Life and the Universe – both are colourful!!
Revealed here is the core of a Massive Globular Cluster Omega Centauri residing some 16,000 light years away from us. This Cluster has around 10 million stars, though the frame clicked here contains just 1,00,000 of them.
Most of the stars here are yellow-white which are the Adult stars (like our Sun) shining due to hydrogen fusion. Once the hydrogen gets over, stars become cooler and larger and are seen here as orange dots. In even later stages, the stars cool down more and gets enlarged – that is when they become Red Giants. These Giants begin to shed their gaseous envelopes. If these stars are massive, after expelling most of their envelope, they are left with a thin layer and a super-hot core. They finally get hot enough to start burning helium. At this stage they mostly emit in ultra-violet. These stars are shown as brilliant blue dots here. When even helium is over, most of the stars become white dwarfs, containing just the burnt-out core. These are the faint blue dots in the image. They can not generate more energy by fusion and gravitationally contract to very small size.