The story of Earth’s demise is intertwined with the life cycle of the Sun, our star, which governs the fate of the solar system. Here’s a detailed timeline outlining the final chapters of Earth and the broader cosmic events leading to its ultimate end:
5 to 7 Billion Years From Now: The Red Giant Phase
- Sun Expands: The Sun will deplete its hydrogen fuel and begin fusing helium, causing it to expand into a red giant, growing to 256 times its current size.
- Inner Planets Destroyed: Mercury and Venus will be engulfed by the expanding Sun as it sweeps through the inner solar system.
- Extreme Heat on Earth: Intense solar radiation will strip Earth’s atmosphere, boil its oceans, and leave a barren, molten surface.
- Loss of Habitability: Earth will no longer be in the habitable zone as temperatures soar, making life impossible.
5 Million Years After the Red Giant Phase: The End of Earth’s Biosphere
- Atmospheric Collapse: The heat will prevent carbon dioxide from being replenished, ending photosynthesis.
- Plant Death: Plants will perish, and oxygen production will cease, leading to the extinction of mammals and birds.
- Microbial Survivors: Only microbial life forms and tardigrades, known for their resilience, will persist for a short time.
7.6 Billion Years From Now: Earth’s Final Days
- Engulfment by the Sun: The Sun’s outer layers will likely engulf Earth and the Moon, reducing them to cosmic debris.
- Formation of a New Habitable Zone: As the red giant expands, the habitable zone will shift outward to the Kuiper Belt. Icy celestial bodies like Triton (Neptune’s moon) and Eris (a dwarf planet) will thaw, potentially harboring liquid water.
Beyond Earth’s Death: The Solar System’s Evolution
- White Dwarf Emerges: After shedding its outer layers, the Sun will collapse into a white dwarf, a dense, Earth-sized stellar remnant.
- Black Dwarf Formation: Over the next 1 quadrillion years, the Sun will cool further, becoming a black dwarf—a cold, dark remnant of its former self.
Life Beyond Earth
- Colonization of the Kuiper Belt: Humans, if they survive, might migrate to the outer solar system. Moons like Triton and Pluto-like dwarf planets could serve as new homes due to their thawed surfaces and liquid water potential.
- Technological Evolution: Advanced technology will be critical to sustaining human life in these distant, frigid worlds.
A Sobering Perspective
This timeline illustrates the transient nature of Earth’s habitability. While humanity’s time on Earth is finite, the possibility of colonizing other worlds in the solar system reflects a hopeful vision of survival and adaptation amid cosmic change.
