Excellent article as usual. I have three comments:

1. I have read many times that if you imagine reversing time you can get to a situation when the entire universe is compressed into a very small space at the beginning of the Big Bang (or start of the great expansion phase). That small space may have been a cubic meter for example. Where exactly was that cube? Seems like it had to be somewhere.

2. Even a loaf of raisin bread has a center of sorts.

3. Of course, we really don't need to know where the "center" was, or is. It doesn't change anything for us really. If the Milky Way was the raisin right on the surface of the loaf, now that would be more interesting. It is truly unbelievable how much astronomers have figured out about the cosmos. Keep up the good work!