Since I spend some of my time thinking about how to localize observations in gravity, I couldn’t help thinking about this question today.
How do we decide that a structure we build today is at the same spatial location as another event that supposedly happened a few thousand years ago?
If we stick to a geocentric perspective, one possibility is to use some local reference frame like rivers or mountains. But these tend to shift quite considerably over the course of a few thousand years.
And why should we localize something just on the crust of the Earth, which is so small compared to the Earth as a whole? But if we broaden our perspective, we now have the problem that the continental plates drift by a couple of centimetres a year. This itself would give us a few tens of metres of drift over a few thousand years, which might be larger than the size of the structure we are building.
Moreover, we are taught to think from a Universal perspective in India. And some of these questions supposedly pertain to the Lord of the Universe. From that perspective, the Earth itself is rather small even within the solar system and our galaxy, let alone the Universe. The galaxies and stars themselves have moved quite a lot in a few thousand years. So, if one were to use a different coordinate system, the “spatial point” where something happened a few thousand years ago might now not lie within the Earth at all or even within the Earth’s orbital trajectory.
From the flags outside our house, I infer that many people around me seem to understand this very well, and so I must be missing something basic. Nevertheless, I can’t help being somewhat puzzled. Any answers?