#xkcd No. 2989
Date: 2024-9-23
Title: Physics Lab Thermostat
Alt text: Hopefully the HVAC people set it to only affect the AIR in the room.
https://xkcd.com/2989/
xkcd
#xkcd No. 3173
Date: 2025-11-26
Title: Satellite Imagery
Alt text: Every weekend I take an ATV out into the desert and spend a day tracing a faint "(C) GOOGLE 2009" watermark across the landscape.
https://xkcd.com/3173/
![Description:
Cueball and Megan stand on either side of a large satellite image of a landscape. A square area in the middle of the image is pixelated.
Transcript:
[Two stick figures, Cueball and Megan, are looking at a large hanging image. Speech bubbles point from them.]
Megan: WAIT, WHEN WAS THIS IMAGERY TAKEN? IS THIS CENSORSHIP THE WORK OF THE CONTRACTOR? ONE OF OUR PEOPLE? FOREIGN ACTORS!? DO WE KNOW WHO'S OPERATING A FACILITY AT THAT LOCATION?
Cueball: WE CAN'T FIND ANYTHING.
[Caption below the panel]
MY HOBBY: SETTING UP BIG COLORED PANELS IN THE MIDDLE OF NOWHERE AS A PRANK ON REMOTE SENSING PEOPLE](/proxy/post_attachment/914780/a71c5acc81.png "Description:
Cueball and Megan stand on either side of a large satellite image of a landscape. A square area in the middle of the image is pixelated.
Transcript:
[Two stick figures, Cueball and Megan, are looking at a large hanging image. Speech bubbles point from them.]
Megan: WAIT, WHEN WAS THIS IMAGERY TAKEN? IS THIS CENSORSHIP THE WORK OF THE CONTRACTOR? ONE OF OUR PEOPLE? FOREIGN ACTORS!? DO WE KNOW WHO'S OPERATING A FACILITY AT THAT LOCATION?
Cueball: WE CAN'T FIND ANYTHING.
[Caption below the panel]
MY HOBBY: SETTING UP BIG COLORED PANELS IN THE MIDDLE OF NOWHERE AS A PRANK ON REMOTE SENSING PEOPLE")
#xkcd No. 3231
Date: 2026-4-10
Title: Lightning
Alt text: Maybe you should wear one too? I guess I'm taller than you, so as long as I have one we're fine.
https://xkcd.com/3231/
![Description:
Two stick figures stand on a rocky, uneven hill in white silhouette against a solid black sky. A massive, jagged bolt of lightning strikes diagonally across the dark sky above them.
Transcript:
Panel 1:
[Megan and Cueball are hiking up a steep white hill against a black sky. A huge bolt of lightning flashes across the top left of the sky.]
Lightning: BOOOOM
Cueball: Don't worry, I'm wearing an anti-static wrist strap.](/proxy/post_attachment/1029597/37e912159e.png "Description:
Two stick figures stand on a rocky, uneven hill in white silhouette against a solid black sky. A massive, jagged bolt of lightning strikes diagonally across the dark sky above them.
Transcript:
Panel 1:
[Megan and Cueball are hiking up a steep white hill against a black sky. A huge bolt of lightning flashes across the top left of the sky.]
Lightning: BOOOOM
Cueball: Don't worry, I'm wearing an anti-static wrist strap.")
#xkcd No. 3174
Date: 2025-11-28
Title: Bridge Clearance
Alt text: A lot of the highway department's budget goes to adjusting the sign whenever the moon passes directly overhead.
https://xkcd.com/3174/
![Description:
A road forks. The left path goes under an overpass with a height sign. The right path is open to the sky with a sign listing a massive vertical limit.
Transcript:
Panel 1:
[A road splits into two distinct paths. The left path leads directly under a low overpass structure. A rectangular road sign stands in front of the bridge.]
Left Sign: BRIDGE
CLEARANCE
10 FT 6 IN
[The right path curves away into a flat, open landscape with absolutely nothing overhead. A matching rectangular sign stands next to this lane.]
Right Sign: NO BRIDGE
CLEARANCE
46 BILLION+
LIGHT-YEARS](/proxy/post_attachment/916030/432a0b8579.png "Description:
A road forks. The left path goes under an overpass with a height sign. The right path is open to the sky with a sign listing a massive vertical limit.
Transcript:
Panel 1:
[A road splits into two distinct paths. The left path leads directly under a low overpass structure. A rectangular road sign stands in front of the bridge.]
Left Sign: BRIDGE
CLEARANCE
10 FT 6 IN
[The right path curves away into a flat, open landscape with absolutely nothing overhead. A matching rectangular sign stands next to this lane.]
Right Sign: NO BRIDGE
CLEARANCE
46 BILLION+
LIGHT-YEARS")
#xkcd No. 2991
Date: 2024-9-27
Title: Beamsplitters
Alt text: Under quantum tax law, photons sent through a beamsplitter don't actually choose which path they took, or incur a tax burden, until their wavefunction collapses when the power is sold.
https://xkcd.com/2991/
#xkcd No. 2993
Date: 2024-10-2
Title: Ingredients
Alt text: Add main-belt asteroids to taste.
https://xkcd.com/2993/
#xkcd No. 2992
Date: 2024-9-30
Title: UK Coal
Alt text: The Watership Down rabbits removed an additional 0.1 nanometers constructing their warren, although that was mostly soil. British rabbits have historically mined very little coal; the sole rabbit-run coal plant was shut down in the 1990s.
https://xkcd.com/2992/
#xkcd No. 3181
Date: 2025-12-15
Title: Jumping Frog Radius
Alt text: Earth's r_jf is approximately 1.5 light-days, leading to general relativity's successful prediction that all the frogs in the Solar System should be found collected on the surface of the Earth.
https://xkcd.com/3181/
![**Description:**
A formula is shown next to a diagram of a frog trying to jump off a small planet but falling back down due to its gravity.
**Transcript:**
[The comic presents a concept called the "Jumping Frog Radius".]
[Top Panel]
On the left is a formula:
r_jf = 2GM / (4.5 m/s)²
On the right is a diagram illustrating the formula. A small planet has its radius labeled "r_jf". A frog jumps from the surface, creating a "RIBBIT" sound effect, but its path arcs back down, landing on the side of the planet with a "PLOP".
[Caption below the panel]
MORE PRACTICALLY USEFUL THAN THE SCHWARZSCHILD RADIUS, THE JUMPING FROG RADIUS IS THE RADIUS AT WHICH AN OBJECT'S GRAVITATIONAL PULL IS SO STRONG THAT EVEN A CHAMPION JUMPING FROG CAN'T ESCAPE.](/proxy/post_attachment/933752/b8b35204d7.png "**Description:**
A formula is shown next to a diagram of a frog trying to jump off a small planet but falling back down due to its gravity.
**Transcript:**
[The comic presents a concept called the \"Jumping Frog Radius\".]
[Top Panel]
On the left is a formula:
r_jf = 2GM / (4.5 m/s)²
On the right is a diagram illustrating the formula. A small planet has its radius labeled \"r_jf\". A frog jumps from the surface, creating a \"RIBBIT\" sound effect, but its path arcs back down, landing on the side of the planet with a \"PLOP\".
[Caption below the panel]
MORE PRACTICALLY USEFUL THAN THE SCHWARZSCHILD RADIUS, THE JUMPING FROG RADIUS IS THE RADIUS AT WHICH AN OBJECT'S GRAVITATIONAL PULL IS SO STRONG THAT EVEN A CHAMPION JUMPING FROG CAN'T ESCAPE.")
#xkcd No. 3175
Date: 2025-12-1
Title: Website Task Flowchart
Alt text: Tired of waiting on hold? Use our website to chat with one of our live agents, who are available to produce words at you 24/7!
https://xkcd.com/3175/
![Description:
A flowchart titled "Doing a Task Using a Company or Organization's Website" with boxes and arrows that show a frustrating, circular process.
Transcript:
Title: DOING A TASK USING A COMPANY OR ORGANIZATION'S WEBSITE:
[The comic is a flowchart detailing a process with multiple paths.]
Path 1: Login
1. Action: GO TO WEBSITE, TRY TO LOG IN
2. Decision: DID IT WORK?
- If NO: Action: SPEND HOURS TROUBLESHOOTING ACCOUNT/LOGIN. This leads to another "DID IT WORK?" decision. If that decision is NO, the path goes to "GIVE UP." If YES, it loops back to "TRY TO DO YOUR TASK."
- If YES: Continue to Path 2.
Path 2: The Task
1. Action: TRY TO DO YOUR TASK
2. Decision: DID IT WORK?
- If NO: Action: SPEND HOURS TROUBLESHOOTING WEBSITE. This leads to another "DID IT WORK?" decision. If that decision is NO, the path goes to "GIVE UP." If YES, it leads to the "Success" outcome.
- If YES: Continue to "Success."
Success Outcome:
Action: NICE! DONE!
Failure Path ("GIVE UP"):
1. Action: GIVE UP AND CALL CUSTOMER SERVICE
2. Action: HOLD MESSAGE: "DID YOU KNOW YOU COULD DO ALL THIS MORE QUICKLY AND EASILY ON OUR WEBSITE? JUST GO TO W-W-W DOT..."
3. Action: THROW PHONE AND LAPTOP INTO THE SEA](/proxy/post_attachment/919091/325cfe91b2.png "Description:
A flowchart titled \"Doing a Task Using a Company or Organization's Website\" with boxes and arrows that show a frustrating, circular process.
Transcript:
Title: DOING A TASK USING A COMPANY OR ORGANIZATION'S WEBSITE:
[The comic is a flowchart detailing a process with multiple paths.]
Path 1: Login
1. Action: GO TO WEBSITE, TRY TO LOG IN
2. Decision: DID IT WORK?
- If NO: Action: SPEND HOURS TROUBLESHOOTING ACCOUNT/LOGIN. This leads to another \"DID IT WORK?\" decision. If that decision is NO, the path goes to \"GIVE UP.\" If YES, it loops back to \"TRY TO DO YOUR TASK.\"
- If YES: Continue to Path 2.
Path 2: The Task
1. Action: TRY TO DO YOUR TASK
2. Decision: DID IT WORK?
- If NO: Action: SPEND HOURS TROUBLESHOOTING WEBSITE. This leads to another \"DID IT WORK?\" decision. If that decision is NO, the path goes to \"GIVE UP.\" If YES, it leads to the \"Success\" outcome.
- If YES: Continue to \"Success.\"
Success Outcome:
Action: NICE! DONE!
Failure Path (\"GIVE UP\"):
1. Action: GIVE UP AND CALL CUSTOMER SERVICE
2. Action: HOLD MESSAGE: \"DID YOU KNOW YOU COULD DO ALL THIS MORE QUICKLY AND EASILY ON OUR WEBSITE? JUST GO TO W-W-W DOT...\"
3. Action: THROW PHONE AND LAPTOP INTO THE SEA")
#xkcd No. 2997
Date: 2024-10-11
Title: Solar Protons
Alt text: If any of you want to meet some cool local oxygen atoms, I can introduce you!
https://xkcd.com/2997/
#xkcd No. 2995
Date: 2024-10-7
Title: University Commas
Alt text: The distinctive 'UCLA comma' and 'Michigan comma' are a long string of commas at the start and end of the sentence respectively.
https://xkcd.com/2995/
#xkcd No. 3002
Date: 2024-10-23
Title: RNAWorld
Alt text: Disney lore: Canonically, because of how Elsa's abiogenesis powers work, Olaf is an RNA-only organism.
https://xkcd.com/3002/
#xkcd No. 3182
Date: 2025-12-17
Title: Telescope Types
Alt text: I'm trying to buy a gravitational lens for my camera, but I can't tell if the manufacturers are listing comoving focal length or proper focal length.
https://xkcd.com/3182/
![Description:
A chart shows thirteen diagrams of telescope cross-sections, illustrating various optical paths and internal components.
Transcript:
Title: TELESCOPE TYPES
PRIME FOCUS: [A diagram of a prime focus reflecting telescope.]
HERSCHELIAN: [A diagram of a Herschelian telescope.]
NEWTONIAN: [A diagram of a Newtonian telescope.]
GALILEAN: [A diagram of a Galilean refracting telescope.]
KEPLERIAN: [A diagram of a Keplerian refracting telescope.]
GREGORIAN: [A diagram of a Gregorian telescope.]
CASSEGRAIN: [A diagram of a Cassegrain telescope.]
LIQUID MIRROR: [A diagram of a spinning liquid mirror, with a straw with lips on the end sipping from it.]
CARDBOARD TUBE: [An empty tube with light passing straight through.]
KALEIDO: [A diagram of a kaleidoscope's interior.]
NARCISSIAN: [A stick figure stands inside a telescope, looking at their own reflection in the primary mirror.]
GRAVITATIONAL: [Light paths bend around a central point inside the telescope tube, as in gravitational lensing.]
GEOLOGICAL: [A telescope's primary mirror is replaced by a small TV. A label reads: TV PLAYING THE CORE (2003).]](/proxy/post_attachment/935895/152f163878.png "Description:
A chart shows thirteen diagrams of telescope cross-sections, illustrating various optical paths and internal components.
Transcript:
Title: TELESCOPE TYPES
PRIME FOCUS: [A diagram of a prime focus reflecting telescope.]
HERSCHELIAN: [A diagram of a Herschelian telescope.]
NEWTONIAN: [A diagram of a Newtonian telescope.]
GALILEAN: [A diagram of a Galilean refracting telescope.]
KEPLERIAN: [A diagram of a Keplerian refracting telescope.]
GREGORIAN: [A diagram of a Gregorian telescope.]
CASSEGRAIN: [A diagram of a Cassegrain telescope.]
LIQUID MIRROR: [A diagram of a spinning liquid mirror, with a straw with lips on the end sipping from it.]
CARDBOARD TUBE: [An empty tube with light passing straight through.]
KALEIDO: [A diagram of a kaleidoscope's interior.]
NARCISSIAN: [A stick figure stands inside a telescope, looking at their own reflection in the primary mirror.]
GRAVITATIONAL: [Light paths bend around a central point inside the telescope tube, as in gravitational lensing.]
GEOLOGICAL: [A telescope's primary mirror is replaced by a small TV. A label reads: TV PLAYING THE CORE (2003).]")
#xkcd No. 3003
Date: 2024-10-25
Title: Sandwich Helix
Alt text: The number one rule of string manipulation is that you’ve got to specify your encodings.
https://xkcd.com/3003/
#xkcd No. 3176
Date: 2025-12-3
Title: Inverted Catenaries
Alt text: Some tires are marketed as 'all-shape tires,' but if driven in a climate with both inverted catenary falls and triangle falls, they wear out really fast.
https://xkcd.com/3176/
#xkcd No. 2998
Date: 2024-10-14
Title: Ravioli-Shaped Objects
Alt text: It's a real accomplishment to mess up a ravioli recipe badly enough that the resulting incident touches all four quadrants of the NFPA hazard diamond.
https://xkcd.com/2998/
#xkcd No. 3191
Date: 2026-1-7
Title: Superstition
Alt text: It's important to teach yourself to feel responsible for random events, because with great responsibility comes great power. That's what my wise Uncle Ben told me right before he died; he might still be alive today if only I'd said rabbit rabbit that year!
https://xkcd.com/3191/
![Description:
Two stick figures, Megan and Cueball, stand next to a smaller stick figure with spiky hair. They are having a conversation.
Transcript:
[A conversation between Cueball, Megan, and a small child.]
Cueball: Oops, I forgot to say "Rabbit Rabbit" on January first!
Megan: Why do you do that?
Cueball: Just a superstition.
Child: What's a superstition?
Cueball: It's a way to train yourself to feel like any bad thing that happens is your fault.](/proxy/post_attachment/957702/a68b570187.png "Description:
Two stick figures, Megan and Cueball, stand next to a smaller stick figure with spiky hair. They are having a conversation.
Transcript:
[A conversation between Cueball, Megan, and a small child.]
Cueball: Oops, I forgot to say \"Rabbit Rabbit\" on January first!
Megan: Why do you do that?
Cueball: Just a superstition.
Child: What's a superstition?
Cueball: It's a way to train yourself to feel like any bad thing that happens is your fault.")
#xkcd No. 3000
Date: 2024-10-18
Title: Experimental Astrophysics
Alt text: Our experiment will be expensive, but we believe it will produce important spin-offs, especially if we manage to hit the sun from the right angle.
https://xkcd.com/3000/
#xkcd No. 3183
Date: 2025-12-19
Title: Pole Vault Pole
Alt text: My goal in life is to be personally responsible for at least one sports rule change.
https://xkcd.com/3183/
![Description:
A stick figure uses oversized and looped poles in creative ways to get over a pole vault bar, such as a giant wheel and a spinning loop.
Transcript:
[The comic is a single panel with two rows showing different ways to exploit the rules of pole vaulting.]
[Top Row: A stick figure approaches a pole vault bar with a pole that is a massive, thick disk, like a giant wheel. In the next image, a very long, flexible pole is simply bent over the bar, forming an arch that a stick figure climbs to get over.]
[Bottom Row: A pole is formed into a large loop. A stick figure gets it spinning, then grabs on, and is flung over the bar by the loop's momentum.]
[Text at the bottom of the comic:]
FUN FACT: THERE ARE NO LIMITS ON THE LENGTH OR DIAMETER OF THE POLE IN POLE VAULT.](/proxy/post_attachment/937179/3e66b5567c.png "Description:
A stick figure uses oversized and looped poles in creative ways to get over a pole vault bar, such as a giant wheel and a spinning loop.
Transcript:
[The comic is a single panel with two rows showing different ways to exploit the rules of pole vaulting.]
[Top Row: A stick figure approaches a pole vault bar with a pole that is a massive, thick disk, like a giant wheel. In the next image, a very long, flexible pole is simply bent over the bar, forming an arch that a stick figure climbs to get over.]
[Bottom Row: A pole is formed into a large loop. A stick figure gets it spinning, then grabs on, and is flung over the bar by the loop's momentum.]
[Text at the bottom of the comic:]
FUN FACT: THERE ARE NO LIMITS ON THE LENGTH OR DIAMETER OF THE POLE IN POLE VAULT.")
#xkcd No. 3075
Date: 2025-4-11
Title: Anachronym Challenge
Alt text: I have to pay with paper money.
https://xkcd.com/3075/
#xkcd No. 3184
Date: 2025-12-22
Title: Funny Numbers
Alt text: In 1899, people were walking around shouting '23' at each other and laughing, and confused reporters were writing articles trying to figure out what it meant.
https://xkcd.com/3184/
![Description:
Four stick figures at a "Mathematical Society 2025 Meeting." One figure points to a list of numbers on a board, circling the number 67.
Transcript:
[A banner hangs at the top of the panel.]
Banner: MATHEMATICAL SOCIETY
2025 MEETING
Unseen Speaker: ANY OTHER NEW DEVELOPMENTS FROM THE YEAR TO COVER BEFORE WE WRAP?
Cueball: OH, THE TEENS PICKED A NEW FUNNY NUMBER.
Figure with a bun: AWW, I'M GLAD TO HEAR THEY'RE STILL DOING THAT.
Megan (at a board with a list of numbers): I'LL ADD IT TO THE LIST.
[The board shows the following list of numbers. The number 67 is circled.]
23 (SKIDOO!)
42 1,337
69 58,008
420 67](/proxy/post_attachment/940713/68b9e928d9.png "Description:
Four stick figures at a \"Mathematical Society 2025 Meeting.\" One figure points to a list of numbers on a board, circling the number 67.
Transcript:
[A banner hangs at the top of the panel.]
Banner: MATHEMATICAL SOCIETY
2025 MEETING
Unseen Speaker: ANY OTHER NEW DEVELOPMENTS FROM THE YEAR TO COVER BEFORE WE WRAP?
Cueball: OH, THE TEENS PICKED A NEW FUNNY NUMBER.
Figure with a bun: AWW, I'M GLAD TO HEAR THEY'RE STILL DOING THAT.
Megan (at a board with a list of numbers): I'LL ADD IT TO THE LIST.
[The board shows the following list of numbers. The number 67 is circled.]
23 (SKIDOO!)
42 1,337
69 58,008
420 67")
#xkcd No. 3185
Date: 2025-12-24
Title: Sauropods
Alt text: Vertebrae Georg
https://xkcd.com/3185/
![Description:
A comic shows a long-necked sauropod crossed out. The next panel shows short-necked sauropods as correct, with many long necks tangled above them.
Transcript:
Panel 1:
[A drawing of a traditional long-necked sauropod dinosaur with a large red X over it.]
Panel 2:
[A drawing of two short-necked sauropods with a green checkmark between them. Above them, a tangled mass of extremely long necks writhes.]
[Caption below the panels]
THANKS TO MODERN PALEONTOLOGICAL RECONSTRUCTIONS, WE NOW KNOW THAT MOST SAUROPODS HAD SHORT NECKS, AND ALL THOSE EXTRA VERTEBRAE BELONGED TO THE SAUROPOD COLONY'S QUEEN.](/proxy/post_attachment/942437/14d85e5875.png "Description:
A comic shows a long-necked sauropod crossed out. The next panel shows short-necked sauropods as correct, with many long necks tangled above them.
Transcript:
Panel 1:
[A drawing of a traditional long-necked sauropod dinosaur with a large red X over it.]
Panel 2:
[A drawing of two short-necked sauropods with a green checkmark between them. Above them, a tangled mass of extremely long necks writhes.]
[Caption below the panels]
THANKS TO MODERN PALEONTOLOGICAL RECONSTRUCTIONS, WE NOW KNOW THAT MOST SAUROPODS HAD SHORT NECKS, AND ALL THOSE EXTRA VERTEBRAE BELONGED TO THE SAUROPOD COLONY'S QUEEN.")
#xkcd No. 3004
Date: 2024-10-28
Title: Wells
Alt text: You do have to be careful, though--sometimes, instead of water, you hit this free fuel that you can sell for a lot of money instead.
https://xkcd.com/3004/
#xkcd No. 3023
Date: 2024-12-11
Title: The Maritime Approximation
Alt text: It works because a nautical mile is based on a degree of latitude, and the Earth (e) is a circle.
https://xkcd.com/3023/
#xkcd No. 3186
Date: 2025-12-26
Title: Truly Universal Outlet
Alt text: Building Inspectors HATE This One Weird Trick
https://xkcd.com/3186/
![Description:
A diagram showing several overlapping, complex cutouts for electrical sockets, each labeled with letters representing different plug types.
Transcript:
[A diagram shows several complex shapes representing combined electrical outlet cutouts. The diagram is labeled as follows:]
IEC TYPE C,E,F,H,J, K,L,N,O
[Additional labels point to various parts of the cutout shapes:]
A,B
D,E,M,O
G
I
L
N
J
I
H
B
K
M
D
G
[Caption below the diagram:]
WIRING TIP: TO MAKE YOUR BUILDING FRIENDLY TO INTERNATIONAL VISITORS, CUT HOLES IN YOUR OUTLET PLATES TO MAKE THEM COMPATIBLE WITH ALL FIFTEEN IEC PLUG TYPES.](/proxy/post_attachment/943908/286bcd4f23.png "Description:
A diagram showing several overlapping, complex cutouts for electrical sockets, each labeled with letters representing different plug types.
Transcript:
[A diagram shows several complex shapes representing combined electrical outlet cutouts. The diagram is labeled as follows:]
IEC TYPE C,E,F,H,J, K,L,N,O
[Additional labels point to various parts of the cutout shapes:]
A,B
D,E,M,O
G
I
L
N
J
I
H
B
K
M
D
G
[Caption below the diagram:]
WIRING TIP: TO MAKE YOUR BUILDING FRIENDLY TO INTERNATIONAL VISITORS, CUT HOLES IN YOUR OUTLET PLATES TO MAKE THEM COMPATIBLE WITH ALL FIFTEEN IEC PLUG TYPES.")