Anyone here know much about Space?

[dappa]

I read in an astronomy book that In 2-3 billion years the sun will run out of hydrogen and then start burning all its helium reserves causing it to become a red giant star. The book said that it would expand as far as the earth either devouring it or scorching really badly like mercury.

I also read that by calculating the speed of light and using it to work out how far light has travelled you could see back into the past, light which supposedly appeared 3 secs after the big bang but there is no earlier evidence of any light before this 3 seconds.