Telling them how a steam engine works.
That would start the industrial revolution earlier and it would end up speeding us up to a more advanced and better future... or to an early extinction by global warming... hmmmm
Maybe explaining an electricity generator would be a better gamble, but it may be very hard to make one back then...
The answer would probably be something sensible, within our ability and something we would be capable of.
We already know how to do this .... we as a collective global civilization just actively refuse to do any of it unless we were forced to, either by war or by the realization that it will mean our extinction.
It's not that we are a thousand years dumber than our descendants .... we are just as intelligent and insightful as our ancestors a thousand years ago ... it's just that our short sightedness and greed gets the best of us.
In many ways we are still a lot like our prehistoric ancestors from 100,000 years ago who believed that our family should control all the unlimited amount of bananas in the jungle.
In a thousand years from now, I honestly think 100PB is small for a thumb drive. I've seen such drastic increase in storage density in my lifetime that, while I don't expect it, I wouldn't be surprised if I see 100PB in single storage devices at some point in my lifetime.
I'm already dealing with PB-sized storage clusters at work, so the need for that k8nd of storage is already there, and necessity drives innovation.
Most plastic that we use shows evidence of endocrine disruption activity and it isnt just BPA as a byproduct of the manufacture of certain plastics. We know it is bad for the environment too. Microplastics are pervasive and also known to have negative health and environmental consequences.
The universe is as far as we can tell so far, devoid of intelligent life other than ourselves. The "great filter" is a collection of hazards that life must avoid. For us
an example would be nuclear war or hostile AI.
1000 years is too little for big evolutionary changes in a species that reproduces as slowly as us. So unless they went full cyborg or generic engineering the changes won't be very big.
Even if crypto does become the next big thing, I doubt bitcoin specifically would still be around. Surely there's much better tech by then. If you're lucky they know about it as the precursor to their current system. And even if for some reason it did stick around that long, the value would be meaningless since you have no idea what inflation is like.
Greetings! I am from the year 1024, can you tell me, in detail, about the death of Basil II Porphyrogenitus and how the Fatimid Caliphate will rise again?
Plot twist: he's frozen alongside Walt Disney, and now he is the Messiah of a new religion. It's followers knock on people's door to convert them. If you don't open the door they'll leave a Confederate flag and a maga hat, which is how they curse you for 3 generations.
I'd want to know what their favorite meal is. 1000 years would likely have a lot of culinary, agriculture, and food production changes. Maybe everyone eats cubes of flavored yeast.
Even if the person I asked had knowledge enough in the field to answer this, I'm not sure I could understand it enough to retain any of it. I don't even understand todays batteries.
Imagine if someone from the 1920s asked you such a question. What would you explain? What frame of reference could they have to understand the answer?
Oh sure. Here is an early video of the primitive technology guy. This was way way before he reached immortality through genetic engineering in episode 1456.