Heya, you might be interested in reading these answers about "How did medieval people envision the future" and "Before 1700, is there any literature that predicts future developments? What did the future look like?"

There are any number of ancient works that might be considered SF but which also might be more properly classed as fantasy as their is no reference to technologies. The epic of Gilgamesh (ca. 200 BCE) - but then there was a boat in that - and Ovid's Metamorphoses (8 CE) come to mind.

The Hindu epic Ramayana (5th - 4th century BCE) has Vimana flying machines which are able to travel into space or under water, and destroy entire cities using advanced weapons. The first book of the Rigveda collection of Sanskrit hymns (1700–1100 BCE), describes mechanical birds jumping into space, and a craft using fire and water containing twelve stamghas (pillars), one wheel, three machines, 300 pivots, and 60 instruments. ]Mukunda, H.S.; S.M.Deshpande; H.R. Nagendra; A. Prabhu; S.P. Govindraju (1974). "A critical study of the work "Vyamanika Shastra""](http://cgpl.iisc.ernet.in/site/Portals/0/Publications/ReferedJournal/ACriticalStudyOfTheWorkVaimanikaShastra.pdf)

Aristophanes included several "fantastic voyage" elements, notably air travel to another world in The Clouds and The Birds (both late 5th century BCE).

Speaking about the book of Revelation, Adam Roberts said: "We are not in the habit, perhaps, of thinking of the Bible as science fiction; but in so far as it does provide us with the myths with which our culture encounters Otherness, the label has a certain appropriateness." [Roberts, Adam (2000). Science Fiction: the New Critical Idiom. Taylor & Francis. p. 49.]

Lucian, the 2nd century CE Syrian, wrote a satire called True History. In it are found a voyage to outer space and conversations with alien life forms (even a "first encounter" event), interplanetary warfare, creatures made by human technology, worlds with alternate physical laws. Fredericks, S.C.: "Lucian's True History as SF", Science Fiction Studies, Vol. 3, No. 1 (March 1976), pp. 49–60

Several "Arabian Nights" tales have sci-fi like elements. The Ebony Horse has a mechanical horse that could fly into outer space. Third Qalandar's Tale has a robot sailor. [just read them if you haven't already]

Chaucer's The Squire’s Tale, one of the Canterbury Tales, features a metal horse able to transport its rider anywhere in the world, post haste. The horse was operated by turning a peg in its ear and whispering certain words to it. [again, I trust the the reader will go read Chaucer if for some bizarre reason they haven't done do already]

In the end the main goal of my question was to find out if there were moments when someone thought "wow, this invention is going to change world!" and goes on to envision in what way that might happen.

Advance warning: I'm still talking about the literary end of things.

In the second half of the 19th century--the rise of true popular literature--a split develops between European and American efforts to forecast futuristic technology in pop fiction. In addition to the ongoing voyage/travel tradition discussed in the [pre-1700 answer] (https://redd.it/3vovzs) (think Jules Verne!), a major subgenre of future warfare poured out of European presses. On one hand, the recognition of European nationalism and international antagonism heavily plays into this genre: Britain's invasion by Germany is a repeat fixture. On the other, should we be surprised to see a focus on military technology? War is instant drama, for fiction! (Of course, this will also lead to the genre's downfall once the reality of World War I interferes with the enchantment of war-as-fiction).

The anonymous 1859 The Air Battle gets credit as the forerunner. While not really scientific per se, it takes the fascinating with airships and air travel into the future. Floating ships that can carry thousands of people fight, well, air battles, but still basically using present ground tactics. (Also, in 6900 slavery and imperialism still exist but now black people subjugate white people, other races what other races, and most of England has sunk.) George Chesney's 1871 "Battle of Dorking" really makes the subgenre take off, and pretty soon you have authors deftly discussing advanced submarines, airships, explosives, the potential of nuclear weapons, and...disintegrator beams (well, they tried). One noteworthy example is Kurt Lasswitz's 1878 Bilder aus der Zukunft, Pictures from the Future. It's short, but he imagines how the use of electricity will be able to power airships much more effectively. (And his future world makes music out of smells, so, there is that.)

It's the dime novels of America, though, that really evoke the "what might be done with future technology" idea. While Europe concerned itself with the present and potential of warfare, the U.S. emerged from the Civil War with a zest for its frontier mythology (and, of course, imperialist wars safely stowed abroad). That's right, a century before George Lucas made Star Wars, the Western and proto-sci-fi genres were already intertwined. "Inventor novels" targeted above all a juvenile/YA market. And their preferred technology, in the century of Pride and Prejudice instead of Pride and Prejudice and Zombies, was steam.

To be clear, this isn't "steampunk" in any appreciable sense. These are ooh-ra U.S.A.! U.S.A.! get the girl, get the glory, escapist literature aimed at boys. (Girls had a "girl aviator" genre of their own, but boys got to be the inventors). But steam is frequently the root of the technological invention that either launches the story or allows the hero to save the day.

This subgenre is launched by, appropriately, Edward Ellis' The Steam Man of the Prairies, which features a steam-powered, humanoid robot who takes the place of horses in ferry the carriage of hero Johnny around the frontier. But Ellis and his novel were quickly overshadowed by Frank Reade and His Steam Man of the Plains, the first of the series of books starring inventor Frank Reade and eventually his teenage son Frank Reade, Jr. Eventually, the Frank Reade series will also introduce electricity as a means of powering futuristic/present technology: submarines, airships, helicopters, cars.

I shall cease my narrative here before discussing Verne and Wells--at that point, read the masters, not the redditors. :)

Swinford argues that Johannes Kepler's Somnium (1608) is the first example of science fiction in the west.

The "future" in the middle ages meant the next world; in this sense The Divine Comedy is "futurology," and absolutely stuffed full of the latest scientific research into what form it will take. The "dream vision," started by Plato, became through a complicated tradition a popular medieval genre. In it's simplest form it is a pedantic, fanciful allegory, where a person recounts falling asleep and seeing some kind of "psychomachia," an allegorical battle of good and evil, but these conventions were flexible. Dante turned it on its head, making the present merely an allegory for the future, the vision the true, stark underlying reality (he has been accused of being a secret materialist his "vision" is so strikingly clear, not vague and mystical; that is, this is no allegory but a factual report--the peasants apparently believed he had actually been to hell). It was also a gigantic, cruel satire on his own times, something Sci-Fi has also been used for. lotta "levels" to it.

Generally, I think most speculative thinkers before the scientific revolution resorted to rhapsodic idealism / superstition rather than empirical technological predictions.