The familiar star at the center of our solar system has had billions of years to mature and ultimately provide life-giving energy to us here on Earth. But a very long time ago, our sun was just a growing baby star. What did the sun look like when it was so young? That's long been a mystery that, if solved, could teach us about the formation of our solar system—so-named because sol is the Latin word for sun—and other stellar systems made up of planets and cosmic objects orbiting stars.