How far away are supernovae? Astronomers find a way to tighten measurements

A team of astronomers studying distant exploding stars has found a way to tighten up the way the distance to them is measured — and in doing so, tighten up measurements of how the Universe is expanding.

This kind of supernova is called a Type Ia. These occur when a small, dense white dwarf accumulates matter on its surface, eventually gathering so much matter the entire star undergoes nuclear fusion. The release of energy is absolutely colossal, equivalent to billions of times the Sun's output....