13 Comments
Dec 22, 2023Liked by Seeds of Science

Our best shot at meeting time travellers is to found a religion. If time travel were invented today, trillions, even quadrillions, would be invested into visiting Jesus or Mohammad.

To really prime the pump, our Prophet should claim to have been visited by time travelers much as Mary or Mohammad were visited by angels.

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Jan 30Liked by Seeds of Science

You're missing a very simple explanation for why no time travelers: no means of creating time travel allows one to go back to a time before the time-travel device/system was created. What makes this plausible is that every speculative time-travel scheme yet proposed by physicists has had this feature. E.g., tachyons for communicating with the past using a "tachyon reflector" receding from us at either a great velocity or great distance, wormholes where one end has been accelerated to near-lightspeed and then returned, Tipler cylinders, etc.

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Jan 14Liked by Seeds of Science

I'd love time travel to become reality, however, after a long time considering the subject I realised why it cannot succeed.

A 'working' time machine, unlike Dr Who's imaginary TARDIS, will not be able to carry sufficient fuel to take the craft to any destination more than a few thousandths of a second <> because the Earth orbits at ~around 30kps, meaning a time machine cannot materialise at it's starting point on the planet, < or > in time.

Given we are considering time travel of years < or > a successful time travel machine would materialise in empty space. It cannot 'rescue' itself by almost immediately trying to return to it's starting time because the moment it materialises it 1. May possess the momentum p it had when it began its journey. 2. It 'will' gain a momentum p+ when the surrounding gravity fields at it's arrival point provide it with gravitational energy.

This means that if the traveller attempts to return to it's starting point, it will return to a different point in space from whence it started. Depending on the panic-period before they realise the danger, they will almost certainly still materialise in the wrong place.

In short, even a successful time travel test of mnore than several nanoseconds will result in disaster. Hence, dissapointed though I am, time travellers will never visit anyone.

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Jan 11Liked by Seeds of Science

I'd love time travel to become reality, however, after a long time considering the subject I realised why it cannot succeed.

A 'working' time machine, unlike Dr Who's imaginary TARDIS, will not be able to carry sufficient fuel to take the craft to any destination more than a few thousandths of a second <> because the Earth orbits at ~around 30kps, meaning a time machine cannot materialise at it's starting point on the planet, < or > in time.

Given we are considering time travel of years < or > a successful time travel machine would materialise in empty space. It cannot 'rescue' itself by almost immediately trying to return to it's starting time because the moment it materialises it 1. May possess the momentum p it had when it began its journey. 2. It 'will' gain a momentum p+ when the surrounding gravity fields at it's arrival point provide it with gravitational energy.

This means that if the traveller attempts to return to it's starting point, it will return to a different point in space from whence it started. Depending on the panic-period before they realise the danger, they will almost certainly still materialise in the wrong place.

In short, even a successful time travel test of mnore than several nanoseconds will result in disaster. Hence, dissapointed though I am, time travellers will never visit anyone.

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The Earth in it's orbit is not, of course, the only momentum p+ source. As well as the Earth orbiting the Sun, the whole Solar System is 'bobbing' up and down inside the galaxy and orbiting the Milky Way black hole. Then add in that the Andromeda and the Milky Way galaxies are drawing themselves together plus the whole of our galaxy cluster has a motion relative to other clusters 'and' superclusters and the chances of being able to 'land' anywhere near the Earth with time travel of more than around an hour or so < or > in time is remote.

In reality, within 2-3 nanoseconds of time travel, the hight probability is that even a successful attempt would appear to fail.

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Dec 21, 2023Liked by Seeds of Science

Suppose we had a way to travel 100,000 years back in time today, at the cost of a billion dollars.

Would we be trading stone spears for goat skins? No.

The economy as of then is negligible compared to the cost.

Would we do it for prestige/science value? Like the moon landings. Quite possibly.

Would we go mining on a massive scale? Could we dig more than a billion dollars of gold or oil out of the fresh untouched mines? Maybe?

Nanotech and AI make setting up a base Much easier. Our current economy is negligable to them. They would have little reason to get involved.

But sending a single nanomachine back to near the big bang, to build a dyson sphere around the first stars. That is something that would likely work out. The amount of energy that a galaxy burns over 10 billion years is large, even compared to the energy needed for time travel. And given self replicating nanotech, only a dustspeck sized nanobot need go back in time.

If you are sending stuff back in time, and the technology of time travel doesn't make going back further much harder, then going back as far as possible makes sense. After all, waiting is easy.

Societies might also want to go back in time for charitable reasons, ie the past is where most of the suffering and death is.

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Yes, what this analysis leaves out is, oddly given that it is the primary preoccupation of earlier analyses like Krugman's, is interest rates/opportunity cost. Obviously, if you can go back in time, you can start making an exponentially compounding fortune which will be available in the future, and you can vastly accelerate the future, which alone would morally justify just about any level of expenditure by the future and renders all of this analysis moot for excluding the most important economic reason to go back (which is certainly not to make chump change by tricks like 'trading stocks somewhat better at a small enough scale to not change history').

Imagine how much faster one could bootstrap industrial civilization in the year 100,000 BC with all knowledge of things like atlatl, bows and arrows, agriculture or metallurgy. If that is too outre for you, then go back to somewhere more reasonable, with very well-established property rights and stable industrial economies, like the USA in 1900; are you really going to argue that there is nothing that a time-traveler can bring back or tell people in 1900 which would not be worth many many trillions of dollars centuries later? (Note that plenty of large fortunes are intact from 1900 to now.) Nothing like how transistors work or how AI works or planes? Stuff like iodization or vitamins in general? Nothing? All completely useless? Even if you bring back entire libraries miniaturized to a grain of sand and readable by optical (or, by 1930s, electron) microscopes?

Note that you can easily skim off a lot of that compounding wealth and stash it in various ways like burying it at pre-arranged coordinates; there's nothing you can stash along the way which the future would not value?

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Jan 2Liked by Seeds of Science

I think the model of the time traveler telling people stuff is silly. I'm thinking more going back in time to ~12 billion years ago, and putting a dyson sphere around every star.

Self replicating nanotech, with ASI, wherever it's released, a dyson sphere will be built in months.

No need for the long and fiddly process of teaching a bunch of cavemen about steel production.

And "property rights" means "you know the root password on the nanobots".

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Dec 23, 2023ยทedited Dec 23, 2023Liked by Seeds of Science

Incidentally, this is strongest with the 'overwriting' approaches to time travel but it is still true with stable time loops too, because all those require is that you 'save the appearances'. So, a stable time-looper can still make extraordinary amounts of money and accelerate economic growth, it just means that their money has to be hidden and that they may be responsible for some (or all) 'pre-existing' economic growth.

For example, it might be that in the 'baseline' history, economic growth is 0% - and all global growth for the past millennia has been due to the traveler intervening behind the scenes, and this is consistent with our observations because he has hiding any traces (eg. discrediting them as 'conspiracy theories'). This would be fully consistent with all observations right now, and is therefore a stable timeloop that we could be in.

And their cut of economic growth can be hidden away for future consumption - perhaps there is some warehouse out there which contains every 'lost' or 'destroyed' artwork, vast corpuses that artists did for an anonymous patron they never met, all the collectibles that disappeared like the first issues of superheroes or Honus Wagner baseball cards; perhaps every rich person is actually a shell for the traveler, or each generation of a fortune the traveler in disguise, with a large fraction of global wealth owned or controlled by the traveler, and so on and so forth.

You might argue that the returns in a stable loop must be much lower than unstable loops because it's bounded by our observation of a poor world compared to possible 'economic speedrun worlds' and by how much the traveler can securely control long-term through any methods, and that's true, but there's still no reason to think that the returns are so near zero in those classes of time-travel that travelers wouldn't bother.

From the future's perspective, an investor into the time traveler invests millions or billions of dollars into time travel, let's say, and then a minute later, receives a letter from the time travel company's lawyer informing them of a warehouse & trust worth hundreds of trillions of dollars which just unlocked, containing the most storied artifacts from throughout human history and financial assets beyond the dreams of avarice. Why *wouldn't* you do that? If you wouldn't, you'd better have a better explanation than 'er, maybe the energy costs are really big, somehow?'. That's quite a bullet to bite compared to the simplest answer that 'we don't see time travelers getting rich off the past because time travel is impossible'...

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author

Thanks for this. Will forward to author, maybe he will want to update paper.

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Dec 20, 2023Liked by Seeds of Science

Interesting read!! Not my area of expertise for sure but I wonder if anyone in this field considers that humans will continue to evolve and that we may not be quite the same in thousands of years. Maybe our brains will be better repositories of knowledge, for example.

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author

very interesting thought!

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Dec 19, 2023Liked by Seeds of Science

A constant conundrum, the time travel paradox, to those of us who toiled in science fiction. Although I question the economic benefit benchmark. Surely this is a preoccupation of our current mindset and not the only reason to do or create anything new. Our only human motive being profit. Or is this perhaps an explanation. Some God minded individual went back in time to create this reality for his own financial benefit. ๐Ÿ™„

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