5–7 Billion Years From Now: The Sun Becomes a Red Giant
- The Sun will exhaust its hydrogen and helium reserves, expanding to 256 times its current size.
- Its outer layers will engulf Mercury and Venus, while Earth will experience extreme heat and radiation.
5 Million Years After Becoming a Red Giant: The Inner Solar System’s Demise
- The red giant’s expansion will sweep through the inner solar system, swallowing Mercury and Venus.
- Earth’s temperatures will soar, leading to the eventual breakdown of its atmosphere.
The Slow Death of Life on Earth
- Carbon dioxide levels will drop as the atmosphere is destroyed, causing plants—key oxygen producers—to die off.
- Mammals and birds, reliant on oxygen, will perish. Creatures needing less oxygen will survive briefly.
- Insects will follow, leaving behind only microbial life.
- Tardigrades, known for their resilience to extreme conditions, will be the last surviving lifeforms.
Extreme Heat and Atmospheric Loss
- Surface temperatures will exceed 2,400 K (2,130 °C or 3,860 °F).
- Rain and windstorms caused by rising temperatures will further erode Earth’s surface.
- The atmosphere will be stripped away, leaving a landscape dominated by metal and metal oxides.
Earth’s Oceans Evaporate
- All water will boil away, leaving a planet covered in lava oceans.
- With no water, tectonic plate movement will cease entirely, halting geological activity.
7.6 Billion Years From Now: Earth’s Final Demise
- Earth and the Moon will likely be engulfed by the red giant.
- The Sun’s expansion will create a new habitable zone stretching into the Kuiper Belt, far beyond Neptune.
- Icy bodies in this zone, such as Neptune’s moon Triton and the dwarf planet Eris, will melt, becoming candidates for human colonies.
Human Survival Beyond Earth
- As Earth becomes uninhabitable, humanity might establish settlements in the outer solar system.
- Liquid water and a more stable environment on moons and dwarf planets could support new homes for humans.
1 Quadrillion Years Later: The Sun’s Ultimate Transformation
- The Sun will eventually collapse into a black dwarf—a cold, dim remnant the size of Earth.
- The once-luminous star that sustained life will become a lifeless celestial body, marking the end of its journey.
This timeline serves as a sobering reminder of Earth’s finite existence and the potential for human adaptation in the vast cosmos.
