The Sun is very small in comparison to other stars in the galaxy and thus, scientists believe it is highly unlikely that it will go out in a giant supernova. It is believed that the Sun will die out at a slower and less sudden rate.

How long would it take for us to die if the Sun exploded?

If the sun were to blow up, life on Earth would certainly end. It takes eight minutes and twenty seconds for light to travel from the sun to the earth, so we would not know that the sun had exploded until eight minutes and twenty seconds after the explosion occurred.

What will happen to the Sun one day?

It means our sun will run out of fuel in its interior. It'll cease the internal thermonuclear reactions that enable stars to shine. It'll swell into a red giant, whose outer layers will engulf Mercury and Venus and likely reach the Earth. Life on Earth will end.