'Massive Fusion Reactor': Will Sun swallow all life on Earth one day?

Produced by Tarun Mishra

Earth’s Fate


Scientists have long studied the life cycle of stars, and a recent discovery has shed light on the eventual demise of our Sun, which will have profound consequences for Earth. While the Sun’s current life phase appears stable, its future evolution will spell the end of life on Earth.

Sun's Current Status

Currently, the Sun functions as a massive fusion reactor, converting hydrogen into helium in its core. This process generates significant energy, with some of it radiating as light. This fusion reaction also provides the pressure necessary to prevent the Sun from collapsing under its own weight.

Hydrogen Supply

In approximately five billion years, the Sun will run out of hydrogen in its core. When this occurs, fusion will slow, and the pressure needed to counteract its gravity will diminish. As a result, the Sun’s core will begin to compress, leading to a series of changes that will have severe consequences for our planet.

A Red Giant


As the core compresses, helium begins to fuse into heavier elements, causing the Sun to become significantly brighter and larger. The Sun will eventually expand to hundreds of times its current size, reaching beyond the orbits of Mercury and Venus, likely vaporising these inner planets.

Photo Credit : Eos.Org

Earth’s Potential Fate

As the Sun swells, Earth’s future is uncertain. While it’s unclear whether Earth will be engulfed by the Sun, the planet is expected to experience extreme heat that will evaporate its oceans and end all forms of life. If Earth is not consumed, it may be pushed farther out into the solar system.

Sun’s Transition

Once the Sun exhausts its fusion capabilities, its core will compress further, while its outer layers will be shed into space. The core will become a white dwarf, a dense stellar remnant, and remain in this state, cooling and fading over billions of years. This transformation marks the final stage of a star like the Sun.

Future of Sun

Astronomers studying white dwarfs recently discovered unusual elements, such as calcium, potassium, and sodium, in the light emitted by these stars. These elements likely originated from planets that the stars had consumed.