5 to 7 Billion Years From Now
- The Sun Becomes a Red Giant
As the Sun depletes its hydrogen and helium fuel, it will expand to 256 times its current size, engulfing much of the inner solar system.
5 Million Years After Becoming a Red Giant
- Mercury and Venus Get Swallowed
The Sun’s expansion will consume Mercury and Venus as it sweeps through the inner solar system. - Carbon Dioxide Depletion
Extreme heat will halt the carbon cycle, leading to the gradual death of all plant life on Earth. - Oxygen Levels Drop
With plants gone, oxygen levels will plummet, killing mammals, birds, and most other life forms dependent on oxygen. - Microbial and Tardigrade Survival
Only microbes and tardigrades—creatures capable of enduring radiation and heat—will persist.
Extreme Conditions and Surface Changes
- Surface Temperatures Rise Above 2,400 K (2,130°C or 3,860°F)
Rain and wind will damage Earth’s surface, leading to the evaporation of all water and the formation of a massive lava ocean. - Loss of Atmosphere and Tectonic Plate Activity
Earth’s atmosphere will vanish, and tectonic plate movement will cease entirely.
7.6 Billion Years From Now
- Earth and the Moon Engulfed by the Sun
The Sun will engulf both Earth and the Moon as it reaches its maximum size during the red giant phase. - A New Habitable Zone Forms in the Kuiper Belt
The Sun’s expansion creates a habitable zone extending into the Kuiper Belt, beyond Neptune. Icy celestial bodies like Neptune’s moon Triton and the dwarf planet Eris could sustain liquid water and become potential new homes for humanity.
1 Quadrillion Years Later
- The Sun Becomes a Black Dwarf
After its red giant and white dwarf phases, the Sun will cool to become a black dwarf, a dense, cold remnant roughly the size of present-day Earth. The Sun’s light and heat, once vital for life, will be no more.
This timeline underscores the eventual fate of Earth and humanity’s potential to find refuge in the outer solar system, where colonies on celestial bodies like Triton and Eris could mark the next chapter in human survival.
