How fast is the universe expanding?

The answer

The universe's expansion rate, called the Hubble constant, is approximately 70 kilometers per second per megaparsec, meaning for every 3.26 million light-years of distance, galaxies recede 70 km/s faster. This expansion means the most distant observable galaxies are moving away faster than light - which is permitted because it's space itself stretching, not objects moving through space. The 2011 Nobel Prize in Physics was awarded for the shocking discovery that this expansion is actually accelerating, driven by the mysterious force called dark energy.