Earth will likely exist for approximately 7.5 billion years.
This lifespan is primarily dictated by the future evolution of our Sun. In about 5 billion years, the Sun will begin to run out of hydrogen fuel in its core. This will cause it to expand dramatically into a red giant star.
The Fate of Earth
- Red Giant Phase: As the Sun enters the red giant phase, it will swell significantly, potentially engulfing Mercury and Venus. While the precise fate of Earth is less certain, it is highly probable that our planet will be either swallowed by the expanding Sun or scorched beyond recognition, rendering it uninhabitable long before actual engulfment.
- Loss of Habitability: Even if Earth somehow survives being engulfed, the immense heat and radiation from the red giant Sun will boil away our atmosphere and oceans, eliminating any possibility of life as we know it. This will occur long before the final 7.5 billion year mark. All life will likely be extinct well before this point.
- Final Absorption: Ultimately, the most probable scenario is that the Sun's expansion will directly lead to Earth being consumed. This event will occur roughly 7.5 billion years from now, marking the end of Earth's existence as a distinct planetary body.
In summary, while the physical Earth might persist in some altered form for a while longer, its habitability and distinct planetary existence are limited by the Sun's lifecycle, with eventual absorption being the most likely outcome in about 7.5 billion years.
