Is the universe expanding?

In 1929, the American astronomer Edwin Hubble discovered that the galaxies are moving apart from each other at high speed. The Universe is expanding like a balloon being inflated. The further apart the galaxies are, the faster they move. For instance, a galaxy 10 million light years away gets 300 km (187 miles) further from us every second. A galaxy ten times further off moves ten times faster, and so on.