Question

Question #a226b

Answer 1

Till about `10^15` (1 quadrillion) years

Explanation:

The Sun will run out of fuel and will eject its layers in a planetary nebula in about `5` billion years, after `5` billion years, it will become a white dwarf .
But white dwarfs still give out SOME light and heat. The estimated time for the Sun to cool enough to become a black dwarf is about 1 quadrillion years or more, when it will no longer emit any kind of radiation and will be invisible to the naked eye.

But for the "`color(blue)"us"`" in the your question, the sun will become a red giant in 5 billion years and engulf Mercury and Venus.

But in `1` billion years or so, there will be 10% increase in the sun's brightness. That would be enough to wipe out all life on earth :(
( unless human beings find some way to alter it by leaving earth... or anything ).