7 stunning images of stars and their journey by NASA 

This is an image depicting early universe. The very first stars born after the big bang, which astronomers call "Population III" stars, are elusive. 

Stars form in large clouds of gas and dust called molecular clouds which are cold and causes gas to clump. Eventually, gravity causes some of these clumps to collapse, friction causes the material to heat up, and leads to a protostar – a baby star. 

Stars at the ends of their lives are out of the main sequence. Our Sun is categorized as a G-type yellow-dwarf main sequence star. It is predicted that our Sun will remain in the main sequence phase for a few billion more years.

U Camelopardalis, or U Cam for short, is a star nearing the end of its life. As stars run low on fuel, they become unstable. Every few thousand years, U Cam coughs out a nearly spherical shell of gas as a layer of helium around its core begins to fuse.   

At the beginning of the end of a star’s life, its core runs out of hydrogen to convert into helium. Eventually, all the star’s outer layers blow away, creating an expanding cloud of dust and gas called a planetary nebula.

The death of a star is seen in a supernova, an explosion so bright that it can outshine the light from an entire galaxy. The white dwarf star is obliterated, sending its debris hurtling into space.

This image shows the effects of the collapse and supernova explosion of a massive star. A black hole (right) was formed in the collapse and debris from the supernova explosion is raining down onto a companion star (left), polluting its atmosphere.

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