KentuckyFC writes "Goldilocks zones are regions around stars that are 'just right' for liquid water and for the chemistry of life as we know it. Now one cosmologist points out that the universe must have been through a Goldilocks epoch, a period in which warm, watery conditions could have existed on almost any planet in the entire cosmos. The key phenomenon here is the cosmic background radiation, the afterglow of the Big Bang which was blazing hot when it first formed. But as the universe expanded, the wavelength of this radiation increased, lowering its energy. Today, it is an icy 3 Kelvin. But somewhere along the way, it must have been between 273 and 300 Kelvin, just right to keep water in liquid form. According to the new calculations, this Goldilocks epoch would have occurred when the universe was about 15 million years old and would have lasted for several million years. And since the first stars had a lifespan of only 3 million years or so, that allows plenty of time for the heavy elements to have formed which are necessary for planet formation and the chemistry of life. Indeed, if live did evolve a this time, it would have predated life on Earth by about 10 billion years."