Astronomy
The Expansion of the Universe and the Hubble Constant
Quick fact
The current expansion rate (the Hubble constant) is about 70 km/s per megaparsec, meaning a galaxy 1 megaparsec away recedes at 70 km/s. But different measuring methods give slightly different values, a puzzle known as the 'Hubble tension'.
Why this is interesting
If everything in the universe is moving away from us, does that mean we're the center of it all? And why is the speed of that expansion still a mystery?