Just as raisins within a leavening ball of dough will appear to recede from one another as the dough expands, so too will galaxies within the Universe expand away from one another as the fabric of space itself expands. In this analogy, the expanding Universe is described by space that “stretches,” but that analogy doesn’t work for every aspect of our expanding Universe. (Credit: Ben Gibson/Big Think; Adobe Stock)

Does the Universe expand by stretching or creating space?

The evidence that the Universe is expanding is overwhelming. But how? By stretching the existing space, or by creating new space itself?

It’s been almost 100 years since humanity first reached a revolutionary conclusion about the nature of our Universe: space itself cannot and…