A breezy evening spent along the shoreline, enjoying the sun set and lying there to gaze at the stars. Doesn’t that sound like the perfect vacation we have always been dreaming about?
The question is, what is this mysterious ball of fire made of? We have all been through the middle school chorus of “Sun is but a star.” As kids we would have wondered about travelling to the sun but would later be sadly made to realise the impossibility of it.
The stars have as big of a lifetime as 5 billion years and that is a really long time to think about. Now, let me take you on a short trip through the timeline of stars, especially ours. Shall we?
Main phase of suns life is the longest period of its lifetime and that amounts to about 10 billion years. During this period, it constantly burns due to the nuclear reactions taking place in its core where hydrogen is converted into helium. Our sun was given 10 billion years to use up all of the hydrogen and now its half way through. What do you think will happen then?
When the sun manages to exhaust all the hydrogen at its disposal, gravity causes its core to shrink and as a result gets hotter. The outer layer that became a little cooler and glows bright red and hence the name red giant which lives for about 2 billion years. At this stage the fuel at the core is helium and when that’s all used up core collapses due to the effect of gravity.
What comes next is the real deal in destroying the star. Collapsing of the core in its previous life leads the heat to blast off the outer layer of the star which drifts into the space. The glowing core illuminates the outer shell and the structure is what we call planetary nebula. Its life period is comparatively short seemingly up to only a few thousand years.
This fading star is just the remains of the core of the original star. It disintegrates very slowly, shining for a long time but weakly. The last stage is a white dwarf losing all its heat and turning into a black dwarf which disappears later.
There goes the end of the life of a star that’s the size of our sun into stardust. Where it all began, there it ends.