The Sun is our sole source of light and heat in the solar system. This is a very common star, a glowing ball of gas held together by its own gravity and powered by nuclear fusion at its center. This lecture briefly focus about Energy Transport within the Sun. The sun has extremely hot core – ionized gas. Temperature falls further from core – more and more non-ionized atoms capture the photons – gas becomes opaque to light in the convection zone. The low density in the photosphere makes it transparent to light – radiation takes over again.