Artist’s impression of the white dwearf star WD1054–226 orbited by clouds of planetary debris and a major planet in the habitable zone. Credit: Mark A. Garlick / markgarlick.com. ============================================================================== The lifespan of the Sun is 12.3 billion years. This is 1.5 billion years shorter than the age of the Universe, 13.8 billion years. If the Sun happened to be born in the first 1.5 billion years of cosmic history, or equivalently at a cosmological redshift above 4 when the first several percent of all stars formed, then it would have turned into a white dwarf by now. There are about...