Wouldn’t travelling forward in time put you in risk of dying and travelling backwards put everyone else in risk?
Before you even get to that, the point everyone forgets is that if you’re using the typical type of zap-and-you’re-in-dinosaur-times method of time travel as invariably imaged by fiction, the planet will be in a very different place in the universe from where you are right now if you travel to any time. Even just a few seconds, in fact.
You’re going to have to come up with one hell of a hand-wave to cover how your location stays glued to some particular spot on the Earth’s surface even as you’re whizzing off decades or centuries into the future or past. It’s probably not even good enough to mumble about local frames of reference or what have you, because there is no such thing as a truly global frame of reference (because what would it be referenced to?) or even static spatial coordinates in the universe. If the simple Newtonian movement of the planet/solar system/galaxy/etc. doesn’t get you then the universe’s constant expansion probably will.
You might want to bring some oxygen and a very fast spacecraft with you.
That’s why Primer is my favorite depiction of time travel. Machine turns on at your destination time, you get in at your departure time, and it spits you out in the past. This sacrifices freedom of travel (you can’t go back to before you first turned the machine on) to solve the point-of-reference problem (the machine moves normally with the Earth).
That first machine must be full of people from all futures the second it turns on
Look I don’t know shit, but I’d imagine this wouldn’t be impossible to calculate with all the constants like earth’s rotation, it’s orbit speed around the sun, the systems orbit speed around the galaxy etc.
But I’m probably wrong.
We can probably make a pretty good guess, but we don’t know everything
Let’s say 10,000 years ago, some giant asteroid passed close enough to earth that its gravity nudged the earth a couple centimeters out of its previous orbit
Maybe since then, that asteroid has continued on its merry way and left the solar system or crashed into Jupiter, or broke apart, or is just out still orbiting the sun somewhere in a place we haven’t detected it, or we have detected it but just haven’t done all the calculations to figure out where that particular space rock was 10k years ago to know that it probably nudged the earth a tiny bit.
Now we transport you back in time and account for all the other movement of the earth, but not that little nudge.
So you’re appearing a few centimeters off from where you should. If you’re lucky, you still end up with solid ground under your feet, or maybe you end up a couple centimeters in the air and you fall on your ass once you blink into existence in the past.
Or maybe you end up with your foot trying to occupy the same space as a rock because you’re a couple centimeters lower than you should be. How does that even play out? Does your foot and the rock explode? Does your foot get stuck inside of the rock? Do they merge into one horrible mess of rock and flesh?
And even if we account for all of the earth’s movements through space, what was at the exact point on earth you’re currently existing in some arbitrary amount of time ago?
Tectonic plates have been drifting around, you gotta account for that, the spot on the north american plate that I’m standing on right wasn’t in the same spot relative to the rest of the earth.
And even accounting for that, which I don’t think we can really do super accurately, there’s erosion and a million other random environmental factors to consider, go back far enough, and the space I’m in right now might have been inside of a mountain or a glacier or something. There might have been a tree growing right where I’m standing. It might have been in the middle of a wildfire or a flash flood, or there might have been a dinosaur standing right where I am now.
Good points. I guess we would only calculate to times where we know there weren’t any cosmic events causing such. Which would severely limit us. I’d be a Guinea pig but know, I’d be dead by then ;0)
Wouldn’t it be better to make the time travel a space ship which takes off, goes to space, time travels, finds the planet, and then travels to it, and lands?
My favorite time travel hand wave is “wibbly wobbly timey wimey stuff”
Spacetime is one word ayoooooooo gottem 🍾🍻🎉
You would definitely get the shits. A watery, explosive, truly bowl-breaking diarrhea, making Montezuma’s revenge seem like a walk in the park. Massive. Awesome.
Couldn’t we eliminate coal from ever existing by transporting wood eating fungi and bacteria back in time to the carboniferous period where the coal deposits were first formed?
Then the industrial period probably never would have happened, or at least delayed a lot
We are all currently traveling through time, though at a forward rate of 1 second per second (within your stationary frame of reference, since time dilation is a thing). But I take that you mean “time travel” as in advancing into the future at a faster rate, or going into the past.
In both cases, we do currently have the means of hermetically-sealed transportation. This is how, I believe, moon samples were collected in the mid 20th Century, since there was a possibility that alien life would be contagious to humans or that humans would destroy any samples of alien life. I think Tom Scott or someone did a video on the topic.
So while the biological risk would complicate time travel and visiting other humans, that alone doesn’t make time travel “impossible” because we could just have the travelers stay in their TARDIS or whatever. Like how people signed wills in 2020 atop automobile hoods.
There are plenty of other reasons why time travel is impossible though.
I highly recommend reading Connie Willis’ The Domesday Book
The thing i dont get about time travel is where is the cosmic tape recorder?
