Just one light year being equal to the distance light travels at 186,000 miles per second times the total number of seconds there are in a year, is difficult enough to comprehend.
I tried to mathematically calculate that distance. The zeroes just killed me. Even after resorting to scientific notation. I'm sure someone here with better math skills than mine can create the equation for the solution, but still the distance is outrageous.
For 12 billion light years? Forget it. I think that kind of distance approaches virtual infinity.
Try thinking about infinity as something that goes on forever without ever ending, and you start going crazy. There's a reason for that. We aren't wired for it.
Not yet, anyway.
Its like many moles of miles...
7e22 miles? That what you got?