Many people might be knowing that sun is a star, a medium star. Here we would discuss how does the light comes from stars. You can say – its simple light comes from the surface of the star. But I would say it is not as simple as it is looking.

Image via Wikipedia

Light from the stars actually starts from the core. Actually in the core of the star fusion takes place which emit photons. Each photon which is being created has to come in the mantle. But not all of the photons are able to reach the mantle. Then in the mantle too, there is same problem. So, the photons which reached the mantle again are all not able to reach the upper mantle. What is happening with photons is that they are reflected back due to reducing refractive index. Now, when the photons reached the upper mantle then there is again struggle between photons to reach the surface. When it reaches the surface then it is ready to go in the universe. This procedure is followed by every star that means even our sun follows this process.

So, think about the actual time which the light takes to reach the earth as light is a packet of photons. I mean to say that light which is coming from sun is not just 8 minutes 30 seconds old but it can be millions of millions year old. These photons were just inside the sun but were not being emitted by the sun. They were just being reflected within the sun.

Again a question comes to mind that if this is the case then – does the brightness of the sun varies? I don’t know about this but what I would like to conclude myself is that yes brightness varies but it varies so less that it is negligible for us.