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).
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