliding, farming&lt;br /&gt;
* Hawaii: volcanoes&lt;br /&gt;
* Idaho: a super volcano, geology&lt;br /&gt;
* Illinois: glaciers, rivers&lt;br /&gt;
* Indiana: glaciers, rivers&lt;br /&gt;
* Iowa: glaciers, farming, rivers&lt;br /&gt;
* Kansas: farming&lt;br /&gt;
* Kentucky: rivers, continents colliding&lt;br /&gt;
* Louisiana: farming, rivers&lt;br /&gt;
* Maine: glaciers&lt;br /&gt;
* Maryland: plates colliding, farming&lt;br /&gt;
* Massachusetts: glaciers&lt;br /&gt;
* Michigan: glaciers&lt;br /&gt;
* Minnesota: glaciers, farming, rivers&lt;br /&gt;
* Mississippi: farming, rivers&lt;br /&gt;
* Missouri: farming, geology, rivers&lt;br /&gt;
* Montana: geology, glaciers&lt;br /&gt;
* Nebraska: farming&lt;br /&gt;
* Nevada: volcanoes, geology, water and time&lt;br /&gt;
* New Hampshire: glaciers&lt;br /&gt;
* New Jersey: glaciers, farming&lt;br /&gt;
* New Mexico: volcanoes, geology, water and time, farming&lt;br /&gt;
* New York: glaciers, ???, continents colliding&lt;br /&gt;
* North Carolina: continents colliding, farming&lt;br /&gt;
* North Dakota: glaciers, farming&lt;br /&gt;
* Ohio: glaciers, rivers&lt;br /&gt;
* Oklahoma: farming, geology&lt;br /&gt;
* Oregon: a plate tectonics speedrun, volcanoes, mega floods, a supervolcano, geology&lt;br /&gt;
* Pennsylvania: glaciers, rivers, continents colliding, farming&lt;br /&gt;
* Rhode Island: glaciers&lt;br /&gt;
* South Carolina: continents colliding, farming&lt;br /&gt;
* South Dakota: glaciers, farming&lt;br /&gt;
* Tennessee: continents colliding, rivers&lt;br /&gt;
* Texas: farming, geology, water and time&lt;br /&gt;
* Utah: geology, volcanoes&lt;br /&gt;
* Vermont: glaciers&lt;br /&gt;
* Virginia: continents colliding, farming&lt;br /&gt;
* Washington: Mega floods, a plate tectonics speedrun&lt;br /&gt;
* West Virginia: rivers, continents colliding&lt;br /&gt;
* Wisconsin: glaciers, rivers&lt;br /&gt;
* Wyoming: a supervolcano, geology, farming&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:[A small panel showing Cueball pointing toward the left and Ponytail standing to his right overlaps the top of a much larger panel containing a map.]&lt;br /&gt;
:Cueball: What's up with this weird landscape?&lt;br /&gt;
:Ponytail: Oh, it was caused by ...&lt;br /&gt;
&lt;br /&gt;
:[The larger panel shows a map of the United States, with southern Canada, northern Mexico, and most of Cuba and the Bahamas visible as well. An inset at lower left shows Alaska along with part of northwest Canada, with a smaller inset showing Hawaii. International borders and coastlines are indicated in black, and state borders are indicated in gray. Red lines divide the United States into irregularly shaped zones (the red lines indicating zones do not cross into the neighboring countries, except in the Alaska inset), with each zone being labeled with red text. Each text label begins with &amp;quot;...&amp;quot; to indicate that it is the conclusion of Ponytail's sentence. The following are the labels used:]&lt;br /&gt;
:[Main map:]&lt;br /&gt;
:... a plate tectonics speedrun&lt;br /&gt;
:... volcanoes&lt;br /&gt;
:... megafloods&lt;br /&gt;
:... a supervolcano&lt;br /&gt;
:... geology&lt;br /&gt;
:... water and time&lt;br /&gt;
:... glaciers&lt;br /&gt;
:... rivers&lt;br /&gt;
:... continents colliding&lt;br /&gt;
:... ???&lt;br /&gt;
:... ongoing disputes between limestone and water&lt;br /&gt;
:[On the main map, the label &amp;quot;... glaciers&amp;quot; appears three times in various places in the same contiguous zone that runs from Washington state to Maine. The label &amp;quot;... farming&amp;quot; appears twice, representing two separate zones, one that runs from Montana to Louisiana and the other that runs from New Jersey to Mississippi. The label &amp;quot;... geology&amp;quot; appears twice on the main map, representing two separate zones, one that runs from Washington state to Texas and the other being a roughly circular region mostly in southern Missouri and northern Arkansas.]&lt;br /&gt;
:[Alaska inset:]&lt;br /&gt;
:... geology&lt;br /&gt;
:... volcanoes&lt;br /&gt;
:... glaciers&lt;br /&gt;
:[Hawaii inset:]&lt;br /&gt;
:... volcanoes&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&amp;lt;noinclude&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[Category:Comics with color]]&lt;br /&gt;
[[Category:US maps]]&lt;br /&gt;
[[Category:Comics featuring Cueball]]&lt;br /&gt;
[[Category:Comics featuring Ponytail]]&lt;br /&gt;
[[Category:Geology]]&lt;br /&gt;
[[Category:Volcanoes]]&lt;/div&gt;</summary>
		<author><name>Mirror Spock</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3221:_Landscape_Features&amp;diff=408623</id>
		<title>3221: Landscape Features</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3221:_Landscape_Features&amp;diff=408623"/>
				<updated>2026-03-21T23:42:11Z</updated>
		
		<summary type="html">&lt;p&gt;Mirror Spock: Added missing states&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 3221&lt;br /&gt;
| date      = March 18, 2026&lt;br /&gt;
| title     = Landscape Features&lt;br /&gt;
| image     = landscape_features_2x.png&lt;br /&gt;
| imagesize = 537x454px&lt;br /&gt;
| noexpand  = true&lt;br /&gt;
| titletext = 'Well, there's speculation that it's due to a mantle hotspot.' --a geologist who's trying to cover up the fact that they didn't hear your question&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
This comic is a map of the United States, purporting to explain some of the most significant elements of the landscape in each region. For each area it names one major geological or human mechanism (plate tectonics, erosion, farming, etc.) which it claims is responsible for the majority of interesting formations and features.&lt;br /&gt;
&lt;br /&gt;
Many of these causes are summarized in a single word answer, which is overly-simplistic when trying to explain a complex landscape. A few phrases are longer, but still don't actually explain much, and some areas are just labeled &amp;quot;geology&amp;quot;, which while lacking in explanatory power, is often solely responsible for some of the most striking landscape features. &amp;quot;Geology&amp;quot; is in fact poor label here, since almost all of the other causes (volcanos, glacial erosion, plate tectonics, etc.) are all elements of geology.  Randall appears to default to &amp;quot;geology&amp;quot; as the cause in areas where the landscape is largely made of metamorphic or igneous rocks (mountainous areas) instead of some alteration of base rock features via volcanos, earthquakes, etc.  However, the actual landscapes in these areas do have specific causes, as shown by the fact that the Appalachians are labeled as &amp;quot;continents colliding&amp;quot; not &amp;quot;geology&amp;quot;.  Similar more detailed explanations could have been given for other areas, for instance {{w|Laramide_orogeny|&amp;quot;one continent sliding under another&amp;quot;}} for the Rocky Mountains compared to &amp;quot;continents colliding&amp;quot; for the Appalachians.&lt;br /&gt;
&lt;br /&gt;
The title text plays off the fact that a large part of geology is concerned with activity in the mantle, so explaining some geologic feature by saying &amp;quot;there's speculation that it's due to a mantle hotspot&amp;quot; does not give much information. The suggestion is that this would let a distracted geologist buy time while responding to a missed question. Many of Earth's seemingly out-of-place features (e.g., {{w|Hawaii hotspot}}, {{w|Iceland}}, the {{w|Snake River Plain}} in Idaho, etc.) form from such mantle hotspots, so it's an easy go-to explanation for many of the geological features people are often most curious about.  This idea was explored recently in [[3141: Mantle Model]].&lt;br /&gt;
&lt;br /&gt;
This map with subdivisions follows up on a number of prior maps representing supposed geographical splits of some conversational outcome or other, such as [[1407: Worst Hurricane]] and [[2108: Carbonated Beverage Language Map]].&lt;br /&gt;
&lt;br /&gt;
===Table of regions===&lt;br /&gt;
{| class=&amp;quot;wikitable sortable&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! Location&lt;br /&gt;
! Description&lt;br /&gt;
! Explanation&lt;br /&gt;
|-&lt;br /&gt;
| Adirondack Mountains&lt;br /&gt;
| ???&lt;br /&gt;
| The Adirondack Mountains are made of billion-year-old rock but were uplifted relatively recently, within the last 5–10 million years. They are still rising today despite being far from any plate boundary, forming a dome with no clear tectonic cause. &lt;br /&gt;
|-&lt;br /&gt;
| Most of northern conterminous U.S.&lt;br /&gt;
| glaciers&lt;br /&gt;
| During the {{w|Last Glacial Period}}, this area was covered by {{w|Laurentide Ice Sheet|an ice sheet}} that left its marks on the landscape, in the form of {{w|moraines}}, {{w|eskers}}, {{w|glacial erratics}}, etc. This is most notable in Wisconsin where bluffs were formed due to the glacier movement.&lt;br /&gt;
|-&lt;br /&gt;
| Appalachian Mountains&lt;br /&gt;
| continents colliding&lt;br /&gt;
| {{w|Geology of the Appalachians|The Appalachian Mountains formed roughly 480 to 300 million years ago}} through a series of continent-continent collisions, culminating in the assembly of the supercontinent Pangaea. The primary collision involved ancestral North America (Laurentia) crashing into Gondwana (Africa/South America), resulting in a Himalayan-scale mountain range.&lt;br /&gt;
|-&lt;br /&gt;
| Mississippi and Ohio River Basins&lt;br /&gt;
| rivers&lt;br /&gt;
| The {{w|Mississippi River}}'s geology has a complex, 70 million year history involving massive sediment deposition, glacial activity, and tectonic shifting. Formed mostly by melting glaciers ~12,000 years ago, it drains a vast, shifting basin, depositing millions of tons of sediment in a massive delta and creating a vast, shifting alluvial plain. The {{w|Ohio_River#Geology|Ohio River's geology}} is similar.&lt;br /&gt;
|-&lt;br /&gt;
| Southeastern U.S.&lt;br /&gt;
| farming&lt;br /&gt;
| Landscape changes from {{w|cotton production in the United States}}, due to the presence of the {{w|Black Belt (geological formation)|Black Belt}}.  From the perspective of landscape features, it would be more accurate to say that they were caused by &amp;quot;erosion&amp;quot; not &amp;quot;farming&amp;quot;.  The Atlantic Coastal Plain is made up of sediments and sedimentary rock eroded from the Appalachian Mountains over millions of years.  The relatively flat landscape and loose fertile soils make farming both easy and productive respectively.  Thus farming is a result of the landscape features, not a cause of them.&lt;br /&gt;
|-&lt;br /&gt;
| Southern Florida&lt;br /&gt;
| ongoing disputes between limestone and water&lt;br /&gt;
| Florida is a vast {{w|karst}} landscape formed by the dissolution of underground limestone and dolostone bedrock by acidic rainwater, resulting in a terrain characterized by sinkholes, springs, caverns, and disappearing streams. This soluble bedrock, formed from ancient marine deposits, covers much of the state, directly connecting surface water to the Floridian aquifer system.&lt;br /&gt;
|-&lt;br /&gt;
| Southern Missouri / Northern Arkansas&lt;br /&gt;
| geology&lt;br /&gt;
| The {{w|Ozark Mountains}}, which are composed primarily of ancient limestone and {{w|dolomite}}, form a rugged landscape characterized by hills, caves, and springs. Prolonged erosion of these soluble rocks has produced extensive karst features, including sinkholes and underground rivers.&lt;br /&gt;
|-&lt;br /&gt;
| {{w|Great Plains}}&lt;br /&gt;
| farming&lt;br /&gt;
| The lack of other major events left the terrain relatively level; as with the Southeastern U.S./Atlantic Seaboard (see above), the cause of the landscape here is erosion of the Rocky Mountains, with the sediments carried by rivers towards the Mississippi basin and creating a flat, even landscape. Areas were historically shaped by either herds of bison or indigenous agriculture, both limiting the growth of forests. &amp;quot;Farming&amp;quot; is likely a reference to the more recent mix of large-scale crop farming (especially staples like wheat and corn) and herding (bison replaced by cattle). European plowing techniques unsuited for the dry plains ultimately resulted in the {{w|Dust Bowl}}, a period of intense erosion and dust storms which reshaped the landscape, and as a response led to the {{w|Great Plains Shelterbelt}}.&lt;br /&gt;
|-&lt;br /&gt;
| Central Idaho / Yellowstone&lt;br /&gt;
| a supervolcano&lt;br /&gt;
| The {{w|Snake River Plain}} is an area of high-elevation flat plain in the otherwise contiguous Rocky Mountains. It was formed by the movement of the continental plate over the {{w|Yellowstone Hotspot}}.&lt;br /&gt;
|-&lt;br /&gt;
| American West surrounding Idaho / Yellowstone&lt;br /&gt;
| geology&lt;br /&gt;
| [[3162: Heart Mountain]]&lt;br /&gt;
|-&lt;br /&gt;
| Immediately off of West coast up to the Four Corners&lt;br /&gt;
| volcanoes&lt;br /&gt;
| A combination of various {{w|volcanic field}}s of different origins, including {{w|Cascade Volcanoes}} in the Pacific Northwest, {{w|Albuquerque volcanic field}} in New Mexico, {{w|San Francisco volcanic field}} in Arizona, and {{w|San Juan volcanic field}} in Colorado.&lt;br /&gt;
|-&lt;br /&gt;
| Eastern Washington&lt;br /&gt;
| megafloods&lt;br /&gt;
| Most likely a reference to the {{w|Missoula floods}} and the {{w|Bonneville flood}}, a series of floods caused by glacial ice dam failures causing massive lakes to flood large regions of present-day eastern Washington. These floods actually continued all the way to the Pacific Ocean, altering the shape of the {{w|Columbia River Gorge}} and flooding much of the {{w|Willamette River}} in western Oregon. The comic may have simplified these to avoid bisecting the adjacent zones along the coast.&lt;br /&gt;
|-&lt;br /&gt;
| West Coast&lt;br /&gt;
| a plate tectonic speedrun&lt;br /&gt;
| Most likely a reference to the significant tectonic activity on the western coast of the US, caused by the collisions of the {{w|Juan de Fuca plate}}, {{w|Pacific plate}}, and the {{w|North American plate}}, as part of the {{w|Ring of Fire}}.&lt;br /&gt;
|-&lt;br /&gt;
| Southwest Desert&lt;br /&gt;
| water and time&lt;br /&gt;
| The sedimentary rock layers exposed in the {{w|geology of the Grand Canyon area}} range in age from about 200 million to nearly 2 billion years old. Uplift of the region started about 75 million years ago during the mountain-building event creating the Rocky Mountains. The opening of the Gulf of California around 6 million years ago enabled a large river to cut its way northeast from the gulf. The new river captured the older drainage to form the ancestral Colorado River, which started to form the Grand Canyon. Wetter climates from ice ages starting 2 million years ago greatly increased excavation of the Grand Canyon, which was nearly as deep 1.2 million years ago as it is now.  &lt;br /&gt;
|-&lt;br /&gt;
| Northern Alaska&lt;br /&gt;
| geology&lt;br /&gt;
| Northern {{w|Geology of Alaska|Alaska geology}} is dominated by the Brooks Range (a major Paleozoic mountain belt) and the Arctic Slope sedimentary basin, containing rich Paleozoic-Mesozoic rock sequences. The region is part of the Arctic Alaska–Chukotka Microplate, shaped by Mesozoic tectonic shifts, including the Arctic Ocean opening and the Brooks Range uplift.&lt;br /&gt;
|-&lt;br /&gt;
| Aleutian Islands&lt;br /&gt;
| volcanoes&lt;br /&gt;
| The Aleutian Islands are a continuation of the Alaskan {{w|Aleutian Range}}, and form part of the {{w|Ring of Fire}}. Most of the islands in the chain bear signs of being formed by volcanoes, and many volcanic cones still exist on the islands today.&lt;br /&gt;
|-&lt;br /&gt;
| Southeast Alaska&lt;br /&gt;
| glaciers&lt;br /&gt;
| This part of Alaska (including {{w|Glacier Bay National Park and Preserve|Glacier Bay National Park and Preserve}}) and western Canada has many glaciers that are still carving the landscape.&lt;br /&gt;
|-&lt;br /&gt;
| Hawaiian island chain&lt;br /&gt;
| volcanoes&lt;br /&gt;
| Hawaii, including the {{w|Northwest Hawaiian Islands}}, and seamounts northwest of it were formed by a tectonic plate moving over a hotspot, with volcanoes erupting and forming land as it went. The entire chain can be seen [https://www.google.com/maps/@34.0555574,-176.5939317,4904085m/data=!3m1!1e3?entry=ttu&amp;amp;g_ep=EgoyMDI2MDMxNS4wIKXMDSoASAFQAw%3D%3D here]. Volcanic fog from the {{w|List of volcanoes in the Hawaiian–Emperor seamount chain|three active volcanoes on the Big Island}} can often be seen on neighboring islands.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Features of each state, alphabetically===&lt;br /&gt;
* Alabama: continents colliding, farming, rivers&lt;br /&gt;
* Alaska: geology, glaciers, volcanoes&lt;br /&gt;
* Arizona: water &amp;amp; time, volcanoes&lt;br /&gt;
* Arkansas: geology, farming, rivers&lt;br /&gt;
* California: a plate tectonics speedrun, volcanoes, water &amp;amp; time&lt;br /&gt;
* Colorado: volcanoes, geology, farming&lt;br /&gt;
* Connecticut: glaciers&lt;br /&gt;
* Delaware: farming&lt;br /&gt;
* District of Columbia: either farming or plates colliding&lt;br /&gt;
* Florida: farming, ongoing disputes between limestone &amp;amp; water&lt;br /&gt;
* Georgia: continents colliding, farming&lt;br /&gt;
* Hawaii: volcanoes&lt;br /&gt;
* Idaho: a super volcano, geology&lt;br /&gt;
* Illinois: glaciers, rivers&lt;br /&gt;
* Indiana: glaciers, rivers&lt;br /&gt;
* Iowa: glaciers, farming, rivers&lt;br /&gt;
* Kansas: farming&lt;br /&gt;
* Kentucky: rivers, continents colliding&lt;br /&gt;
* Louisiana: farming, rivers&lt;br /&gt;
* Maine: glaciers&lt;br /&gt;
* Maryland: plates colliding, farming&lt;br /&gt;
* Massachusetts: glaciers&lt;br /&gt;
* Michigan: glaciers&lt;br /&gt;
* Minnesota: glaciers, farming, rivers&lt;br /&gt;
* Mississippi: farming, rivers&lt;br /&gt;
* Missouri: farming, geology, rivers&lt;br /&gt;
* Montana: geology, glaciers&lt;br /&gt;
* Nebraska: farming&lt;br /&gt;
* Nevada: volcanoes, geology, water &amp;amp; time&lt;br /&gt;
* New Hampshire: glaciers&lt;br /&gt;
* New Jersey: glaciers, farming&lt;br /&gt;
* New Mexico: volcanoes, geology, water &amp;amp; time, farming&lt;br /&gt;
* New York: glaciers, ???, continents colliding&lt;br /&gt;
* North Carolina: continents colliding, farming&lt;br /&gt;
* North Dakota: glaciers, farming&lt;br /&gt;
* Ohio: glaciers, rivers&lt;br /&gt;
* Oklahoma: farming, geology&lt;br /&gt;
* Oregon: a plate tectonics speedrun, volcanoes, mega floods, a supervolcano, geology&lt;br /&gt;
* Pennsylvania: glaciers, rivers, continents colliding, farming&lt;br /&gt;
* Rhode Island: glaciers&lt;br /&gt;
* South Carolina: continents colliding, farming&lt;br /&gt;
* South Dakota: glaciers, farming&lt;br /&gt;
* Tennessee: continents colliding, rivers&lt;br /&gt;
* Texas: farming, geology, water &amp;amp; time&lt;br /&gt;
* Utah: geology, volcanoes&lt;br /&gt;
* Vermont: glaciers&lt;br /&gt;
* Virginia: continents colliding, farming&lt;br /&gt;
* Washington: Mega floods, a plate tectonics speedrun&lt;br /&gt;
* West Virginia: rivers, continents colliding&lt;br /&gt;
* Wisconsin: glaciers, rivers&lt;br /&gt;
* Wyoming: a supervolcano, geology, farming&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:[A small panel showing Cueball pointing toward the left and Ponytail standing to his right overlaps the top of a much larger panel containing a map.]&lt;br /&gt;
:Cueball: What's up with this weird landscape?&lt;br /&gt;
:Ponytail: Oh, it was caused by ...&lt;br /&gt;
&lt;br /&gt;
:[The larger panel shows a map of the United States, with southern Canada, northern Mexico, and most of Cuba and the Bahamas visible as well. An inset at lower left shows Alaska along with part of northwest Canada, with a smaller inset showing Hawaii. International borders and coastlines are indicated in black, and state borders are indicated in gray. Red lines divide the United States into irregularly shaped zones (the red lines indicating zones do not cross into the neighboring countries, except in the Alaska inset), with each zone being labeled with red text. Each text label begins with &amp;quot;...&amp;quot; to indicate that it is the conclusion of Ponytail's sentence. The following are the labels used:]&lt;br /&gt;
:[Main map:]&lt;br /&gt;
:... a plate tectonics speedrun&lt;br /&gt;
:... volcanoes&lt;br /&gt;
:... megafloods&lt;br /&gt;
:... a supervolcano&lt;br /&gt;
:... geology&lt;br /&gt;
:... water and time&lt;br /&gt;
:... glaciers&lt;br /&gt;
:... rivers&lt;br /&gt;
:... continents colliding&lt;br /&gt;
:... ???&lt;br /&gt;
:... ongoing disputes between limestone and water&lt;br /&gt;
:[On the main map, the label &amp;quot;... glaciers&amp;quot; appears three times in various places in the same contiguous zone that runs from Washington state to Maine. The label &amp;quot;... farming&amp;quot; appears twice, representing two separate zones, one that runs from Montana to Louisiana and the other that runs from New Jersey to Mississippi. The label &amp;quot;... geology&amp;quot; appears twice on the main map, representing two separate zones, one that runs from Washington state to Texas and the other being a roughly circular region mostly in southern Missouri and northern Arkansas.]&lt;br /&gt;
:[Alaska inset:]&lt;br /&gt;
:... geology&lt;br /&gt;
:... volcanoes&lt;br /&gt;
:... glaciers&lt;br /&gt;
:[Hawaii inset:]&lt;br /&gt;
:... volcanoes&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&amp;lt;noinclude&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[Category:Comics with color]]&lt;br /&gt;
[[Category:US maps]]&lt;br /&gt;
[[Category:Comics featuring Cueball]]&lt;br /&gt;
[[Category:Comics featuring Ponytail]]&lt;br /&gt;
[[Category:Geology]]&lt;br /&gt;
[[Category:Volcanoes]]&lt;/div&gt;</summary>
		<author><name>Mirror Spock</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3221:_Landscape_Features&amp;diff=408604</id>
		<title>3221: Landscape Features</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3221:_Landscape_Features&amp;diff=408604"/>
				<updated>2026-03-21T04:39:46Z</updated>
		
		<summary type="html">&lt;p&gt;Mirror Spock: Added TN&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 3221&lt;br /&gt;
| date      = March 18, 2026&lt;br /&gt;
| title     = Landscape Features&lt;br /&gt;
| image     = landscape_features_2x.png&lt;br /&gt;
| imagesize = 537x454px&lt;br /&gt;
| noexpand  = true&lt;br /&gt;
| titletext = 'Well, there's speculation that it's due to a mantle hotspot.' --a geologist who's trying to cover up the fact that they didn't hear your question&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
This comic is a map of the United States, purporting to explain some of the most significant elements of the landscape in each region. For each area it names one major geological or human mechanism (plate tectonics, erosion, farming, etc.) which it claims is responsible for the majority of interesting formations and features.&lt;br /&gt;
&lt;br /&gt;
Many of these causes are summarized in a single word answer, which is overly-simplistic when trying to explain a complex landscape. A few phrases are longer, but still don't actually explain much, and some areas are just labeled &amp;quot;geology&amp;quot;, which while lacking in explanatory power, is often solely responsible for some of the most striking landscape features. &amp;quot;Geology&amp;quot; is in fact poor label here, since almost all of the other causes (volcanos, glacial erosion, plate tectonics, etc.) are all elements of geology.  Randall appears to default to &amp;quot;geology&amp;quot; as the cause in areas where the landscape is largely made of metamorphic or igneous rocks (mountainous areas) instead of some alteration of base rock features via volcanos, earthquakes, etc.  However, the actual landscapes in these areas do have specific causes, as shown by the fact that the Appalachians are labeled as &amp;quot;continents colliding&amp;quot; not &amp;quot;geology&amp;quot;.  Similar more detailed explanations could have been given for other areas, for instance {{w|Laramide_orogeny|&amp;quot;one continent sliding under another&amp;quot;}} for the Rocky Mountains compared to &amp;quot;continents colliding&amp;quot; for the Appalachians.&lt;br /&gt;
&lt;br /&gt;
The title text plays off the fact that a large part of geology is concerned with activity in the mantle, so explaining some geologic feature by saying &amp;quot;there's speculation that it's due to a mantle hotspot&amp;quot; does not give much information. The suggestion is that this would let a distracted geologist buy time while responding to a missed question. Many of Earth's seemingly out-of-place features (e.g., {{w|Hawaii hotspot}}, {{w|Iceland}}, the {{w|Snake River Plain}} in Idaho, etc.) form from such mantle hotspots, so it's an easy go-to explanation for many of the geological features people are often most curious about.  This idea was explored recently in [[3141: Mantle Model]].&lt;br /&gt;
&lt;br /&gt;
This map with subdivisions follows up on a number of prior maps representing supposed geographical splits of some conversational outcome or other, such as [[1407: Worst Hurricane]] and [[2108: Carbonated Beverage Language Map]].&lt;br /&gt;
&lt;br /&gt;
===Table of regions===&lt;br /&gt;
{| class=&amp;quot;wikitable sortable&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! Location&lt;br /&gt;
! Description&lt;br /&gt;
! Explanation&lt;br /&gt;
|-&lt;br /&gt;
| Adirondack Mountains&lt;br /&gt;
| ???&lt;br /&gt;
| The Adirondack Mountains are made of billion-year-old rock but were uplifted relatively recently, within the last 5–10 million years. They are still rising today despite being far from any plate boundary, forming a dome with no clear tectonic cause. &lt;br /&gt;
|-&lt;br /&gt;
| Most of northern conterminous U.S.&lt;br /&gt;
| glaciers&lt;br /&gt;
| During the {{w|Last Glacial Period}}, this area was covered by {{w|Laurentide Ice Sheet|an ice sheet}} that left its marks on the landscape, in the form of {{w|moraines}}, {{w|eskers}}, {{w|glacial erratics}}, etc. This is most notable in Wisconsin where bluffs were formed due to the glacier movement.&lt;br /&gt;
|-&lt;br /&gt;
| Appalachian Mountains&lt;br /&gt;
| continents colliding&lt;br /&gt;
| {{w|Geology of the Appalachians|The Appalachian Mountains formed roughly 480 to 300 million years ago}} through a series of continent-continent collisions, culminating in the assembly of the supercontinent Pangaea. The primary collision involved ancestral North America (Laurentia) crashing into Gondwana (Africa/South America), resulting in a Himalayan-scale mountain range.&lt;br /&gt;
|-&lt;br /&gt;
| Mississippi and Ohio River Basins&lt;br /&gt;
| rivers&lt;br /&gt;
| The {{w|Mississippi River}}'s geology has a complex, 70 million year history involving massive sediment deposition, glacial activity, and tectonic shifting. Formed mostly by melting glaciers ~12,000 years ago, it drains a vast, shifting basin, depositing millions of tons of sediment in a massive delta and creating a vast, shifting alluvial plain. The {{w|Ohio_River#Geology|Ohio River's geology}} is similar.&lt;br /&gt;
|-&lt;br /&gt;
| Southeastern U.S.&lt;br /&gt;
| farming&lt;br /&gt;
| Landscape changes from {{w|cotton production in the United States}}, due to the presence of the {{w|Black Belt (geological formation)|Black Belt}}.  From the perspective of landscape features, it would be more accurate to say that they were caused by &amp;quot;erosion&amp;quot; not &amp;quot;farming&amp;quot;.  The Atlantic Coastal Plain is made up of sediments and sedimentary rock eroded from the Appalachian Mountains over millions of years.  The relatively flat landscape and loose fertile soils make farming both easy and productive respectively.  Thus farming is a result of the landscape features, not a cause of them.&lt;br /&gt;
|-&lt;br /&gt;
| Southern Florida&lt;br /&gt;
| ongoing disputes between limestone and water&lt;br /&gt;
| Florida is a vast {{w|karst}} landscape formed by the dissolution of underground limestone and dolostone bedrock by acidic rainwater, resulting in a terrain characterized by sinkholes, springs, caverns, and disappearing streams. This soluble bedrock, formed from ancient marine deposits, covers much of the state, directly connecting surface water to the Floridian aquifer system.&lt;br /&gt;
|-&lt;br /&gt;
| Southern Missouri / Northern Arkansas&lt;br /&gt;
| geology&lt;br /&gt;
| The {{w|Ozark Mountains}}, which are composed primarily of ancient limestone and {{w|dolomite}}, form a rugged landscape characterized by hills, caves, and springs. Prolonged erosion of these soluble rocks has produced extensive karst features, including sinkholes and underground rivers.&lt;br /&gt;
|-&lt;br /&gt;
| {{w|Great Plains}}&lt;br /&gt;
| farming&lt;br /&gt;
| The lack of other major events left the terrain relatively level; as with the Southeastern U.S./Atlantic Seaboard (see above), the cause of the landscape here is erosion of the Rocky Mountains, with the sediments carried by rivers towards the Mississippi basin and creating a flat, even landscape. Areas were historically shaped by either herds of bison or indigenous agriculture, both limiting the growth of forests. &amp;quot;Farming&amp;quot; is likely a reference to the more recent mix of large-scale crop farming (especially staples like wheat and corn) and herding (bison replaced by cattle). European plowing techniques unsuited for the dry plains ultimately resulted in the {{w|Dust Bowl}}, a period of intense erosion and dust storms which reshaped the landscape, and as a response led to the {{w|Great Plains Shelterbelt}}.&lt;br /&gt;
|-&lt;br /&gt;
| Central Idaho / Yellowstone&lt;br /&gt;
| a supervolcano&lt;br /&gt;
| The {{w|Snake River Plain}} is an area of high-elevation flat plain in the otherwise contiguous Rocky Mountains. It was formed by the movement of the continental plate over the {{w|Yellowstone Hotspot}}.&lt;br /&gt;
|-&lt;br /&gt;
| American West surrounding Idaho / Yellowstone&lt;br /&gt;
| geology&lt;br /&gt;
| [[3162: Heart Mountain]]&lt;br /&gt;
|-&lt;br /&gt;
| Immediately off of West coast up to the Four Corners&lt;br /&gt;
| volcanoes&lt;br /&gt;
| A combination of various {{w|volcanic field}}s of different origins, including {{w|Cascade Volcanoes}} in the Pacific Northwest, {{w|Albuquerque volcanic field}} in New Mexico, {{w|San Francisco volcanic field}} in Arizona, and {{w|San Juan volcanic field}} in Colorado.&lt;br /&gt;
|-&lt;br /&gt;
| Eastern Washington&lt;br /&gt;
| megafloods&lt;br /&gt;
| Most likely a reference to the {{w|Missoula floods}} and the {{w|Bonneville flood}}, a series of floods caused by glacial ice dam failures causing massive lakes to flood large regions of present-day eastern Washington. These floods actually continued all the way to the Pacific Ocean, altering the shape of the {{w|Columbia River Gorge}} and flooding much of the {{w|Willamette River}} in western Oregon. The comic may have simplified these to avoid bisecting the adjacent zones along the coast.&lt;br /&gt;
|-&lt;br /&gt;
| West Coast&lt;br /&gt;
| a plate tectonic speedrun&lt;br /&gt;
| Most likely a reference to the significant tectonic activity on the western coast of the US, caused by the collisions of the {{w|Juan de Fuca plate}}, {{w|Pacific plate}}, and the {{w|North American plate}}, as part of the {{w|Ring of Fire}}.&lt;br /&gt;
|-&lt;br /&gt;
| Southwest Desert&lt;br /&gt;
| water and time&lt;br /&gt;
| The sedimentary rock layers exposed in the {{w|geology of the Grand Canyon area}} range in age from about 200 million to nearly 2 billion years old. Uplift of the region started about 75 million years ago during the mountain-building event creating the Rocky Mountains. The opening of the Gulf of California around 6 million years ago enabled a large river to cut its way northeast from the gulf. The new river captured the older drainage to form the ancestral Colorado River, which started to form the Grand Canyon. Wetter climates from ice ages starting 2 million years ago greatly increased excavation of the Grand Canyon, which was nearly as deep 1.2 million years ago as it is now.  &lt;br /&gt;
|-&lt;br /&gt;
| Northern Alaska&lt;br /&gt;
| geology&lt;br /&gt;
| Northern {{w|Geology of Alaska|Alaska geology}} is dominated by the Brooks Range (a major Paleozoic mountain belt) and the Arctic Slope sedimentary basin, containing rich Paleozoic-Mesozoic rock sequences. The region is part of the Arctic Alaska–Chukotka Microplate, shaped by Mesozoic tectonic shifts, including the Arctic Ocean opening and the Brooks Range uplift.&lt;br /&gt;
|-&lt;br /&gt;
| Aleutian Islands&lt;br /&gt;
| volcanoes&lt;br /&gt;
| The Aleutian Islands are a continuation of the Alaskan {{w|Aleutian Range}}, and form part of the {{w|Ring of Fire}}. Most of the islands in the chain bear signs of being formed by volcanoes, and many volcanic cones still exist on the islands today.&lt;br /&gt;
|-&lt;br /&gt;
| Southeast Alaska&lt;br /&gt;
| glaciers&lt;br /&gt;
| This part of Alaska (including {{w|Glacier Bay National Park and Preserve|Glacier Bay National Park and Preserve}}) and western Canada has many glaciers that are still carving the landscape.&lt;br /&gt;
|-&lt;br /&gt;
| Hawaiian island chain&lt;br /&gt;
| volcanoes&lt;br /&gt;
| Hawaii, including the {{w|Northwest Hawaiian Islands}}, and seamounts northwest of it were formed by a tectonic plate moving over a hotspot, with volcanoes erupting and forming land as it went. The entire chain can be seen [https://www.google.com/maps/@34.0555574,-176.5939317,4904085m/data=!3m1!1e3?entry=ttu&amp;amp;g_ep=EgoyMDI2MDMxNS4wIKXMDSoASAFQAw%3D%3D here]. Volcanic fog from the {{w|List of volcanoes in the Hawaiian–Emperor seamount chain|three active volcanoes on the Big Island}} can often be seen on neighboring islands.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Features of each state, alphabetically===&lt;br /&gt;
* Alaska: geology, glaciers, volcanoes&lt;br /&gt;
* Arizona: water &amp;amp; time, volcanoes&lt;br /&gt;
* Arkansas: geology, farming, rivers&lt;br /&gt;
* California: a plate tectonics speedrun, volcanoes, water &amp;amp; time&lt;br /&gt;
* Colorado: volcanoes, geology, farming&lt;br /&gt;
* Connecticut: glaciers&lt;br /&gt;
* Delaware: farming&lt;br /&gt;
* District of Columbia: either farming or plates colliding&lt;br /&gt;
* Florida: farming, ongoing disputes between limestone &amp;amp; water&lt;br /&gt;
* Hawaii: volcanoes&lt;br /&gt;
* Idaho: a super volcano, geology&lt;br /&gt;
* Illinois: glaciers, rivers&lt;br /&gt;
* Indiana: glaciers, rivers&lt;br /&gt;
* Iowa: glaciers, farming, rivers&lt;br /&gt;
* Kansas: farming&lt;br /&gt;
* Kentucky: rivers, continents colliding&lt;br /&gt;
* Maine: glaciers&lt;br /&gt;
* Maryland: plates colliding, farming&lt;br /&gt;
* Massachusetts: glaciers&lt;br /&gt;
* Michigan: glaciers&lt;br /&gt;
* Minnesota: glaciers, farming, rivers&lt;br /&gt;
* Missouri: farming, geology, rivers&lt;br /&gt;
* Montana: geology, glaciers&lt;br /&gt;
* Nebraska: farming&lt;br /&gt;
* Nevada: volcanoes, geology, water &amp;amp; time&lt;br /&gt;
* New Hampshire: glaciers&lt;br /&gt;
* New Jersey: glaciers, farming&lt;br /&gt;
* New Mexico: volcanoes, geology, water &amp;amp; time, farming&lt;br /&gt;
* New York: glaciers, ???, continents colliding&lt;br /&gt;
* North Dakota: glaciers, farming&lt;br /&gt;
* Ohio: glaciers, rivers&lt;br /&gt;
* Oklahoma: farming, geology&lt;br /&gt;
* Oregon: a plate tectonics speedrun, volcanoes, mega floods, a supervolcano, geology&lt;br /&gt;
* Pennsylvania: glaciers, rivers, continents colliding, farming&lt;br /&gt;
* Rhode Island: glaciers&lt;br /&gt;
* South Dakota: glaciers, farming&lt;br /&gt;
* Tennessee: continents colliding, rivers&lt;br /&gt;
* Texas: farming, geology, water &amp;amp; time&lt;br /&gt;
* Utah: geology, volcanoes&lt;br /&gt;
* Vermont: glaciers&lt;br /&gt;
* Virginia: continents colliding, farming&lt;br /&gt;
* Washington: Mega floods, a plate tectonics speedrun&lt;br /&gt;
* West Virginia: rivers, continents colliding&lt;br /&gt;
* Wisconsin: glaciers, rivers&lt;br /&gt;
* Wyoming: a supervolcano, geology, farming&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:[A small panel showing Cueball pointing toward the left and Ponytail standing to his right overlaps the top of a much larger panel containing a map.]&lt;br /&gt;
:Cueball: What's up with this weird landscape?&lt;br /&gt;
:Ponytail: Oh, it was caused by ...&lt;br /&gt;
&lt;br /&gt;
:[The larger panel shows a map of the United States, with southern Canada, northern Mexico, and most of Cuba and the Bahamas visible as well. An inset at lower left shows Alaska along with part of northwest Canada, with a smaller inset showing Hawaii. International borders and coastlines are indicated in black, and state borders are indicated in gray. Red lines divide the United States into irregularly shaped zones (the red lines indicating zones do not cross into the neighboring countries, except in the Alaska inset), with each zone being labeled with red text. Each text label begins with &amp;quot;...&amp;quot; to indicate that it is the conclusion of Ponytail's sentence. The following are the labels used:]&lt;br /&gt;
:[Main map:]&lt;br /&gt;
:... a plate tectonics speedrun&lt;br /&gt;
:... volcanoes&lt;br /&gt;
:... megafloods&lt;br /&gt;
:... a supervolcano&lt;br /&gt;
:... geology&lt;br /&gt;
:... water and time&lt;br /&gt;
:... glaciers&lt;br /&gt;
:... rivers&lt;br /&gt;
:... continents colliding&lt;br /&gt;
:... ???&lt;br /&gt;
:... ongoing disputes between limestone and water&lt;br /&gt;
:[On the main map, the label &amp;quot;... glaciers&amp;quot; appears three times in various places in the same contiguous zone that runs from Washington state to Maine. The label &amp;quot;... farming&amp;quot; appears twice, representing two separate zones, one that runs from Montana to Louisiana and the other that runs from New Jersey to Mississippi. The label &amp;quot;... geology&amp;quot; appears twice on the main map, representing two separate zones, one that runs from Washington state to Texas and the other being a roughly circular region mostly in southern Missouri and northern Arkansas.]&lt;br /&gt;
:[Alaska inset:]&lt;br /&gt;
:... geology&lt;br /&gt;
:... volcanoes&lt;br /&gt;
:... glaciers&lt;br /&gt;
:[Hawaii inset:]&lt;br /&gt;
:... volcanoes&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&amp;lt;noinclude&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[Category:Comics with color]]&lt;br /&gt;
[[Category:US maps]]&lt;br /&gt;
[[Category:Comics featuring Cueball]]&lt;br /&gt;
[[Category:Comics featuring Ponytail]]&lt;br /&gt;
[[Category:Geology]]&lt;br /&gt;
[[Category:Volcanoes]]&lt;/div&gt;</summary>
		<author><name>Mirror Spock</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3156:_Planetary_Rings&amp;diff=389111</id>
		<title>3156: Planetary Rings</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3156:_Planetary_Rings&amp;diff=389111"/>
				<updated>2025-10-18T11:39:15Z</updated>
		
		<summary type="html">&lt;p&gt;Mirror Spock: made list a table&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 3156&lt;br /&gt;
| date      = October 17, 2025&lt;br /&gt;
| title     = Planetary Rings&lt;br /&gt;
| image     = planetary_rings_2x.png&lt;br /&gt;
| imagesize = 356x279px&lt;br /&gt;
| noexpand  = true&lt;br /&gt;
| titletext = If you don't know where you are on Earth, the angle of satellite dishes can help constrain your latitude. If some of them are pointing straight up, you're probably near the Equator, right under the ring.&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
{{incomplete|This page was created by an off-axis satellite dish. Don't remove this notice too soon.}}&lt;br /&gt;
A {{w|ring system|planetary ring}} is a disc of small objects and other material orbiting a planet. The most well known are the rings of {{w|Saturn}}, which were discovered by {{w|Galileo Galilei}}, but all the {{w|gas giant}} planets in the Solar System have rings, as do some minor planets and moons.&lt;br /&gt;
&lt;br /&gt;
Earth does not have a natural ring system, although it's theorized that it [https://web.archive.org/web/20250401024532/https://time.com/7022440/earth-ring-like-saturn-study/ may have had one] in the distant past. However, since the 1950s (slightly over 68 years before this comic's publication), we have launched many artificial satellites into Earth orbit. The ones specifically in {{w|geostationary orbit}} (the {{w|Syncom|first}} of these being launched in 1964) are in the equatorial plane (as are some with different {{w|orbital period}}s), so they can be considered to constitute an artificial ring system. (Other satellites operate within various other {{w|orbital plane}}s, including {{w|geosynchronous orbit}}s that are not strictly geostationary, creating {{w|File:Starlink_SpaceX_1584_satellites_72_Planes_22each.png|various other}} halo-like clouds.)&lt;br /&gt;
&lt;br /&gt;
{{w|Satellite dishes}} are used to communicate with most of these devices. If they are stationary that means they are pointed at a {{w|geostationary satellite}} in middle and low latitudes, or a {{w|Molniya orbit}} satellite constellation in higher latitudes. Not all dishes are pointed at the geostationary orbit, but in that case, if they are used for communicating with satellites in other orbits or with space probes, they must move continuously to track the satellite/probe. &lt;br /&gt;
&lt;br /&gt;
(Note 1 - there are motorized dishes that can move between some number of pre-programmed positions to select which geostationary satellite to use at a given moment.&lt;br /&gt;
Note 2 - there are antennas which can &amp;quot;point&amp;quot; at different directions by {{w|Phased array|electronic means}}, without physically moving (eg, {{w|Starlink}} user terminals).)&lt;br /&gt;
&lt;br /&gt;
In terms of mass, Earth's ring system is tiny compared to other planetary ring systems in the Solar System. In descending order of mass, these are Saturn (10&amp;lt;sup&amp;gt;19&amp;lt;/sup&amp;gt; kg [https://www.science.org/doi/10.1126/science.aat2965]), Uranus (10&amp;lt;sup&amp;gt;16&amp;lt;/sup&amp;gt; kg [https://en.wikipedia.org/wiki/Rings_of_Uranus]), Jupiter (between 10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt; and 10&amp;lt;sup&amp;gt;16&amp;lt;/sup&amp;gt; kg [https://pages.astro.umd.edu/~dphamil/research/preprints/BurSimSho03.pdf]), Neptune (10&amp;lt;sup&amp;gt;15&amp;lt;/sup&amp;gt; kg [https://en.wikipedia.org/wiki/Rings_of_Neptune]). Assuming 580 satellites (active and inactive, 1/2° slots) in geostationary orbit [https://en.wikipedia.org/wiki/List_of_satellites_in_geosynchronous_orbit] and a typical mass of 1,000 kg, Earth's ring system has a mass of 5.8x10&amp;lt;sup&amp;gt;5&amp;lt;/sup&amp;gt; kg (580,000 kg).&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
{{incomplete transcript|Don't remove this notice too soon.}}&lt;br /&gt;
&lt;br /&gt;
:[On the left side of the single panel, a table with words and checkboxes:]&lt;br /&gt;
{|&lt;br /&gt;
| style=&amp;quot;text-align:right;text-decoration:underline;&amp;quot; | Planet || style=&amp;quot;text-decoration:underline;&amp;quot; | Rings? &lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;text-align:right;&amp;quot; | Mercury || ☐&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;text-align:right;&amp;quot; | Venus || ☐&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;text-align:right;&amp;quot; | Earth || style=&amp;quot;color:red;&amp;quot; | ☑&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;text-align:right;&amp;quot; | Mars || ☐&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;text-align:right;&amp;quot; | Jupiter || ☑&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;text-align:right;&amp;quot; | Saturn || ☑&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;text-align:right;&amp;quot; | Uranus || ☑&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;text-align:right;&amp;quot; | Neptune || ☑&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
:[On the right side of the single panel, a drawing of the Earth from space, with Africa in view. Many dots represent the satellites, and most of them are in an ellipse. An arrow points to it:]&lt;br /&gt;
:Geostationary satellite belt&lt;br /&gt;
&lt;br /&gt;
:[Caption below the panel:]&lt;br /&gt;
: Astronomy fact: a century ago, Earth didn't have rings, but we have one now! It's where all the satellite dishes are pointed.&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&amp;lt;noinclude&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[Category:Facts]]&lt;br /&gt;
[[Category:Astronomy]]&lt;br /&gt;
[[Category:Comics with color]]&lt;br /&gt;
[[Category:Comics with red annotations]] &amp;lt;!-- the single tick that it is... --&amp;gt;&lt;/div&gt;</summary>
		<author><name>Mirror Spock</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3156:_Planetary_Rings&amp;diff=389110</id>
		<title>3156: Planetary Rings</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3156:_Planetary_Rings&amp;diff=389110"/>
				<updated>2025-10-18T10:24:21Z</updated>
		
		<summary type="html">&lt;p&gt;Mirror Spock: /* Transcript */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 3156&lt;br /&gt;
| date      = October 17, 2025&lt;br /&gt;
| title     = Planetary Rings&lt;br /&gt;
| image     = planetary_rings_2x.png&lt;br /&gt;
| imagesize = 356x279px&lt;br /&gt;
| noexpand  = true&lt;br /&gt;
| titletext = If you don't know where you are on Earth, the angle of satellite dishes can help constrain your latitude. If some of them are pointing straight up, you're probably near the Equator, right under the ring.&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
{{incomplete|This page was created by an off-axis satellite dish. Don't remove this notice too soon.}}&lt;br /&gt;
A {{w|ring system|planetary ring}} is a disc of small objects and other material orbiting a planet. The most well known are the rings of {{w|Saturn}}, which were discovered by {{w|Galileo Galilei}}, but all the {{w|gas giant}} planets in the Solar System have rings, as do some minor planets and moons.&lt;br /&gt;
&lt;br /&gt;
Earth does not have a natural ring system, although it's theorized that it [https://web.archive.org/web/20250401024532/https://time.com/7022440/earth-ring-like-saturn-study/ may have had one] in the distant past. However, since the 1950s (slightly over 68 years before this comic's publication), we have launched many artificial satellites into Earth orbit. The ones specifically in {{w|geostationary orbit}} (the {{w|Syncom|first}} of these being launched in 1964) are in the equatorial plane (as are some with different {{w|orbital period}}s), so they can be considered to constitute an artificial ring system. (Other satellites operate within various other {{w|orbital plane}}s, including {{w|geosynchronous orbit}}s that are not strictly geostationary, creating {{w|File:Starlink_SpaceX_1584_satellites_72_Planes_22each.png|various other}} halo-like clouds.)&lt;br /&gt;
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{{w|Satellite dishes}} are used to communicate with most of these devices. If they are stationary that means they are pointed at a {{w|geostationary satellite}} in middle and low latitudes, or a {{w|Molniya orbit}} satellite constellation in higher latitudes. Not all dishes are pointed at the geostationary orbit, but in that case, if they are used for communicating with satellites in other orbits or with space probes, they must move continuously to track the satellite/probe. &lt;br /&gt;
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(Note 1 - there are motorized dishes that can move between some number of pre-programmed positions to select which geostationary satellite to use at a given moment.&lt;br /&gt;
Note 2 - there are antennas which can &amp;quot;point&amp;quot; at different directions by {{w|Phased array|electronic means}}, without physically moving (eg, {{w|Starlink}} user terminals).)&lt;br /&gt;
&lt;br /&gt;
In terms of mass, Earth's ring system is tiny compared to other planetary ring systems in the Solar System. In descending order of mass, these are Saturn (10&amp;lt;sup&amp;gt;19&amp;lt;/sup&amp;gt; kg [https://www.science.org/doi/10.1126/science.aat2965]), Uranus (10&amp;lt;sup&amp;gt;16&amp;lt;/sup&amp;gt; kg [https://en.wikipedia.org/wiki/Rings_of_Uranus]), Jupiter (between 10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt; and 10&amp;lt;sup&amp;gt;16&amp;lt;/sup&amp;gt; kg [https://pages.astro.umd.edu/~dphamil/research/preprints/BurSimSho03.pdf]), Neptune (10&amp;lt;sup&amp;gt;15&amp;lt;/sup&amp;gt; kg [https://en.wikipedia.org/wiki/Rings_of_Neptune]). Assuming 580 satellites (active and inactive, 1/2° slots) in geostationary orbit [https://en.wikipedia.org/wiki/List_of_satellites_in_geosynchronous_orbit] and a typical mass of 1,000 kg, Earth's ring system has a mass of 5.8x10&amp;lt;sup&amp;gt;5&amp;lt;/sup&amp;gt; kg (580,000 kg).&lt;br /&gt;
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==Transcript==&lt;br /&gt;
{{incomplete transcript|Don't remove this notice too soon.}}&lt;br /&gt;
&lt;br /&gt;
:[On the left side of the single panel, a table with words and checkboxes:]&lt;br /&gt;
: Planet Rings? [Underline]&lt;br /&gt;
: Mercury ☐&lt;br /&gt;
: Venus ☐&lt;br /&gt;
: Earth ☑ [Red]&lt;br /&gt;
: Mars ☐&lt;br /&gt;
: Jupiter ☑&lt;br /&gt;
: Saturn ☑&lt;br /&gt;
: Uranus ☑&lt;br /&gt;
: Neptune ☑&lt;br /&gt;
&lt;br /&gt;
:[On the right side of the single panel, a drawing of the Earth from space, with Africa in view. Many dots represent the satellites, and most of them are in an ellipse. An arrow points to it:]&lt;br /&gt;
:Geostationary satellite belt&lt;br /&gt;
&lt;br /&gt;
:[Caption below the panel:]&lt;br /&gt;
: Astronomy fact: a century ago, Earth didn't have rings, but we have one now! It's where all the satellite dishes are pointed.&lt;br /&gt;
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{{comic discussion}}&amp;lt;noinclude&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[Category:Facts]]&lt;br /&gt;
[[Category:Astronomy]]&lt;br /&gt;
[[Category:Comics with color]]&lt;br /&gt;
[[Category:Comics with red annotations]] &amp;lt;!-- the single tick that it is... --&amp;gt;&lt;/div&gt;</summary>
		<author><name>Mirror Spock</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=Talk:2121:_Light_Pollution&amp;diff=171079</id>
		<title>Talk:2121: Light Pollution</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=Talk:2121:_Light_Pollution&amp;diff=171079"/>
				<updated>2019-03-13T02:32:08Z</updated>
		
		<summary type="html">&lt;p&gt;Mirror Spock: added comment about web of triangles&lt;/p&gt;
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&lt;div&gt;&amp;lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&amp;gt;&lt;br /&gt;
Small error in this comic. It's not possible to tile a sphere with just hexagons. https://stackoverflow.com/questions/749264/covering-earth-with-hexagonal-map-tiles&lt;br /&gt;
[[User:AlanKilian|AlanKilian]] ([[User talk:AlanKilian|talk]]) 16:03, 8 March 2019 (UTC)&lt;br /&gt;
:Six triangles form a hexagon - just an explanation for people with less mathematical or geometric knowledge. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 16:17, 8 March 2019 (UTC)&lt;br /&gt;
::but a indefinite large group of triangles doesn't automatically transform to hexagons, since it could be overlapping hexagons, or hexagons with their interim spaces filled up by triangles?--[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 16:29, 8 March 2019 (UTC)&lt;br /&gt;
:::Look at that hexagons (consisting of six triangles), each fitting to the next, and you will understand that this is only possible in a plane but not in a sphere. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 16:37, 8 March 2019 (UTC)&lt;br /&gt;
::::Yes, but if the triangles are not actually equilateral then they could form a sphere.  And if the sphere is big enough (I think solar-system-surrouding or bigger counts) then you probably wouldn't be able to see it with the naked eye.  [[User:Shamino|Shamino]] ([[User talk:Shamino|talk]]) 17:08, 8 March 2019 (UTC)&lt;br /&gt;
:::::But can it form a [https://www.explainxkcd.com/wiki/index.php/1365:_Inflation basketball?] [[User:Netherin5|Netherin5]] ([[User talk:Netherin5|talk]]) 17:24, 8 March 2019 (UTC)&lt;br /&gt;
:Your eyes are making the hexagons up.  Some triangles would be left over if you tried to make every group of 6 triangles a hexagon.  Triangle arrays like this are commonly used in computer graphics, as they are the closest approximation to a sphere: https://mft-dev.dk/wp-content/uploads/2014/05/icosahedron_frame_sub3.gif [[Special:Contributions/162.158.79.185|162.158.79.185]] 17:25, 8 March 2019 (UTC)&lt;br /&gt;
::Not really. On a plane, there are only three {{W|tesselation|tesselations}} made only of identical regular polygons: {{W|triangular tiling}}, {{W|square tiling}} or {{W|hexagonal tiling}}. But since a regular hexagon can be divided into six equilateral triangles, the tiling in the picture can be seen as both triangular and hexagonal. The leaving out you write about may have come from another tesselation which uses hexagons and triangles, the {{W|trihexagonal tiling}}. On a sphere, there's a completely different discussion as there's no tesselations, only approximations of them. {{unsigned|Malgond}}&lt;br /&gt;
:Rather than a tessellation of hexagons, I see a {{W|The Tholian Web|web of triangles}}. [[User:Mirror Spock|Mirror Spock]] ([[User talk:Mirror Spock|talk]]) 02:32, 13 March 2019 (UTC)&lt;br /&gt;
There is no way to know that the triangles shown are equilateral (in fact, as drawn here they're quite ''un''even). All 3D renderings are in fact assembled from uneven-sided triangles, including renderings attempting to approximate rounded surfaces. And yes, you can buy a ball tiled only with triangles; they're not even-sided, but you can't tell with the naked eye. Also, there ''is'' one roughly spherical shape tiled only with equilateral triangles: It's the shape found on a 20-sided die. Skyboxes intended to minimize viewing angle distortions use triangles that are very nearly, but not quite equilateral. In fact, ''all shapes'' that use flat planes to tile a sphere can be broken down into triangles of one degree of asymmetry or another. Your argument is invalid. &lt;br /&gt;
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 22:51, 8 March 2019 (UTC)&lt;br /&gt;
:Y'all need to stop arguing about the geometry and look at this picture of a (approximation of a) sphere made out of triangular pyramids: https://www.google.com/url?sa=i&amp;amp;source=images&amp;amp;cd=&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=2ahUKEwjvhZHLoPTgAhXmhVQKHRLnDSwQjRx6BAgBEAU&amp;amp;url=http%3A%2F%2Fblog.zacharyabel.com%2Ftag%2Fspheres%2F&amp;amp;psig=AOvVaw2-zrroG1RBFI-t2GHyHt-9&amp;amp;ust=1552193238617042 [[User:Tplaza64|Tplaza64]] ([[User talk:Tplaza64|talk]]) 04:50, 9 March 2019 (UTC)&lt;br /&gt;
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::Also note that we see just small part of sky there, so it's fully possible the few deformed/missing triangles are outside of what we see. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 23:49, 8 March 2019 (UTC)&lt;br /&gt;
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: An interactive sphere divided into hexagonals - where is the trick? [http://pub.ist.ac.at/~edels/hexasphere/ Hexagonal tiling of the two-dimensional sphere] Sebastian --[[Special:Contributions/172.68.110.64|172.68.110.64]] 16:11, 12 March 2019 (UTC)&lt;br /&gt;
::The &amp;quot;trick&amp;quot; is that you are making the unwarranted assumption that every hexagon in the matrix is composed from six identical equilateral triangles.  Which can't possible be the case for it to form a non-flat surface.  A hexagon composed of six equilateral triangles will have each vertex at exactly 120 degrees.  Three of them joined at a corner ''must'' add up to 360 degrees and therefore must lie flat and therefore can't curve into 3-space.  The fact that the surface does curve means that the sum of the angles at those vertices adds up to something less than 360 degrees, which means at least some of the hexagons have vertices that are less than 120 degrees (and they are therefore not composed of equilateral triangles, but isosceles triangles instead, since the hexagons appear to be uniform).  Once you realize that the angles on the hexagons' vertices are less than 120 degrees, the solution to the problem is figuring out exactly what angles are needed to form a sphere of a given size.  This may be a hard problem to solve, but definitely not impossible. [[User:Shamino|Shamino]] ([[User talk:Shamino|talk]]) 16:37, 12 March 2019 (UTC) &lt;br /&gt;
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Oh man where are the conspiracy nuts from a few weeks ago ;-) [[User:Cgrimes85|Cgrimes85]] ([[User talk:Cgrimes85|talk]]) 17:03, 8 March 2019 (UTC)&lt;br /&gt;
:Hey, I think this works like Beetlejuice. Shush. Don’t jinx it. [[User:Netherin5|Netherin5]] ([[User talk:Netherin5|talk]]) 17:24, 8 March 2019 (UTC)&lt;br /&gt;
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Ok, I know most of the discussion is focused on the lattice, but are the ships a reference to something? LOTR maybe? Also there’s nothing about the title text at all, and the (more probable than LOTR) Lovecraft reference, considering the mentions of insanity, cosmic horror, and color. (I believe the book was Cool Air?) [[User:Netherin5|Netherin5]] ([[User talk:Netherin5|talk]]) 17:24, 8 March 2019 (UTC)&lt;br /&gt;
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I think it's notable that the world actually works this way.  The sky is full of drones, satellites, {{w|Mesosphere#Exploration_and_uses|nearcraft}}, and we basically can't see them, but they can freely observe us, transmit things to us, and drop things on us. [[Special:Contributions/162.158.79.185|162.158.79.185]] 17:34, 8 March 2019 (UTC)&lt;br /&gt;
:While there are drones, satellites and various tools astronauts dropped all around the sky, the reason we can't see them is simply size (they are too small), not light pollution. The features mentioned in strip are gigantic. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 23:49, 8 March 2019 (UTC)&lt;br /&gt;
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I may be too nerdy, but my mind went to Spelljammer on this. [[Special:Contributions/172.69.62.160|172.69.62.160]] 18:44, 8 March 2019 (UTC)&lt;br /&gt;
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:My thoughts exactly! it perfectly fits Spelljammer crystal spheres. I think it should be included in the explanation (and if not, then at least the source of the whole concept- https://en.wikipedia.org/wiki/The_Crystal_Spheres) [[Special:Contributions/162.158.92.34|162.158.92.34]] 00:13, 9 March 2019 (UTC)&lt;br /&gt;
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I went to the sky at the end of [https://www.imdb.com/title/tt0139809/ Thirteenth Floor].  But the one image I can find suggests that was rectangular. [[User:Jordan Brown|Jordan Brown]] ([[User talk:Jordan Brown|talk]]) 21:47, 8 March 2019 (UTC)&lt;br /&gt;
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Anybody understands relationship between singular lattice and plural spheres? Is there any lattice that holds the spheres in ancient astronomy?&lt;br /&gt;
: Suddenly penny dropped: it is &amp;lt;i&amp;gt;crystal lattice&amp;lt;/i&amp;gt;!!!!!11&lt;br /&gt;
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By the way, the way the lattice really works is that it's a geodesic sphere - sometimes, five triangles meet in a vertex to ensure that the surface closes on itself to form a sphere. It's actually impossible to get a sphere with only 6 triangles in a vertex, aka a &amp;quot;hexagonal tiling&amp;quot;: http://www.alaricstephen.com/main-featured/2016/8/15/eulers-gem-applied-to-geodesic-domes.&lt;br /&gt;
[[Special:Contributions/173.245.48.63|173.245.48.63]] 21:28, 10 March 2019 (UTC)&lt;br /&gt;
: Only if you restrict yourself to using equilateral triangles.  If you're allowed to vary the lengths of the edges, then the sum of angles at the center of each &amp;quot;hexagon&amp;quot; will be less than 360 degrees, causing the &amp;quot;hexagon&amp;quot; to flex into a non-planar shape.  If you're using these to construct cosmic structures, the difference needed would be minuscule and undetectable to the naked eye.  [[User:Shamino|Shamino]] ([[User talk:Shamino|talk]]) 13:03, 12 March 2019 (UTC)&lt;br /&gt;
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Note that you *would* see regular patterns in the cosmic Big Bang remnant radiation in some cosmological models (think of Arcade scrollers, just in 3D). Citation needed no longer: https://www.nature.com/articles/nature01944 [[Special:Contributions/198.41.242.46|198.41.242.46]] 10:29, 11 March 2019 (UTC)&lt;br /&gt;
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'''Earth Temperature Timeline in the foot of the page'''&lt;br /&gt;
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Has anyone noticed that the Earth Temperature Timeline is in the list of the classic comics at the bottom? I looked on the wayback machine and it looks like it appeared on March 1, but i didnt see anybody mention it on the other talk pages since. Maybe I just missed it though. [[User:Choochoobob123|Choochoobob123]] ([[User talk:Choochoobob123|talk]]) 13:59, 11 March 2019 (UTC)&lt;/div&gt;</summary>
		<author><name>Mirror Spock</name></author>	</entry>

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