Stars are born and they die just like humans but the process is far more complicated and just amazingly beautiful. They are born in a stunning nebula and they die with a beautiful supernova or probably a hyper-nova or something else.
Nebulae are stellar nurseries, they literally create stars. Due to the turbulence inside these mega clouds, gas and dust begin to collapse under their own gravitation. As the layer thickens, the center or the core starts heating up. This stage of a star is called a protostar which later turns into a star. A dense, hot core is formed in the center which starts pulling even more gases and dusts which may form planets in the future.
This process takes millions of years. Then the energy from fusion keeps the star away from collapsing under its own gravitation. Inside the core of a new star, Hydrogen atoms undergo nuclear fusion to produce Helium and releasing energy which we see in the form of heat and light which is achieved by a process known as quantum tunneling. This inner energy stops the star from contracting under it’s own gravitation.
But Hydrogen in a star is limited and so is it’s fusion. Once a star uses up all the Hydrogen it’s core starts collapsing and the outer hydrogen still goes under fusion. This leads to swelling up of the star and converting it into a red giant which grows and swallows the nearby planets. Stars with large mass even starts fusing heavier elements in their core to obtain elements like iron. These reactions leads to pulsation in a stars brightness and the stars starts shredding of it’s outer layer.
After this the stars die in a variety of processes based on their mass. Average sized stars like our own Sun grows into a red giant and then sheds of it’s outer layers leaving the core open. This core then slowly cools down to form a massive but comparatively small star known as white dwarf. They are have a size nearly equal to that of Earth’s but their densities are extremely huge, a dwarf star has mass of an average star and size of a planet! A teaspoon of a white dwarf can weigh as high as Mount Everest!! This fate is limited to the stars having mass 1.4 times that of Sun.
Some white dwarf’s life doesn’t stop here, they soon turn into a cloud of dirt and gas called as Nebula. This occurs when a white dwarf is really close to it’s binary star, here the white dwarf starts pulling the outer layer of the companion star creating a cocoon of dust and gases. When there are enough gases, hydrogen goes under fusion and creates explosions. The surface of the white dwarf literally starts exploding and it becomes way too bright!
Stars over 8 solar masses die in a blazing fury of explosions. They create supernovae after dying. When a massive star’s core reaches a stage where it has completely fused all the elements and only iron is left in it’s core, it starts collapsing under it’s own gravitational pull. The star now can no longer support it’s own mass and the core with the surface starts collapsing. At this stage star produces enormous amount of energy with throwing off it’s outer layer in the vast space, the core continues to collapse and the star shrinks by a huge ratio. For some weeks or even months, these stars goes brighter than their own galaxy and die in a beautiful supernovae explosion!! Some even bigger stars are theorized to produce even big explosion called as a hypernova.
After the occurrence of supernova, the star continues to shrink and reaches the next stage of it’s life known as a neutron star. If the left over stellar core remnant has a mass between 1.4 to 3 solar masses, it is destined to be a neutron star. These stars are formed when the stellar core continues to collapse under it’s own gravitation and at the end combines protons with electrons creating a star completely made up of neutrons. A neutron star is similar to an atom with huge density and size. They have extremely huge gravitational pull and magnetic field. Because of this magnetic field, particles are accumulated around the poles of the star creating a beam of radiation just like a beam of light produced by lighthouses. Neutron stars also rotate at an unimaginable speed ranging from a few rotations per second to around 700!! Such rapidly spinning neutron stars are called pulsars.
Stellar cores with mass greater than 3 solar masses transforms into something which is probably the most confusing as well as the most beautiful object in the universe, a black hole! A black hole is formed when a stellar core keeps on collapsing under it’s own gravitation and forms a hole or a singularity. A black hole’s gravitational pull is so strong that even electromagnetic radiations like visible light cannot escape it! A black hole can’t be detected by observing light but can be detected by it’s gravitational power which is even capable of bending the spacetime to a great extent!
These novae and supernovae would soon start giving birth to all new stars by using the elements left behind during the death of an old star and this process continues till eternity. In this was, one of the most beautiful processes on the world never ends and keeps on giving life to it’s original!