How did we get here? Where are we going? And how long will it take? These questions are as old as humanity itself, and, if they’ve already been asked by other species elsewhere in the Universe, potentially very much older than that.
They are also some of the fundamental questions we are trying to answer in the study of the Universe, called cosmology. One cosmological conundrum is how fast the Universe is expanding, which is measured by a number called the Hubble constant. And there is quite a bit of tension around it.
