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The Life Cycle of Stars

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Stars are not permanent fixtures in the sky; they are born, they evolve, and eventually, they die. A star's life begins in a nebula, a vast cloud of dust and hydrogen gas. Gravity causes pockets of this gas to collapse and heat up, forming a protostar. When the core temperature becomes high enough, nuclear fusion begins, converting hydrogen into helium and releasing massive amounts of energy. This marks the birth of a star.

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A star remains in its "main sequence" phase for billions of years, maintaining a stable balance between the inward pull of gravity and the outward pressure of fusion. Our Sun is currently in this phase. However, a star's ultimate fate depends almost entirely on its mass.

[Image of life cycle of stars diagram]

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Average-mass stars, like the Sun, will eventually run out of hydrogen fuel. They will expand and cool to become Red Giants. After shedding their outer layers, the core will shrink to become a White Dwarf, a small, dense remnant that slowly fades over time.

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In contrast, massive stars have a much more violent end. When they exhaust their fuel, the core collapses instantly, triggering a massive explosion known as a supernova. Depending on the remaining mass, the core may become a neutron star or, if the star was extremely massive, collapse completely to form a black hole.