The truly spectacular part comes much later.
In roughly 5 billion years, the Sun is expected to exhaust much of the hydrogen fuel available for fusion in its core and begin evolving into a red giant. Its outer layers will expand enormously.
During this stage, the inner Solar System will become an extraordinarily hostile environment.
Mercury and Venus are expected to be engulfed. The ultimate fate of Earth is less certain in the details because it depends on factors including how much mass the Sun loses and how Earth’s orbit responds.
NASA’s current descriptions therefore often say that Earth may be destroyed or engulfed during the Sun’s red-giant evolution rather than presenting a precise guaranteed date.
The Sun Will Not Explode Like a Supernova
Another common misconception is that the Sun will eventually explode.
It won’t.
The Sun does not have enough mass to end its life as a supernova. Instead, after its red-giant stages, it will shed its outer layers and leave behind a dense stellar remnant known as a white dwarf.
NASA describes this final transformation as part of the normal life cycle expected for a star like our Sun.
So When Will Life End?
There isn’t one exact scientifically established date.
A more accurate timeline looks something like this:
Today: Earth remains within the Sun’s habitable environment.
About 1 billion years from now: Increasing solar brightness may make Earth’s environment progressively less suitable for complex life, with major changes to the atmosphere and oxygen cycle expected on roughly billion-year timescales.
Around 1–2 billion years from now: Many models suggest Earth could become largely uninhabitable for higher forms of life as the planet becomes hotter and loses water.
Around 5 billion years from now: The Sun is expected to enter its red-giant phase and expand dramatically.
Afterward: The Sun will eventually shed its outer layers and become a white dwarf.
Could Life Survive Somewhere Else?
See more on the next page