Actually, Ryan, that isn’t true.
I can, given the right software not only calculate the specific location of the earth 30 years ago, where it will be thirty years hence.
Based on the presumption that the sun is sitting still you can calculate the precise location of the earth at any time.
Given that the above is not true – that is the sun is traveling through space at several thousand miles per second, as well, as the planets moving about it, and the entire arm of the galaxy in which we reside is moving as well… it is more difficult, BUT not impossible.
As Captain Kirk once said to his crew after the battle with Khan, “he is thinking in two dimensions only”… we are thinking in three only. The fourth, time, is traveling away from us as precisely the same rate as it was a few moments ago. Given this we can calcuate the exact location based on several factors, knowing the current location of the sun, the past location of the sun and then figuring the future location of the sun.
Given this, we know that our Eart travels in an ellipse around the sun at a given speed over 365.25 days per year. That tells us the Earth will be in a specific location 30 years from now.
Personally, I’ve taken tracking programs meant for satellites and calulated the projected location of Near Earth Asteroids several times. If *I* can do it, certainly an advanced computer from the future can figure out where we are now.