A Last Perfect Day.

We know that our Sun is 4.5 billion years old. At the present time our Sun is burning about 70% hydrogen and 30% helium and is a main sequence G2 class star. People say our Sun is a ordinary star, but compared to what? If you could look at all the stars you can see, you would see that our Sun is actually among the top 10% of all comparable stars in mass. The Sun converts 700 million tons of hydrogen into helium each second, the helium is the by product of the fusion that takes place. In about 1.3 billion years our Sun will increase 15% in brightness. In 4 billion years our Suns hydrogen will be exhausted and our Sun will begin to burn helium.
It will swell in size and swallow the planet Mercury. This means the Earth and all who are on it will have a last perfect day.Our atmosphere will be slowly stripped away as the Sun slowly sheds its atmosphere in waves. our oceans and lakes will boil away to space. After the helium is gone it begins to burn carbon as its atmosphere swells past Venus, Earth and maybe half way to Mars.
The Earth will melt with fervent heat. Then the Sun will throw one last tantrum, its atmosphere will be pulled in as the Suns core collapses to the size of the Earth, then the pressure in its core grows to high for gravity to hold it in. Then the biggest explosion the Earth will experience will happen. In one last violent gasp the Sun will shed its atmosphere out in all directions.
Our Sun will become a white dwarf star leaving the Earth as a burned cinder. And the new Earth sized Sun will slowly dim only to leave the Earth cloaked in the eternal darkness of space. More information about astronomy can be found at Astronomy Pictures, Telescope Set Up Guide Illustrated. or Squidoo Astronomy Group.