We all know that one day the distance between the Earth and the sun will be zero. They will be bonded with gravity. My Question is which side of the earth will face toward the sun? I can't calculate that. Someone please calculate and don't say it's impossible.
We all know that one day the distance between the Earth and the sun will be zero.
This may be true, as the sun will get much bigger and engulf the Earth. But this is irrelevant to the rest of the question, which seems to be about tidal locking.
They will be bonded with gravity.
The Earth is already gravitationally bound to the sun. But it isn't tidally locked. The Earth+moon has too much angular momentum to ever become tidally locked to the sun. It will be engulfed by the sun before it becomes tidally locked.
which side of the earth will face toward the sun
As noted above, the Earth will continue to rotate and will not become tidally locked.
Even if it would become tidally locked it would be impossible to calculate. It is like putting a battery into a clock and asking exactly what time the battery will run out. You can't measure the present nor predict the future with enough accuracy to forecast such things
In other words. This won't happen, and if it does we can't calculate it. It's impossible.