3251: Time Machine Conversation

2026-05-28T09:23:38Z

2A02:810B:5413:EE00:7091:6DEE:97A3:2C43: just fixed a small grammatical error and a typo

{{comic
| number = 3251
| date = May 27, 2026
| title = Time Machine Conversation
| image = time_machine_conversation_2x.png
| imagesize = 691x344px
| noexpand = true
| titletext = It's possible to do sea navigation without a compass, but you'll have to get some spoilers from the Polynesians.
}}

==Explanation==
{{incomplete|Spoiler alert! This page was created in the past. Don't remove this notice too soon.}}
This comic points out how many devices quite commonly used today would have been quite improbable-sounding before their creation - a topic which [[3199|has been]] [[2809|covered before]]. In this comic, [[Cueball]] uses a time machine to travel to the {{w|Iron Age}} and has a conversation with an ancient-times version of [[Hairbun]]. She seems to be a farmer, since she's holding a pretty modern-looking {{w|Hoe (tool)|hoe}}. He starts a conversation with her, but is quickly amazed at how she doesn't yet know about now quite commonly used things like {{W|compasses}}. While explaining a compass he then accidentally also 'spoils' the concept of {{w|Spoiler (media)|spoiler}}. It is thought that

The title text has [[Cueball]] about to unleash another spoiler on navigating by not using compasses, but stops himself before saying it. However, he does still end up accidentally revealing that {{w|Polynesians}} know about it - though whether this was another unintentional slip or a deliberate clue left for [[Hairbun]] is unclear. It is thought that so-called '{{w|Polynesian navigation}}' used other methods of marine navigation, ({{w|celestial navigation}}, observation of birds, ocean swells, and wind patterns). However, as the Polynesians lived in the Pacific, which would be difficult to reach from Hairbun's location, the clue is useless. It is unclear where Hairbun is, but it is likely that she is in {{w|Europe}}, which is where the Iron Age is normally said to be in.

The comic is based on shaky ground, as it's not clear how they're able to communicate so easily, unless it's {{tvtropes|TranslatorMicrobes|part of the function}} of the time-travel technology. While humans did have language for thousands of years by this time, it would be very far removed from modern English, yet somehow they understand each other's speech.

The magnetic compass was first invented in China around 200 BCE, well after the end of the Iron Age, but it wasn't used for navigation until the 11th century AD. So for an Iron Age farmer the concept of a - as Cueball put it - 'weird rock that always points north' would seem quite ridiculous, hence the joke.

The modern meaning of "spoiler" didn't arise until the 1970s. Spoiler warnings became common on {{w|Usenet newsgroups}} in the late 1980s. Cueball may have created a {{w|temporal paradox}} by introducing the concept thousands of years earlier, although any such 'change' made to that time might easily have been forgotten again (even already have been {{w|Novikov self-consistency principle|a pre-existing component of the timeline}}) in the two or three thousand years since this encounter. In any event, while telling people thousands of years ago that there was a way to make a compass might have changed history significantly, telling them that there are stories that they would enjoy less if they knew the ending before hearing the story seems less likely to have made a significant impact. It's also likely that, even if the term 'spoiler' was adopted by these Iron Age people, it would long have fallen out of use by the time it came to be invented in the late twentieth century. However, according to chaos theory, this interaction might cause a chain of events that will lead to Cueball not existing, creating a paradox.

[[:Category:Time travel|Time Travel is a reoccurring theme on xkcd]]

==Transcript==

:[1st Panel. Cueball is on the left with a ghostly halo around him. Hairbun is on the right, holding a hoe vertically.]
:Cueball: Oh hi! Guess my time machine works. How's life in the Iron Age?
:Hairbun: Not bad. Developing new kinds of plows.
:Cueball: Cool.
:Hairbun: And my brother was just lost at sea.

:[2nd Panel. Only Cueball is shown, with Hairbun out of the panel.]
:Cueball: I'm sorry.
:Hairbun [from outside the right side]: It's OK. I think sea navigation is probably impossible.

:[3rd Panel. Cueball and Hairbun are both shown again.]
:Cueball: Oh yeah, you don't have the compass, right?
:Hairbun: The what?
:Cueball: The weird rock that always points north?
:Hairbun: What are you '''talking''' about?

:[4th Panel. Cueball and Hairbun are both shown. Cueball holds his hand to his chin.]
:Cueball: It '''does''' sound ridiculous when I say it out loud. Anyway, spoilers for the magnetic compass. Sorry.
:Hairbun: What's a spoiler?
:Cueball: ...Spoilers for the concept of a spoiler, too.

{{comic discussion}}<noinclude>
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairbun]]
[[Category:Time travel]]

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3251: Time Machine Conversation