The Earth as a planet will likely end in about 7.5 billion years when the Sun enters its red giant phase and expands beyond Earth's current orbit, eventually swallowing the planet. However, life on Earth is expected to become unlivable much sooner—approximately 1 billion to 1.3 billion years from now—due to the Sun's increasing heat causing the oceans to evaporate and oxygen levels to collapse, making the atmosphere inhospitable for complex life and humans.

Key timeline points:

• In about 1 billion years, Earth's atmosphere will lose sufficient oxygen for complex life due to rising solar radiation, ending breathable air and harming photosynthesis.

• Around 1.3 billion years from now, sustained heat and humidity will make Earth physiologically uninhabitable for humans.

• In 2-3 billion years, runaway greenhouse effects will make surface conditions extreme, eventually boiling off oceans and extinguishing all life forms.

• Approximately 7.5 billion years in the future, Earth likely will be engulfed by the expanding Sun as it transforms into a red giant, causing the physical destruction of the planet.

There is also a possibility humanity could cause extinction earlier through environmental degradation, but the natural, long-term cosmic destiny gives a rough scale for the end of life and the planet itself.

Thus, Earth's end as a physical planet is billions of years away, but life as we know it faces extinction within about a billion years due to solar evolution.