The team explores one of the greatest discoveries of modern astronomy - that our universe is expanding - and the new questions it raises about how the cosmos works. In the 1920s, astronomers studying galaxies realised they were moving away from us, with the most distant ones receding the fastest. The conclusion was revolutionary: space itself was stretching, and the universe was expanding in every direction. But once this discovery was made, a new challenge emerged – how fast is the universe expanding, and what could that tell us about its age, size and ultimate fate?