The time machine would use gravity so it can arrive at the same relative position in a different time. But that only gets you on the planet, not the same position on the planet.
How would rotational movement be accounted for in a generic way?
If the machine has the ability to jump in time and space (needed to land in the same spot) then it would be a real waste to use it only on earth.
So we would need a mathematical model of the entire universe that is accurate to the metre over all time. This N body is much harder than the 3 body problem.
Or we use gravity and other methods to track relative stationary position.
So, what other methods can be used to determine rotation?
So all travels to new planets require 2 jumps. One to get near and measure the rotation, and one to actually land. I’d prefer something more efficient.
Also there is the assumption that the surface rotational velocity is constant over time. This is only true for solid planets without gas or liquid centers. Insides can spin at different speeds than the surface.
What? This whole thread is discussing how a time only device is useless.
No, some are talking about how it needs to detect gravitation from other planets.
That has nothing to do with a time machine working on earth.
The time machine would use gravity so it can arrive at the same relative position in a different time. But that only gets you on the planet, not the same position on the planet.
How would rotational movement be accounted for in a generic way?
I don’t know how it would be accounted for in your imagine time-machine. Because they don’t exist.
What I do know. Is that you don’t need gravity to “detect” earths rotational speed. Because we already know what it is.
We know the rotational speed, but this time machine wouldn’t.
And is there a reason you couldn’t program that data into the machine?
Doesn’t that sound like something you’d need? Along with a mathematical model of how earth orbits the sun?
If the machine has the ability to jump in time and space (needed to land in the same spot) then it would be a real waste to use it only on earth.
So we would need a mathematical model of the entire universe that is accurate to the metre over all time. This N body is much harder than the 3 body problem.
Or we use gravity and other methods to track relative stationary position.
So, what other methods can be used to determine rotation?
Jesus fucking Christ. We can still calculate the rotation of a body like we normally do.
You observe it. Wait 1 seconds. Observe it again. And the delta in position is your rotational speed per second.
That is the method. The only one
So all travels to new planets require 2 jumps. One to get near and measure the rotation, and one to actually land. I’d prefer something more efficient.
Also there is the assumption that the surface rotational velocity is constant over time. This is only true for solid planets without gas or liquid centers. Insides can spin at different speeds than the surface.