t there is no sign of a center of the universe where it all began, the unverse is infinite and has always been infinite

 The upshot is that there is no sign of a center of the universe. So much for the “giant firecracker.”

 A third conclusion is that there is no sign of an edge of the universe, no place where we run out of either matter or space. This is what the ancient Greeks recognized as infinite, unbounded, without limits. This is also the exact opposite of a giant firecracker, for which there is a moving boundary between the space filled with debris, and the space outside that.

 The actual universe appears to be infinite now, and if so it has probably always been infinite. It’s often said that the whole universe we can now observe was once compressed into a volume the size of a golf ball, but we should imagine that the golf ball is only a tiny piece of a universe that was infinite even then. The unending infinite universe is expanding into itself.