See?
Heinlein’s The Door Into Summer deals with this (guy goes back in time and patents objects he knows will exist in the future, thus making loads of money), and of course H2G2 has lots of this, including going backwards in time to build a huge building you need today, and some resultant paradox that I can’t quite remember now…
This reminds me of the Futurama where Fry went back in time and became his own grandfather by impregnanting his grandmother.
Time loops are also used extensively in a novel by the name of Time’s Square - I forget the author.
I don’t think so. Donnie Darko’s time travel was not closed-off like the examples here.
Heinlein did quite a few of these stories. In “By his bootstraps” a notebook is created by the time-loop, and in “All you zombies”, the protagonist is shown to be both his own father and mother, i.e., he himself was the product of the time-loop.
Stanislaw Lem’s Tales of Pilot Pirx had my favorite time loop story. Pirx had to create a time loop somehow (using a giant sta’rs gravity well, maybe?) so he would have someone to help him fix his spaceship. Turned out that his future self was something of a jerk. At one point, he had a ship full of Pirxes running around, none of whom were cooperating with each other. Eventually, two child Pirxes ended up fixing the ship. Great stuff.
Also, Lem’s Cyberiad was a hoot.
RR
A site and a book that will give you more on time travel than you ever wanted to know.
The Time Machine. Check the Links page for a long list of books and movies.
Time Machines: Time Travel in Physics, Metaphysics, and Science Fiction, by Paul J. Nahin.
Just to chime in another pop culture reference… in Harry Harrison’s ‘stainless steel rat saves the world’, the villain known only as ‘He’, turns out to be a living djinn, in that he is never born, and never dies… His travels through time form an closed loop. Once the loop is closed, his career is finished, because he can never break out of his history and try any other scheme. I have to admit, that notion is pretty far out.
I like the term… can we extend it as far as ‘djinn meme’ or ‘djinn idea’ to express a concept/idea/thought that was never conceived independently by any person but can be traced back entirely to a time travel loop? (For instance, bringing the five weyrs forward in ‘dragonflight’ – Lessa guesses that it has already happened because of the historical circumstances of the dragonrider’s disappearance, and the question song, but then she goes back in time, suggests to the past dragonriders that they should come forward, and basically tells the masterharper at that time that he has to write the question song. 
)
PS: always be wary of the information in a djinn meme - false facts can be generated by those temporal causality loops as easily as true facts.
Yeah, fun book.
Question: if you managed to stretch out the time loop, would you end up with “slow djinn?”
RR
A few other examples:
David Gerrold, *The Man Who Folded Himself *
A time traveller turns out to be his own father, his own mother, his own son and his own daughter. And also his own grandfather, or was it uncle.
Star Trek movies - no spoiler required. In Star Trek IV the crew travel back in time. to raise a little money, Kirk sells a pair of antique spectacles. In the future, Doc McCoy buys the same pair of specs, and gives it to Kirk for his birthday.
Meanwhile Scotty gives the secret of transparent aluminum to it’s inventor, who wouldn’t have discovered it otherwise.
Iffy.
While Kirk’s comments in the antique store amusingly hint that those spectacles might, three hundred years later, be the ones McCoy purchases for him, we don’t know that they are.
And again, with the Transparent Aluminum - Scotty’s comment is ‘How do we know he didn’t invent the stuff?’ One, I find it odd that Mr. Scott, master engineer, doesn’t remember the name of the man who invented this important starship material. Two - again, we’re not certain of the djinn effect here. Someone across the country might’ve been developing it at the same time as the Enterprise crew was handing it over to this manufacturer.
They want to replace a Cathedral with a new building. In order to meet a deadline, they go back in time to build it. It takes so long to build the new building that the Cathedral is never built. This makes postcards of it extremely valuable.
There have been many with the same sort of idea. In the one I remember (well, cannot recall the author or title), back in the Mists of Time, some chap visits the ancient equivalent of a bank, and deposits an odd looking coin, saying that he will return after some set amount of time to claim the return on his investment. Anyway, he returns many times over the years, and his investment grows in value - 1000s of years of compound interest will do that. As we reach the present, the original odd coin starts to look very familiar…
In the denouement, the investor suddenly decides to liquidate, turning his investment into hard cash. He does this so that he can build his time machine which he’s been working on for many years.
Now who was that author / story title? Hmmm.
Yeah, two good examples of how it can be hard to tell a true djinn effect from a relatively simple time loop. The spectacles are obviously the same ones that mccoy has already purchased for kirk, but we don’t know for sure that the loop closes and mccoy also purchases them AFTER they get sold to the antiques store. (For one thing, you’d expect a certain amount of wear and tear over a few centuries, even if only on a molecular level, and if that damage isn’t repaired then the djinn effect can’t take place.)
The best way to look at the non-djinn hypothesis is that for those several hundred years there might be two different copies of that pair of glasses somewhere on earth… (until first contact, when presumably the copy that kirk sells might be taken off-world.)
Did that make any sense??
Yup.
Also, Star Trek is a bad example to use for this sort of thing because the ST universe allows causality paradoxes. If you go back in time and erase your own future existence - you’re still there, back in time, and relatively okay. Even if you go back to your correct time, you’ll still be okay. If you and a buddy go back and your buddy kills your past self, you’re still there in the past with him. You don’t pull a Marty McFly and fade out. (Witness the Enterprise episodes - Shockwave, pts 1 & 2 for an illustration. Or ST : First Contact - The Enterprise E gets a nice view of the Borg-dominated Earth as they’re plowing into the temporal anomaly)
IIRC they say that they are protected from the changes they are witnessing to the earth by the time vortex doohickey they were in.
Of course, Star Trek plays fast and loose with all of this but hey, it’s fiction and fun to watch. Any fiction that uses time travel will have to make assumptions and take liberties that can have holes poked in it if you want to. I am serious that I think Bill and Ted’s Excellent Adventure actually got time paradox weirdness more right than most movies. Of course they offer no explanations…it just is and our heroes move blissfully ignorant through all of it not questioning which is part of its charm.
Yes, they were protected because they were already being displaced in time.
According to this article, Paul Nahin from UNH says that Bill and Ted is the most scientifically sound time-travel movie ever made.
Check the bottom of this page:
Another one:
Terry Pratchett, Pyramids
Dios the high priest has lived for thousands of years, advising the line of kings. At the end, he gets blasted back into the past, where he meets the first king, and starts to tell him about pyramids and gods and stuff. His staff carries the image of a snake with it’s tail in it’s mouth, probably highly significant but he doesn’t know what it means.