It is not new that the Sun, with only one million years of age, was brighter than now. However, a group of scientists at the Max Planck Institute of Extraterrestrial Physics in Germany have assured that the young Sun was warmer and brighter than they believed. The protosol is four times brighter than the current one and its surface was 500 degrees hotter.
At that time, the Sun was a protostar and it was still about to begin the nuclear fusion of the hydrogen that the stars have. However, the leading researcher of this group, Günther Wuchterl, has stated that the gas contraction that occurred during star formation would emit more energy than the fusion that is now occurring in the Sun. No wonder, therefore, that protostar emits brighter rays than the current Sun.
He points out that if the protostars are brighter than the existing models advertise, their age may be greater than previously thought. This conclusion can cause major changes in astronomy, as it can change the way scientists date young stars.