The Sun is currently about 4.6 billion years old and is predicted to die at around 10 to 11 billion years old, meaning it has roughly another 5 to 6 billion years to live. When it dies, it will go through a red giant phase, expand significantly (engulfing Mercury, Venus, and possibly Earth), then shed its outer layers, and finally become a white dwarf star. After that, it will gradually cool and fade over trillions of years.
Sun's Age and Lifetime
- The Sun is about 4.6 billion years old, roughly halfway through its main sequence lifetime.
- Stars like the Sun typically burn for about 9 to 10 billion years in the main sequence phase.
Final Stages
- In about 5 billion years, the Sun will exhaust hydrogen in its core, stop hydrogen fusion, and start expanding into a red giant.
- During the red giant phase, its outer layers will expand out to roughly the orbit of Mars, engulfing the inner planets including Earth.
- After the red giant phase, the Sun will shed its outer layers forming a planetary nebula and the core will shrink to become a white dwarf, a dense, cooling star that no longer produces fusion energy but glows from residual heat.
- The white dwarf will slowly cool over trillions of years, eventually becoming a black dwarf with negligible energy output.
Thus, the Sun will be about 10 to 11 billion years old when it "dies" by leaving behind a white dwarf after the red giant phase.
