The Sun Explosion?

I understand that the sun is going to hit supernova one day. When is that day? Will the sun shoot a solar flare that hits earth and destroys it? When will the world end? I hear that the sun is do it grow larger. It will burn Mercury and then Venus. It will get very near us then hit nova which means die down to the size of normal star. The world will soon become into another ice age. It is do to do this in 29 years from now.