Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The radiation zone is the middle zone in the Sun''s interior. Energy travels out of the core into the radiation zone. Energy travels through the radiation zone in the form of electromagnetic radiation. The radiation zone is so dense that the waves bounce around. The energy may not leave the radiation zone for millions of years. The radiation zone is directly below the convection zone and directly above the core. It takes an average of 171,000 years for energy from the core to leave the radiation zone.