3047: Rotary Tool

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Landscape Features

|< < Prev #3221 (March 18, 2026)

Title text: '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

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Explanation

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.

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 "geology", which while lacking in explanatory power, is often solely responsible for some of the most striking landscape features.

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 "there's speculation that it's due to a mantle hotspot" 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., Hawaii hotspot, Iceland, the 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 map with subdivisions follows up on a number of prior (non-cursed) maps representing (supposed) geographical splits of some conversational outcome or other, such as 1407: Worst Hurricane and 2108: Carbonated Beverage Language Map.

Table of regions

Location	Description	Explanation
Adirondack Mountains	???	The Adirondack Mountains are made of billion-year-old rock but were uplifted relatively recently, within the last 5–10 million years. They’re still rising today despite being far from any plate boundary, forming a dome with no clear tectonic cause, thus the "???" due to an ongoing mystery as to their formation.
Most of northern conterminous U.S.	glaciers	During the Last Glacial Period, this area was covered by an ice sheet that left its marks on the landscape, in the form of moraines, eskers, glacial erratics, etc. This is most notable in Wisconsin where bluffs were formed due to the glacier movement.
Appalachian Mountains	continents colliding	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.
Mississippi and Ohio River Basins	rivers	The 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 Ohio River's geology is similar.
Southeastern U.S.	farming	Landscape changes from cotton production in the United States, due to the presence of the Black Belt.
Southern Florida	ongoing disputes between limestone and water	Florida is a vast 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.
Southern Missouri / Northern Arkansas	geology	The Ozark Mountains, which are composed primarily of ancient limestone and 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.
Great Plains	farming	The lack of other major events left the terrain relatively level, and areas were historically shaped by either herds of bison or indigenous agriculture, both limiting the growth of forests. "Farming" 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).
Central Idaho / Yellowstone	a supervolcano	The 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 Yellowstone Hotspot.
American West surrounding Idaho / Yellowstone	geology	3162: Heart Mountain
Immediately off of West coast up to the Four Corners	volcanoes	A combination of various volcanic fields of different origins, including Cascade Volcanoes in the Pacific Northwest, Albuquerque volcanic field in New Mexico, San Francisco volcanic field in Arizona, and San Juan volcanic field in Colorado.
Eastern Washington	megafloods	Most likely a reference to the Missoula floods and the 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 Columbia River Gorge and flooding much of the Willamette River in western Oregon. The comic may have simplified these to avoid bisecting the adjacent zones along the coast.
West Coast	a plate tectonic speedrun	Most likely a reference to the significant tectonic activity on the western coast of the US, caused by the collisions of the Juan de Fuca plate, Pacific plate, and the North American plate, as part of the Ring of Fire.
Southwest Desert	water and time	The nearly 40 major sedimentary rock layers exposed in the 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 largely responsible for 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 in turn started to form the Grand Canyon. Wetter climates brought upon by 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.
Northern Alaska	geology	Northern 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.
Aleutian Islands	volcanoes	The Aleutian Islands are a continuation of the Alaskan Aleutian Range, and form part of the 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.
Southeast Alaska	glaciers	This part of Alaska (including Glacier Bay National Park and Preserve) and western Canada has many glaciers that are still carving the landscape.
Hawaiian island chain	volcanoes	Hawaii, including the 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 here. Volcanic fog from the three active volcanoes on the Big Island can often be seen on neighboring islands.

Features of each state, alphabetically

• Alaska: geology, glaciers, volcanoes
• Arizona: water & time, volcanoes
• Arkansas: geology, farming, rivers
• California: a plate tectonics speedrun, volcanoes, water & time
• Colorado: volcanoes, geology, farming
• Connecticut: glaciers
• Delaware: farming
• District of Columbia: either farming or plates colliding
• Florida: farming, ongoing disputes between limestone & water
• Hawaii: volcanoes
• Idaho: a super volcano, geology
• Illinois: glaciers, rivers
• Indiana: glaciers, rivers
• Iowa: glaciers, farming, rivers
• Kansas: farming
• Kentucky: rivers, continents colliding
• Maine: glaciers
• Maryland: plates colliding, farming
• Massachusetts: glaciers
• Michigan: glaciers
• Minnesota: glaciers, farming, rivers
• Missouri: farming, geology, rivers
• Montana: geology, glaciers
• Nebraska: farming
• Nevada: volcanoes, geology, water & time
• New Hampshire: glaciers
• New Jersey: glaciers, farming
• New Mexico: volcanoes, geology, water & time, farming
• New York: glaciers, ???, continents colliding
• North Dakota: glaciers, farming
• Ohio: glaciers, rivers
• Oklahoma: farming, geology
• Oregon: a plate tectonics speedrun, volcanoes, mega floods, a supervolcano, geology
• Pennsylvania: glaciers, rivers, continents colliding, farming
• Rhode Island: glaciers
• South Dakota: glaciers, farming
• Texas: farming, geology, water & time
• Utah: geology, volcanoes
• Vermont: glaciers
• Virginia: continents colliding, farming
• Washington: Mega floods, a plate tectonics speedrun
• West Virginia: rivers, continents colliding
• Wisconsin: glaciers, rivers
• Wyoming: a supervolcano, geology, farming

Transcript

[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.]

Cueball: What's up with this weird landscape?

Ponytail: Oh, it was caused by ...

[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 "..." to indicate that it is the conclusion of Ponytail's sentence. The following are the labels used:]

[Main map:]

... a plate tectonics speedrun

... volcanoes

... megafloods

... a supervolcano

... geology

... water and time

... glaciers

... rivers

... continents colliding

... ???

... ongoing disputes between limestone and water

[On the main map, the label "... glaciers" appears three times in various places in the same contiguous zone that runs from Washington state to Maine. The label "... farming" 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 "... geology" 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.]

[Alaska inset:]

... geology

... volcanoes

... glaciers

[Hawaii inset:]

... volcanoes

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Discussion

How come it's at 0.017 RPM for a minute?? and yet 1 RPM for a second? pls fix this randall Midnightvortigaunt (talk) 18:01, 5 February 2025 (UTC)

Its 0.017 RPM for the minute hand. The minute hand revolves once per hour or at 1/60 RPM ≈ 0,017 RPM --172.71.148.59 18:14, 5 February 2025 (UTC)

Ohhh that makes sense I didn't think about it like that Midnightvortigaunt (talk) 19:27, 5 February 2025 (UTC)

Mr.Dude (talk) 17:20, 7 February 2025 (UTC) I wonder what torque is needed to launch the average backyard telescope worthy of a tracking mount at Mach 8 given standard state pressures and temperatures of perhaps average conditions found in Randall’s back yard.

How come the comment above is invisible to me? 172.68.245.229 18:03, 5 February 2025 (UTC)

Possibly because people indented with spaces rather than with colons? 162.158.79.77 19:40, 5 February 2025 (UTC)

72 RPM for a record player...? 162.158.74.25 18:08, 5 February 2025 (UTC)

I could only find 78 RPM disks in the german wikipedia. 172.70.114.56 18:41, 5 February 2025 (UTC)

I came here to make the same comment: 72 is most probably a typo. The old records (at this date, very old, since the transition to vinyl records was 1948 to 1958 (in the US)) were 78 rpm, not 72 rpm https://en.wikipedia.org/wiki/Phonograph_record Rps (talk) 19:30, 5 February 2025 (UTC)

72 is (for example) relevent to font sizes (size 1 = 1/72 of an inch, size 72 = 1 inch), which might therefore have envaigled Randall's head for numbers by a different route, and got him confused. Conceivably he has had to deal with playing old 78s, but probably not for a long time... even the retro-revival of vinyl, recently, has probably not had quite so many old old records released to fill such nostalgic needs. So an easy brain-fudge/thinko to trip over on. 162.158.74.48 00:54, 6 February 2025 (UTC)

There used to be a record label call 72RPM records. 172.69.229.146 (talk) 19:07, 5 February 2025 (UTC) (please sign your comments with ~~~~)

We need one of those tables in here. DollarStoreBa'al (talk) 18:37, 5 February 2025 (UTC)

I made a change to the explanation that all of these numbers are realistic because, I checked out the speed of dental drills and they really do rotate that fast. I haven't checked out all of the other tools, but I suspect that they are also accurate. If you find that any of them are misstated, please correct my correction. Rtanenbaum (talk) 22:38, 5 February 2025 (UTC)

TABLE REQUEST When someone uploads a table, I'd like to recommend a second column for the frequency / reciprocal of the speed. "0.000000000073 minutes" is one every 13.7 billion minutes, or ~26,000 years. Thanks! 172.70.46.107 20:20, 5 February 2025 (UTC)

Me again. Should the column header "revolution time" be "rotation time"? In every instance, the axis of motion is within the object itself; even the second/minute/hour hands go around the axis. 141.101.76.73 16:41, 6 February 2025 (UTC)

TRIVIA 16 2/3 RPM phonographs were used for some voice-recorings back in the day. 172.68.26.24 21:01, 5 February 2025 (UTC)

My parent's old record player (60's, probably) had 4 possible speeds: 16, 33, 45, 78. By the early 80's the current ones only had 33 and 45. Rps (talk) 16:59, 7 February 2025 (UTC)

Album goes back to stacks of 78s. A symphony or opera would be 2, 3, 4 or more disks. They were bound like a photo-album with a leaf for each disk. "78" wasn't "standardized" until the format was fading. 3600-rpm motor and 46-tooth gear is incomplete (one tooth gear??) Early discs were from 60 to 130 rpm. Users would adjust speed by ear (also to ease pitch-matching for karaoke). Only as LPs arrived did someone invent the number "78.26 rpm" (no recordplayer and few lathes of the period were near that accurate). --PRR (talk) 02:34, 6 February 2025 (UTC)

Indeed, my parents had a large collection of old records and at least one had a speed marking of 80rpm.--172.68.186.43 09:17, 6 February 2025 (UTC)

With wind-up players, a lot of them started off playing at one speed and ended playing at a completely different one anyway...172.68.186.50 09:43, 6 February 2025 (UTC)

I suspect there's not many consumers needing a Uranium Enrichment Centrifuge... at least outside of a few countries in the Middle East. --172.70.58.6 08:50, 6 February 2025 (UTC)

Might face some regulatory / export license issues too.172.70.86.129 11:34, 6 February 2025 (UTC)

I feel like there was a lost opportunity to have Dr. Who's Sonic Screwdriver on the list. Maybe the rpms are unknown.162.158.159.107 13:05, 6 February 2025 (UTC)

The table says that 0.00070 "seems off; a sidereal day is 23.93 hours". That's just because (like all of the other settings) 0.00070 is quoted with only 2 significant digits. Every period between 23.64 and 23.98 hours would round to 0.00070 RPM. 162.158.134.199 13:58, 6 February 2025 (UTC)

The question I have is: why are dental drill speeds so high? 172.70.247.92 17:21, 6 February 2025 (UTC)

"why are dental drill speeds so high?" It hurts less. (Are you old enough to remember routine use of belt-driven dental drills?) You can cut a given amount of material (wood, steel, tooth) quickly with heavy force or high speed. Neither is really fun, but hi-speed is generally preferred. --PRR (talk) 19:08, 6 February 2025 (UTC)

Although some materials behave badly to heat (either work-hardening, for some alloys, or melting/burning, like plastics) and that's why variable-speed hand-drills/etc usefully have low speeds (for essentially the same force, when that's done via reostat rather than an actual gearbox). On the few occasions I've had my teeth drilled, I'm pretty sure I've detected the pungent smell of fried tooth-fragments, but it was nothing like as strong as smelling my own nose-flesh being burnt one of the times I had it cauterised to try (and fail) to prevent excessive nosebleeds. 172.69.79.139 21:15, 6 February 2025 (UTC)

The latest NMR CPMAS probes send their rotors to go at 9.6 Mrpm, M=mega. [1] --172.69.109.172 21:56, 7 February 2025 (UTC)

Should we list the rotor diameters to achieve the mach 8 speed mentioned in the title text in the table? I don't think that we should. guess who (if you desire conversing | what i have done) 06:01, 24 February 2025 (UTC)

I (obviously since I worked it all out) think it is in the spirit of the ridiculous idea of the comic and XKCD generally to do these calculations. That said, I'm getting different numbers than your update to make it Mach 8. Denver87 (talk) 16:21, 24 February 2025 (UTC)

I get the following: 4,799au, 74,866km, 37,733km, 3,144km, 52.4km, 1,588m, 1,165m, 728m, 175m, 34.9m, 21.0m, 149.7cm, 87.3cm, 174.7mm. Denver87 (talk) 16:21, 24 February 2025 (UTC)

Happy to share calculation notes, but here's the example for the dental drill: 300,000rpm = 5,000 rps; diameter of: 174.7mm --> circumference of: pi * 174.7mm = 548.8mm; 548.8mm * 5000rps = 2,744,000mm/sec = 2744m/sec; Mach 8 = 8 * 343m/sec = 2744m/sec. Denver87 (talk) 16:21, 24 February 2025 (UTC)

If you agree with the calculations, one of us can at least update it. Denver87 (talk) 16:21, 24 February 2025 (UTC)
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