like jeffus was commenting, it's about horizons. the authors are starting with common reference point for simplicity not implying we are at the centre, also technically they start the scale right of centre on the slide to show the scope of reducibility in size to the planck length, as jeffus comments there is so little we understand about this quantum reality and as we discover its mechanics a picture of the universe on a grand scale becomes clearer. they're making no comment on a centre of the universe, which quantum mechanically and cosmologically have a very different meaning or none, one could almost say the universe on a grand scale has multiple centres (groups of superclusters of galaxy gravitational bound), but technically there is no centre in our universe as there's no centre point for its expansion, it happens everywhere at once.@derek But that graphic starts, here, on earth, with the smallest of molecules. How can you possible say we are not the centre?