A Discussion of Time Travel from the 1900s

I don’t remember the last time I had an idle email conversation. I used to do them all the time with friends, but as with most things, technology changes our social interactions.

This email exchange sat on my personal website for years, and I thought I’d rescue it from an archive. It’s an incomplete conversation… the process for converting the emails into HTML at the time was laborious, and I never got back to finishing the page.

For the record, I am the one known as Dinoczar, my old username from back in the day.  RedVelvetCakes can be followed on Twitter, if that’s your thing.

A Discussion of Time Travel

with only a few tangential excursions
between RedVelvetCakes and Dinoczar
August 1999

From: RedVelvetCakes
Sent: Wednesday, August 25, 1999 8:58 AM
To: DinoCzar
Subject: Something you’ll like


http://www.movie-mistakes.com/specifics/starwars.htm#starwars


From: DinoCzar
To: RedVelvetCakes


Aye, that is funny.

It sort of inspires me to write a page/essay on Time Travel in movies… how people have messed it up in the past, how it could be done right, etc…

I’m not sure I have enough web MB to handle all the inconsistencies in the Back to the Future trilogy…

 


From: RedVelvetCakes
To: DinoCzar

It sort of inspires me to write a page/essay on Time Travel in movies… how people have messed it up in the past, how it could be done right, etc… I’m not sure I have enough web MB to handle all the inconsistencies in the Back to the Future trilogy…

I was much more bothered by BttF’s lame anachronistic ironic jokes (“his names’ Calvin; it says so on his underwear”) and its thoughtless racism (it seems to imply Chuck Berry couldn’t have defined rock’n’roll without some help from a white teenager).

Time travel tends to fall apart logically no matter how carefully you write it. Larry Niven wrote a great essay on why time travel is impossible and the beliefs you have to suspend to write it. He covers the well-known “grandfather paradox,” but also some lesser-known inconsistencies, like: time travel violates conservation of matter, since you and your machine exist _twice_ in the universe when you move through time.

 

 


From: DinoCzar
To: RedVelvetCakes

I was much more bothered by BttF’s lame anachronistic ironic jokes (“his names’ Calvin; it says so on his underwear”) and its thoughtless racism (it seems to imply Chuck Berry couldn’t have defined rock’n’roll without some help from a white teenager).

I didn’t care for the anachronistic “humor” myself (I cringe at the “heavy” jokes every time I hear them).

As for the racism… hmmm. I think the Chuck Berry thing is a bit reaching. If you pay attention to the BttF time travel convention, Chuck Berry DID originally define rock n’ roll, in the same way that the Lone Pines mall was originally the Twin Pines mall before Marty ran over the tree. The Chuck Berry racism theory would hold up better under the 12 Monkeys time travel convention that time isn’t changed by travelers.

However, I will admit that in BttF2, finding a black family in his house in the “hellish ghetto” 1985 is not a very wise choice.

Time travel tends to fall apart logically no matter how carefully you write it. Larry Niven wrote a great essay on why time travel is impossible and the beliefs you have to suspend to write it. He covers the well-known “grandfather paradox,” but also some lesser-known inconsistencies, like: time travel violates conservation of matter, since you and your machine exist _twice_ in the universe when you move through time.

It seems you could, from a dramatic perspective if not a scientific one, get around that bug by displacing an equal mass to your original time when you travel to a new one.

Or perhaps convervation of mass is time-independant. After all, you’re not creating mass, just moving it. If you consider time as comparable to a dimension in space, you don’t violate conservation of mass when you move a mass to a new location, because you’ve vacated it from the previous location. If you move it in time, then you’ve vacated it from the previous “location” in time.

I should very much like to read that Larry Niven essay, though.

As with any movie, you suspend your disbelief to a certain extent. Whether it’s by believing that dragons exist, or the very basic believing that you’re actually watching things happen, as opposed to a series of rapidly projected still images artificially invented by cinematographers and directors.

With time travel, if you start with the basic premise that time travel is possible, then I think it’s possible to create a credible, logical plotline that deals with the inherent problems, e.g. the “grandfather paradox”. 12 Monkeys did it well, I think. Very simply saying “you can’t change the past because it’s already happened” worked well for it, I think.

 

 


From: RedVelvetCakes
To: DinoCzar

I didn’t care for the anachronistic “humor” myself (I cringe at the “heavy” jokes every time I hear them).

If they’d been less forced I wouldn’t have minded so much. Like the “Pepsi Free” gag…no teenage boy I’ve ever known drank diet soda or fretted about his sugar intake, so there was no reason to include that joke.

roll, in the same way that the Lone Pines mall was originally the Twin Pines mall before Marty ran over the tree. The Chuck Berry racism theory would hold up better under the 12 Monkeys time travel convention that time isn’t changed by travelers.

I don’t mean to say the racism was deliberate or even conscious. But it’s a valid way to read that scene, and the fact that Zemeckis would include it so breezily, as just a gag along the same lines as Marty accidentally “inventing” the skateboard, speaks volumes about his shallowness as a director. That’s why it irritates me.

The Twin Pines/Lone Pine gag was one of my favorite bits in the movie. Probably because it’s so subtly-done; many people miss it entirely.

However, I will admit that in BttF2, finding a black family in his house in the “hellish ghetto” 1985 is not a very wise choice.

I didn’t even remember that. I think I’ve repressed my memories of the second movie. My favorite was the third one, mostly for the spectacular sequence with the train and the canyon. Whoo-ee! Big fun!

It seems you could, from a dramatic perspective if not a scientific one, get around that bug by displacing an equal mass to your original time when you travel to a new one.

That’s a fun idea! Imagine taking off in your time machine and leaving behind in your lab an equivalent mass of Cretaceous-era soil. Teeming with Cretaceous-era microbes and insects! Ryan, you’ve just made up a premise for a great sf story!

Or perhaps convervation of mass is time-independant. After all, you’re not creating mass, just moving it. If you consider time as comparable to a dimension in space, you don’t violate conservation of mass when you move a mass to a new location, because you’ve vacated it from the previous location. If you move it in time, then you’ve vacated it from the previous “location” in time.

That occurred to me when I read the essay, but it doesn’t hold up if you’re being rigorous with your physics. Think about the expansion of the universe: it’s undeniably time-dependent, and also mass-dependent. It expands at the rate it does because of the amount of matter in it, and that’s constant over time.

I should very much like to read that Larry Niven essay, though.

I’d lend it to you if I owned it. It’s in a collection of his essays called “All the Myriad Ways” which my friend Jack lent me for a story I never wrote about a girl who can teleport (he’s got a teleportation-theory essay in it too). You should get it; it also includes his famous “Man of Steel, Woman of Kleenex” speculation about Lois and Clark’s sex life.

With time travel, if you start with the basic premise that time travel is possible, then I think it’s possible to create a credible, logical plotline that deals with the inherent problems, e.g. the “grandfather paradox”. 12 Monkeys did it well, I think. Very simply saying “you can’t change the past because it’s already happened” worked well for it, I think.

Yes, it did make sense, although the story suffered a little for it. I wanted more of a surprise at the end.

The most workable time travel assumption, in my view, is to use the “many worlds theory.” You’re not really traveling back to the Iron Age, you’re just going to a parallel universe where it’s currently the Iron Age. They did this at least once on Sliders, where they slide to a world where the local Quinn was only 11.

Oh, one more mention: Roger Zelazny wrote a fun novel called Roadmarks, wherein there’s a highway through time. One mile = one year, and the exit ramps take you to various alternate timelines. But it’s easy to get lost. The main character travels the road in a step-side Ford pickup, and the highway patrol keeps pulling him over for trying to take machine guns back to the ancient Greeks. Seems he’s always believed the Greeks should have won at Marathon…

 


From: DinoCzar
To: RedVelvetCakes

I didn’t care for the anachronistic “humor” myself (I cringe at the “heavy” jokes every time I hear them).

If they’d been less forced I wouldn’t have minded so much. Like the “Pepsi Free” gag…no teenage boy I’ve ever known drank diet soda or fretted about his sugar intake, so there was no reason to include that joke.

The thing that bothers me even MORE than that is that Pepsi Free was a _caffiene_ free drink, not a _sugar_ free drink. The gag reaches even more…

That’s a fun idea! Imagine taking off in your time machine and leaving behind in your lab an equivalent mass of Cretaceous-era soil. Teeming with Cretaceous-era microbes and insects! Ryan, you’ve just made up a premise for a great sf story!

You write it, I’ll sit back and collect the residuals…

The most workable time travel assumption, in my view, is to use the “many worlds theory.” You’re not really traveling back to the Iron Age, you’re just going to a parallel universe where it’s currently the Iron Age. They did this at least once on Sliders, where they slide to a world where the local Quinn was only 11.

I agree. I think that BttF had an interesting idea in the “branching parallel universe” vein that they completely failed to develop. In BttF2, Doc Brown draws the diagram that shows how they are in the “hell future branch” of the universe caused by Bif’s traveling back in time. They talk about how they can’t get back to “their” branch in time without going back to change what Bif had done. Never mind that the “old” Bif managed to get back to that branch to give them back the time machine, although that is probably explained by the metatime delay between when changes occur in the past and when they “catch up” to the future (e.g. the picture of Marty and his siblings gradually fade away instead of all of a sudden.)

My ideal time travel story would say, when you go back in time, you create a “possibility branch”, the difference between it and the one you just came from being your arrival. So, if you travel forward in time, you travel along your current time branch. Unfortunately, you can never get back to your original time branch, because your original time branch never had you arriving in the past. It takes care of the grandfather paradox, because you could never kill the grandfather in your “birth branch” because you could never get there.

Oh, one more mention: Roger Zelazny wrote a fun novel called Roadmarks, wherein there’s a highway through time. One mile = one year, and the exit ramps take you to various alternate timelines. But it’s easy to get lost. The main character travels the road in a step-side Ford pickup, and the highway patrol keeps pulling him over for trying to take machine guns back to the ancient Greeks. Seems he’s always believed the Greeks should have won at Marathon…

did you ever see that New Twilight Zone (I believe it was NTZ, it could have been one of the other modern weird stuff tv shows…) where the future was being built by blue guys? There was a construction crew out ahead of us in time building an earth for every minute. If nobody was going to be in an alley for that minute, they wouldn’t build it. It was a fun little concept. The story was about a couple that got left behind in a minute of time. The construction crew came to demolish the old minute and found them there. They got taken forward in time by the foreman, who told them they couldn’t return to real time. They excaped and hid until real time caught up to them. Funny!

 

 


From: RedVelvetCakes
To: DinoCzar

The thing that bothers me even MORE than that is that Pepsi Free was a _caffiene_ free drink, not a _sugar_ free drink. The gag reaches even more…

Are you sure about that? I thought Pepsi Free was the forerunner to Diet Pepsi, and that it came in a caf and a non-caf version.

That’s a fun idea! Imagine taking off in your time machine and leaving behind in your lab an equivalent mass of Cretaceous-era soil. Teeming with Cretaceous-era microbes and insects! Ryan, you’ve just made up a premise for a great sf story!

You write it, I’ll sit back and collect the residuals…

Deal.

to that branch to give them back the time machine, although that is probably explained by the metatime delay between when changes occur in the past and when they “catch up” to the future (e.g. the picture of Marty and his siblings gradually fade away instead of all of a sudden.)

Those plot details are fuzzy in my mind. But that whole plan of Biff’s illustrates just how not-smart he (or Zemeckis) was. Giving the book to his younger self didn’t help _him_ (aged Biff) at all! When he went back to his own time, the other Biff would be the rich and famous one, and he’d still be a loser. Only now, a universe-displaced loser.

You mention the photograph, and that reminds me of another problem with the first movie. The idea was that Marty would cease to exist unless he got his parents together, right? But they way he changed his father’s personality makes it fair to assume their sex life would be very different…at least, they’d probably get it on sooner and more often. It follows that it’d be just as unlikely for the particular ovum and sperm that became Marty to achieve union. Marty shouldn’t have been able to save himself or his siblings that way.

But we could go on all day. Why don’t we just pronounce BttF a creative failure and move on?

My ideal time travel story would say, when you go back in time, you create a “possibility branch”, the difference between it and the one you just came from being your arrival. So, if you travel forward in time, you travel along your current time branch. Unfortunately, you can never get back to your original time branch, because your original time branch never had you arriving in the past. It takes care of the grandfather paradox, because you could never kill the grandfather in your “birth branch” because you could never get there.

Yes, exactly! That’s how I’ve always liked it. A variation I’ve thought of is that you ALWAYS return to your original branch, automatically. So if you want to see what the world would’ve been like without Hitler, you’ll have to stick around in the past after preventing his birth to find out.

time. The construction crew came to demolish the old minute and found them there. They got taken forward in time by the foreman, who told them they couldn’t return to real time. They excaped and hid until real time caught up to them. Funny!

That does sound funny. Did it star anyone well-known?

Did you read the “Danny Dunn” books when you were a kid? They were like Beverly Cleary’s books for the nine- and ten-year-old set, only they had a science fiction focus. They included:

Danny Dunn and the Smallifying Ray
Danny Dunn and the Anti-Gravity Paint
Danny Dunn and the Automatic House

…etc. One of the books was about a time machine, which Danny’s gaurdian, Professor Bullfinch, built into his lab, so the whole room moved through time. First Danny, the Professor, Danny’s girlfriend Irene and their best friend Joe moved forward about four days, where they accidentally picked up an alternate version of Joe. They named him Possible Joe. Then they went back in time two hundred years, where the time machine (as is typical in such stories) promptly broke down. They had an adventure with Benjamin Franklin, who helped them return to their proper time.

It was a fun book. When I was ten. But even now I have to smile at “Possible Joe.”

 

 


From: DinoCzar
To: RedVelvetCakes

[The thing that bothers me even MORE than that is that Pepsi Free was a _caffiene_ free drink, not a _sugar_ free drink. The gag reaches even more…]

Are you sure about that? I thought Pepsi Free was the forerunner to Diet Pepsi, and that it came in a caf and a non-caf version.

I’m 99.9% sure of that. I went as a can of Pepsi Free for the halloween the year before BttF came out, and I never would have gone as a Diet drink. While I’ll admit to being a Coke and Pepsi drinker at one time, I was NEVER a diet drinker of any sort.

I believe Pepsi Light was the forerunner to Diet Pepsi; it had a lemony flavour that made it my mother’s favorite drink, until it was discontinued. She mourns it to this day.

******
Yep, I just went and checked the web:

http://www.cool-drinks.com/Root%20Folder/CoolDrinksHistory.html

This page shows when drinks came out. Diet Pepsi was introduced in 1964, Pepsi Light in 1975, and Pepsi Free and DIET Pepsi Free came out in 1982 (the same year as the Delorean… hmmm…) So Pepsi-Cola was the forerunner to Diet Pepsi, and Pepsi Free had a Diet Pepsi Free version…

[You mention the photograph, and that reminds me of another problem with the first movie. The idea was that Marty would cease to exist unless he got his parents together, right? But they way he changed his father’s personality makes it fair to assume their sex life would be very different…at least, they’d probably get it on sooner and more often. It follows that it’d be just as unlikely for the particular ovum and sperm that became Marty to achieve union. Marty shouldn’t have been able to save himself or his siblings that way.]

But we could go on all day. Why don’t we just pronounce BttF a creative failure and move on?

Yeah, boy howdy. Once you start messin’ around on that level, it gets hairy. You certainly don’t need to go through all the trouble of actually _killing_ your grandfather to keep you from being born. Just give ’em a shake to toss the sperm around…

[My ideal time travel story would say, when you go back in time, you create a “possibility branch”, the difference between it and the one you just came from being your arrival. So, if you travel forward in time, you travel along your current time branch. Unfortunately, you can never get back to your original time branch, because your original time branch never had you arriving in the past. It takes care of the grandfather paradox, because you could never kill the grandfather in your “birth branch” because you could never get there.]

Yes, exactly! That’s how I’ve always liked it. A variation I’ve thought of is that you ALWAYS return to your original branch, automatically. So if you want to see what the world would’ve been like without Hitler, you’ll have to stick around in the past after preventing his birth to find out.

Oooo… I like that. Hmmm…

[time. The construction crew came to demolish the old minute and found them there. They got taken forward in time by the foreman, who told them they couldn’t return to real time. They excaped and hid until real time caught up to them. Funny!]

That does sound funny. Did it star anyone well-known?

Not that I can remember…

Did you read the “Danny Dunn” books when you were a kid?

Ohhhh, yes. That and the Great Brain series were my favorites.

…etc. One of the books was about a time machine, which Danny’s gaurdian, Professor Bullfinch, built into his lab, so the whole room moved through time. First Danny, the Professor, Danny’s girlfriend Irene and their best friend Joe moved forward about four days, where they accidentally picked up an alternate version of Joe. They named him Possible Joe. Then they went back in time two hundred years, where the time machine (as is typical in such stories) promptly broke down. They had an adventure with Benjamin Franklin, who helped them return to their proper time. It was a fun book. When I was ten. But even now I have to smile at “Possible Joe.”

Yes. As I was reading the book, I kept screaming “why doesn’t Possible Joe TELL them what’s about to happen?!?!?! He’s already DONE it!”. Joe didn’t strike me as the sort who had moral qualms with meddling with the past…

I was just thinking about a story I wrote in 7th grade about time travel. It was basically an exercise with the grandfather paradox. A character invents a time machine based on a complex network of rubber bands and cola cans, whereby if you pluck the appropriate rubber band, the entire structure resonates at a frequency just right to rip a hole in space-time that drops you into the time you want. Anyway, the time machine inventor does this, and ends up landing in front of a moving car, which swerves and crashes into a tree, which kills his grandfather, who was driving. Then my explanation of what happens is that space-time splits into two, with one world having neither the grandfather nor the grandson, and the other being a hellish unstable world with probability waves sweeping across the landscape causing people to pop in and out of existence. That was the end of the story (3 pages long, whaddaya gonna do?), but now I’m thinking that might be an interesting premise… what sort of adventures could you have on a world where space-time has been corrupted because of the grandfather paradox…

You know what? I don’t really HAVE to create the web page about time travel anymore. I could just post these messages on my site, with an index…

Hmmm…

 


From: RedVelvetCakes
To: DinoCzar

Are you sure about that? I thought Pepsi Free was the forerunner to Diet Pepsi, and that it came in a caf and a non-caf version.

I’m 99.9% sure of that. I went as a can of Pepsi Free for the halloween the year before BttF came out, and I never would have gone as a Diet drink. While I’ll admit to being a Coke and Pepsi drinker at one time, I was NEVER a diet drinker of any sort.

Okay, I concede the point.

I believe Pepsi Light was the forerunner to Diet Pepsi; it had a lemony flavour that made it my mother’s favorite drink, until it was discontinued. She mourns it to this day.
******
Yep, I just went and checked the web:
http://www.cool-drinks.com/Root%20Folder/CoolDrinksHistory.html
This page shows when drinks came out. Diet Pepsi was introduced in 1964, Pepsi Light in

I said OKAY, already!

1975, and Pepsi Free and DIET Pepsi Free came out in 1982 (the same year as the Delorean… hmmm…) So Pepsi-Cola was the forerunner to Diet Pepsi, and Pepsi Free had a

Have there been any DeLorean electric conversions?

I’m thinking about converting my Tracker. Want to help?

[on all day. Why don’t we just pronounce BttF a creative failure and move on?]
Yeah, boy howdy. Once you start messin’ around on that level, it gets hairy. You certainly don’t need to go through all the trouble of actually _killing_ your grandfather to keep you from being born. Just give ’em a shake to toss the sperm around…

Exactly. As Bradbury demonstrates in “Sound of Thunder,” the smallest of intrusions can have far-reaching cascade effects.

Yes, exactly! That’s how I’ve always liked it. A variation I’ve thought of is that you ALWAYS return to your original branch, automatically. So if you want to see what the world would’ve been like without Hitler, you’ll have to stick around in the past after preventing his birth to find out.]
Oooo… I like that. Hmmm…

Yeah.

[Did you read the “Danny Dunn” books when you were a kid?]

Ohhhh, yes. That and the Great Brain series were my favorites.

Wow! I’m surprised. Most people I know who are even a couple of years younger than me seem to have missed out on Danny Dunn. I think my favorite was the one where they went into an unexplored cave and Dr. Grimes got lost.

Yes. As I was reading the book, I kept screaming “why doesn’t Possible Joe TELL them what’s about to happen?!?!?! He’s already DONE it!”. Joe didn’t strike me as the sort who had moral qualms with meddling with the past…

I recall that at the end of the book, a few days after their return, Joe came into the lab and told them he had just lived through the adventure all over again, and he remembered everything but was unable to speak or act any differently than he had the first time. But he relived the experience as Joe, NOT as Possible Joe, and that never made any sense to me.

I hope someday I marry a woman broad-minded enough to let me name our son Possible Joe.

I was just thinking about a story I wrote in 7th grade about time travel. It was

existence.
That was the end of the story (3 pages long, whaddaya gonna do?), but now I’m thinking that might be an interesting premise… what sort of adventures could you have on a world where space-time has been corrupted because of the grandfather paradox…

I don’t know. What sort? You’d need to define very carefully and specifically the effects of said “corruption.”

That’s pretty sophisticated writing for a 7th-grader. I wrote a story in high school about a kid who steals a time-travel device and decides to go back in time, murder the author of a famous novel before he wrote it, then come back to the present and publish the novel as his own. He does so, but during the trip home he remembers that it was his parents’ favorite book and that they met at a lit class about it. On arrival in the present…blink! He’s gone. A ham-handed morality tale with an O. Henry ending; not my finest work.

You know what? I don’t really HAVE to create the web page about time travel anymore. I could just post these messages on my site, with an index…

Go for it, bubba!

 


From: DinoCzar
To: RedVelvetCakes

1975, and Pepsi Free and DIET Pepsi Free came out in 1982 (the same year as the Delorean… hmmm…)
Have there been any DeLorean electric conversions?]

You mean, aside from the Doc Brown conversion? I dunno. That’s my dream conversion right there.

I’m thinking about converting my Tracker. Want to help?]

For real? Yikes. I certainly would. What’re you gonna drive in the meantime?

Wow! I’m surprised. Most people I know who are even a couple of years younger than me seem to have missed out on Danny Dunn. I think my favorite was the one where they went into an unexplored cave and Dr. Grimes got lost.]

Hmmm… I don’t remember that one. I can only remember the anti-gravity paint and the time travel one. Although, I’m sure I read more…

[Yes. As I was reading the book, I kept screaming “why doesn’t Possible Joe TELL them what’s about to happen?!?!?! He’s already DONE it!”. Joe didn’t strike me as the sort who had moral qualms with meddling with the past…]

I recall that at the end of the book, a few days after their return, Joe came into the lab and told them he had just lived through the adventure all over again, and he remembered everything but was unable to speak or act any differently than he had the first time. But he relived the experience as Joe, NOT as Possible Joe, and that never made any sense to me.

Hmmm… you know. You’re right. I remember that now, as well. How odd.

I hope someday I marry a woman broad-minded enough to let me name our son Possible Joe.

Perhaps you could just name him Joe, and then CALL him Possible Joe. But I would definitely go for the full legal name of Possible J. RedVelvetCakes.

That was the end of the story (3 pages long, whaddaya gonna do?), but now I’m thinking that might be an interesting premise… what sort of adventures could you have on a world where space-time has been corrupted because of the grandfather paradox… I don’t know. What sort? You’d need to define very carefully and specifically the effects of said “corruption.”

Well, it could almost be a fantasy as opposed to sci-fi story. All sorts of different anomolies all over the planet, each one the basis for a short story set in this world. A Discworld sortof thing. I dunno. Writing stories is pretty far down on my list of priorities right now.

You know what? I don’t really HAVE to create the web page about time travel anymore. I could just post these messages on my site, with an index…
Go for it, bubba!

Okay.