Ask Ethan: How long does it take planets to form?
Here in our Universe, there were many profound steps that needed to occur in order for creatures like humans to be able to arise. We needed to forge heavy elements in previous generations of stars: elements that the Universe wasn’t born with, but that are required to enable molecules that can link up to form complex bonds and macroscopic structures. We needed enough of those elements so that when new stars formed, rocky planets could arise around them. And we needed enough time to pass so that life could not only arise, but thrive and evolve to give rise to highly differentiated organisms. Some 4.5 billion years after the formation of planet Earth, here we are, asking and answering many profound aspects of one of the grandest questions of all: how did we get here? Many variants of these grand questions often arise when we engage our curiosity. Where did we come from? What enabled our existence? What path did the Universe take to give rise to us? At just three years old, this week’s …









