You know, we’re overlooking another very practical reason that we’re not plagued by tourists from the future.
WE (the earth, sun, solar system, galaxy) are MOVING REALLY FAST.
It always bugged me that HG Wells missed this point in his book as well as every other author I’m aware of. If you were to ‘beam out’ of time and go backwards you would then ‘reappear’ in time where you left, which would be in a place the earth is today but WASN’T yesterday. You’d then have to trek many miles through empty space to ‘go back’ to where the earth was in history.
To imagine this another way, the earth is rotating at about 720 miles per hour average.
(e.g. rough numbers 7926 mile diameter*(pi=3.141)/24 hour day=1036 mph but I’m not on the equator, I’m around SF California so I’m interpolating it’s about 720 or so…like I said… FAST)
Now imagine you beam back in time 10 seconds. You’d be displaced 2miles! And thats just in relation to the surface of the earth!
Then you have the rotation of the planet around the Sun. Let’s assume it’s a perfect circle (please) so the approximate speed around the Sun would be:
2x(radius=AU=~93,000,000 miles)xPi(3.141)/365days (or 8760 hours)= ~65000 mph or in that 10second backtrack…180 miles off the surface of the earth.
Then you have the motion of the solar system in the galaxy AND the motion of the galaxy ‘out’ from the big-bang and well… I think you get the picture.
It might be fun to figure out a ‘real’ distance per second but then you’d have to account for the 186million mile arc of the orbit of the earth and such… and what good would it be anyway but, it’d be interesting.
Given that small variations in mass and energy (cosmicly speaking) can affect trajectories, I wonder if predicting the relative position of the earch relative to time in the past is even possible. It might be a paradox in that if you were to spend the energy and project a ‘mass’ back through time that it might affect the trajectory of the earth enough so as to not put you where you are today and thus make a paradox in that you couldn’t really say where the earth was. Kind of a 4th dimensional quantum uncertainty principle.
Time travel is cool.
-UnderDog