For Discussion: Time Travel Myths

[maninahat]

I always wondered if a time traveler wouldn't spread a super contagious disease by being there, or vice versa, contracting a deadly disease thought to be eliminated. Also if food in the past centuries being actually eatable without destroying your stomach.

Food wouldn't be a problem, you can try out recipes from centuries or millenia ago, there are re-enactors into period cooking. I don't think disease would be such a problem, most of the potentially nasty contagious diseases you are unlikely to be carrying when you go back in time. Most things you want to avoid are things that'd likely be killing the locals and making it obvious you want to avoid.

I don't think that's true. I catch all kinds of horrible things time each I go to India/Pakistan, just from eating ordinary food. Basically food in developing countries isn't completely sanitary, and that is only going to be worse way back when, where people didn't do basic things like pasteurise milk. On top of that, we'd probably dislike the taste of most food available; wealthy Medieval people, as they could afford it, overspiced everything. Meanwhile peasants had their pottage, which is apparently pretty gross.

Diseases would be a problem. If you've been vaccinated, you'd probably be safe from a lot of the big killers like measles or rubella, but you are almost certainly going to bring a lot of strains of modern mutations of old diseases back to the past, which would in the long run make things even worse when you consider these peasant losers haven't even had chance to discover germ theory or anti-biotics yet, and a lot of the things we're bringing back are already becoming anti-biotic proof. Basically you're going to have to do all the leg work to stop these guys dying around you.

 

[Thaluikhain]

I don't think that's true. I catch all kinds of horrible things time each I go to India/Pakistan, just from eating ordinary food. Basically food in developing countries isn't completely sanitary, and that is only going to be worse way back when, where people didn't do basic things like pasteurise milk. On top of that, we'd probably dislike the taste of most food available; wealthy Medieval people, as they could afford it, overspiced everything. Meanwhile peasants had their pottage, which is apparently pretty gross.

Certainly, but that's not the food per se, that's the lack of hygiene. Whether or not we'd actually like the food is another issue, yeah. Though, I suggest looking at https://www.youtube.com/user/jastownsendandson/videos loads of videos about 18th century cooking (amongst other things).

you are almost certainly going to bring a lot of strains of modern mutations of old diseases back to the past

Why? If you went back to the past right now, what diseases are you currently carrying?

Maybe you might have a nasty flu or something, but flu outbreaks were something they'd get every so often anyway. You'd not be helping introducing another flu strain, sure, but I don't see why it'd be worse than usual.

 

[Major_Tom]

The heroes' pilot, who also invented the time machine, says he's able to cannibalize the navigation system for circuits and wiring but needs iron to repair the hole and replace "a couple" of capacitors. To do this, his shopping list includes: "salt, glass jars, copper or tin, and a forge... and to learn blacksmithing."

Our heroes infiltrate the nearby fort. The pilot secures a couple wine bottles, an iron plate, a couple copper canteens and something that looks like a candle wrapped up in a burlap sack, but it could very well be a citrus or something for the acid. He is then able to use the forge to pound the metal into the shapes he needs.

The unknown is how powerful a capacitor is needed.

That actually checks out, saltwater can be used instead. In fact, original capacitors (called Leyden jars) were invented 9 years prior, in 1745. They are easy to make and can withstand very high voltages. Unfortunately for our heroes, they have very low capacitance which measures in pico or nanofarads, while your average modern capacitor measures in microfarads. That means they would need to build thousands of those jars just to replace a single capacitor.

 

[digipinky75910]

A multimeter is not shown, but it's not unreasonable to suggest there might be one stored aboard.

There's also a bit of a time crunch, as the local fort blames them (rightly) for killing one of their men, and they have only til they're discovered.

The time crunch could kill the whole thing. Even if you had a multimeter you would still have to forge a capacitor, test it, then make another increasing or decreasing capacitance... dialing it in would take time it seems they don't really have. Possible, but you would have to get fairly lucky on one of your first couple of tries... otherwise no.

It's assumed they are in the fort foraging and manufacturing supplies for a handful of hours (one time traveler wonders what is taking the pilot so long) until someone arrives at the fort looking for them - the pilot gets back with his team saying he has what he needs, just as a french soldier arrives at the gate looking for them. Our heroes see this and jump the wall out while the soldiers search the fort. (One of the time travelers said it's only a matter of time before their footprints are found.) The time travelers return to the time machine on foot and have enough time to fix the hole and complete the capacitors and within a few minutes the soldiers arrive on horseback. Doesn't look like they have enough time to do much if any testing.

(Unless the testing occurred in an edit and it is just now being completed at the same time someone else is just finishing repairing the hole. Time is funny in edits. Either way, still not a lot of time.) We don't even see him installing the capacitors.

I'm just as impressed they were able to bang the plate onto the hole which is on the side of a sphere. Either he had the curvature calculations memorized and was able to match the curve in the fort, or was somehow able to bang it into shape with little supplies at the site.

 

[digipinky75910]

That actually checks out, saltwater can be used instead. In fact, original capacitors (called Leyden jars) were invented 9 years prior, in 1745. They are easy to make and can withstand very high voltages. Unfortunately for our heroes, they have very low capacitance which measures in pico or nanofarads, while your average modern capacitor measures in microfarads. That means they would need to build thousands of those jars just to replace a single capacitor.

I remember Mythbusters did an episode on ancient batteries - they weren't effective at powering modern devices, but could deliver quite a shock to a human.

It's hard to say whether the capacitor is meant to jumpstart the time machine, power the whole thing, or just power a circuit board.

 

[digipinky75910]

Using a train to push a Delorean in Back to the Future 3 is implausible primarily because a Delorian's wheels are much wider apart than the train track. To look like it does in the movie, Doc Brown would have to take most of the body work apart, shorten the axles, than reattach everything so that it looks as though he didn't do anything. Also, it's not really clear how the machine works at 88 miles an hour; does just the whole car have to be going 88, or does it have to be "driving" that fast? If it's the former, you don't even need to put the car on the tracks at all

Terminal velocity of a falling Delorian is probably over 88, and there was a fairly big gorge nearby. If it's the former just push it off the cliff. At nearly 10 m per second/per second it should reach 88mph fairly quickly.

Here's an edit, it just occurred to me that the Delorean in the movie conserves momentum through the time "portal" (however you would want to say it.) I guess at that point braking does have to be considered. You would have to really re work the "off a cliff" solution I guess.

Couple problems with the jump off a cliff theory - as it does not travel through space, (technically) you would arrive at the same speed and location in the future, still falling. Even if "driving" down the cliff, there's still a high chance it would "off-road" flipping or crashing on the way down, slowing and killing you before ever reaching top speed.

 

[digipinky75910]

Please forgive me for necroposting, but this is one of my favorite threads I started.

Does anyone have any idea what sort of citrus would be readily available during the revolutionary era in the American northeast?

I've wondered how the Deloreon even works - how *much* of the Deloreon must be traveling at 88mph? Do you have to be contained inside? WHat if something is attached to it from the outside? How much of the Deloreon is dedicated to time travel and how much to just.. land travel? Can ya throw it on a bike or motorcycle?

One of the big problems with time-traveling into the future is being without perfect knowledge of the geography. Going from 1955->1985 worked fine as our heroes had a very good idea of exactly where they'd end up. The roads/lot was certainly clear (as long as there's no traffic or pedestrians in the way.) And going from anytime-> 2015 was fine as the car could fly and maneuver around obstacles.

Going from 1885-> 1985 would be problematic, especially since they're likely to have to horse-haul the thing to more obscure territories and they likely don't have a 1985 map of the area they're likely to take off from (and re-enter to.) Besides the train and tracks, the only confirmed building still standing is the clock tower, so there's not a lot for reference. The good thing about the train run is they know it's still there in 1985, and it's likely to be flat. They need the track to be straight to push it properly. If the Deloreon could run under its own power, the area is mostly desert, not sure if sand or rough road would hinder acceleration, but finding enough road shouldn't be a problem.

If you could get the engine working, what would you do next? How would you chart your path?

 

[Thaluikhain]

Please forgive me for necroposting, but this is one of my favorite threads I started.

Does anyone have any idea what sort of citrus would be readily available during the revolutionary era in the American northeast?

I think most citrus would have been imported, and during the American War of Independence importing anything was a problem. Now, your big reason for shipping citrus fruits would have been to combat scurvy, but IIRC, the leading doctor in Britain at the time was massively opposed to using citrus for that, which caused serious problems for the Royal Navy, and you'd not see so much of it about. As an aside, people in the colonies tried spruce beer, it (or the means to make it) was included in the rations for soldiers, as the Native Americans cured scurvy with a drink made from spruce needles, but making it into a beer destroys the vitamin C, which was unknown back then.

 

[Terminal Blue]

I think most citrus would have been imported, and during the American War of Independence importing anything was a problem. Now, your big reason for shipping citrus fruits would have been to combat scurvy, but IIRC, the leading doctor in Britain at the time was massively opposed to using citrus for that, which caused serious problems for the Royal Navy, and you'd not see so much of it about. As an aside, people in the colonies tried spruce beer, it (or the means to make it) was included in the rations for soldiers, as the Native Americans cured scurvy with a drink made from spruce needles, but making it into a beer destroys the vitamin C, which was unknown back then.

One interesting alternative that is actually better than citrus in many ways is sauerkraut. It's made with cabbage, which can be grown in temperate climates, and the fermentation both increases its vitamin C content and keeps it preserved for a really long time.

Although citruses are famous for "curing" scurvy, long term sauerkraut was a much more practical solution.

 

[Thaluikhain]

One interesting alternative that is actually better than citrus in many ways is sauerkraut. It's made with cabbage, which can be grown in temperate climates, and the fermentation both increases its vitamin C content and keeps it preserved for a really long time.

One problem with that (according to a book I read on the subject recently, at least) is that while sauerkraut has enough Vitamin C to stop you from getting scurvy (at least for a few months), it's not enough to cure it once symptoms develop (though it'd help to slow things getting worse). There was much more interest in curing scurvy once it developed than in preventing it. And, of course, people like John Pringle who refused to let go of their theory for scurvy, if something happened to change his mind (or if he'd died and been replaced), things could have been quite different.

 

[Terminal Blue]

One problem with that (according to a book I read on the subject recently, at least) is that while sauerkraut has enough Vitamin C to stop you from getting scurvy (at least for a few months), it's not enough to cure it once symptoms develop (though it'd help to slow things getting worse).

It largely depends on the cabbage and how it's processed. Red cabbages in particular can be extremely high in vitamin C, several times higher than green cabbage. However, I don't think this was known until the 20th century.

 

[Dalisclock]

I always wondered if a time traveler wouldn't spread a super contagious disease by being there, or vice versa, contracting a deadly disease thought to be eliminated. Also if food in the past centuries being actually eatable without destroying your stomach.

Food wouldn't be a problem, you can try out recipes from centuries or millenia ago, there are re-enactors into period cooking. I don't think disease would be such a problem, most of the potentially nasty contagious diseases you are unlikely to be carrying when you go back in time. Most things you want to avoid are things that'd likely be killing the locals and making it obvious you want to avoid.

I don't think that's true. I catch all kinds of horrible things time each I go to India/Pakistan, just from eating ordinary food. Basically food in developing countries isn't completely sanitary, and that is only going to be worse way back when, where people didn't do basic things like pasteurise milk. On top of that, we'd probably dislike the taste of most food available; wealthy Medieval people, as they could afford it, overspiced everything. Meanwhile peasants had their pottage, which is apparently pretty gross.

Diseases would be a problem. If you've been vaccinated, you'd probably be safe from a lot of the big killers like measles or rubella, but you are almost certainly going to bring a lot of strains of modern mutations of old diseases back to the past, which would in the long run make things even worse when you consider these peasant losers haven't even had chance to discover germ theory or anti-biotics yet, and a lot of the things we're bringing back are already becoming anti-biotic proof. Basically you're going to have to do all the leg work to stop these guys dying around you.

I'd be worried the other way too. Coming back to the present and possibly carrying strains of diseases we don't really have anymore. There's the chance of causing a pandemic without even realizing it because you got bitten by a plague flea(or something like that) and didn't realize it until you got back.

Not to mention there's also the problem with lack of basic sanitation, at least in major cities. Just drinking the water is libel to make you sick because water quality wasn't really a big thing in a lot of places and Sewer systems kinda disappeared in Europe from the end of the roman era till the enlightenment swung around(can't speak for the rest of the world). The chance of picking up some kind of nasty bateria is pretty high because even if you are taking precautions, the people around you probably aren't.

 

[Satinavian]

I'd be worried the other way too. Coming back to the present and possibly carrying strains of diseases we don't really have anymore. There's the chance of causing a pandemic without even realizing it because you got bitten by a plague flea(or something like that) and didn't realize it until you got back.

Not to mention there's also the problem with lack of basic sanitation, at least in major cities. Just drinking the water is libel to make you sick because water quality wasn't really a big thing in a lot of places and Sewer systems kinda disappeared in Europe from the end of the roman era till the enlightenment swung around(can't speak for the rest of the world). The chance of picking up some kind of nasty bateria is pretty high because even if you are taking precautions, the people around you probably aren't.

Most horrible deseases of the past can lie dormant somewhere and come back anytime. That would not change too much. Also many of those would not be as problematic nowadays because of other cicumstances.

Taking your example of the the Great Plague, that one is caused by Yersinia Pestis, a bacterium, if taken from the past, which would be susceptible to basically every antibioticum ever discovered. And it is not that easily transmissible from person to person, because it relies on intermediate hosts that are far less common in modern society.

The Plague still exists, it is not an extinct deseases. There are even modern antibiotic resistant strains that still produce a high mortality rate. But the two biggest outbreaks in the 20th century did cost around 1000 lifes in the twenties and less than 200 in the nineties, where a big outbreak in the 19th centuries meant tens of millions dead. It is simply not the same kind of threat anymore.


Past deseases are a problem for the time traveller. But bringing them back would not be a problem for modern society. However bringing modern deseases into the past could be quite dangerous for the past.

 

[digipinky75910]

Wow! This thread is so educational! I effing love fiction!

 

[Agema]

Can you really make a train engine push a delorean up to 90 mph

Surely.

and build a refrigerator capable of making ice cubes in 1885?

Artificial refrigeration was invented in the 1700s, and was powerful enough to act as a freezer in the mid-1800s, so definitely.

Can you repair a delorean with a leaking fuel tank in 1885?

Don't see why not. Disassemble the car, put some kind of patch on, reassemble, done.

Can you make a capacitor using materials found in a fort in the French and Indian war?

Probably. You basically just need some metal you can put in the right shape and something like thin waxed paper. Making a battery of any significant power would be a much greater challenge.

If you left a modern handgun in 1754, could someone with gun knowledge of the time safely create bullets for it - or would it just explode, potentially killing the wielder?

Maybe. I think they'd also need to understand how to make a modern bullet - they might be able to work it out from spent ammo, though.

The concept of a cartridge filled with gunpowder and a bullet would be simply enough and could be manufactured (if to lower quality and effectiveness). What I'm less sure about is the primer: I don't know if they had the knowledge of chemicals for a suitable one at the time. Even if they could make it, I'd expect a significant risk of misfires.

Old guns like muskets exploded usually because of overloading with gunpowder (sometimes caused by build-up of unburnt residue from previous firing) and the relatively poor quality of materials. Modern guns should (theoretically) have higher quality metal to be more robust and as the gunpowder amount is controlled by cartridge, overloading is less likely.

 

[Thaluikhain]

Old guns like muskets exploded usually because of overloading with gunpowder (sometimes caused by build-up of unburnt residue from previous firing) and the relatively poor quality of materials. Modern guns should (theoretically) have higher quality metal to be more robust and as the gunpowder amount is controlled by cartridge, overloading is less likely.

It's possible to put too much powder in a cartridge, though, if a mistake is made. OTOH, modern powder is rather more powerful than what they had a few centuries back, so you'd have the opposite problem.

You'd want your "modern handgun" to be a derringer or revolver because you'd have all sorts of problems getting it to cycle with wimpy ammunition. Losing the handgun and taking a pump action shotgun would be a good idea, they can be very forgiving of all sorts of weird ammunition.

 

[Dalisclock]

I'd be worried the other way too. Coming back to the present and possibly carrying strains of diseases we don't really have anymore. There's the chance of causing a pandemic without even realizing it because you got bitten by a plague flea(or something like that) and didn't realize it until you got back.

Not to mention there's also the problem with lack of basic sanitation, at least in major cities. Just drinking the water is libel to make you sick because water quality wasn't really a big thing in a lot of places and Sewer systems kinda disappeared in Europe from the end of the roman era till the enlightenment swung around(can't speak for the rest of the world). The chance of picking up some kind of nasty bateria is pretty high because even if you are taking precautions, the people around you probably aren't.

Most horrible deseases of the past can lie dormant somewhere and come back anytime. That would not change too much. Also many of those would not be as problematic nowadays because of other cicumstances.

Taking your example of the the Great Plague, that one is caused by Yersinia Pestis, a bacterium, if taken from the past, which would be susceptible to basically every antibioticum ever discovered. And it is not that easily transmissible from person to person, because it relies on intermediate hosts that are far less common in modern society.

The Plague still exists, it is not an extinct deseases. There are even modern antibiotic resistant strains that still produce a high mortality rate. But the two biggest outbreaks in the 20th century did cost around 1000 lifes in the twenties and less than 200 in the nineties, where a big outbreak in the 19th centuries meant tens of millions dead. It is simply not the same kind of threat anymore.


Past deseases are a problem for the time traveller. But bringing them back would not be a problem for modern society. However bringing modern deseases into the past could be quite dangerous for the past.

I wasn't aware of that. Appreciate the education.

 

[Terminal Blue]

Don't see why not. Disassemble the car, put some kind of patch on, reassemble, done.

Both gas and electric welding existed at that point, as well.

What I'm less sure about is the primer: I don't know if they had the knowledge of chemicals for a suitable one at the time. Even if they could make it, I'd expect a significant risk of misfires.

Primer wasn't available until the 19th century. It's possible a person with knowledge of modern chemistry could make mercury fulminate from ingredients available in the 18th century, but in practice this wasn't done until 1800.

All 18th century guns used gunpowder as an igniter as well as propellant.

 

[Drathnoxis]

I think about stuff like this a fair bit. When I'm doing something like trying to study I'll just start thinking about what I might be able to do if I was suddenly transported back 1000 years with only the knowledge I currently possess, what modern technology I could recreate, if I know enough to get instated as the kings magician or inventor or whatever. Almost makes me want to go and look things up so I'll know how to do them, just in case... before I remember that I should stop procrastinating and keep studying.

 

[Terminal Blue]

I think about stuff like this a fair bit. When I'm doing something like trying to study I'll just start thinking about what I might be able to do if I was suddenly transported back 1000 years with only the knowledge I currently possess, what modern technology I could recreate, if I know enough to get instated as the kings magician or inventor or whatever. Almost makes me want to go and look things up so I'll know how to do them, just in case... before I remember that I should stop procrastinating and keep studying.

Yup, done this thought experiment too.

The thing is, going back 1000 years it kind of doesn't matter. At that point, noone is going to be able to understand your modern English. You'd just be a weird vagrant babbling nonsense, and society of that time was not kind to vagrants and the insane. Early modern people might be able to understand you sometimes, but you'd probably miss a lot of meaning.

As mentioned, you'd also be a walking biohazard to anyone in these time periods, so you'd want to avoid contaminating people with any modern diseases. Basically you'd have to quarantine yourself for a while after arriving to ensure you didn't pass anything on.

Weirdly, one thing a modern person in the past could potentially be pretty good at is medicine. Even if you have no practical medical skills, as long as you passed high school biology your understanding of the theory will be light years ahead of most European doctors until the 18th century at least, and much of the practice is going to be common sense. Whether you could actually establish yourself as a medical authority would be quite another matter though, and largely dependent on resolving the language barrier.