WASHINGTON : Astronomers have spotted orbiting around a young star a newborn planet that took only 3 million years to form - quite swift in cosmic terms - in a discovery that challenges the current understanding of the speed of planetary formation. This infant world, estimated at around 10 to 20 times the mass of Earth, is one of the youngest planets beyond our solar system - called exoplanets - ever discovered. It resides alongside the remnants of the disk of dense gas and dust circling the