Light can take 1 lakh years from the core of the Sun to its surface.

Sunrise

Light is the fastest thing in the universe. The second fastest thing is shadow. Light takes only 499 seconds or we can say 8  minutes 20 seconds from Sun's surface to earth, a distance called 1 astronomical unit. A bit convincing but what if the the light itself takes 100,000 years from the core of sun to its surface. Yes it's true, so it is also true that we receive sunlight which approx 10,000 to 170,000 years old.

            

                                 The sun is 1.3927 million km far from us so why light takes a long time to  reach its surface. A simple reason is that the density of the core is incredibly high, 150 times greater than water. All the atoms are very tightly jammed. For example, a pair of  hydrogen atoms fuse together to create a helium atom and release a lot of energy in form of gamma rays. The rays can travel only few millimeters before the are absorbed by an atom and then re radiated. This process continues. 

         

                                  So while in 8  minutes, a photon of light can travel 150 million km from Sun to Earth and in that same time Gamma rays inside Sun's core will travel just only about 13 centimeters. Which is a very slow rate of delivery.