this post was submitted on 23 Aug 2024
395 points (99.5% liked)

xkcd

8757 readers
80 users here now

A community for a webcomic of romance, sarcasm, math, and language.

founded 1 year ago
MODERATORS
 

alt text:

Many a hungry time traveler has Googled 'trilobites shellfish allergy' only to find their carrier had no coverage in the Ordovician.

https://explainxkcd.com/2976/

top 48 comments
sorted by: hot top controversial new old
[–] [email protected] 3 points 2 months ago

Mammalia are a footnote in earths history.

[–] [email protected] 17 points 2 months ago (4 children)

[off topic]

One of my favorite time travel novels is 'The Big Time' by Fritz Leiber.

The two big ideas in the book. First, that there's a Law of Conservation of Reality. Go back in time and shoot Hitler. He dies. Then gets better, really fast. Twenty minutes after you shoot him, he's fine. Spend your whole life shooting him and the history books will just ignore it. It takes an army of time travelers working night and day to get any changes to stick.

Second idea. There are two armies, both trying to change the past/future. They have been at it since before the Big Bang and will go on until the Heat Death of the Universe. They recruit humans but no human has ever seen the big bosses, just low ranking stooges.

[–] [email protected] 0 points 2 months ago* (last edited 2 months ago)

Ctrl+F Hitler, ah, there it is. I feel like the xkcd comic missed an opportunity to have a 1932-1945 segment in there about the biggest cause of death for time travelers being OTHER time travelers killing them before they can successfully go back in time and kill Hitler, lol.

Re: conservation of reality, I feel like if I went back and shot Hitler, I would miss, or be stopped by security, or bad weather, or my gun would misfire, or even if I managed to actually do it, he'd be replaced by a look alike, and then it would turn out the guy we always thought was Hitler was actually just an actor, or something. Like if someone went back and killed baby Adolph when he was six months old, the parents would adopt another kid and name IT adolph, and there you go. Whatever happened happened and can't be undone, not through magic resuscitation of a corpse, but through smooth and natural intervention of reality itself, if that makes sense..

[–] [email protected] 2 points 2 months ago (1 children)

But that neccessitates a predetermined fate.

[–] [email protected] 2 points 2 months ago

. It takes an army of time travelers working night and day to get any changes to stick.

Changes do occur in the story. The participants talk about the 'Change Winds' and how people can just disappear because thier timeline has been shifted and their parents never met.

[–] [email protected] 3 points 2 months ago (1 children)

He dies.

That's an unusual take on it. That would definitely have been recorded somewhere as a miraculous recovery. Usually it's written that the time travelling assassin fails in such a way that no-one notices, and if they do have some kind of effect, generally ends up being the cause of the history they were taught rather than the changer of it.

[–] [email protected] 4 points 2 months ago

The author did a few stories based on the 'Change War.'

In one, a time traveler goes back and takes the bullets out of a gun, hoping to prevent a death. There's no gunshot, but the victim is hit by a meteor and dies anyway. The idea is that Time is immutable and almost impossible to change with only one set of hands.

[–] [email protected] 10 points 2 months ago (2 children)

The first one was also used in the short series "11.22.63". Going back to change things results in huge amounts of temporal inertia to overcome.

[–] [email protected] 1 points 2 months ago

Which was originally a Stephen King novel.

[–] [email protected] 4 points 2 months ago* (last edited 2 months ago) (1 children)

And the second one reminds of the TV series "Travelers", with future factions of time travelers emerging from the changes of previous time travelers in the past. It's worth noticing that time travelers from "Travelers" only displaces their mind consciousnesses, not their entire bodies.

[–] [email protected] 2 points 2 months ago

Watched a couple of episodes, didn't get to the time war part. May check it out.

[–] [email protected] 56 points 2 months ago (2 children)
[–] [email protected] 21 points 2 months ago (1 children)

There is no cosmic frame of reference. Earth is moving, the sun is moving, the galaxy is moving, but you can choose any frame of reference within that. It'd be really silly to use the suns frame of reference, you'd use Earth's.

[–] [email protected] 29 points 2 months ago (3 children)

A time machine is a teleportation machine. If we can imagine a time machine existing, a teleportation machine isn't really far fetched.

[–] [email protected] 3 points 2 months ago

A time machine is a faster than light drive.

Well, the other way 'round, really, but same difference.

And to come back you need a slower than (but very close to) light drive.

[–] [email protected] 0 points 2 months ago

well, if you rewind time and stay in the box, the box would probably stay on earth, but I have no idea how time travel would work.

[–] [email protected] 25 points 2 months ago* (last edited 2 months ago) (1 children)

I cannot wait for time travel to exist so all the pedants online can be like “um actually, it’s a space-time machine”

Edit: because I am also pedantic like this.

[–] [email protected] 1 points 2 months ago

Truly the most culturally relevant development from the technology!

[–] [email protected] 39 points 2 months ago (1 children)

#1, during all eras: they didn't get the space-travel part in space-time correct.

[–] [email protected] 8 points 2 months ago

Wouldn’t that just be asphyxiation?

[–] [email protected] 19 points 2 months ago (12 children)

But what about time travelers who go forward in time

[–] [email protected] 3 points 2 months ago

Dad comes home with the milk

[–] [email protected] 1 points 2 months ago

It's a spectrum from "low and slow" up to "broiled."

[–] [email protected] 3 points 2 months ago
[–] [email protected] 8 points 2 months ago

Believe it or not, jail

....and asphyxiation.

[–] [email protected] 4 points 2 months ago

Time machine door gets stuck

[–] [email protected] 11 points 2 months ago
[–] [email protected] 13 points 2 months ago

Autoerotic asphyxiation

[–] [email protected] 4 points 2 months ago
[–] [email protected] 3 points 2 months ago

Mole people.

[–] [email protected] 3 points 2 months ago

Asphyxiation

[–] [email protected] 5 points 2 months ago

Robot raptors

[–] [email protected] 11 points 2 months ago