A constant radiation in the microwave range, the background radiation, has long told cosmologists that something important happened 380,000 years after the Big Bang. At that time, electrons and protons recombined to form molecular hydrogen, so that space finally became transparent, allowing light to propagate. We can still measure the remnants of this light, shifted into the infrared. But a lot happened shortly after the Big Bang. The very early universe was determined by time-varying scalar fields, after the inflation phase there should have been an energy transfer from inflaton particles to regular matter, there were various phase transitions,…