nah, the reason is: when you travel back in time, our galaxy, solar system and planet are in different absolute universal positions. so you end up alone in deep space and by the time the planet reaches your position the time you traveled back has passed, making it absolutely useless and life threatening.
Pretty sure there is no absolute universal position, everything in the universe being in motion relative to everything else as the universe expands, but that does not disprove your point anyways.
The reason it doesn’t disprove it is because the assumption “time travel works” is really just saying, if we ignore some basic rules of physics, what happens to what’s left? It’s a nonesense premise to debate what is basically nothing more than science fiction.
Could the rules we know about the universe be wrong? Absolutely! But discovering those new rules is what will answer that question. Till then, we might as well try and say Harry Potter is just quantum mechanics.
Look up Dr. Ronald L Mallett. This astrophysicist has some interesting takes on practical time travel. There's a great interview with him by Fraser Cain of Universe Today.
You can use the cosmic microwave background as a universal reference frame. Relative to that we move at about 370 km/s, depending on the time of the year.
This is a basic fact overlooked by almost every time travel sci-fi. We wouldn't just jump into a machine and poof be in the exact same location 1,000 years ago.
It would be more like trying to land a spaceship on a planet light years away, there would have to be calculations for position and gravity. All sorts of crap before you even solve the impossible problem of turning back the clock.
Also we'd first have to figure out how to travel faster than light to even hope to break the riddle of time travel.
As fun as it is to theorize time travel would be impossibly complex and probably devastating to try.
Imagine what an object would do with all those forces behind it suddenly slamming into a object moving much slower, it would be like a time bullet that would tear apart the planet and punch a hole in space. We would likely achieve a black hole and destroy all of earth before we could see what earth looked like 1,000 years ago.
This is a basic fact overlooked by almost every time travel sci-fi. We wouldn’t just jump into a machine and poof be in the exact same location 1,000 years ago.
It would be more like trying to land a spaceship on a planet light years away, there would have to be calculations for position and gravity. All sorts of crap before you even solve the impossible problem of turning back the clock.
If the only reason you find the premise of traveling through time preposterous is that they didn't do the basic research to make it work, why not just assume they did? It's a fictional world. Just go with it.
For many I assume the device provides some kind of space-time anchor relative to itself, so when you go through the magic door it's already attached to itself on the other end. The "itself" on the other end doesn't need to be the whole machine, just enough molecules or whatever to lock on to. I like this idea because 1, it still leaves room for error so it isn't perfect and 2, I can stop thinking about it and enjoy the stupid movie.
Have you noticed the flashing light in the sky? It started last year. It gets a little brighter every night. I only used to notice it when I was out of town, but now I can see it in the city. It blinks pretty quickly, probably twice a second. Some blinks are longer than others. If you watch long enough, it repeats. Short. Short. Short. Long. Long. Long. Short. Short. Short.
This makes me wonder... We just had an eclipse. We knew the position and timing of the celestial dance. We know them way into the future and the past and they're highly accurate. We know the arcs and paths of other planets and their moons.
Are we accurate enough with our time telling and spatial understanding that someone could, to within a few meters, accurately calculate exactly where in space a specific point on the earth was at a specific time?
What would it take for us to become that accurate?